Experimental study on photocatalytic CO2 reduction performance of ZnS/CdS-TiO2 nanotube array thin films

Abstract

Abstract The effect of CdS/ZnS composite-sensitized TiO2 nanotube array (TNTA) on the photocatalytic reduction of CO2 was studied. CdS/ZnS quantum dots sensitized TNTA by successive ionic layer adsorption and reaction (SILAR) cycle method, and CdS/ZnS-TNTA composite semiconductor materials were prepared. The loading amount of CdS/ZnS depends on the number of SILAR cycles. The effects of SILAR cycle times, the CO2 volume flow, and light intensity on the photocatalytic CO2 reduction performance were studied. The main product of the photocatalytic reduction of CO2 was methanol; the performance was 2.73 times higher than that of bare TNTA, the optimal SILAR cycle was 10, the light absorption sideband was red shifted to 524 nm, and the optimal CO2 volume flow rate was 20.5 mL/min. The final yield was as high as 255.49 nmol/(cm2-cat h). CdS/ZnS quantum dot sensitization mainly broadened the wavelength range of the catalyst’s response to visible light, inhibited the recombination of electron–hole pairs to a certain extent, and greatly improved the photocatalytic performance under visible light.