Hydrogenation of N-ethylcarbazole(NEC),the hydrogen lean form of a liquid organic hydrogen carrier,on TiO2 supported Ru-Ni bimetallic catalysts is investigated.Crystal structure of TiO2 plays a critical role on the hy...Hydrogenation of N-ethylcarbazole(NEC),the hydrogen lean form of a liquid organic hydrogen carrier,on TiO2 supported Ru-Ni bimetallic catalysts is investigated.Crystal structure of TiO2 plays a critical role on the hydrogenation activity and selectivity towards fully hydrogenated product.Ru/anatase catalyst exhibits higher selectivity but lower reactivity compared to Ru/rutile catalyst.Ni addition significantly promotes the performance of Ru/anatase catalyst while causes severe performance deterioration of Ru/rutile catalyst.Commercial P25,a mixture of anatase and rutile phases in approximate ratio A/R1/4,is found to be the best TiO2 support for NEC hydrogenation.Ru/P25 catalyst outperforms both Ru/rutile and Ru/anatase and its activity can be further slightly improved by Ni addition.The unexpected synergism between the two different TiO2 phases for Ru based NEC hydrogenation catalysts is related to metal-support interaction and Ru-Ni interaction.展开更多
Strategy of anchoring alloy nanoparticles made up of the efficient catalytic element(e.g.,Ni,Fe)on dodecyl sulfate(DS^(-))-intercalated NiFe layered double hydroxides(DS^(-)-NiFe LDH)obtained by a convenient one-step ...Strategy of anchoring alloy nanoparticles made up of the efficient catalytic element(e.g.,Ni,Fe)on dodecyl sulfate(DS^(-))-intercalated NiFe layered double hydroxides(DS^(-)-NiFe LDH)obtained by a convenient one-step hydrothermal coprecipitation method for essentially enhancing oxygen evolution reaction(OER)performance was proposed.The results of structural characterization indicate Pt_(2)FeNi alloy nanoparticles evenly distribute on the surface of DS^(-)-NiFe LDH.The sizes of the Pt_(2)FeNi nanoparticles,closely related to their OER performance,could be wellcontrolled by adjusting the amount of H;PtCl;addition.The composite structure of as-prepared product was stable during processes of synthesis,exfoliation,self-assembly,and subsequent electrocatalytic OER.Rigorous electrochemical test proving the contributing catalytic active sites was located at the interface between Pt_(2)FeNi and DS^(-)-NiFe LDH,and the Ni and Fe were the major active elements while O atoms are adsorption sites.The formation of Pt_(2)FeNi nanoparticles could greatly prompt the reduction of Tafel slope.The best-performing Pt_(2)FeNi/DS^(-)-NiFe LDH with a Pt content of 0.98 wt%achieved low overpotential of 204 mV at 10 mA cm^(-2)and 262 mV at 50 mA cm^(-2).This work provides a convenient and effective strategy to create additional active sites for enhancing OER performance of NiFe LDH and make contribution to its wide application.展开更多
Lead-free inorganic copper-silver-bismuth-halide materials have attracted more and more attention due to their environmental friendliness,high element abundance,and low cost.Here,we developed a strategy of one-step ga...Lead-free inorganic copper-silver-bismuth-halide materials have attracted more and more attention due to their environmental friendliness,high element abundance,and low cost.Here,we developed a strategy of one-step gas-solid-phase diffusioninduced reaction to fabricate a series of bandgap-tunable Cu_(a)Agm_(1)Bim_(2)I_(n)/CuI bilayer films due to the atomic diffusion effect for the first time.By designing and regulating the sputtered Cu/Ag/Bi metal film thickness,the bandgap of Cu_(a)Agm_(1)Bim_(2)I_(n)/CuI could be reduced from 2.06 to 1.78 eV.Solar cells with the structure of FTO/TiO_(2)/Cu_(a)Agm_(1)Bim_(2)I_(n)/CuI/carbon were constructed,yielding a champion power conversion efficiency of 2.76%,which is the highest reported for this class of materials owing to the bandgap reduction and the peculiar bilayer structure.The current work provides a practical path for developing the next generation of efficient,stable,and environmentally friendly photovoltaic materials.展开更多
Magnesium hydride （MgH2） is a high-capacity anode material for lithium ion batteries, which suffers from poor cycling stability. In this stud）~ we describe a thermal plasma-based approach to prepare homogeneous MgH...Magnesium hydride （MgH2） is a high-capacity anode material for lithium ion batteries, which suffers from poor cycling stability. In this stud）~ we describe a thermal plasma-based approach to prepare homogeneous MgH2/C nanocomposites with very high cycling stability. In this process, magnesium evaporation is coupled with carbon generation from the plasma decomposition of acetylene, leading to a homogeneous Mg/C nanocomposite, which can be easily converted to MgH2/C by hydrogenation. The MgH2/C nanocomposite achieves a high reversible capacity of up to 620 mAh·g^-1 after 1,000 cycles with an ultralow decay rate of only 0.0036% per cycle, which represents a significantly improved performance compared to previous results.展开更多
