Exploiting high-efficiency Ni-based materials for electrocatalytic urea oxidation reaction(UOR) is critical for urea-related technologies.The catalytic site density,intrinsic activity,charge transfer,and mass diffusio...Exploiting high-efficiency Ni-based materials for electrocatalytic urea oxidation reaction(UOR) is critical for urea-related technologies.The catalytic site density,intrinsic activity,charge transfer,and mass diffusion determine overall electrocatalytic efficiency.Simultaneous modulation over the above four factors promises advanced electrocatalysis,yet challenging.Herein we propose a systematic regulation tactic over composition and geometric structure,constructing a nanocomposite comprising Mn doped Ni_(3)N nanoparticles anchored on reduced graphene oxide(rGO/Mn-Ni_(3)N),achieving elegant integration of four design principles into one,thereby eminently boosting UOR.Particularly,Mn doping in Ni_(3)N can modulate electronic state to induce intrinsic activity regulation.Combining metallic Mn-Ni_(3)N with rGO to engineer hierarchical architecture not only promotes charge transfer,but also enriches active site population.Intriguingly,improved hydrophilicity could impart better electrolyte penetration and gas escape.Consequently,such system-optimized rGO/Mn-Ni_(3)N demonstrates state-of-the-art-level UOR electrocatalysis.This work offers a novel paradigm to create advanced catalysts via systematic and integrated modulation.展开更多
近年来,基于BiVO_(4)光阳极的光电催化分解水技术引起人们的关注.我们通过水热-氨化法制备出Ni_(3)N纳米颗粒,首次将其作为助催化剂修饰到BiVO_(4)光阳极上光电催化分解水.实验表明, Ni_(3)N纳米颗粒成功负载到BiVO_(4)光阳极表面并可...近年来,基于BiVO_(4)光阳极的光电催化分解水技术引起人们的关注.我们通过水热-氨化法制备出Ni_(3)N纳米颗粒,首次将其作为助催化剂修饰到BiVO_(4)光阳极上光电催化分解水.实验表明, Ni_(3)N纳米颗粒成功负载到BiVO_(4)光阳极表面并可有效抑制表面电荷复合以及提高光电催化分解水性能.在1.23 V v. RHE处光电流密度可达3.23mA/cm^(2).此外, Ni_(3)N/BiVO_(4)光阳极的最大值ABPE值达0.88%,并呈现出良好的稳定性.展开更多
Electrocatalytic CO_(2)reduction into CO has been regarded as one of the most promising strategies for sustainable carbon cycles at ambient conditions,but still faces challenges to achieve both high product selectivit...Electrocatalytic CO_(2)reduction into CO has been regarded as one of the most promising strategies for sustainable carbon cycles at ambient conditions,but still faces challenges to achieve both high product selectivity and large current density.Here,we report a Ni_(4)N/Ni_(3)ZnC_(0.7)heterostructured electrocatalyst embedded in accordion-like N-doped carbon through a simple molten salt annealing strategy.The optimal Ni_(4)N/Ni_(3)ZnC_(0.7)electrocatalyst achieves a high CO Faraday efficiency of 92.3%and a large total current density of-15.8 m A cm^(-2)at-0.8 V versus reversible hydrogen electrode,together with a long-term stability about 30 h.Density functional theory results reveal that the energy barrier for*COOH intermediate formation largely decreased on Ni_(4)N/Ni_(3)ZnC_(0.7)heterostructure compared with Ni_(4)N and Ni_(3)ZnC_(0.7),thus giving rise to enhanced activity and selectivity.A rechargeable Zn-CO_(2)battery is further assembled with Ni_(4)N/Ni_(3)ZnC_(0.7)catalyst as the cathode,which shows a maximum power density of 0.85 mW cm^(-2)and excellent stability.展开更多
Exploring bifunctional electrocatalysts with high-efficiency and stability toward overall water splitting is desirable for sustainable energy technologies,yet challenging.Herein,we report the construction of Ni_(3)N o...Exploring bifunctional electrocatalysts with high-efficiency and stability toward overall water splitting is desirable for sustainable energy technologies,yet challenging.Herein,we report the construction of Ni_(3)N on the surface of Ni-MOF-74 through an in-situ nitriding process.The obtained Ni-MOF-74/Ni_(3)N exhibits remarkable HER activity with an overpotential of 73 mV to deliver 10 mA cm^(-2).Theoretical calculations and experimental study demonstrate the electron transport between Ni_(3)N and Ni-MOF-74,leading to the improved H_(2)O adsorption,optimized hydrogen adsorption,and increased H_(ad)diffusion,which contributes to the enhanced HER performance.Besides,the obtained Ni-MOF-74/Ni_(3)N also possesses outstanding activity toward OER and overall water splitting.展开更多
