Boosted photoreduction of diluted CO_(2) through oxygen vacancy engineering in NiO nanoplatelets

Converting carbon dioxide(CO_(2))to diverse value-added products through photocatalysis can validly alleviate the critical issues of greenhouse effect and energy shortages simultaneously.In particular,based on practical considerations,exploring novel catalysts to achieve efficient photoreduction of diluted CO_(2) is necessary and urgent.However,this process is extremely challenging owing to the disturbance of competitive adsorption at low CO_(2) concentration.Herein,we delicately synthesize oxygen vacancy-laden NiO nanoplatelets(r-NiO)via calcination under Ar protection to reduce diluted CO_(2) through visible light irradiation(>400 nm)assisted by a Ru-based photosensitizer.Benefitting from the strongly CO_(2) adsorption energy of oxygen vacancies,which was confirmed by density functional calculations,the r-NiO catalysts exhibit higher activity and selectivity(6.28×10^(3)µmol·h^(−1)·g^(−1);82.11%)for diluted CO_(2)-to-CO conversion than that of the normal NiO(3.94×10^(3)µmol·h^(−1)·g^(−1);65.26%).Besides,the presence of oxygen vacancies can also promote the separation of electron-hole pairs.Our research demonstrates that oxygen vacancies could act as promising candidates for photocatalytic CO_(2) reduction,offering fundamental guidance for the actual photoreduction of diluted CO_(2) in the future.