Modification of nickel sulfide cocatalysts is considered to be a promising approach for efficient enhancement of the photocatalytic hydrogen production performance of g-C3N4.Providing more NiS cocatalyst to function a...Modification of nickel sulfide cocatalysts is considered to be a promising approach for efficient enhancement of the photocatalytic hydrogen production performance of g-C3N4.Providing more NiS cocatalyst to function as active sites of g-C3N4 is still highly desirable.To realize this goal,in this work,a facile sulfur-mediated photodeposition approach was developed.Specifically,photogenerated electrons excited by visible light reduce the S molecules absorbed on g-C3N4 surface to S^2‒,and subsequently NiS cocatalyst is formed in situ on the g-C3N4 surface by a combination of Ni2+and S2‒due to their small solubility product constant(Ksp=3.2×10^‒19).This approach has several advantages.The NiS cocatalyst is clearly in situ deposited on the photogenerated electron transfer sites of g-C3N4,and thus provides more active sites for H2 production.In addition,this method utilizes solar energy with mild reaction conditions at room temperature.Consequently,the synthesized NiS/g-C3N4 photocatalyst achieves excellent hydrogen generation performance with the performance of the optimal sample(244μmol h^‒1 g^‒1)close to that of 1 wt%Pt/g-C3N4(316μmol h^‒1 g^‒1,a well-known excellent photocatalyst).More importantly,the present sulfur-mediated photodeposition route is versatile and facile and can be used to deposit various metal sulfides such as CoSx,CuSx and AgSx on the g-C3N4 surface,and all the resulting metal sulfide-modified g-C3N4 photocatalysts exhibit improved H2-production performance.Our study offers a novel insight for the synthesis of high-efficiency photocatalysts.展开更多
The development of efficient photocatalytic H2-evolution materials requires both rapid electron transfer and an effective interfacial catalysis reaction for H2 production. In addition to the well-known noble metals, l...The development of efficient photocatalytic H2-evolution materials requires both rapid electron transfer and an effective interfacial catalysis reaction for H2 production. In addition to the well-known noble metals, low-cost and earth-abundant non-noble metals can also act as electron- transfer mediators to modify photocatalysts. However, as almost all non-noble metals lack the interfacial catalytic active sites required for the H2-evolution reaction, the enhancement of the photocatalytic performance is limited. Therefore, the development of new interfacial active sites on metal-modified photocatalysts is of considerable importance. In this study, to enhance the photocatalytic evolution of H2 by Ni-modified TiO2, the formation of NiSx as interfacial active sites was promoted on the surface of Ni nanoparticles. Specifically, the co-modified TiO2/Ni-NiSx photocatalysts were prepared via a two-step process involving the photoinduced deposition of Ni on the TiO2 surface and the subsequent formation of NiSx on the Ni surface by a hydrothermal reaction method. It was found that the TiO2/Ni-NiSx photocatalysts exhibited enhanced photocatalytic H2-evolution activity. In particular, TiO2/Ni-NiSx(30%) showed the highest photocatalytic rate (223.74 μmol h.1), which was greater than those of TiO2, TiO2/Ni, and TiO2/NiSx by factors of 22.2, 8.0, and 2.2, respectively. The improved H2-evolution performance of TiO2/Ni-NiSx could be attributed to the excellent synergistic effect of Ni and NiSx, where Ni nanoparticles function as effective mediators to transfer electrons from the TiO2 surface and NiSx serves as interfacial active sites to capture H+ ions from solution and promote the interfacial H2-evolution reaction. The synergistic effect of the non-noble metal cocatalyst and the interfacial active sites may provide new insights for the design of highly efficient photocatalytic materials.展开更多
Conventional hexagonal dimolybdenum carbide(Mo2 C) as a good cocatalyst has been widely applied for the enhanced photocatalytic hydrogen production of various photocatalysts. Compared with the hexagonal Mo2 C, however...Conventional hexagonal dimolybdenum carbide(Mo2 C) as a good cocatalyst has been widely applied for the enhanced photocatalytic hydrogen production of various photocatalysts. Compared with the hexagonal Mo2 C, however, the investigation about cubic molybdenum carbide(Mo C) is still very limited in photocatalytic field. In this study, carbon-coated cubic molybdenum carbide(MoC@C) nanoparticle was synthesized and used as an effective cocatalyst to improve the H2-evolution efficiency of Ti O2. The cubic MoC@C can be obtained by adjusting the mass ratio of C3 N3(NH2)3 to(NH4)6 Mo7 O(24)(2:1) and controlling the calcination temperature to 800 °C. When the above cubic MoC@C nanoparticles were evenly loaded on the Ti O2 via a sonication-assisted deposition, a homogeneous composite of TiO2/MoC@C was formed due to the strong coupling interface between TiO2 and cubic MoC nanoparticles. More importantly, the highest H2-production rate of Ti O-12/MoC@C reached 504 μmol hg^(-1)(AQE=1.43%), which was 50 times as high as that of the pure TiO2. The enhanced performance of TiO2/MoC@C can be attributed to the synergistic effect of carbon layer as an electron mediator and the cubic MoC as interfacial H2-evolution active sites. This work provides a feasible guideline to develop high-efficiency Mo-based cocatalysts for potential applications in the H2-evolution field.展开更多
