Photocorrosion is one of the main challenges in photoelectrochemical water splitting. Traditional methods for degradation assessment, such as chronoamperometry or electrolyte/electrode post-analysis, provide limited information on the degradation mechanisms and kinetics. To address this issue, a new setup, which is based on a light source, an electrochemical cell, and an on-line inductively coupled plasma mass spectrometer (ICP-MS), has been developed. The first results on the photocorrosion of a commercial WO₃ powder on Au are demonstrated in this work. It is shown that, in the absence of light, WO₃ is stable in a wide potential range. On the other hand, in the presence of light, it dissolves proportionally to the anodic photocurrent. The latter is explained by the formation of aqueous tungsten complexes with the electrolyte that are thermodynamically more stable than WO₃. As can be anticipated from these initial results, the novel method will enable the characterization of a wide range of photoelectrochemical materials, and thus eventually lead to the development of long-term stable devices.

光腐蚀是光电化学水分解的主要挑战之一。传统的降解评估方法，例如计时电流分析法或电解质/电极后分析，提供了有关降解机理和动力学的有限信息。为了解决这个问题，已经开发了一种基于光源，电化学电池和在线电感耦合等离子体质谱仪（ICP-MS）的新设置。这项工作证明了商用WO ₃粉末在Au上发生光腐蚀的初步结果。结果表明，在没有光的情况下，WO ₃在很宽的电位范围内保持稳定。另一方面，在光的存在下，它与阳极光电流成比例地溶解。后者通过与电解质形成水钨配合物来解释，该水配合物在热力学上比WO ₃更稳定。从这些初步结果可以预见，该新方法将能够表征多种光电化学材料，从而最终导致长期稳定器件的发展。