Abstract
Abstract Industrial revolution resulted in increased inputs of green house gases, among which carbon dioxide (CO2) is the major contributor. Excessive emission of CO2 is considered to be the major cause for global warming and ocean acidification. This eventually has made a significant impact on global climate and ecology. Thus, reducing CO2 concentration in the atmosphere will be an important topic. In this study, we use titanium dioxide (TiO2) nanoparticles as catalyst for reducing carbon dioxide to methanol. We prepared TiO2/SiO2 thin film by layer-by-layer technique and characterized by scanning electron microscope, time of flight-secondary ion mass spectrometer and goniometer. Analysis results revealed that adsorption ability of first layer and roughness of substrate surface had an important effect on the film density. Besides, each layer was mixed with TiO2 and SiO2 nanoparticles rather than completely separated. The hydrophilicity was enhanced when increasing the number of layer; the film became superhydrophilic when coating to 6 layers. In CO2 photoreduction experiment, we used a lab-built photoreactor combined with analytical system to analyze the product of CO2 reduction. The results indicated that the photocatalytic efficiency increased with the number of layer and the yield of methanol reached maximum, 6.5 □mol, when the layer number was 8.