Silver‐modified semiconductor photocatalysts typically exhibit enhanced photocatalytic activitytoward the degradation of organic substances.In comparison,their hydrogen‐evolution rates arerelatively low owing to poo...Silver‐modified semiconductor photocatalysts typically exhibit enhanced photocatalytic activitytoward the degradation of organic substances.In comparison,their hydrogen‐evolution rates arerelatively low owing to poor interfacial catalytic reactions to producing hydrogen.In the presentstudy,thiocyanate anions(SCN–)as interfacial catalytic active sites were selectively adsorbed ontothe Ag surface of g‐C3N4/Ag photocatalyst to promote interfacial H2‐evolution reactions.The thiocyanate‐modified g‐C3N4/Ag(g‐C3N4/Ag‐SCN)photocatalysts were synthesized via photodepositionof metallic Ag on g‐C3N4and subsequent selective adsorption of SCN– ions on the Ag surface by animpregnation method.The resulting g‐C3N4/Ag‐SCN photocatalysts exhibited considerably higherphotocatalytic H2‐evolution activity than the g‐C3N4,g‐C3N4/Ag,and g‐C3N4/SCN photocatalysts.Furthermore,the g‐C3N4/Ag‐SCN photocatalyst displayed the highest H2‐evolution rate(3.9μmolh?1)when the concentration of the SCN– ions was adjusted to0.3mmol L?1.The H2‐evolution rateobtained was higher than those of g‐C3N4(0.15μmol h?1)and g‐C3N4/Ag(0.71μmol h?1).Consideringthe enhanced performance of g‐C3N4/Ag upon minimal addition of SCN– ions,a synergistic effectof metallic Ag and SCN– ions is proposed―the Ag nanoparticles act as an effective electron‐transfermediator for the steady capture and rapid transportation of photogenerated electrons,while theadsorbed SCN– ions serve as an interfacial active site to effectively absorb protons from solution andpromote rapid interfacial H2‐evolution reactions.Considering the present facile synthesis and itshigh efficacy,the present work may provide new insights into preparing high‐performance photocatalytic materials展开更多
Noble metal palladium(Pd)is well‐known as excellent photocatalytic cocatalyst,but its strong adsorption to hydrogen causes its limited H2‐evolution activity.In this study,the transition metal Cu was successfully int...Noble metal palladium(Pd)is well‐known as excellent photocatalytic cocatalyst,but its strong adsorption to hydrogen causes its limited H2‐evolution activity.In this study,the transition metal Cu was successfully introduced into the metallic Pd to weaken its hydrogen‐adsorption strength to improve its interfacial H_(2)‐evolution rate via the Pd‐Cu alloying effect.Herein,the ultrasmall Pd_(100−x)Cu_(x) alloy nanodots(2−5 nm)as a novel H_(2)‐evolution cocatalyst were integrated with the TiO_(2) through a simple NaH_(2)PO_(2)‐mediated co‐deposition route.The resulting Pd_(100−x)Cu_(x)/TiO_(2) sample shows the significantly enhanced photocatalytic H_(2)‐generation performance(269.2μmol h^(−1)),which is much higher than the bare TiO2.Based on in situ irradiated X‐ray photoelectron spectroscopy(ISI‐XPS)and density functional theory(DFT)results,the as‐formed Pd_(100−x)Cu_(x) alloy nanodots can effectively promote the separation of photo‐generated charges and weak the adsorption strength for hydrogen to optimize the process of hydrogen‐desorption process on Pd_(75)Cu_(25) alloy,thus leading to high photocatalytic H_(2)‐evolution activity.Herein,the weakened H adsorption of Pd_(75)Cu_(25) cocatalyst can be ascribed to the formation of electron‐rich Pd after the introduction of weak electronegativity Cu.The present work about optimizing electronic structure for promoting interfacial reaction activity provides a new sight for the development of the highly efficient photocatalysts.展开更多
Effective charge separation and rapid interfacial H_(2) production are imperative for the construction of efficient photocatalysts.Compared to Pt,the metallic Ag co‐catalyst with its strong electron‐trapping ability...Effective charge separation and rapid interfacial H_(2) production are imperative for the construction of efficient photocatalysts.Compared to Pt,the metallic Ag co‐catalyst with its strong electron‐trapping ability and excellent electronic conductivity typically exhibits an extremely limited photocatalytic H_(2-)evolution rate owing to its sluggish interfacial H_(2)‐generation reaction.In this study,amorphous AgSe_(x) was incorporated in situ onto metallic Ag as a novel and excellent H_(2)‐evolution active site to boost the interfacial H_(2)‐generation rate of Ag nanoparticles in a TiO_(2)/Ag system.Core‐shell Ag@AgSe_(x)nanoparticle‐modified TiO_(2)photocatalysts were prepared via a two‐step pathway involving the photodeposition of metallic Ag and the selective surface selenization of metallic Ag to yield amorphous AgSe_(x)shells.The as‐prepared TiO_(2)/Ag@AgSe_(x)(20μL)photocatalyst exhibited an excellent H_(2‐)production performance of 853.0μmol h^(-1)g^(-1),prominently outperforming the TiO_(2)and TiO_(2)/Ag samples by factors of 11.6 and 2.4,respectively.Experimental investigations and DFT calculations revealed that the enhanced H_(2‐)generation activity of the TiO_(2)/Ag@AgSe_(x)photocatalyst could be accounted by synergistic interactions of the Ag@AgSe_(x)co‐catalyst.Essentially,the metallic Ag core could quickly capture and transport the photoinduced electrons from TiO_(2)to the amorphous AgSe_(x)shell,whereas the amorphous AgSe_(x)shell provided large active sites for boosting the interfacial H_(2)evolution.This study offers a facile route for the construction of novel core‐shell co‐catalysts for sustainable H_(2)evolution.展开更多
