In addition to nanomaterial design and optimization, the choice of solvent and reaction conditions plays a crucial role in the efficiency and selectivity of photocatalytic CO 2 reduction. Solvents with appropriate polarity and solubility for CO 2 can facilitate its absorption and reaction on the catalyst surface. Moreover, the reaction conditions, including temperature, pressure, and reactant concentrations, need to be carefully controlled to optimize the conversion rates and selectivity towards desired products. Understanding the underlying mechanisms and reaction pathways involved in photocatalytic CO 2 reduction is essential for further improving the efficiency of nanomaterial-based catalysts. Computational modeling, spectroscopic techniques, and electrochemical analysis provide valuable insights into the charge transfer processes, CO 2 adsorption, and reaction intermediates. These studies help elucidate the key factors influencing the photocatalytic activity and guide the rational design of advanced nanomaterials.