N-Ethylcarbazole(NEC)is one of the most promising liquid organic hydrogen carriers(LOHCs),but its application is limited by sluggish kinetics due to lack of high-efficiency,low-cost catalysts.This work reports a cobal...N-Ethylcarbazole(NEC)is one of the most promising liquid organic hydrogen carriers(LOHCs),but its application is limited by sluggish kinetics due to lack of high-efficiency,low-cost catalysts.This work reports a cobalt(Co)-based catalyst promoted by nonstoichiometric yttrium hydride(YH_(3−x))to achieve high-efficiency,reversible hydrogen storage in NEC,with>5.5 wt%reversible hydrogen storage capacity could be achieved below 473 K,and with good kinetics.The YH_(3−x)-promoted Co-based catalyst is the first non-noble metal catalyst with high activity for NEC hydrogenation and 12H-NEC dehydrogenation reactions.A mechanistic study suggests that YH_(3−x)facilitates the reversible hydrogen transfer both in the hydrogenation and the dehydrogenation reactions.The nonstoichiometric YH_(3−x)contained both lattice H and H vacancies with tunable H chemical potential serve as the H donor and H acceptor for reversible hydrogen transfer.Our results support the practical application of LOHCs and inspire new approaches for the utilization of conventional metal hydrides to promote versatile H transfer reactions.展开更多
基金NSFC (Nos. 21771006, U1607126 and 51771002)MOST of China (No. 2017YFB0405902)Beijing Municipal Commission of Science and Technology (Z17110000091702)
文摘Hydrogenation of N-ethylcarbazole(NEC),the hydrogen lean form of a liquid organic hydrogen carrier,on TiO2 supported Ru-Ni bimetallic catalysts is investigated.Crystal structure of TiO2 plays a critical role on the hydrogenation activity and selectivity towards fully hydrogenated product.Ru/anatase catalyst exhibits higher selectivity but lower reactivity compared to Ru/rutile catalyst.Ni addition significantly promotes the performance of Ru/anatase catalyst while causes severe performance deterioration of Ru/rutile catalyst.Commercial P25,a mixture of anatase and rutile phases in approximate ratio A/R1/4,is found to be the best TiO2 support for NEC hydrogenation.Ru/P25 catalyst outperforms both Ru/rutile and Ru/anatase and its activity can be further slightly improved by Ni addition.The unexpected synergism between the two different TiO2 phases for Ru based NEC hydrogenation catalysts is related to metal-support interaction and Ru-Ni interaction.
基金the financial support by the National Natural Science Foundation of China(51874357,51872333,U20A20123)Innovative Research Group of Hunan Provincial Natural Science Foundation of China(2019JJ10006)support from Shenghua Scholar Program of Central South University.R.M.acknowledges support from JSPS KAKENNHI(18H03869)。
文摘Strategy of anchoring alloy nanoparticles made up of the efficient catalytic element(e.g.,Ni,Fe)on dodecyl sulfate(DS^(-))-intercalated NiFe layered double hydroxides(DS^(-)-NiFe LDH)obtained by a convenient one-step hydrothermal coprecipitation method for essentially enhancing oxygen evolution reaction(OER)performance was proposed.The results of structural characterization indicate Pt_(2)FeNi alloy nanoparticles evenly distribute on the surface of DS^(-)-NiFe LDH.The sizes of the Pt_(2)FeNi nanoparticles,closely related to their OER performance,could be wellcontrolled by adjusting the amount of H;PtCl;addition.The composite structure of as-prepared product was stable during processes of synthesis,exfoliation,self-assembly,and subsequent electrocatalytic OER.Rigorous electrochemical test proving the contributing catalytic active sites was located at the interface between Pt_(2)FeNi and DS^(-)-NiFe LDH,and the Ni and Fe were the major active elements while O atoms are adsorption sites.The formation of Pt_(2)FeNi nanoparticles could greatly prompt the reduction of Tafel slope.The best-performing Pt_(2)FeNi/DS^(-)-NiFe LDH with a Pt content of 0.98 wt%achieved low overpotential of 204 mV at 10 mA cm^(-2)and 262 mV at 50 mA cm^(-2).This work provides a convenient and effective strategy to create additional active sites for enhancing OER performance of NiFe LDH and make contribution to its wide application.
