Influence of various operational parameters in enhancing photocatalytic reduction efficiency of carbon dioxide in a photoreactor: A review

Photocatalytic CO2 reduction is a rapidly evolving sustainable approach for CO2 reduction and renewable fuel production. The photocatalytic conversion efficiency of CO2 depends on many operational aspects. This review focuses on some of the important operational and intrinsic parameters that significantly influence CO2 photocatalytic reduction efficiency. The critical parameters studied are temperature, pH, pressure, catalyst size, catalytic doping, reaction time, reaction time, feed ratio, reducing agents, type of solvent, the wavelength of the light source, light intensity, and effect of direct solar radiation. The temperature directly impacts photocatalytic reduction. Similarly, the effect of pressure was systematically discussed. The morphology of photocatalysts and their effects on CO2 reduction efficiency and products selectivity are also deliberated. The review also focuses on a detailed assessment of the role of photoreactor design with the various photocatalytic reactor, their geometry, operating mode and phases. The reaction pathways for specific products are discussed based on several characterization techniques. Hence, this work gives a deeper understanding of the influential operational parameters affecting CO2 photoreduction and provides new directions on optimizing them to enhance the photoreduction efficiency of CO2 to renewable fuels. (C) 2021 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.