Photocatalytic materials have attracted more and more attention in the world due to their great potential in solar energy conversion and environmental remediation.We were honored to host the 3rd Chinese Symposium on P...Photocatalytic materials have attracted more and more attention in the world due to their great potential in solar energy conversion and environmental remediation.We were honored to host the 3rd Chinese Symposium on Photocatalytic Materials(CSPM3)in Wuhan on December 11-14,2020,and hereby express our sincere thanks to all the vips and delegates attending this conference.展开更多
In addition to the electron transfer,the appropriate H-adsorption affinity of active centers on the metal cocatalyst surface is quite important for high hydrogen-production activity of cocatalyst-modified photo-cataly...In addition to the electron transfer,the appropriate H-adsorption affinity of active centers on the metal cocatalyst surface is quite important for high hydrogen-production activity of cocatalyst-modified photo-catalysts.The typical Cu and Ru metal cocatalysts clearly exhibit a weak Cu-H bond and a strong Ru-H bond,respectively,resulting in limited activity for photocatalytic H_(2)evolution.In this work,an ingenious strategy of self-optimized H-adsorption affinity in CuRu alloy cocatalyst is developed to simultaneously reinforce the Cu-H bond and weaken the Ru-H bond by the intrinsic electron transfer from Cu to Ru atom.The CuRu alloy nanoparticles(2-3 nm)were deposited on the TiO_(2)surface to prepare CuRu/TiO_(2)through a one-step photoreduction method.Photocatalytic tests exhibited that the highest H_(2)-production rate of CuRu/TiO_(2)photocatalyst reached up to 5.316 mmol h^(-1)g^(-1),which was 24.80,1.86,and 2.60 times higher than that of the TiO_(2),Cu/TiO_(2),and Ru/TiO_(2),respectively.Based on the characterization results and theoretical calculations,the CuRu alloy cocatalyst exhibits excellent self-optimized H-adsorption affinity via the spontaneous electron transfer from Cu to Ru atom,which can greatly accelerate the photocatalytic H_(2)-production rate of TiO_(2).This work provides a feasible idea for the self-optimized H-adsorption affinity of metal active sites in the photocatalytic H_(2)-generation field.展开更多
Developing efficient,stable,and low-cost novel electron-cocatalysts is crucial for photocatalytic hydrogen evolution reaction.Herein,amorphous Ni-P alloy particles were successfully modified onto g-C3N4 to construct t...Developing efficient,stable,and low-cost novel electron-cocatalysts is crucial for photocatalytic hydrogen evolution reaction.Herein,amorphous Ni-P alloy particles were successfully modified onto g-C3N4 to construct the Ni-P/g-C3N4 photocatalyst through a simple and green triethanolamine(TEOA)-mediated photodeposition method.It was found that the TEOA could serve as an excellent complexing agent to coordinate with Ni2+to form[Ni(TEOA)]^2+complex,which can promote the rapid and effective deposition of amorphous Ni-P alloy on the g-C3N4 surface.Photocatalytic tests suggest that the hydrogen-evolution performance of gC3N4 can be greatly promoted through integrating amorphous Ni-P alloy.Especially,the Ni-P/g-C3N4(5 wt%)exhibits the superior H2-generation activity(118.2μmol h^-1g^-1),which is almost 35.8 times that of bare g-C3N4.Furthermore,the amorphous Ni-P alloy cocatalyst can also serve as the general hydrogen-production cocatalyst to greatly enhance the photocatalytic performance of traditional semiconductor materials such as Ti O2 and Cd S.Based on the present results,the mechanism of the amorphous Ni-P alloy as the high-efficiency electron transfer medium was proposed for the boosted H2-generation rate.The present facile route may broaden the horizons for the efficient development of highly active cocatalysts in photocatalytic field.展开更多
Hexagonal molybdenum carbide(Mo_(2)C)as an effective non-noble cocatalyst is intensively researched in the photocatalytic H_(2)-evolution field owing to its Pt-like H^(+)-adsorption ability and good conductivity.Howev...Hexagonal molybdenum carbide(Mo_(2)C)as an effective non-noble cocatalyst is intensively researched in the photocatalytic H_(2)-evolution field owing to its Pt-like H^(+)-adsorption ability and good conductivity.However,hexagonal Mo_(2)C-modified photocatalysts possess a limited H_(2)-evolution rate because of the weak H-desorption ability.Tofurther improve the activity,cubic MoC was introduced into Mo_(2)C toform the carbon-modified MoC-Mo_(2)C nanoparticles(MoC-Mo_(2)C@C)by a calcination method.The resultant MoC-Mo_(2)C@C(ca.5 nm)was eventually coupled with Ti0_(2)to acquire high-efficiency Ti0_(2)/MoC-Mo_(2)C@C by electrostatic self-assembly.The highest H_(2)-generation rate of Ti0_(2)/MoC-Mo_(2)C@C reached of 918μmol·h^(-1)·g^(-1)which was 91.8,2.7,and 1.5 times than that of the Ti0_(2),TiO_(2)/MoC@C,and Ti0_(2)/Mo_(2)C@C,respectively.The enhanced rate of Ti0_(2)attributes to the carbon layer as cocatalyst to transmit electrons and the hetero-phase MoC-Mo_(2)C as H_(2)-generation active sites to boost H_(2)-evolution reaction.This research offers a novel insight to design photocatalytic materials for energy applications.展开更多
