Nanoengineering of photocatalytic electrode materials toward net zero emissions

New technologies for CO2 reuse with a goal toward net zero carbon emissions are being actively investigated. Photocatalytic reactions are hampered by fast recombination of photogenerated electron-hole pairs within semiconductors, accounting for their low efficiency. Photoelectrocatalysis (PEC), a hybrid of photocatalysis and electrocatalysis, is proposed as an attractive alternative. In PEC, the external voltage bias promotes the extraction and transportation of photogenerated charges from one electrode to the other, thereby decreasing their recombination rates. However, PEC still has other important concerns associated with photocatalytic semiconductor materials, such as low electrical conductivity and insufficient visible light absorption. Consequently, strategies are considered to engineer and synthesize more efficient photoelectrocatalysts. In this review, we examine some strategies to improve PEC materials. Then, we explore some ingeniously nanostructured catalysts designed for application in the PEC CO2 reduction reaction. We conclude with some perspectives and future trends in this exciting field of research.