Recent Progress in Photocathode Interface Engineering for Photoelectrochemical CO₂ Reduction Reaction to C₁ or C₂₊ Products

Photoelectrochemical (PEC) systems harness light absorption to initiate chemical reactions, while electrochemical reactions facilitate the conversion of reactants into desired products, ensuring more efficient and sustainable energy conversion in PECs. Central to optimizing the performance of PECs was the pivotal role played by interface engineering. This intricate process involves manipulating material interfaces at the atomic or nanoscale to enhance charge transfer, improve catalytic activity, and address limitations associated with bulk materials. The careful tuning of factors such as band gap, surface energy, crystallinity, defect characteristics, and structural attributes through interface engineering led to superior catalytic efficiency. Specifically, interface engineering significantly enhanced the efficiency of semiconductor-based PECs. Engineers strategically designed heterojunctions and manipulated catalyst surface properties to optimize the separation and migration of photogenerated charge carriers, minimizing recombination losses and improving performance overall. This review categorizes the discussion into four sections focusing on the interface engineering of PECs, providing valuable insights into recent research trends. Overall, the synergy between PECs and interface engineering holds tremendous promise for advancing renewable energy technologies and addressing environmental challenges by offering innovative solutions for sustainable energy conversion and storage.