电化学水分解作为一种生产高纯度氢气的绿色技术,虽然前景广阔,但阳极析氧反应(OER)动力学缓慢,严重制约了其能量转换效率.目前,电化学水分解系统主要以淡水作为原料.然而,大规模使用淡水进行分解无疑会给淡水资源带来沉重负担.相比之下...电化学水分解作为一种生产高纯度氢气的绿色技术,虽然前景广阔,但阳极析氧反应(OER)动力学缓慢,严重制约了其能量转换效率.目前,电化学水分解系统主要以淡水作为原料.然而,大规模使用淡水进行分解无疑会给淡水资源带来沉重负担.相比之下,占水资源总量96%以上的海水,因其丰富的储量,成为替代淡水的理想选择.然而,由于海水中含有大量的氯离子,会引发与OER的竞争性氯析出反应(ClER)形成次氯酸盐(ClO^(–)),导致活性位点失活,严重降低催化剂的活性和稳定性.因此,如何在利用海水进行电化学水分解的同时,有效抑制ClER的发生,是当前亟待解决的科学问题.在最新催化剂研究中,金属有机框架(MOF)凭借其高孔隙率、大比表面积和分散的活性位点,在电化学水分解中展现出良好的性能.然而,MOF的电子导电性和OER反应能垒受限于氧原子p轨道与金属原子d轨道间的电子云重叠.因此,设计MOF活性位点的电子结构,促进自发电子转移,对于提升导电性和OER效率至关重要.界面工程能优化MOF活性位点的电子结构,增强局部电荷再分配,从而提高OER活性.为满足工业高电流密度需求,构建富含缺陷的异质结构是关键,其能暴露更多OER活性位点,优化质量传递,缩短电子迁移路径.结合高导电、可调电子结构的NiS晶体相,构建MOF非晶/NiS晶体异质界面,可调控电子结构并加速电荷转移.目前,关于MOF基非晶/晶异质界面催化剂用于海水氧化的报道尚少,这一方向具有巨大潜力.本文通过两步法耦合策略,成功在泡沫镍基底上制备了NiFe-MOF@NiS异质结构催化剂.首先,利用硫温和改性腐蚀方法在泡沫镍基体生长晶相NiS纳米片;随后,通过电沉积处理在NiS表面生长非晶相NiFe-MOF纳米颗粒.理论计算结果表明,NiFe-MOF和NiS之间的电子相互作用可以加速电荷转移,有效调节金属位点的d带中心,从而优化含氧中间体的吸附能力.与NiFe-MOF和NiS相比,NiFe-MOF@NiS/NF催化剂对OOH*中间体的吸附能力更为突出,这大大降低了速率决定步骤(O*→OOH*)的反应能垒,为高效催化OER提供了理论支撑.实验结果表明,在1 mol L^(‒1)KOH和碱性海水电解液中,NiFe-MOF@NiS/NF催化剂仅需要346和355 mV的低过电位,即可驱动500 mA cm^(–2)的大电流密度.Tafel斜率和电化学阻抗谱的结果表明,该催化剂具有较好的OER动力学特征.此外,质量活性和转换频率结果表明,NiFe-MOF@NiS/NF催化剂展现出良好的本征催化活性.多步恒电流阶梯曲线以及在100和500 mA cm‒2电流密度下的计时电位曲线结果表明,NiFe-MOF@NiS/NF催化剂具有出色的长期稳定性.通过对在碱性海水电解液OER反应后的NiFe-MOF@NiS/NF催化剂进行表征发现,在OER过程中,NiS物种会在阳极电压下自重构形成硫酸盐膜,可以显著抑制Cl–离子在催化剂表面的吸附,使NiFe-MOF@NiS/NF催化剂在海水电解质中具有强大的耐腐蚀性.这一特性使得NiFe-MOF@NiS/NF催化剂在碱性KOH和碱性海水中均能保持较好的OER活性和稳定性,性能超过了商业RuO_(2)以及大多数报道的其他MOF基的催化剂.综上所述,本文通过简便易行的合成策略,制备了高性能的NiFe-MOF@NiS异质结催化剂,其表现出高效电解海水性能和稳定性.本工作为合理设计高活性、稳定性、选择性的MOF基抗氯腐蚀催化剂以提高碱性海水的OER性能提供了新视角.展开更多
Cathode interfacial materials(CIMs)stand as critical elemental in organic solar cells(OSCs),which can align energy levels,and foster ohmic contacts between the cathode and active layer of the OSCs.Nevertheless,the lag...Cathode interfacial materials(CIMs)stand as critical elemental in organic solar cells(OSCs),which can align energy levels,and foster ohmic contacts between the cathode and active layer of the OSCs.Nevertheless,the lagging advancement in CIMs has concurrently engendered the oversight of theoretical inquiries pertaining to the impact of molecular structure on their performance.Delving into this realm,we present two propeller-shaped isomers,4,4',4''-(benzo[1,2-b:3,4-b':5,6-b'']trithiophene-2,5,8-triyl)tris(2-(3-(dimethylamino)propyl)-1H-benzo[de]isoquinoline-1,3(2H)-dione)(3ONIN)and 6,6',6''-(benzo[1,2-b:3,4-b':5,6-b'']trithiophene-2,5,8-triyl)tris(2-(3-(dimethylamino)propyl)-1H-benzo[de]isoquinoline-1,3(2H)-dione)(3PNIN),distinguished by their molecular planarity,as a promising foundation for crafting highly efficient OSCs.This study illuminates the superiority of 3PNIN with more plane structure,exemplified by its enhanced molar extinction coefficient,deeper lowest unoccupied