A promising strategy to mitigate both energy shortage and global warming is the conversion of CO₂ into chemicals that can be used as fuels (chemical fuels) by utilizing renewable energy sources. Up to date, solar-driven CO₂ reduction has been achieved with photochemical (PC) and photoelectrochemical (PEC) systems or electrochemical cells combined with a photovoltaic system (PV-EC). This study is intended to compare and highlight the state-of-the-art PEC systems for CO₂ reduction and show the limitation factors that still hinder their widespread utilization. The review starts with a description of semiconducting photocatalyst properties and fundamental understanding of PEC CO₂ reduction process. Then, the most significant performance metrics used for evaluation of PEC systems are explained in details. In addition, recent progress in PEC CO₂ reduction systems is summarized and classified in different categories according to the chemical product. Different strategies such as doping, combination of two or more semiconductors, synthesis of nanostructured materials, passivation layers and co-catalysts that enhance light absorption, chemical stability, charge transfer and reduce ohmic losses and overpotentials of photoactive materials are reviewed. Besides the improvement of photocatalysts, research progress on the front of PEC reactor design, combined with the development of advanced modelling tools and characterization techniques are expected to bring PEC CO₂ reduction a step closer to commercialization.

缓解能源短缺和全球变暖的一项有前途的策略是通过利用可再生能源将CO ₂转化为可用作燃料（化学燃料）的化学物质。迄今为止，已经通过光化学（PC）和光电化学（PEC）系统或结合了光伏系统（PV-EC）的电化学电池实现了太阳能驱动的CO ₂还原。这项研究旨在比较和强调用于减少CO ₂的最先进PEC系统，并显示仍然阻碍其广泛使用的限制因素。这篇综述从对半导体光催化剂性能的描述和对PEC CO _2的基本理解开始还原过程。然后，详细解释了用于评估PEC系统的最重要的性能指标。另外，根据化学产品，总结了PEC CO ₂还原系统的最新进展并将其分类为不同的类别。审查了不同的策略，例如掺杂，两种或多种半导体的组合，纳米结构材料的合成，钝化层和助催化剂，这些方法增强了光敏材料的光吸收，化学稳定性，电荷转移并降低了欧姆损失和超电势。除了改进光催化剂外，PEC反应器设计方面的研究进展以及先进建模工具和表征技术的开发有望带来PEC CO ₂ 减少迈向商业化的一步。