CdS photocorrosion is one of the most important factors that greatly affect the photocatalytic H_(2)-production rate and long-time stability.However,the reported works about CdS photocorrosion are mainly focused on th...CdS photocorrosion is one of the most important factors that greatly affect the photocatalytic H_(2)-production rate and long-time stability.However,the reported works about CdS photocorrosion are mainly focused on the surface oxidation by photogenerated holes,while the possible reduction of lattice Cd^(2+) by photogenerated electrons is usually ignored.In this work,the lattice Cd^(2+) reduction by photogenerated electrons during CdS photocorrosion were carefully investigated to reveal its potential effect on the microstructure change and photocatalytic H_(2)-production performance of CdS photocatalyst based on the two typical Na_(2)S-Na_(2)SO_(3) and lactic acid H_(2)-evolution systems.It was found that many isolated metallic Cd nanoparticles(5–50 nm)were produced on the CdS surface in the Na_(2)S-Na_(2)SO_(3) system,causing its serious destroy of CdS surface and a gradually decreased photocatalytic activity,while only a metallic Cd layer(2-3 nm)is homogeneously coated on the CdS surface in the lactic acid system,leading to an increased H-evolution rate.In fact,once a certain amount of metallic Cd was produced on the CdS surface,the resulting CdS-Cd composites can present a stable photocatalytic H_(2)-production activity and excellent stability for the final CdS-Cd photocatalysts.Hence,a photoinduced self-stability mechanism of CdS photocatalyst has been proposed,namely,the spontaneously produced metallic Cd contributes to the transformation of unstable CdS into stable CdS-Cd structure,with the simultaneous realization of final stable H_(2)-evolution performance.展开更多
Exploiting efficient and low-cost cocatalyst with a facile grafting strategy is of critical importance for significantly boosting the photocatalytic H2-evolution activity.In this study,S2^--adsorbed MoSx nanoparticle ...Exploiting efficient and low-cost cocatalyst with a facile grafting strategy is of critical importance for significantly boosting the photocatalytic H2-evolution activity.In this study,S2^--adsorbed MoSx nanoparticle as a superior H2-evolutoin cocatalyst was successfully grafted on the TiO2 surface to greatly boost its photocatalytic activity via one-step lactic acid-induced synthesis strategy.Herein,the lactic acid can induce the homogeneous production of amorphous MoSx(a-MoSx)nanoparticles from MoS42-precursor,while the symbiotic S2^-ions can be easily and availably self-adsorbed on the a-Mo Sxsurface,resulting in the formation of S2^--adsorbed a-Mo Sxnanoparticles with a small size of 0.5-3 nm.Photocatalytic results manifested that the S2^--adsorbed Mo Sxnanoparticles could dramatically facilitate the H2-generation rate of TiO2 photocatalysts(3452μmol h^-1 g^-1,AQE=16.5%).In situ irradiated XPS in conjunction with transient-state PL and photoelectrochemical tests reveal that the improved H_(2)-generation activity can be ascribed to the synergistic effect of boosted interfacial charge transfer from TiO_(2) to S^(2-)adsorbed Mo Sx and the superior H_(2)-evolution reaction on self-adsorbed S_(2-)ions.In addition,the S^(2-)-adsorbed Mo Sx nanoparticles can also act as the general H_(2)-generation cocatalyst to obviously promote the activity of other typical host photocatalysts such as g-C_(3) N_(4) and Cd S.This work provides an innovative approach to develop high-efficiency Mo Sx-based cocatalyst with boosted interfacial charge transfer toward highly efficient photocatalytic materials.展开更多
Traditional bulk MoS_(2) as an effective H_(2)-evolution cocatalyst is mainly subjected to the weak hydrogen-adsorption ability of highporpotion saturated S,resulting in a slow interfacial H_(2)-evolution reaction.In ...Traditional bulk MoS_(2) as an effective H_(2)-evolution cocatalyst is mainly subjected to the weak hydrogen-adsorption ability of highporpotion saturated S,resulting in a slow interfacial H_(2)-evolution reaction.In this paper,an efficient strategy for enhancing hydrogen adsorption of saturated S by manipulating electron density through O atoms is proposed to boost photocatalytic performance of CdS.Simultaneously,amorphization of MoS_(2) can further increase the unsaturated active S sites.Herein,oxygencontained amorphous MoS_(x)(a-MoOS_(x))nanoparticles(10-30 nm)were tightly loaded on the CdS surface through a mild photoinduced deposition method by using(NH_(4))_(2)[MoO(S_(4))_(2)]solution as the precursor at room temperature.The photocatalytic H_(2)-evolution result showed that the a-MoOS_(x)/CdS performed the superior H_(2)-production activity(382μmol·h^(-1),apparent quantum efficiencies(AQE)=11.83%)with a lot of visual H_(2)bubbles,which was 54.6,2.5,and 5.1 times as high as that of CdS,MoS_(x)/CdS,and annealed a-MoOS_(x)/CdS,respectively.Characterizations and density functional theory(DFT)calculations revealed the mechanism of improved H_(2)-evolution activity is that the O heteroatom in amorphous MoOS_(x) can enhance the atomic H-adsorption ability by manipulating the electron density to form electron-deficient S^((2-δ)-)sites.This study provides a new idea to improve the efficiency and number of H_(2)-evolution active sites for developing efficient cocatalysts in the field of photocatalytic hydrogen evolution.展开更多
