Temperature-Dependent Water Oxidation Kinetics: Implications and Insights

作者：Tianying Liu, Pan Wang, Wei Li, David Z. Wang, David Z. Wang, Damith D. Lekamge, Boqiang Chen, Frances A. Houle, Matthias M. Waegele, Dunwei Wang, Dunwei Wang · 发表于：ACS Central Science · 年份：2024 · DOI：10.1021/acscentsci.4c01415 · 被引用次数：6 · 研究领域：Electrocatalysts for Energy Conversion、Advanced Photocatalysis Techniques、Copper-based nanomaterials and applications

High Resolution Image Download MS PowerPoint Slide As a vital process for solar fuel synthesis, water oxidation remains a challenging reaction to perform using durable and cost-effective systems. Despite decades of intense research, our understanding of the detailed processes involved is still limited, particularly under photochemical conditions. Recent research has shown that the overall kinetics of water oxidation by a molecular dyad depends on the coordination between photocharge generation and the subsequent chemical steps. This work explores similar effects of heterogeneous solar water oxidation systems. By varying a key variable, the reaction temperature, we discovered distinctly different behaviors on two model systems, TiO 2 and Fe 2 O 3 . TiO 2 exhibited a monotonically increasing water oxidation performance with rising temperature across the entire applied potential range, between 0.1 and 1.5 V vs the reversible hydrogen electrode (RHE). In contrast, Fe 2 O 3 showed increased performance with increasing temperature at high applied potentials (>1.2 V vs RHE) but decreased performance at low applied potentials (<1.2 V vs RHE). This decrease in performance with temperature on Fe 2 O 3 was attributed to an increased level of electron–hole recombination, as confirmed by intensity-modulated photocurrent spectroscopy (IMPS). The origin of the differing temperature dependences on TiO 2 and Fe 2 O 3 was further ascribed to their different surface chemical kinetics. These res...