Transition metal chalcogenides will be in situ transformed into metal oxyhydroxides during oxygen evolution reaction(OER) process in alkaline medium.However,most of these compounds only undergo surface reconstruction ...Transition metal chalcogenides will be in situ transformed into metal oxyhydroxides during oxygen evolution reaction(OER) process in alkaline medium.However,most of these compounds only undergo surface reconstruction under operating conditions,which contains a large percentage of inactive atoms in the core,thus limiting the exposure of the active sites.Here,we synthesize a Ni-Mo-Se precatalyst with three-dimensional hierarchical structure and develop a facile on-site electrochemical activation strategy for achieving deep reconstruction of the precatalyst.Using the combination of multiple spectroscopic characterizations and high resolution electron microscopy techniques,we unravel that the Ni-Mo-Se precatalyst is deeply reconstructed into γ-NiOOH with co-leaching of Mo and Se after the anodic oxidation.Such flower-like γ-NiOOH is constituted by distorted ultrathin nanosheets with a thickness of ~4.5 nm and contains abundant intercalated species such as water and OH^(-)/CO_(3)^(2-) thus offering a large quantity of accessible active sites.To reach the current density of 10 mA cm^(-2),the derived electrode requires an overpotential of only 244 mV,outperforming almost all the reported analogues.This work highlights the reconstruction chemistry and provides a simple method for the preparation of efficient OER electrocatalyst.展开更多
Tuning surface electron transfer process by sulfur(S)-vacancies engineering is an efficient strategy to develop high-efficient catalysts for electroreduction N_(2) reaction(NRR). Herein, the distinct Sb_(2)S_(3) nanor...Tuning surface electron transfer process by sulfur(S)-vacancies engineering is an efficient strategy to develop high-efficient catalysts for electroreduction N_(2) reaction(NRR). Herein, the distinct Sb_(2)S_(3) nanorods with S-vacancies(Sv-Sb_(2)S_(3)) have been synthesized by a simple twostep method including hydrothermal and hydrogenation in H_(2)/Ar atmosphere, which shows improved performance for NRR with the NH_(3) yield rate of 10.85 μg h^(-1) mgcat^(-1) at-0.4 V vs. RHE, the faradaic efficiency(FE) of 3.75% at -0.3 V vs. RHE and excellent stability for 24 h, largely outperforming bulk Sb_(2)S_(3). X-ray photoelectron spectroscopy(XPS) and density function theory(DFT) calculations demonstrate that the abundant S-vacancies can create an electron-deficient environment and modulate the electron delocalization in Sv-Sb_(2)S_(3), which can not only facilitate the N_(2) molecule adsorption, but also activate the N≡N, resulting in the enhanced performance for NRR.展开更多
基金supported by the grants from the Natural Science Foundation of China (22072062)。
文摘Transition metal chalcogenides will be in situ transformed into metal oxyhydroxides during oxygen evolution reaction(OER) process in alkaline medium.However,most of these compounds only undergo surface reconstruction under operating conditions,which contains a large percentage of inactive atoms in the core,thus limiting the exposure of the active sites.Here,we synthesize a Ni-Mo-Se precatalyst with three-dimensional hierarchical structure and develop a facile on-site electrochemical activation strategy for achieving deep reconstruction of the precatalyst.Using the combination of multiple spectroscopic characterizations and high resolution electron microscopy techniques,we unravel that the Ni-Mo-Se precatalyst is deeply reconstructed into γ-NiOOH with co-leaching of Mo and Se after the anodic oxidation.Such flower-like γ-NiOOH is constituted by distorted ultrathin nanosheets with a thickness of ~4.5 nm and contains abundant intercalated species such as water and OH^(-)/CO_(3)^(2-) thus offering a large quantity of accessible active sites.To reach the current density of 10 mA cm^(-2),the derived electrode requires an overpotential of only 244 mV,outperforming almost all the reported analogues.This work highlights the reconstruction chemistry and provides a simple method for the preparation of efficient OER electrocatalyst.
基金supported by Natural Science Foundation of China (NSFC no. 21673105)the Science and Technology Program of Gansu Province of China (Grant No.1717JR5RA194)。
文摘Tuning surface electron transfer process by sulfur(S)-vacancies engineering is an efficient strategy to develop high-efficient catalysts for electroreduction N_(2) reaction(NRR). Herein, the distinct Sb_(2)S_(3) nanorods with S-vacancies(Sv-Sb_(2)S_(3)) have been synthesized by a simple twostep method including hydrothermal and hydrogenation in H_(2)/Ar atmosphere, which shows improved performance for NRR with the NH_(3) yield rate of 10.85 μg h^(-1) mgcat^(-1) at-0.4 V vs. RHE, the faradaic efficiency(FE) of 3.75% at -0.3 V vs. RHE and excellent stability for 24 h, largely outperforming bulk Sb_(2)S_(3). X-ray photoelectron spectroscopy(XPS) and density function theory(DFT) calculations demonstrate that the abundant S-vacancies can create an electron-deficient environment and modulate the electron delocalization in Sv-Sb_(2)S_(3), which can not only facilitate the N_(2) molecule adsorption, but also activate the N≡N, resulting in the enhanced performance for NRR.