文摘Modification of nickel sulfide cocatalysts is considered to be a promising approach for efficient enhancement of the photocatalytic hydrogen production performance of g-C3N4.Providing more NiS cocatalyst to function as active sites of g-C3N4 is still highly desirable.To realize this goal,in this work,a facile sulfur-mediated photodeposition approach was developed.Specifically,photogenerated electrons excited by visible light reduce the S molecules absorbed on g-C3N4 surface to S^2‒,and subsequently NiS cocatalyst is formed in situ on the g-C3N4 surface by a combination of Ni2+and S2‒due to their small solubility product constant(Ksp=3.2×10^‒19).This approach has several advantages.The NiS cocatalyst is clearly in situ deposited on the photogenerated electron transfer sites of g-C3N4,and thus provides more active sites for H2 production.In addition,this method utilizes solar energy with mild reaction conditions at room temperature.Consequently,the synthesized NiS/g-C3N4 photocatalyst achieves excellent hydrogen generation performance with the performance of the optimal sample(244μmol h^‒1 g^‒1)close to that of 1 wt%Pt/g-C3N4(316μmol h^‒1 g^‒1,a well-known excellent photocatalyst).More importantly,the present sulfur-mediated photodeposition route is versatile and facile and can be used to deposit various metal sulfides such as CoSx,CuSx and AgSx on the g-C3N4 surface,and all the resulting metal sulfide-modified g-C3N4 photocatalysts exhibit improved H2-production performance.Our study offers a novel insight for the synthesis of high-efficiency photocatalysts.
基金supported by the National Natural Science Foundation of China(21477094)the Fundamental Research Funds for the Central Universities(WUT 2017IB002)~~
文摘The development of efficient photocatalytic H2-evolution materials requires both rapid electron transfer and an effective interfacial catalysis reaction for H2 production. In addition to the well-known noble metals, low-cost and earth-abundant non-noble metals can also act as electron- transfer mediators to modify photocatalysts. However, as almost all non-noble metals lack the interfacial catalytic active sites required for the H2-evolution reaction, the enhancement of the photocatalytic performance is limited. Therefore, the development of new interfacial active sites on metal-modified photocatalysts is of considerable importance. In this study, to enhance the photocatalytic evolution of H2 by Ni-modified TiO2, the formation of NiSx as interfacial active sites was promoted on the surface of Ni nanoparticles. Specifically, the co-modified TiO2/Ni-NiSx photocatalysts were prepared via a two-step process involving the photoinduced deposition of Ni on the TiO2 surface and the subsequent formation of NiSx on the Ni surface by a hydrothermal reaction method. It was found that the TiO2/Ni-NiSx photocatalysts exhibited enhanced photocatalytic H2-evolution activity. In particular, TiO2/Ni-NiSx(30%) showed the highest photocatalytic rate (223.74 μmol h.1), which was greater than those of TiO2, TiO2/Ni, and TiO2/NiSx by factors of 22.2, 8.0, and 2.2, respectively. The improved H2-evolution performance of TiO2/Ni-NiSx could be attributed to the excellent synergistic effect of Ni and NiSx, where Ni nanoparticles function as effective mediators to transfer electrons from the TiO2 surface and NiSx serves as interfacial active sites to capture H+ ions from solution and promote the interfacial H2-evolution reaction. The synergistic effect of the non-noble metal cocatalyst and the interfacial active sites may provide new insights for the design of highly efficient photocatalytic materials.
基金supported by the National Natural Science Foundation of China (51872221 and 21771142)the Fundamental Research Funds for the Central Universities (WUT 2019IB002)。
文摘Conventional hexagonal dimolybdenum carbide(Mo2 C) as a good cocatalyst has been widely applied for the enhanced photocatalytic hydrogen production of various photocatalysts. Compared with the hexagonal Mo2 C, however, the investigation about cubic molybdenum carbide(Mo C) is still very limited in photocatalytic field. In this study, carbon-coated cubic molybdenum carbide(MoC@C) nanoparticle was synthesized and used as an effective cocatalyst to improve the H2-evolution efficiency of Ti O2. The cubic MoC@C can be obtained by adjusting the mass ratio of C3 N3(NH2)3 to(NH4)6 Mo7 O(24)(2:1) and controlling the calcination temperature to 800 °C. When the above cubic MoC@C nanoparticles were evenly loaded on the Ti O2 via a sonication-assisted deposition, a homogeneous composite of TiO2/MoC@C was formed due to the strong coupling interface between TiO2 and cubic MoC nanoparticles. More importantly, the highest H2-production rate of Ti O-12/MoC@C reached 504 μmol hg^(-1)(AQE=1.43%), which was 50 times as high as that of the pure TiO2. The enhanced performance of TiO2/MoC@C can be attributed to the synergistic effect of carbon layer as an electron mediator and the cubic MoC as interfacial H2-evolution active sites. This work provides a feasible guideline to develop high-efficiency Mo-based cocatalysts for potential applications in the H2-evolution field.
