Ruthenium-based catalyst is one of the most active catalysts for oxygen evolution reaction(OER)in acid media.However,the strong bonding between the Ru sites and oxygen intermediates leads to high overpotential to trig...Ruthenium-based catalyst is one of the most active catalysts for oxygen evolution reaction(OER)in acid media.However,the strong bonding between the Ru sites and oxygen intermediates leads to high overpotential to trigger the OER process.Hence,pyrochlore rare-earth ruthenate(RE_(2)-Ru_(2)O_(7))structures with a series of rare-earth elements(Nd,Sm,Gd,Er,and Yb)were constructed to tune the electronic structure of the Ru sites.Surface structure analysis indicated that the increase of the radius of the rare-earth cations resulted in higher content of defective oxygen(the percentage of the defective oxygen increased from 29.5% to 49.7%) in the RE_(2)Ru_(2)O_(7) structure due to the weakened hybridization of the Ru-O bond.This reduced the valence states of the Ru sites and enlarged the gap between the 4d band center and the Fermi level(E_(F))of Ru,resulting in the weakened adsorption of oxygen intermediates and the improved OER performance in acid media.Among the as-prepared ruthenium pyrochlores,Nd_(2)Ru_(2)O_(7) displayed the lowest OER onset overpotential(210 mV)and Tafel slope(58.48 mV dec^(-1)),as well as 30 times higher intrinsic activity and much higher durability than the state-of-art RuO_(2) catalyst.展开更多
基金supported by the National Key Research and Development Project(2018YFB1502401)the National Natural Science Foundation of China(21771018 and 21875004)+3 种基金the Royal Society and Newton Fund through Newton Advanced Fellowship award(NAF\R1\191294)the Program for Changjiang Scholars and Innovation Research Team in the University(IRT1205)the Fundamental Research Funds for the Central Universitiesthe long-term subsidy mechanism from the Ministry of Finance and the Ministry of Education of China。
文摘Ruthenium-based catalyst is one of the most active catalysts for oxygen evolution reaction(OER)in acid media.However,the strong bonding between the Ru sites and oxygen intermediates leads to high overpotential to trigger the OER process.Hence,pyrochlore rare-earth ruthenate(RE_(2)-Ru_(2)O_(7))structures with a series of rare-earth elements(Nd,Sm,Gd,Er,and Yb)were constructed to tune the electronic structure of the Ru sites.Surface structure analysis indicated that the increase of the radius of the rare-earth cations resulted in higher content of defective oxygen(the percentage of the defective oxygen increased from 29.5% to 49.7%) in the RE_(2)Ru_(2)O_(7) structure due to the weakened hybridization of the Ru-O bond.This reduced the valence states of the Ru sites and enlarged the gap between the 4d band center and the Fermi level(E_(F))of Ru,resulting in the weakened adsorption of oxygen intermediates and the improved OER performance in acid media.Among the as-prepared ruthenium pyrochlores,Nd_(2)Ru_(2)O_(7) displayed the lowest OER onset overpotential(210 mV)and Tafel slope(58.48 mV dec^(-1)),as well as 30 times higher intrinsic activity and much higher durability than the state-of-art RuO_(2) catalyst.
