Study Of Photoreduction Of CO₂ On Rare Earth And Copper Modified TiO₂ Nanoparticles

CO₂ emission reduction is one of the most important issues among different countries and various areas. Photocatalytic reduction of CO₂ to synthesis low-carbon organic matter has theoretical and practical significance. But conversion efficiency of the reaction is relatively low, which is the problem researchers have been focused on for a long time. In this study, we synthesized a series of rare earth (RE) and copper modified TiO₂ nano-photocatalysts to evaluate the activities of CO₂ photoreduction. Further more, we optimized the reaction conditions to improve the reaction efficiency.TiO₂ nano-particles were synthesized by sol-gel method. The RE (La, Nd, Y) doped, the RE and copper co-doped and CuO composite modified TiO₂ nano-particles were prepared for photocatalytic reduction of CO₂. The prepared particles were characterized using XRD, TEM, and XPS. And the activities of the photocatalysts were estimated by the yield of formaldehyde. The results showed that the modified TiO₂ nano-particles had better activities and smaller crystal grain size than the bare TiO₂. The comparison of catalytic efficiency between different rear earth doped materials showed La>Nd>Y, and the best doping amount was 0.1wt.%. Regarding La as the research subject, the catalytic efficiency varied by changing the modification method, which showed La-CuO/TiO₂>La-TiO₂>La/Cu-TiO₂. The best photocatalyst was La-CuO/TiO₂ with La doping amount of 0.1wt.%, and the yield of formaldehyde was 953.53μmol/g·cat..This research further investigated the optimum conditions of photocatalytic reduction of CO₂, including illumination time, initial pH value of reaction solution, CO₂ flow rate and the addition amount of hole scavenger. The results showed that the optimum conditions of CO₂ photoreduction were as follows: illumination time was 6h, pH value was 10, CO₂ flow rate was 30mL/min, and addition amount of methanol was 1.0mol/L.