基金supported by the National Natural Science Foundation of China(51472192,21477094,21771142)the Fundamental Research Funds for the Central Universities(WUT 2017IB002)~~
文摘Silver‐modified semiconductor photocatalysts typically exhibit enhanced photocatalytic activitytoward the degradation of organic substances.In comparison,their hydrogen‐evolution rates arerelatively low owing to poor interfacial catalytic reactions to producing hydrogen.In the presentstudy,thiocyanate anions(SCN–)as interfacial catalytic active sites were selectively adsorbed ontothe Ag surface of g‐C3N4/Ag photocatalyst to promote interfacial H2‐evolution reactions.The thiocyanate‐modified g‐C3N4/Ag(g‐C3N4/Ag‐SCN)photocatalysts were synthesized via photodepositionof metallic Ag on g‐C3N4and subsequent selective adsorption of SCN– ions on the Ag surface by animpregnation method.The resulting g‐C3N4/Ag‐SCN photocatalysts exhibited considerably higherphotocatalytic H2‐evolution activity than the g‐C3N4,g‐C3N4/Ag,and g‐C3N4/SCN photocatalysts.Furthermore,the g‐C3N4/Ag‐SCN photocatalyst displayed the highest H2‐evolution rate(3.9μmolh?1)when the concentration of the SCN– ions was adjusted to0.3mmol L?1.The H2‐evolution rateobtained was higher than those of g‐C3N4(0.15μmol h?1)and g‐C3N4/Ag(0.71μmol h?1).Consideringthe enhanced performance of g‐C3N4/Ag upon minimal addition of SCN– ions,a synergistic effectof metallic Ag and SCN– ions is proposed―the Ag nanoparticles act as an effective electron‐transfermediator for the steady capture and rapid transportation of photogenerated electrons,while theadsorbed SCN– ions serve as an interfacial active site to effectively absorb protons from solution andpromote rapid interfacial H2‐evolution reactions.Considering the present facile synthesis and itshigh efficacy,the present work may provide new insights into preparing high‐performance photocatalytic materials
文摘Noble metal palladium(Pd)is well‐known as excellent photocatalytic cocatalyst,but its strong adsorption to hydrogen causes its limited H2‐evolution activity.In this study,the transition metal Cu was successfully introduced into the metallic Pd to weaken its hydrogen‐adsorption strength to improve its interfacial H_(2)‐evolution rate via the Pd‐Cu alloying effect.Herein,the ultrasmall Pd_(100−x)Cu_(x) alloy nanodots(2−5 nm)as a novel H_(2)‐evolution cocatalyst were integrated with the TiO_(2) through a simple NaH_(2)PO_(2)‐mediated co‐deposition route.The resulting Pd_(100−x)Cu_(x)/TiO_(2) sample shows the significantly enhanced photocatalytic H_(2)‐generation performance(269.2μmol h^(−1)),which is much higher than the bare TiO2.Based on in situ irradiated X‐ray photoelectron spectroscopy(ISI‐XPS)and density functional theory(DFT)results,the as‐formed Pd_(100−x)Cu_(x) alloy nanodots can effectively promote the separation of photo‐generated charges and weak the adsorption strength for hydrogen to optimize the process of hydrogen‐desorption process on Pd_(75)Cu_(25) alloy,thus leading to high photocatalytic H_(2)‐evolution activity.Herein,the weakened H adsorption of Pd_(75)Cu_(25) cocatalyst can be ascribed to the formation of electron‐rich Pd after the introduction of weak electronegativity Cu.The present work about optimizing electronic structure for promoting interfacial reaction activity provides a new sight for the development of the highly efficient photocatalysts.
文摘Effective charge separation and rapid interfacial H_(2) production are imperative for the construction of efficient photocatalysts.Compared to Pt,the metallic Ag co‐catalyst with its strong electron‐trapping ability and excellent electronic conductivity typically exhibits an extremely limited photocatalytic H_(2-)evolution rate owing to its sluggish interfacial H_(2)‐generation reaction.In this study,amorphous AgSe_(x) was incorporated in situ onto metallic Ag as a novel and excellent H_(2)‐evolution active site to boost the interfacial H_(2)‐generation rate of Ag nanoparticles in a TiO_(2)/Ag system.Core‐shell Ag@AgSe_(x)nanoparticle‐modified TiO_(2)photocatalysts were prepared via a two‐step pathway involving the photodeposition of metallic Ag and the selective surface selenization of metallic Ag to yield amorphous AgSe_(x)shells.The as‐prepared TiO_(2)/Ag@AgSe_(x)(20μL)photocatalyst exhibited an excellent H_(2‐)production performance of 853.0μmol h^(-1)g^(-1),prominently outperforming the TiO_(2)and TiO_(2)/Ag samples by factors of 11.6 and 2.4,respectively.Experimental investigations and DFT calculations revealed that the enhanced H_(2‐)generation activity of the TiO_(2)/Ag@AgSe_(x)photocatalyst could be accounted by synergistic interactions of the Ag@AgSe_(x)co‐catalyst.Essentially,the metallic Ag core could quickly capture and transport the photoinduced electrons from TiO_(2)to the amorphous AgSe_(x)shell,whereas the amorphous AgSe_(x)shell provided large active sites for boosting the interfacial H_(2)evolution.This study offers a facile route for the construction of novel core‐shell co‐catalysts for sustainable H_(2)evolution.
