Both MnOx and g‐C3N4 have been proved to be active in the catalytic oxidation of NO,and their individual mechanisms for catalytic NO conversion have also been investigated.However,the mechanism of photo‐thermal cata...Both MnOx and g‐C3N4 have been proved to be active in the catalytic oxidation of NO,and their individual mechanisms for catalytic NO conversion have also been investigated.However,the mechanism of photo‐thermal catalysis of the MnOx/g‐C3N4 composite remains unresolved.In this paper,MnOx/g‐C3N4 catalysts with different molar ratios were synthesized by the precipitation approach at room temperature.The as‐prepared catalysts exhibit excellent synergistic photo‐thermal catalytic performance towards the purification of NO in air.The MnOx/g‐C3N4 catalysts contain MnOx with different valence states on the surface of g‐C3N4.The thermal catalytic reaction for NO oxidation on MnOx and the photo‐thermal catalytic reaction on 1:5 MnOx/g‐C3N4 were investigated by in situ diffuse reflectance infrared Fourier transform spectroscopy(in situ DRIFTS).The results show that light exerted a weak effect on NO oxidation over MnOx,and it exerted a positive synergistic effect on NO conversion over 1:5 MnOx/g‐C3N4.A synergistic photo‐thermal catalytic cycle of NO oxidation on MnOx/g‐C3N4 is proposed.Specifically,photo‐generated electrons(e?)are transferred to MnOx and participate in the synergistic photo‐thermal reduction cycle(Mn4+→Mn3+→Mn2+).The reverse cycle(Mn2+→Mn3+→Mn4+)can regenerate the active oxygen vacancy sites and inject electrons into the g‐C3N4 hole(h+).The active oxygen(O?)was generated in the redox cycles among manganese species(Mn4+/Mn3+/Mn2+)and could oxidize the intermediates(NOH and N2O2?)to final products(NO2?and NO3?).This paper can provide insightful guidance for the development of better catalysts for NOx purification.展开更多
文摘Both MnOx and g‐C3N4 have been proved to be active in the catalytic oxidation of NO,and their individual mechanisms for catalytic NO conversion have also been investigated.However,the mechanism of photo‐thermal catalysis of the MnOx/g‐C3N4 composite remains unresolved.In this paper,MnOx/g‐C3N4 catalysts with different molar ratios were synthesized by the precipitation approach at room temperature.The as‐prepared catalysts exhibit excellent synergistic photo‐thermal catalytic performance towards the purification of NO in air.The MnOx/g‐C3N4 catalysts contain MnOx with different valence states on the surface of g‐C3N4.The thermal catalytic reaction for NO oxidation on MnOx and the photo‐thermal catalytic reaction on 1:5 MnOx/g‐C3N4 were investigated by in situ diffuse reflectance infrared Fourier transform spectroscopy(in situ DRIFTS).The results show that light exerted a weak effect on NO oxidation over MnOx,and it exerted a positive synergistic effect on NO conversion over 1:5 MnOx/g‐C3N4.A synergistic photo‐thermal catalytic cycle of NO oxidation on MnOx/g‐C3N4 is proposed.Specifically,photo‐generated electrons(e?)are transferred to MnOx and participate in the synergistic photo‐thermal reduction cycle(Mn4+→Mn3+→Mn2+).The reverse cycle(Mn2+→Mn3+→Mn4+)can regenerate the active oxygen vacancy sites and inject electrons into the g‐C3N4 hole(h+).The active oxygen(O?)was generated in the redox cycles among manganese species(Mn4+/Mn3+/Mn2+)and could oxidize the intermediates(NOH and N2O2?)to final products(NO2?and NO3?).This paper can provide insightful guidance for the development of better catalysts for NOx purification.
