Most biological photoredox reactions occur in sophisticated molecular assemblies consisting of highly organized light-harvesting moieties and catalytic centers. Mimicking these prototypes by creating supramolecular assemblies could be a potentially viable approach toward artificial photosynthesis. Although self-assembled organic materials are known to carry out water splitting reactions, developing self-assembled organic materials for photocatalytic overall water splitting still remains a critical challenge. Herein, we first demonstrate that crystalline organic nanosheets assembled from linear oligo(phenylene butadiynylene) (OPB) are able to catalyze overall water splitting under visible light irradiation. Further investigations reveal that the photocatalytic activity of self-assembled organic structures is closely related to the crystalline structure along with the corresponding electronic structure. Structural disorders in OPB nanosheets and extrinsic factors such as adsorbed water molecules will induce the formation of electron traps which can make the OPB nanosheets thermodynamically unfavorable for photocatalytic overall water splitting. The deactivation mechanism unveiled in this study provides crucial insights into the assembling of artificial organic materials for future solar-to-chemical energy conversion.

大多数生物光氧化还原反应发生在由高度组织化的光捕获部分和催化中心组成的复杂分子组装体中。通过创建超分子组件来模仿这些原型可能是一种潜在可行的人工光合作用方法。尽管已知自组装有机材料可以进行水分解反应，但开发用于光催化全分解水的自组装有机材料仍然是一个严峻的挑战。在此，我们首先证明由线性低聚（亚苯基丁二炔基）（OPB）组装的结晶有机纳米片能够在可见光照射下催化整体水分解。进一步的研究表明，自组装有机结构的光催化活性与晶体结构以及相应的电子结构密切相关。OPB纳米片中的结构紊乱和吸附水分子等外在因素会诱导电子陷阱的形成，这会使OPB纳米片在热力学上不利于光催化全水分解。本研究中揭示的失活机制为未来太阳能转化为化学能的人造有机材料的组装提供了重要的见解。OPB纳米片中的结构紊乱和吸附水分子等外在因素会诱导电子陷阱的形成，这会使OPB纳米片在热力学上不利于光催化全水分解。本研究中揭示的失活机制为未来太阳能转化为化学能的人造有机材料的组装提供了重要的见解。OPB纳米片中的结构紊乱和吸附水分子等外在因素会诱导电子陷阱的形成，这会使OPB纳米片在热力学上不利于光催化全水分解。本研究中揭示的失活机制为未来太阳能转化为化学能的人造有机材料的组装提供了重要的见解。