羰基合成与选择氧化国家重点实验室（OSSO）知识库

A novel material of porous Co₃O₄/CuO hollow polyhedral nanocages (HPNCs) derived-from metal-organic frameworks (MOF) for photocatalytic water oxidation was reported for the first time and the molar ratio of Co/Cu in this kind material was optimized. The Co₃O₄/CuO HPNCs composites were characterized by multiple experiments (FETEM, HRTEM, SEM, TGA, PXRD, EDX, ICP-AES, BET, XPS) to confirm the structure and the component. A high turnover frequency (TOF) of 4.9 × 10⁻³ s⁻¹ per metal atom was obtained over Co₃O₄/CuO-3 HPNCs, which is comparable to those published cobalt based catalysts. At the same time, Co₃O₄/CuO-3 HPNCs showed a maximum oxygen yield of 50% and quantum yield of 49%. This composite of Co₃O₄/CuO HPNCs containing heterojunctions may enhance the photocatalytic performance of water oxidation.Various characterization methods prove that Co₃O₄/CuO HPNCs composites are stable and robust heterogeneous photocatalytic catalysts that can be used repeatedly without any loss in activity. According to the experimental results, we speculate that there are two kinds of reaction mechanisms in this light-driven water oxidation system. One mechanism is widely accepted that high valence metal species play a role in the reaction system. The other one is that the heterojunctions of Co₃O₄/CuO HPNCs make a great contribution to improve the activity of photocatalytic water oxidation. Meanwhile, we put forward a new idea to design a series of metal oxide catalysts with heterojunctions derived from MOF for light-driven water oxidation.