Photoactive Metal–Organic Framework and Its Film for Light-Driven Hydrogen Production and Carbon Dioxide Reduction

The design of a new photocatalytic system and integrating the essential components in a structurally controlled manner to create artificially photosynthetic systems is high desirable. By incorporating a photoactive triphenylamine moiety to assemble a Gd-based metal–organic framework as a heterogeneous photosensitizer, new artificial systems were constructed for the proton and carbon dioxide reduction under irradiation. The assembled MOFs exhibited a one-dimensional metal-oxygen pillar that was connected together by the depronated TCA3– ligands to form a three-dimensional noninterpenetrating porous framework. The combining of proton reduction and/or the carbon dioxide reduction catalysts, i.e., the Fe-Fe hydrogenase active site models and the Ni­(Cyclam) complexes, initiated a photoinduced single electron transfer from its excited state to the substrate. The system exhibited an initial TOF of 320 h–1 of hydrogen per catalyst and an overall quantum yield of about 0.21% and is able to reduce carbon dioxide under irradiation. The deposit of the photoactive Gd-TCA into the film of an α-Al2O3 plate provided a platform for the practical applications through prolonging the lifetime of the artifical system and allowed the easily operated devices being recyclable as a promising photocatalytic system.

研发新型光催化体系，并以结构可控的方式整合关键组分以构建人工光合系统，具有极高的研究价值与应用需求。通过引入光活性三苯胺单元，构建钆基金属有机框架（metal–organic framework, MOF）作为非均相光敏剂，成功制备出可在光照条件下实现质子还原与二氧化碳还原的新型人工体系。所制备的金属有机框架具有一维金属氧柱结构，该结构经去质子化的TCA³⁻配体相互连接，最终形成三维非互穿多孔骨架。将质子还原与二氧化碳还原催化剂——即铁铁氢化酶活性位点模型与镍-环胺（Ni(Cyclam)）配合物——引入体系后，可触发光诱导单电子从其激发态转移至底物。该体系初始转换频率（Turnover Frequency, TOF）可达每催化剂320 h⁻¹，总量子产率约为0.21%，且可在光照条件下实现二氧化碳还原。将光活性Gd-TCA沉积至α-三氧化二铝（α-Al₂O₃）基板的薄膜中，可通过延长人工体系的使用寿命为实际应用提供平台，同时使操作简便的装置具备可回收性，成为极具应用前景的光催化体系。