molecular orbital(LUMO)and highest occupied molecular orbital(HOMO)energy levels,intensified self-doping effect,heightened electron mobility,and elevated conductivity,in comparison to its counterpart,3ONIN.As a result,3PNIN and 3ONIN-treated OSC devices yield efficiencies of 17.73%and 16.82%,respectively.This finding serves as a compelling validation of the critical role played by molecular planarity in influencing CIM performance.展开更多
Defect engineering on metal-organic frameworks(MOFs)provides high flexibility to rationally design advanced oxygen evolution reaction(OER)catalysts with low overpotential and high stability.However,fundamental underst...Defect engineering on metal-organic frameworks(MOFs)provides high flexibility to rationally design advanced oxygen evolution reaction(OER)catalysts with low overpotential and high stability.However,fundamental understanding the effect of defect concentration on catalytic OER activity is still quite ambiguous.Herein,the Co-MOF-Dx catalysts with regulated oxygen defects concentration are deliberately constructed via coupling one-pot solvothermal synthesis with NaBH_(4)chemical reduction process.Experimental findings propose that the oxygen defect concentration within Co-MOF-Dx gradually increases with raising the NaBH_(4)content,which could provide a flexible platform to tailor the electronic structure around active Co site and optimize adsorption/desorption capacity of oxygen intermediates.When the introduction content of NaBH_(4)is up to 5 mg,the resulting abundant unsaturated coordination defects could endow the Co-MOF-D5 catalyst with optimized electronic structure and more exposed active sites for improving charge transfer and adsorption/desorption capacity.It is found that the optimized Co-MOF-D5 can drive the current density of 10 mA cm^(-2)only at a low overpotential of 300 mV with the small Tafel slope of 53.1 mV dec^(-1)in alkaline medium.This work sheds light on the way for the development of high-performance MOF catalysts via modulating defect concentration.展开更多
Developing highly efficient,easy-to-make and cost-effective bifunctional electrocatalysts for water splitting with lower cell voltages is crucial to producing massive hydrogen fuel.In response,the coupled hierarchical...Developing highly efficient,easy-to-make and cost-effective bifunctional electrocatalysts for water splitting with lower cell voltages is crucial to producing massive hydrogen fuel.In response,the coupled hierarchical Ni/Fe-based MOF nanosheet arrays with embedded metal sulfide nanoclusters onto nickel foam skeleton(denoted as Fe-Ni_(3)S_(2)@NiFe-MOF/NF)are fabricated,in which the Fe-Ni_(3)S_(2) clusters could effectively restrain the aggregation of the layer metal-organic frameworks(MOF)nanosheets and adjust the local