基金supported by National Natural Science Foundation of China(Grant No.52072327,62074052,61874159)Zhongyuan Thousand Talents(Zhongyuan Scholars)Program of Henan Province(202101510004)+6 种基金Higher Education and Teaching Reformation Project(2014SJGLX064)Academic Degrees&Graduate Education Reform Project of Henan Province(2021SJGLX060Y)Key research and development projects of Universities in Henan Province(20A140026)the Scientific Research Innovation Team of Xuchang University(2022CXTD008)Science and Technology Project of Henan Province(222102230009).L.Ding thanks the National Key Research and Development Program of China(2022YFB3803300)the open research fund of Songshan Lake Materials Laboratory(2021SLABFK02)the National Natural Science Foundation of China(21961160720).
文摘Lead-free inorganic copper-silver-bismuth-halide materials have attracted more and more attention due to their environmental friendliness,high element abundance,and low cost.Here,we developed a strategy of one-step gas-solid-phase diffusioninduced reaction to fabricate a series of bandgap-tunable Cu_(a)Agm_(1)Bim_(2)I_(n)/CuI bilayer films due to the atomic diffusion effect for the first time.By designing and regulating the sputtered Cu/Ag/Bi metal film thickness,the bandgap of Cu_(a)Agm_(1)Bim_(2)I_(n)/CuI could be reduced from 2.06 to 1.78 eV.Solar cells with the structure of FTO/TiO_(2)/Cu_(a)Agm_(1)Bim_(2)I_(n)/CuI/carbon were constructed,yielding a champion power conversion efficiency of 2.76%,which is the highest reported for this class of materials owing to the bandgap reduction and the peculiar bilayer structure.The current work provides a practical path for developing the next generation of efficient,stable,and environmentally friendly photovoltaic materials.
基金This study is supported by the National Natural Science Foundation of China （Nos. U1607126, 51431001 and 21771006）.
文摘Magnesium hydride （MgH2） is a high-capacity anode material for lithium ion batteries, which suffers from poor cycling stability. In this stud）~ we describe a thermal plasma-based approach to prepare homogeneous MgH2/C nanocomposites with very high cycling stability. In this process, magnesium evaporation is coupled with carbon generation from the plasma decomposition of acetylene, leading to a homogeneous Mg/C nanocomposite, which can be easily converted to MgH2/C by hydrogenation. The MgH2/C nanocomposite achieves a high reversible capacity of up to 620 mAh·g^-1 after 1,000 cycles with an ultralow decay rate of only 0.0036% per cycle, which represents a significantly improved performance compared to previous results.
基金This research was made possible as a result of a generous grant from MOST of China(no.2018YFB1502102)NSFC(nos.21771006,51771002,and 51971004).
文摘N-Ethylcarbazole(NEC)is one of the most promising liquid organic hydrogen carriers(LOHCs),but its application is limited by sluggish kinetics due to lack of high-efficiency,low-cost catalysts.This work reports a cobalt(Co)-based catalyst promoted by nonstoichiometric yttrium hydride(YH_(3−x))to achieve high-efficiency,reversible hydrogen storage in NEC,with>5.5 wt%reversible hydrogen storage capacity could be achieved below 473 K,and with good kinetics.The YH_(3−x)-promoted Co-based catalyst is the first non-noble metal catalyst with high activity for NEC hydrogenation and 12H-NEC dehydrogenation reactions.A mechanistic study suggests that YH_(3−x)facilitates the reversible hydrogen transfer both in the hydrogenation and the dehydrogenation reactions.The nonstoichiometric YH_(3−x)contained both lattice H and H vacancies with tunable H chemical potential serve as the H donor and H acceptor for reversible hydrogen transfer.Our results support the practical application of LOHCs and inspire new approaches for the utilization of conventional metal hydrides to promote versatile H transfer reactions.