基金The CSPM3 meeting was supported by the National Key R&D Program of China(2018YFB1502001)NSFC 51961135303,51932007 and U1905215).
文摘Photocatalytic materials have attracted more and more attention in the world due to their great potential in solar energy conversion and environmental remediation.We were honored to host the 3rd Chinese Symposium on Photocatalytic Materials(CSPM3)in Wuhan on December 11-14,2020,and hereby express our sincere thanks to all the vips and delegates attending this conference.
基金supported by the National Natural Science Foun-dation of China(Nos.22178275 and U22A20147)the Natural Science Foundation of Hubei Province of China(No.2022CFA001).
文摘In addition to the electron transfer,the appropriate H-adsorption affinity of active centers on the metal cocatalyst surface is quite important for high hydrogen-production activity of cocatalyst-modified photo-catalysts.The typical Cu and Ru metal cocatalysts clearly exhibit a weak Cu-H bond and a strong Ru-H bond,respectively,resulting in limited activity for photocatalytic H_(2)evolution.In this work,an ingenious strategy of self-optimized H-adsorption affinity in CuRu alloy cocatalyst is developed to simultaneously reinforce the Cu-H bond and weaken the Ru-H bond by the intrinsic electron transfer from Cu to Ru atom.The CuRu alloy nanoparticles(2-3 nm)were deposited on the TiO_(2)surface to prepare CuRu/TiO_(2)through a one-step photoreduction method.Photocatalytic tests exhibited that the highest H_(2)-production rate of CuRu/TiO_(2)photocatalyst reached up to 5.316 mmol h^(-1)g^(-1),which was 24.80,1.86,and 2.60 times higher than that of the TiO_(2),Cu/TiO_(2),and Ru/TiO_(2),respectively.Based on the characterization results and theoretical calculations,the CuRu alloy cocatalyst exhibits excellent self-optimized H-adsorption affinity via the spontaneous electron transfer from Cu to Ru atom,which can greatly accelerate the photocatalytic H_(2)-production rate of TiO_(2).This work provides a feasible idea for the self-optimized H-adsorption affinity of metal active sites in the photocatalytic H_(2)-generation field.
基金supported by the National Natural Science Foundation of China(21771142 and 51672203)the Fun-damental Research Funds for the Central Universities(WUT 2019IB002)。
文摘Developing efficient,stable,and low-cost novel electron-cocatalysts is crucial for photocatalytic hydrogen evolution reaction.Herein,amorphous Ni-P alloy particles were successfully modified onto g-C3N4 to construct the Ni-P/g-C3N4 photocatalyst through a simple and green triethanolamine(TEOA)-mediated photodeposition method.It was found that the TEOA could serve as an excellent complexing agent to coordinate with Ni2+to form[Ni(TEOA)]^2+complex,which can promote the rapid and effective deposition of amorphous Ni-P alloy on the g-C3N4 surface.Photocatalytic tests suggest that the hydrogen-evolution performance of gC3N4 can be greatly promoted through integrating amorphous Ni-P alloy.Especially,the Ni-P/g-C3N4(5 wt%)exhibits the superior H2-generation activity(118.2μmol h^-1g^-1),which is almost 35.8 times that of bare g-C3N4.Furthermore,the amorphous Ni-P alloy cocatalyst can also serve as the general hydrogen-production cocatalyst to greatly enhance the photocatalytic performance of traditional semiconductor materials such as Ti O2 and Cd S.Based on the present results,the mechanism of the amorphous Ni-P alloy as the high-efficiency electron transfer medium was proposed for the boosted H2-generation rate.The present facile route may broaden the horizons for the efficient development of highly active cocatalysts in photocatalytic field.
基金the National Natural Science Foundation of China(Nos.51872221,21771142)the Fundamental Research Funds for the Central Universities(No.WUT2019IB002).
文摘Hexagonal molybdenum carbide(Mo_(2)C)as an effective non-noble cocatalyst is intensively researched in the photocatalytic H_(2)-evolution field owing to its Pt-like H^(+)-adsorption ability and good conductivity.However,hexagonal Mo_(2)C-modified photocatalysts possess a limited H_(2)-evolution rate because of the weak H-desorption ability.Tofurther improve the activity,cubic MoC was introduced into Mo_(2)C toform the carbon-modified MoC-Mo_(2)C nanoparticles(MoC-Mo_(2)C@C)by a calcination method.The resultant MoC-Mo_(2)C@C(ca.5 nm)was eventually coupled with Ti0_(2)to acquire high-efficiency Ti0_(2)/MoC-Mo_(2)C@C by electrostatic self-assembly.The highest H_(2)-generation rate of Ti0_(2)/MoC-Mo_(2)C@C reached of 918μmol·h^(-1)·g^(-1)which was 91.8,2.7,and 1.5 times than that of the Ti0_(2),TiO_(2)/MoC@C,and Ti0_(2)/Mo_(2)C@C,respectively.The enhanced rate of Ti0_(2)attributes to the carbon layer as cocatalyst to transmit electrons and the hetero-phase MoC-Mo_(2)C as H_(2)-generation active sites to boost H_(2)-evolution reaction.This research offers a novel insight to design photocatalytic materials for energy applications.