electronic structures of MOFs nanosheets.Benefiting from the rapid charge transfer and the exposure of abundant active sites,the well-designed Fe-Ni_(3)S_(2)@NiFe-MOF/NF displays excellent oxygen evolution reaction(OER)and hydrogen evolution reaction(HER)performance.More importantly,when equipped in the alkaline water electrolyzer,the Fe-Ni_(3)S_(2)@Ni Fe-MOF/NF enables the system with a mere 1.6 V for achieving the current density of 10 mA cm^(-2).This work offers a paradigm for designing efficient bifunctional HER/OER electrocatalysts based on the hybrid materials of nanostructured metal sulfide and MOF.展开更多
Interface engineering has gradually attracted substantial research interest in constructing active bifunctional catalysts toward urea electrolysis.The fundamental understanding of the crystallinity transition of the c...Interface engineering has gradually attracted substantial research interest in constructing active bifunctional catalysts toward urea electrolysis.The fundamental understanding of the crystallinity transition of the components on both sides of the interface is extremely significant for realizing controllable construction of catalysts through interface engineering,but it still remains a challenge.Herein,the Ni/NiO heterogenous nanoparticles are successfully fabricated on the porous N-doped carbon spheres by a facile hydrothermal and subsequent pyrolysis strategy.And for the first time we show the experimental observation that the Ni/NiO interface can be fine-tuned via simply tailoring the heating rate during pyrolysis process,in which the crystalline/amorphous or crystalline/crystalline Ni/NiO heterostructure is deliberately constructed on the porous N-doped carbon spheres(named as CA-Ni/NiO@NCS or CC-Ni/NiO@NCS,respectively).By taking advantage of the unique porous architecture and the synergistic effect between crystalline Ni and amorphous NiO,the well-designed CA-Ni/NiO@NCS displays more remarkable urea oxidation reaction(UOR)and hydrogen evolution reaction(HER)activity than its crystalline/crystalline counterpart of CC-Ni/NiO@NCS.Particularly,the whole assembled two-electrode electrolytic cell using the elaborate CANi/NiO@NCS both as the anode and cathode can realize the current density of 10 mA·cm^(−2)at a super low voltage of 1.475 V(264 mV less than that of pure water electrolysis),as well as remarkable prolonged stability over 63 h.Besides,the H_(2)evolution driven by an AA battery and a commercial solar cell is also studied to enlighten practical applications for the future.展开更多
