Designing low-cost and high-performance catalysts of electrocatalytic oxygen evolution reaction(OER)has always been one of the hot topics in current research.Hexagonal perovskite materials show great application poten...Designing low-cost and high-performance catalysts of electrocatalytic oxygen evolution reaction(OER)has always been one of the hot topics in current research.Hexagonal perovskite materials show great application potential in this field.Here,we synthesized 5%Iridium(Ir)-doped hexagonal phase perovskite BaCo_(0.8)Fe_(0.15)Ir_(0.05)O_(3–δ)(BCFI).Using the Rietveld method to refine the structure,combining with the spherical aberration corrected high-angle annular dark-field scanning transmission electron microscopy(HAADF-STEM)atomic imaging,we found that BCFI is a ten-layer hexagonal(10H)structure,which belongs to the Purn:x-wiley:1001604X:media:cjoc202200200:cjoc202200200-math-0001m2 space group.In addition,BCFI shows excellent OER catalytic effect and good stability in 1 mol/L KOH solution,and the overpotential reaches 294 mV at a current density of 10 mA cm^(–2).The reduction of Cobalt(Co)valence state induced by Ir doping significantly enhances the OER activity of BCFI.Meanwhile,density functional theory(DFT)calculations show that the 2p-band center of oxygen(O)in BCFI is closer to the Fermi level than that in undoped BaCo_(0.8)Fe_(0.15)Ir_(0.05)O_(3–δ)(BCF),which is beneficial to the OER.This work reveals a novel 10H-BCFI material with excellent OER performance,and provides a basis for the design of hexagonal perovskite materials in OER and other energy conversion fields.展开更多
基金This workwas supported by the National Natural Science Foundation of China(No.21671182)the National Key R&D Program of China(No.2021YFB4001401).
文摘Designing low-cost and high-performance catalysts of electrocatalytic oxygen evolution reaction(OER)has always been one of the hot topics in current research.Hexagonal perovskite materials show great application potential in this field.Here,we synthesized 5%Iridium(Ir)-doped hexagonal phase perovskite BaCo_(0.8)Fe_(0.15)Ir_(0.05)O_(3–δ)(BCFI).Using the Rietveld method to refine the structure,combining with the spherical aberration corrected high-angle annular dark-field scanning transmission electron microscopy(HAADF-STEM)atomic imaging,we found that BCFI is a ten-layer hexagonal(10H)structure,which belongs to the Purn:x-wiley:1001604X:media:cjoc202200200:cjoc202200200-math-0001m2 space group.In addition,BCFI shows excellent OER catalytic effect and good stability in 1 mol/L KOH solution,and the overpotential reaches 294 mV at a current density of 10 mA cm^(–2).The reduction of Cobalt(Co)valence state induced by Ir doping significantly enhances the OER activity of BCFI.Meanwhile,density functional theory(DFT)calculations show that the 2p-band center of oxygen(O)in BCFI is closer to the Fermi level than that in undoped BaCo_(0.8)Fe_(0.15)Ir_(0.05)O_(3–δ)(BCF),which is beneficial to the OER.This work reveals a novel 10H-BCFI material with excellent OER performance,and provides a basis for the design of hexagonal perovskite materials in OER and other energy conversion fields.