Oxygen evolution reaction(OER)and hydrogen evolution reaction(HER)are the key processes in water splitting.Compared with the two-electron process in HER,the four-electron process of OER is slow because of the more com...Oxygen evolution reaction(OER)and hydrogen evolution reaction(HER)are the key processes in water splitting.Compared with the two-electron process in HER,the four-electron process of OER is slow because of the more complex series of reactions.Therefore,a good understanding of the direct O_(2) evolution mechanism(DOEM)in OER is crucial to design high-efficiency catalysts to overcome the limitations imposed by the conventional adsorption evolution mechanism.In this work,honeycomb Ni_(3)N-Co_(3)N was prepared on carbon cloth(Ni_(3)N-Co_(3)N/CC)to investigate the DOEM.Density functional theory and in situ Raman scattering spectroscopy demonstrated that the OER process on Ni_(3)N-Co_(3)N/CC proceeded via the DOEM pathway,in which Ni_(3)N and Co_(3)N share the roles of dragging OH^(-),splitting off H-O bonds,and adsorbing other OH^(-),leading to significantly reduced Gibbs’s energy barriers of ΔG_(*OH) to ΔG_(O*)and ΔG_(O*)to ΔG_(O*OH).Moreover,the vertical honeycomb structure and conductive CC substrate contributed to the structural stability,conductivity,and quick O_(2) release capability.The Ni_(3)N-Co_(3)N/CC required low overpotentials of 320 and 495 mV to reach a current density of 10 and 100 mA cm^(-2),respectively.Moreover,the Ni_(3)N-Co_(3)N/CC delivered excellent stability with>90% retention of the initial current density over an 80-h-long test.展开更多
The high unoccupied d band energy of Ni_(3)N basically results in weak orbital coupling with water molecule,consequently leading to slow water dissociation kinetics.Herein,we demonstrate Cr doping can downshift the un...The high unoccupied d band energy of Ni_(3)N basically results in weak orbital coupling with water molecule,consequently leading to slow water dissociation kinetics.Herein,we demonstrate Cr doping can downshift the unoccupied d orbitals and strengthen the interfacial orbital coupling to boost the water dissociation kinetics.The prepared Cr-Ni_(3)N/Ni displays an impressive overpotential of 37 mV at 10 mA·cmgeo-2,close to the benchmark Pt/C in 1.0 M KOH solution.Refined structural analysis reveals the Cr dopant exists as the Cr-N_(6)states and the average d band energy of Ni_(3)N is also lowered.Density functional theory calculation further confirms the downshifted d band energy can strengthen the orbital coupling between the unpaired electrons in O 2p and the unoccupied state of Ni 3d,which thus facilitates the water adsorption and dissociation.The work provides a new concept to achieve on-demand functions for hydrogen evolution catalysis and beyond,by regulating the interfacial orbital coupling.展开更多
基金supported by the National Natural Science Foundation of China (52002412 and 22072186)the Natural Science Foundation of Guangdong Province (2021A1515010575)the Fundamental Research Funds for the Central Universities, Sun Yat-sen University (23lgbj017)。
文摘Exploiting high-efficiency Ni-based materials for electrocatalytic urea oxidation reaction(UOR) is critical for urea-related technologies.The catalytic site density,intrinsic activity,charge transfer,and mass diffusion determine overall electrocatalytic efficiency.Simultaneous modulation over the above four factors promises advanced electrocatalysis,yet challenging.Herein we propose a systematic regulation tactic over composition and geometric structure,constructing a nanocomposite comprising Mn doped Ni_(3)N nanoparticles anchored on reduced graphene oxide(rGO/Mn-Ni_(3)N),achieving elegant integration of four design principles into one,thereby eminently boosting UOR.Particularly,Mn doping in Ni_(3)N can modulate electronic state to induce intrinsic activity regulation.Combining metallic Mn-Ni_(3)N with rGO to engineer hierarchical architecture not only promotes charge transfer,but also enriches active site population.Intriguingly,improved hydrophilicity could impart better electrolyte penetration and gas escape.Consequently,such system-optimized rGO/Mn-Ni_(3)N demonstrates state-of-the-art-level UOR electrocatalysis.This work offers a novel paradigm to create advanced catalysts via systematic and integrated modulation.
文摘近年来,基于BiVO_(4)光阳极的光电催化分解水技术引起人们的关注.我们通过水热-氨化法制备出Ni_(3)N纳米颗粒,首次将其作为助催化剂修饰到BiVO_(4)光阳极上光电催化分解水.实验表明, Ni_(3)N纳米颗粒成功负载到BiVO_(4)光阳极表面并可有效抑制表面电荷复合以及提高光电催化分解水性能.在1.23 V v. RHE处光电流密度可达3.23mA/cm^(2).此外, Ni_(3)N/BiVO_(4)光阳极的最大值ABPE值达0.88%,并呈现出良好的稳定性.