Deliberate modulation of the electronic structure via interface engineering is one of promising perspectives to build advanced catalysts for urea oxidation reaction(UOR)at high current densities.However,it still remai...Deliberate modulation of the electronic structure via interface engineering is one of promising perspectives to build advanced catalysts for urea oxidation reaction(UOR)at high current densities.However,it still remains some challenges originating from the intrinsically sluggish UOR dynamics and the high energy barrier for urea adsorption.In response,we report the coupled NiSe_(2)nanowrinkles with Ni_(5)P_(4)nanorods heterogeneous structure onto Ni foam(denoted as NiSe_(2)@Ni_(5)P_(4)/NF)through successive phosphorization and selenization strategy,in which the produced closely contacted interface could provide high-flux electron transfer pathways.Theoretical findings decipher that the fast charge transfer takes place at the interfacial region from Ni_(5)P_(4)to NiSe_(2),which is conducive to optimizing adsorption energy of urea molecules.As expected,the well-designed NiSe_(2)@Ni_(5)P_(4)/NF only requires the low potential of 1.402 V at the current density of 500 mA·cm^(-2).More importantly,a small Tafel slope of 27.6 mV·dec^(-1),a high turnover frequency(TOF)value of 1.037 s^(-1)as well as the prolonged stability of 950 h at the current density of 100 mA·cm^(-2)are also achieved.This study enriches the understanding on the electronic structure modulation via interface engineering and offers bright prospect to design advanced UOR catalysts.展开更多
文摘电化学水分解作为一种生产高纯度氢气的绿色技术,虽然前景广阔,但阳极析氧反应(OER)动力学缓慢,严重制约了其能量转换效率.目前,电化学水分解系统主要以淡水作为原料.然而,大规模使用淡水进行分解无疑会给淡水资源带来沉重负担.相比之下,占水资源总量96%以上的海水,因其丰富的储量,成为替代淡水的理想选择.然而,由于海水中含有大量的氯离子,会引发与OER的竞争性氯析出反应(ClER)形成次氯酸盐(ClO^(–)),导致活性位点失活,严重降低催化剂的活性和稳定性.因此,如何在利用海水进行电化学水分解的同时,有效抑制ClER的发生,是当前亟待解决的科学问题.在最新催化剂研究中,金属有机框架(MOF)凭借其高孔隙率、大比表面积和分散的活性位点,在电化学水分解中展现出良好的性能.然而,MOF的电子导电性和OER反应能垒受限于氧原子p轨道与金属原子d轨道间的电子云重叠.因此,设计MOF活性位点的电子结构,促进自发电子转移,对于提升导电性和OER效率至关重要.界面工程能优化MOF活性位点的电子结构,增强局部电荷再分配,从而提高OER活性.为满足工业高电流密度需求,构建富含缺陷的异质结构是关键,其能暴露更多OER活性位点,优化质量传递,缩短电子迁移路径.结合高导电、可调电子结构的NiS晶体相,构建MOF非晶/NiS晶体异质界面,可调控电子结构并加速电荷转移.目前,关于MOF基非晶/晶异质界面催化剂用于海水氧化的报道尚少,这一方向具有巨大潜力.本文通过两步法耦合策略,成功在泡沫镍基底上制备了NiFe-MOF@NiS异质结构催化剂.首先,利用硫温和改性腐蚀方法在泡沫镍基体生长晶相NiS纳米片;随后,通过电沉积处理在NiS表面生长非晶相NiFe-MOF纳米颗粒.理论计算结果表明,NiFe-MOF和NiS之间的电子相互作用可以加速电荷转移,有效调节金属位点的d带中心,从而优化含氧中间体的吸附能力.与NiFe-MOF和NiS相比,NiFe-MOF@NiS/NF催化剂对OOH*中间体的吸附能力更为突出,这大大降低了速率决定步骤(O*→OOH*)的反应能垒,为高效催化OER提供了理论支撑.实验结果表明,在1 mol L^(‒1)KOH和碱性海水电解液中,NiFe-MOF@NiS/NF催化剂仅需要346和355 mV的低过电位,即可驱动500 mA cm^(–2)的大电流密度.Tafel斜率和电化学阻抗谱的结果表明,该催化剂具有较好的OER动力学特征.此外,质量活性和转换频率结果表明,NiFe-MOF@NiS/NF催化剂展现出良好的本征催化活性.多步恒电流阶梯曲线以及在100和500 mA cm‒2电流密度下的计时电位曲线结果表明,NiFe-MOF@NiS/NF催化剂具有出色的长期稳定性.通过对在碱性海水电解液OER反应后的NiFe-MOF@NiS/NF催化剂进行表征发现,在OER过程中,NiS物种会在阳极电压下自重构形成硫酸盐膜,可以显著抑制Cl–离子在催化剂表面的吸附,使NiFe-MOF@NiS/NF催化剂在海水电解质中具有强大的耐腐蚀性.这一特性使得NiFe-MOF@NiS/NF催化剂在碱性KOH和碱性海水中均能保持较好的OER活性和稳定性,性能超过了商业RuO_(2)以及大多数报道的其他MOF基的催化剂.综上所述,本文通过简便易行的合成策略,制备了高性能的NiFe-MOF@NiS异质结催化剂,其表现出高效电解海水性能和稳定性.本工作为合理设计高活性、稳定性、选择性的MOF基抗氯腐蚀催化剂以提高碱性海水的OER性能提供了新视角.
