Development of Nanocatalysts for Enhanced Biomass Photocatalytic Reactions

Abstract

With the increasingly severe environmental pollution problem, green chemistry reactions are gaining importance. The use of recyclable catalysts and renewable energy sources is a challenging yet crucial topic. Solar energy, being abundant and eco-friendly, is a key renewable resource. However, conventional photocatalysts often exhibit poor carrier transfer and optical response. Developing new visible light catalysts to enhance photocatalytic reactions is thus essential. In this thesis, we first investigated the co-reduction of carbon dioxide and nitrate under visible light to produce urea. The nitrogen fertilizer industry, especially urea production, significantly contributes to greenhouse gas emissions and energy consumption. Solar urea synthesis faces challenges like low efficiency and yield due to inefficient energy conversion and complex reaction pathways. We synthesized the Cs2CuBr4/TiO2-Ar (CCBT-Ar) nanoreactor by in-situ growing TiOx and carbon nanosheets on Cs2CuBr4 (CCB). This nanoreactor facilitated visible light-induced urea synthesis from CO2 and nitrate waste. The oxygen vacancies in TiOx enhanced the reaction process by acting as efficient electron reservoirs, reducing recombination, and facilitating electron redistribution. Consequently, the nanoreactor showed high solar urea yield and selectivity, even in challenging wastewater conditions. This approach provides a novel and sustainable method for producing value-added chemicals while reducing carbon emissions. Additionally, we developed a novel photocatalyst, SnS2-O2-CsPbBr3 (SSO-CPB), for the selective oxidation of glycerol under visible light to produce glycolic acid. Glycerol, a biodiesel by-product, limits the widespread use of biodiesel. SSO-CPB, forming a type-Ⅱ heterojunction, improved the charge separation ability and reaction efficiency. The loading of CPB enriched electrons on SSO, enhancing reaction efficiency.