Sunlight-driven photocatalytic overall water splitting (OWS) presents a promising route towards solar-to-chemical energy conversion. However, OWS has been realized with only a few photocatalysts. Among the major reasons for this paucity are the reverse reactions that occur between OWS products, including hydrogen, oxygen and reactive intermediate species, on the photocatalyst surface. In this study we found that decorating the Rh co-catalyst of the benchmark photocatalyst GaN–ZnO with Al₂O₃ species by atomic layer deposition can suppress these reverse reactions to a great extent and consequently enhance the photocatalytic OWS activity by more than an order of magnitude, with an apparent quantum efficiency increase from 0.3% to 7.1% at 420 nm. The partial coverage of Rh surface sites with inert oxides can effectively suppress the reverse reactions by blocking the reduction/oxidation cycle of Rh atoms during the photocatalytic OWS reaction.

阳光驱动的光催化全水分解 (OWS) 为太阳能到化学能的转换提供了一条有前途的途径。然而，OWS 仅通过少数光催化剂实现。造成这种缺乏的主要原因之一是 OWS 产物之间发生的逆反应，包括光催化剂表面上的氢、氧和活性中间体。在这项研究中，我们发现用 Al ₂ O _{3修饰基准光催化剂 GaN-ZnO 的 Rh 助催化剂}通过原子层沉积的物种可以在很大程度上抑制这些逆反应，从而将光催化 OWS 活性提高一个数量级以上，表观量子效率在 420 nm 处从 0.3% 增加到 7.1%。用惰性氧化物部分覆盖Rh表面位点可以通过阻断光催化OWS反应过程中Rh原子的还原/氧化循环来有效抑制逆反应。