Solar water splitting by means of photoelectrochemical (PEC) cells offers the promise to produce cost-effective renewable and clean fuel from abundant sunlight and water. Lately, the realization of promise of concurrent hydrogen (H₂) production along with alternate oxidation reaction (which is less energetically demanding than the water oxidation reaction) has also become a subject of intense global research interests. At present, developing inexpensive, non-toxic, and earth-abundant semiconductor-based photoelectrodes (i.e. photocathode and photoanode) with a high stability is of great importance in achieving economically viable H₂ production and value-added chemicals. This review summarizes recent advances in these photoelectrodes along with contemporary understanding of key factors responsible for high solar-to-hydrogen efficiency, device stability, and highlights a promising new research trend of alternate oxidation reactions at photoanodes. First, we outline recent developments of novel photoelectrode materials using high-throughput computational screening integrated with ab-initio calculations. We proceed to discuss the merits and major challenges of these novel and existing photoelectrodes and links the strategies used to overcome these challenges to achieve economically viable solar H₂ generation. Several important studies on the emerging new trend of alternate oxidations reactions at photoanodes toward value-added chemicals are then detailed with particular emphasis is placed on dependency of photoanode design on type of organic feedstocks and desired products from the oxidation reaction. We also emphasize the development of tandem devices for overall water splitting using these photoelectrodes with high onset potentials. Finally, we provide not only promising future directions for each material system, but also a critical assessment and outlook on how these earth-abundant photoelectrodes could lead to a potential large-scale implementation of water splitting devices.

通过光电化学 (PEC) 电池进行太阳能水分解有望利用充足的阳光和水生产具有成本效益的可再生清洁燃料。最近，实现同时产生氢气 (H ₂ ) 和交替氧化反应（比水氧化反应对能量的要求更低）的承诺也已成为全球研究兴趣浓厚的主题。目前，开发廉价、无毒、地球资源丰富、稳定性高的半导体基光电极（即光电阴极和光电阳极）对于实现经济上可行的 H _{2具有重要意义。}生产和增值化学品。这篇综述总结了这些光电极的最新进展，以及当代对导致高太阳能制氢效率、设备稳定性的关键因素的理解，并强调了光阳极交替氧化反应的一个有前途的新研究趋势。首先，我们概述了使用高通量计算筛选与从头计算相结合的新型光电极材料的最新进展。我们继续讨论这些新型和现有光电极的优点和主要挑战，并将用于克服这些挑战以实现经济上可行的太阳能 H _{2的策略联系起来}一代。然后详细介绍了关于光阳极上交替氧化反应向增值化学品的新趋势的几项重要研究，特别强调了光阳极设计对有机原料类型和氧化反应所需产物的依赖性。我们还强调了使用这些具有高起始电位的光电极开发用于整体水分解的串联装置。最后，我们不仅为每个材料系统提供了有希望的未来方向，而且还对这些地球上丰富的光电极如何导致潜在的大规模实施水分解装置进行了批判性评估和展望。