基金supported by the National Natural Science Foundation of China(No.22105189).
文摘Cathode interfacial materials(CIMs)stand as critical elemental in organic solar cells(OSCs),which can align energy levels,and foster ohmic contacts between the cathode and active layer of the OSCs.Nevertheless,the lagging advancement in CIMs has concurrently engendered the oversight of theoretical inquiries pertaining to the impact of molecular structure on their performance.Delving into this realm,we present two propeller-shaped isomers,4,4',4''-(benzo[1,2-b:3,4-b':5,6-b'']trithiophene-2,5,8-triyl)tris(2-(3-(dimethylamino)propyl)-1H-benzo[de]isoquinoline-1,3(2H)-dione)(3ONIN)and 6,6',6''-(benzo[1,2-b:3,4-b':5,6-b'']trithiophene-2,5,8-triyl)tris(2-(3-(dimethylamino)propyl)-1H-benzo[de]isoquinoline-1,3(2H)-dione)(3PNIN),distinguished by their molecular planarity,as a promising foundation for crafting highly efficient OSCs.This study illuminates the superiority of 3PNIN with more plane structure,exemplified by its enhanced molar extinction coefficient,deeper lowest unoccupied molecular orbital(LUMO)and highest occupied molecular orbital(HOMO)energy levels,intensified self-doping effect,heightened electron mobility,and elevated conductivity,in comparison to its counterpart,3ONIN.As a result,3PNIN and 3ONIN-treated OSC devices yield efficiencies of 17.73%and 16.82%,respectively.This finding serves as a compelling validation of the critical role played by molecular planarity in influencing CIM performance.
基金supported by the National Natural Science Foundation of China(52261145700,22279124)the Natural Science Foundation of Shandong Province(ZR202ZD30)Qingdao New Energy Shandong Laboratory Open Project(QNESL OP202307)
文摘Defect engineering on metal-organic frameworks(MOFs)provides high flexibility to rationally design advanced oxygen evolution reaction(OER)catalysts with low overpotential and high stability.However,fundamental understanding the effect of defect concentration on catalytic OER activity is still quite ambiguous.Herein,the Co-MOF-Dx catalysts with regulated oxygen defects concentration are deliberately constructed via coupling one-pot solvothermal synthesis with NaBH_(4)chemical reduction process.Experimental findings propose that the oxygen defect concentration within Co-MOF-Dx gradually increases with raising the NaBH_(4)content,which could provide a flexible platform to tailor the electronic structure around active Co site and optimize adsorption/desorption capacity of oxygen intermediates.When the introduction content of NaBH_(4)is up to 5 mg,the resulting abundant unsaturated coordination defects could endow the Co-MOF-D5 catalyst with optimized electronic structure and more exposed active sites for improving charge transfer and adsorption/desorption capacity.It is found that the optimized Co-MOF-D5 can drive the current density of 10 mA cm^(-2)only at a low overpotential of 300 mV with the small Tafel slope of 53.1 mV dec^(-1)in alkaline medium.This work sheds light on the way for the development of high-performance MOF catalysts via modulating defect concentration.
基金financially supported by the Natural Science Foundation of Shandong Province (ZR2020ZD10)the National Natural Science Foundation of China (21775142)。
文摘Developing highly efficient,easy-to-make and cost-effective bifunctional electrocatalysts for water splitting with lower cell voltages is crucial to producing massive hydrogen fuel.In response,the coupled hierarchical Ni/Fe-based MOF nanosheet arrays with embedded metal sulfide nanoclusters onto nickel foam skeleton(denoted as Fe-Ni_(3)S_(2)@NiFe-MOF/NF)are fabricated,in which the Fe-Ni_(3)S_(2) clusters could effectively restrain the aggregation of the layer metal-organic frameworks(MOF)nanosheets and adjust the local electronic structures of MOFs nanosheets.Benefiting from the rapid charge transfer and the exposure of abundant active sites,the well-designed Fe-Ni_(3)S_(2)@NiFe-MOF/NF displays excellent oxygen evolution reaction(OER)and hydrogen evolution reaction(HER)performance.More importantly,when equipped in the alkaline water electrolyzer,the Fe-Ni_(3)S_(2)@Ni Fe-MOF/NF enables the system with a mere 1.6 V for achieving the current density of 10 mA cm^(-2).This work offers a paradigm for designing efficient bifunctional HER/OER electrocatalysts based on the hybrid materials of nanostructured metal sulfide and MOF.