基金the National Natural Science Foundation of China(Nos.22075220 and 51872221)the 111 Project(No.B18038)。
文摘CdS photocorrosion is one of the most important factors that greatly affect the photocatalytic H_(2)-production rate and long-time stability.However,the reported works about CdS photocorrosion are mainly focused on the surface oxidation by photogenerated holes,while the possible reduction of lattice Cd^(2+) by photogenerated electrons is usually ignored.In this work,the lattice Cd^(2+) reduction by photogenerated electrons during CdS photocorrosion were carefully investigated to reveal its potential effect on the microstructure change and photocatalytic H_(2)-production performance of CdS photocatalyst based on the two typical Na_(2)S-Na_(2)SO_(3) and lactic acid H_(2)-evolution systems.It was found that many isolated metallic Cd nanoparticles(5–50 nm)were produced on the CdS surface in the Na_(2)S-Na_(2)SO_(3) system,causing its serious destroy of CdS surface and a gradually decreased photocatalytic activity,while only a metallic Cd layer(2-3 nm)is homogeneously coated on the CdS surface in the lactic acid system,leading to an increased H-evolution rate.In fact,once a certain amount of metallic Cd was produced on the CdS surface,the resulting CdS-Cd composites can present a stable photocatalytic H_(2)-production activity and excellent stability for the final CdS-Cd photocatalysts.Hence,a photoinduced self-stability mechanism of CdS photocatalyst has been proposed,namely,the spontaneously produced metallic Cd contributes to the transformation of unstable CdS into stable CdS-Cd structure,with the simultaneous realization of final stable H_(2)-evolution performance.
基金financially supported by the National Natural Science Foundation of China(Nos.51872221 and 21771142)the Fundamental Research Funds for the Central Universities(No.WUT 2019IB002)。
文摘Exploiting efficient and low-cost cocatalyst with a facile grafting strategy is of critical importance for significantly boosting the photocatalytic H2-evolution activity.In this study,S2^--adsorbed MoSx nanoparticle as a superior H2-evolutoin cocatalyst was successfully grafted on the TiO2 surface to greatly boost its photocatalytic activity via one-step lactic acid-induced synthesis strategy.Herein,the lactic acid can induce the homogeneous production of amorphous MoSx(a-MoSx)nanoparticles from MoS42-precursor,while the symbiotic S2^-ions can be easily and availably self-adsorbed on the a-Mo Sxsurface,resulting in the formation of S2^--adsorbed a-Mo Sxnanoparticles with a small size of 0.5-3 nm.Photocatalytic results manifested that the S2^--adsorbed Mo Sxnanoparticles could dramatically facilitate the H2-generation rate of TiO2 photocatalysts(3452μmol h^-1 g^-1,AQE=16.5%).In situ irradiated XPS in conjunction with transient-state PL and photoelectrochemical tests reveal that the improved H_(2)-generation activity can be ascribed to the synergistic effect of boosted interfacial charge transfer from TiO_(2) to S^(2-)adsorbed Mo Sx and the superior H_(2)-evolution reaction on self-adsorbed S_(2-)ions.In addition,the S^(2-)-adsorbed Mo Sx nanoparticles can also act as the general H_(2)-generation cocatalyst to obviously promote the activity of other typical host photocatalysts such as g-C_(3) N_(4) and Cd S.This work provides an innovative approach to develop high-efficiency Mo Sx-based cocatalyst with boosted interfacial charge transfer toward highly efficient photocatalytic materials.
基金This work was supported by the National Natural Science Foundation of China(No.22178275)the Natural Science Foundation of Hubei Province of China(No.2022CFA001).
文摘Traditional bulk MoS_(2) as an effective H_(2)-evolution cocatalyst is mainly subjected to the weak hydrogen-adsorption ability of highporpotion saturated S,resulting in a slow interfacial H_(2)-evolution reaction.In this paper,an efficient strategy for enhancing hydrogen adsorption of saturated S by manipulating electron density through O atoms is proposed to boost photocatalytic performance of CdS.Simultaneously,amorphization of MoS_(2) can further increase the unsaturated active S sites.Herein,oxygencontained amorphous MoS_(x)(a-MoOS_(x))nanoparticles(10-30 nm)were tightly loaded on the CdS surface through a mild photoinduced deposition method by using(NH_(4))_(2)[MoO(S_(4))_(2)]solution as the precursor at room temperature.The photocatalytic H_(2)-evolution result showed that the a-MoOS_(x)/CdS performed the superior H_(2)-production activity(382μmol·h^(-1),apparent quantum efficiencies(AQE)=11.83%)with a lot of visual H_(2)bubbles,which was 54.6,2.5,and 5.1 times as high as that of CdS,MoS_(x)/CdS,and annealed a-MoOS_(x)/CdS,respectively.Characterizations and density functional theory(DFT)calculations revealed the mechanism of improved H_(2)-evolution activity is that the O heteroatom in amorphous MoOS_(x) can enhance the atomic H-adsorption ability by manipulating the electron density to form electron-deficient S^((2-δ)-)sites.This study provides a new idea to improve the efficiency and number of H_(2)-evolution active sites for developing efficient cocatalysts in the field of photocatalytic hydrogen evolution.
