Asymmetric oxygen vacancies in La2FeMO6 double perovskite for boosting oxygen activation and H2S selective oxidation
Tuning oxygen vacancy (VO) in metal oxides catalysts that efficiently activates O2 molecule to pro-mote oxidation reactions remains challenging.Herein,transition metal (M=Mn,Co,and Mo) doping was used to moderate the coordination environment of VO in La2FeMO6 and promote activity for selective oxidation of hydrogen sulfide (H2S).Various techniques reveal that the introduction of Mn and Co forms the homogeneous double perovskite phase,which results in the formation of asym-metric VO.Although these asymmetric VO are more difficult to form than symmetric Fe-VO-Fe due to the shorter bond distance and stronger bond strength of Fe-O,they are more conducive to the dis-sociation of O2 molecules.Among them,the formed rich Fe-VO-Mn sites from the alternate substitu-tion of Mn to Fe boosted the activation of O2 molecules of Mn-substituted LaFeO3.Therefore,en-hanced catalytic activity and outstanding sulfur selectivity were achieved as a result of promoted oxygen mobility and reducibility.This work provides an attractive strategy for rational design of advanced oxidation catalysts.
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