基金financially supported by the National Key Research and Development Program,China(2018YFB1502503)the 2021 Talent Introduction Project of Chongqing Medical and Pharmaceutical College(ygz2021104)。
文摘Electrocatalytic CO_(2)reduction into CO has been regarded as one of the most promising strategies for sustainable carbon cycles at ambient conditions,but still faces challenges to achieve both high product selectivity and large current density.Here,we report a Ni_(4)N/Ni_(3)ZnC_(0.7)heterostructured electrocatalyst embedded in accordion-like N-doped carbon through a simple molten salt annealing strategy.The optimal Ni_(4)N/Ni_(3)ZnC_(0.7)electrocatalyst achieves a high CO Faraday efficiency of 92.3%and a large total current density of-15.8 m A cm^(-2)at-0.8 V versus reversible hydrogen electrode,together with a long-term stability about 30 h.Density functional theory results reveal that the energy barrier for*COOH intermediate formation largely decreased on Ni_(4)N/Ni_(3)ZnC_(0.7)heterostructure compared with Ni_(4)N and Ni_(3)ZnC_(0.7),thus giving rise to enhanced activity and selectivity.A rechargeable Zn-CO_(2)battery is further assembled with Ni_(4)N/Ni_(3)ZnC_(0.7)catalyst as the cathode,which shows a maximum power density of 0.85 mW cm^(-2)and excellent stability.
基金financially supported by the National Natural Science Foundation of China(21972107)Natural Science Foundation of Hubei Province(2020CFA095)Natural Science Foundation of Jiangsu Province(BK20191186)。
文摘Exploring bifunctional electrocatalysts with high-efficiency and stability toward overall water splitting is desirable for sustainable energy technologies,yet challenging.Herein,we report the construction of Ni_(3)N on the surface of Ni-MOF-74 through an in-situ nitriding process.The obtained Ni-MOF-74/Ni_(3)N exhibits remarkable HER activity with an overpotential of 73 mV to deliver 10 mA cm^(-2).Theoretical calculations and experimental study demonstrate the electron transport between Ni_(3)N and Ni-MOF-74,leading to the improved H_(2)O adsorption,optimized hydrogen adsorption,and increased H_(ad)diffusion,which contributes to the enhanced HER performance.Besides,the obtained Ni-MOF-74/Ni_(3)N also possesses outstanding activity toward OER and overall water splitting.
基金financially supported by the City University of Hong Kong HK Tech 300(SF202109174)the National Natural Science Foundation of China(51902118)the International Postdoctoral Exchange Fellowship program(PC2021026)。
文摘Oxygen evolution reaction(OER)and hydrogen evolution reaction(HER)are the key processes in water splitting.Compared with the two-electron process in HER,the four-electron process of OER is slow because of the more complex series of reactions.Therefore,a good understanding of the direct O_(2) evolution mechanism(DOEM)in OER is crucial to design high-efficiency catalysts to overcome the limitations imposed by the conventional adsorption evolution mechanism.In this work,honeycomb Ni_(3)N-Co_(3)N was prepared on carbon cloth(Ni_(3)N-Co_(3)N/CC)to investigate the DOEM.Density functional theory and in situ Raman scattering spectroscopy demonstrated that the OER process on Ni_(3)N-Co_(3)N/CC proceeded via the DOEM pathway,in which Ni_(3)N and Co_(3)N share the roles of dragging OH^(-),splitting off H-O bonds,and adsorbing other OH^(-),leading to significantly reduced Gibbs’s energy barriers of ΔG_(*OH) to ΔG_(O*)and ΔG_(O*)to ΔG_(O*OH).Moreover,the vertical honeycomb structure and conductive CC substrate contributed to the structural stability,conductivity,and quick O_(2) release capability.The Ni_(3)N-Co_(3)N/CC required low overpotentials of 320 and 495 mV to reach a current density of 10 and 100 mA cm^(-2),respectively.Moreover,the Ni_(3)N-Co_(3)N/CC delivered excellent stability with>90% retention of the initial current density over an 80-h-long test.
基金The work was supported by the National Natural Science Foundation of China(Nos.21771169 and 11722543)the National Key Research and Development Program of China(No.2017YFA0206703)+1 种基金Anhui Provincial Natural Science Foundation(No.BJ2060190077)Collaborative Innovation Program of Hefei Science Center,CAS,and the Fundamental Research Funds for the Central Universities(Nos.WK2060190074,WK2060190081,WK2310000066,and WK2060000015).
文摘The high unoccupied d band energy of Ni_(3)N basically results in weak orbital coupling with water molecule,consequently leading to slow water dissociation kinetics.Herein,we demonstrate Cr doping can downshift the unoccupied d orbitals and strengthen the interfacial orbital coupling to boost the water dissociation kinetics.The prepared Cr-Ni_(3)N/Ni displays an impressive overpotential of 37 mV at 10 mA·cmgeo-2,close to the benchmark Pt/C in 1.0 M KOH solution.Refined structural analysis reveals the Cr dopant exists as the Cr-N_(6)states and the average d band energy of Ni_(3)N is also lowered.Density functional theory calculation further confirms the downshifted d band energy can strengthen the orbital coupling between the unpaired electrons in O 2p and the unoccupied state of Ni 3d,which thus facilitates the water adsorption and dissociation.The work provides a new concept to achieve on-demand functions for hydrogen evolution catalysis and beyond,by regulating the interfacial orbital coupling.