基金the National Natural Science Foundation of China(No.21775142)the Natural Science Foundation of Shandong Province(No.ZR2020ZD10)the Deputyship for Research&Innovation,Ministry of Education in Saudi Arabia(project number 510).
文摘Interface engineering has gradually attracted substantial research interest in constructing active bifunctional catalysts toward urea electrolysis.The fundamental understanding of the crystallinity transition of the components on both sides of the interface is extremely significant for realizing controllable construction of catalysts through interface engineering,but it still remains a challenge.Herein,the Ni/NiO heterogenous nanoparticles are successfully fabricated on the porous N-doped carbon spheres by a facile hydrothermal and subsequent pyrolysis strategy.And for the first time we show the experimental observation that the Ni/NiO interface can be fine-tuned via simply tailoring the heating rate during pyrolysis process,in which the crystalline/amorphous or crystalline/crystalline Ni/NiO heterostructure is deliberately constructed on the porous N-doped carbon spheres(named as CA-Ni/NiO@NCS or CC-Ni/NiO@NCS,respectively).By taking advantage of the unique porous architecture and the synergistic effect between crystalline Ni and amorphous NiO,the well-designed CA-Ni/NiO@NCS displays more remarkable urea oxidation reaction(UOR)and hydrogen evolution reaction(HER)activity than its crystalline/crystalline counterpart of CC-Ni/NiO@NCS.Particularly,the whole assembled two-electrode electrolytic cell using the elaborate CANi/NiO@NCS both as the anode and cathode can realize the current density of 10 mA·cm^(−2)at a super low voltage of 1.475 V(264 mV less than that of pure water electrolysis),as well as remarkable prolonged stability over 63 h.Besides,the H_(2)evolution driven by an AA battery and a commercial solar cell is also studied to enlighten practical applications for the future.
基金The authors extend their appreciation to the Deanship of Scientific Research at Imam Mohammad Ibn Saud Islamic University(IMSIU)for funding and supporting this work through Research Partnership Program(No.RP-21-09-75).
文摘Deliberate modulation of the electronic structure via interface engineering is one of promising perspectives to build advanced catalysts for urea oxidation reaction(UOR)at high current densities.However,it still remains some challenges originating from the intrinsically sluggish UOR dynamics and the high energy barrier for urea adsorption.In response,we report the coupled NiSe_(2)nanowrinkles with Ni_(5)P_(4)nanorods heterogeneous structure onto Ni foam(denoted as NiSe_(2)@Ni_(5)P_(4)/NF)through successive phosphorization and selenization strategy,in which the produced closely contacted interface could provide high-flux electron transfer pathways.Theoretical findings decipher that the fast charge transfer takes place at the interfacial region from Ni_(5)P_(4)to NiSe_(2),which is conducive to optimizing adsorption energy of urea molecules.As expected,the well-designed NiSe_(2)@Ni_(5)P_(4)/NF only requires the low potential of 1.402 V at the current density of 500 mA·cm^(-2).More importantly,a small Tafel slope of 27.6 mV·dec^(-1),a high turnover frequency(TOF)value of 1.037 s^(-1)as well as the prolonged stability of 950 h at the current density of 100 mA·cm^(-2)are also achieved.This study enriches the understanding on the electronic structure modulation via interface engineering and offers bright prospect to design advanced UOR catalysts.
