Experimental study on photocatalytic reduction of carbon dioxide to methanol

In this paper, modified sol-gel method was used to prepare TiO₂ solid particles modified by Cu and La at different temperatures. XRD, BET, SEM, TG/DSC and other methods were used to analyze the physicochemical properties, and the catalyst performance test was carried out. The results showed that the calcination temperature mainly affected the crystal form of TiO₂: when the calcination temperature didn't exceed 500°C, TiO₂ mainly existed in the anatase crystal form; 600°C was the crystal phase transition temperature of TiO₂ from anatase to rutile, when anatase only accounted for about 38%, the rest were rutile; at 700°C, TiO₂ was all converted to rutile, which has strong thermal stability; TiO₂ obtained by calcining at 400°C had low crystallinity and contained more amorphous TiO₂. The 2wt.% Cu/TiO₂ prepared by calcining at 500°C had the best surface properties in the experimental range. The photocatalytic reaction was carried. It was found that the highest yield of methanol was obtained by using the TiO₂ catalyst prepared by calcining at 500°C, the catalytic activity of anatase was much higher than that of rutile, and amorphous TiO₂ does not have catalytic activity. The reaction temperature had great influence on the catalytic activity.