Study on electro-assisted photocatalytic high selective conversion of CO2 in air
In recent years,the concentration of CO2 in the air has increased year by year,and a technology is urgently needed to convert low-concentration CO2 in the air into high value-added products.In this study,an electro-assisted photo-catalytic system with double cells and double interfaces was designed,and Cu was loaded on titanium dioxide nanoarrays(TNTAs)by polydopamine modification.During the catalytic process,some Cu was oxidized to CuO to form a p-n junction.Under the condition of no sacrificial agent and alkaline absorption liquid,CO2 in the air was stably,efficiently and selec-tively converted into CO by electro-assisted photocatalysis.Specifically,under the assistance of+0.8 V potential,the CO yield reached 113.7 μmol/(m2·h)after 8 h of UV irradiation,which was 2.53 times that of TNTAs[45 μmol/(m2·h)].After 5 cycles with 8 h as a cycle,the CO yield was about 72.4%of the first cycle.The improvement of photocatalytic performance was attributed to the introduction of Cu,which increased the spectral absorption range,improved the utilization of visible light,and inhibited the recombination of photogenerated carriers.In addition,when a positive potential was applied,the cur-rent direction was the same as the current direction of the internal electric field of the p-n junction,which further promoted the migration of electrons,and the electron-hole pair was more effectively separated,so that the photocatalytic reduction of CO2 by the composite material was further improved.This study promoted the development of photocatalytic technology to practical applications and provided new insights and support for the carbon cycle.
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