Introducing and stabilizing oxygen vacancies in oxide catalysts is considered to be a promising strategy for improving catalytic activity and durability.Herein,we quantitatively create oxygen vacancies in the lattice ...Introducing and stabilizing oxygen vacancies in oxide catalysts is considered to be a promising strategy for improving catalytic activity and durability.Herein,we quantitatively create oxygen vacancies in the lattice of porous single-crystallineβ-Ga_(2)O_(3)monoliths by reduction treatments and stabilize them through the long-range ordering of crystal lattice to enhance catalytic activity and durability.The combination analysis of time-of-flight neutron powder diffraction and extended x-ray absorption fine structure discloses that the preferential generation of oxygen vacancy tends to occur at the site of tetrahedral coordination oxygen ions(O_(Ⅲ)sites),which contributes to the formation of unsaturated Ga-O coordination in the monoclinic phase.The oxygen vacancies are randomly distributed in lattice even though some of them are present in the form of domain defect in the PSC Ga_(2)O_(3)monoliths after the reduction treatment.The number of oxygen vacancies in the reduced monoliths gives 2.32×10^(13),2.87×10^(13),and 3.45×10^(13)mg^(-1)for the Ga_(2)O_(2.952),Ga_(2)O_(2.895),and Ga_(2)O_(2.880),respectively.We therefore demonstrate the exceptionally high C_(2)H_(4)selectivity of~100%at the C_(2)H_(6)conversion of~37%for nonoxidative dehydrogenation of C_(2)H_(6)to C_(2)H_(4).We further demonstrate the excellent durability even at 620℃for 240 h of continuous operation.展开更多
基金the Natural Science Foundation of China(22325506,22379147,22002167,22101282,and 22279142)the Youth Innovation Promotion of Chinese Academy of Sciences(2023318)the Natural Science Foundation of Fujian Province(2020J05082 and 2020J01113).
文摘Introducing and stabilizing oxygen vacancies in oxide catalysts is considered to be a promising strategy for improving catalytic activity and durability.Herein,we quantitatively create oxygen vacancies in the lattice of porous single-crystallineβ-Ga_(2)O_(3)monoliths by reduction treatments and stabilize them through the long-range ordering of crystal lattice to enhance catalytic activity and durability.The combination analysis of time-of-flight neutron powder diffraction and extended x-ray absorption fine structure discloses that the preferential generation of oxygen vacancy tends to occur at the site of tetrahedral coordination oxygen ions(O_(Ⅲ)sites),which contributes to the formation of unsaturated Ga-O coordination in the monoclinic phase.The oxygen vacancies are randomly distributed in lattice even though some of them are present in the form of domain defect in the PSC Ga_(2)O_(3)monoliths after the reduction treatment.The number of oxygen vacancies in the reduced monoliths gives 2.32×10^(13),2.87×10^(13),and 3.45×10^(13)mg^(-1)for the Ga_(2)O_(2.952),Ga_(2)O_(2.895),and Ga_(2)O_(2.880),respectively.We therefore demonstrate the exceptionally high C_(2)H_(4)selectivity of~100%at the C_(2)H_(6)conversion of~37%for nonoxidative dehydrogenation of C_(2)H_(6)to C_(2)H_(4).We further demonstrate the excellent durability even at 620℃for 240 h of continuous operation.
