Zhou Guanda, Aletsee Clara C, Lemperle Anna, Rieth Tim, Mengel Lucia, Gao Jianyong, Tschurl Martin, Heiz Ueli, Sharp Ian D
Walter Schottky Institute, Technical University of Munich, Garching 85748, Germany.
Physics Department, TUM School of Natural Sciences, Technical University of Munich, Garching 85748, Germany.
ACS Catal. 2025 Jul 16;15(15):13048-13058. doi: 10.1021/acscatal.5c03025. eCollection 2025 Aug 1.
The photoelectrochemical hydrogen peroxide evolution reaction (HPER) has attracted increasing attention as an environmentally friendly approach to generate a commercially and industrially valuable water oxidation product. BiVO photoanodes operated in bicarbonate-containing electrolytes have been shown to offer remarkable performance characteristics for HPER, with HCO serving as a reaction mediator. However, the factors affecting the stability of both the semiconductor photoanode and the aqueous electrolyte remain poorly understood. Here, we investigated BiVO photoanodes to quantitatively assess the roles of electrolyte composition, bias potential, and illumination on competitive reaction pathways associated with HPER, oxygen evolution reaction, and photocorrosion. Our results confirm that HCO serves as a highly efficient mediator, leading to rapid hole extraction and near complete suppression of interfacial recombination on BiVO. In addition, these favorable hole transfer kinetics significantly decrease the rate of photocorrosion, leading to dramatically enhanced stability compared to bicarbonate-free electrolytes. While the elevated pH of unbuffered bicarbonate electrolyte leads to gradual chemical attack of BiVO, the stability is greatly enhanced in near-neutral buffered bicarbonate electrolytes. Finally, we confirm that HCO is regenerated during the photoanodic reaction, though pH swings during operation in an unbuffered electrolyte can lead to electrolyte instabilities. Overall, we find that BiVO photoanodes operating in buffered bicarbonate-containing solutions exhibit significantly enhanced stability and can efficiently drive water oxidation reactions, including HPER, thus providing a route to robust production of high value oxidation products.
光电化学过氧化氢析出反应（HPER）作为一种生成具有商业和工业价值的水氧化产物的环保方法，已引起越来越多的关注。在含碳酸氢盐的电解质中运行的BiVO光阳极已被证明在HPER方面具有卓越的性能特征，其中HCO充当反应介质。然而，影响半导体光阳极和水性电解质稳定性的因素仍知之甚少。在此，我们研究了BiVO光阳极，以定量评估电解质组成、偏置电位和光照对与HPER、析氧反应和光腐蚀相关的竞争反应途径的作用。我们的结果证实，HCO充当高效介质，导致快速的空穴提取并几乎完全抑制BiVO上的界面复合。此外，这些有利的空穴转移动力学显著降低了光腐蚀速率，与无碳酸氢盐的电解质相比，稳定性得到显著提高。虽然未缓冲的碳酸氢盐电解质的升高pH值会导致BiVO的逐渐化学侵蚀，但在近中性缓冲的碳酸氢盐电解质中稳定性大大提高。最后，我们证实HCO在光阳极反应过程中会再生，尽管在未缓冲的电解质中运行期间的pH值波动会导致电解质不稳定。总体而言，我们发现，在含缓冲碳酸氢盐的溶液中运行的BiVO光阳极表现出显著提高的稳定性，并且可以有效地驱动水氧化反应，包括HPER，从而为稳健生产高价值氧化产物提供了一条途径。
