Utilizing solar energy to achieve artificial photosynthesis of chemical fuel is prevalent in tackling excessive CO2 emission and fossil fuel depletion. Grievous charge recombination and weak redox capability aggravate the CO2 photoreduction performance. Engineering tailored morphology and constructing matched heterostructure are two significant schemes to ameliorate the CO2 photoconversion efficiency of g-C3N4-based composite. Herein, a novel S-scheme ultrathin porous g-C3N4(UPCN)/Ag2MoO4 (AMO) composite was designed by in-situ growing tetragonal alpha-AMO nanoparticles (NPs) (5-30 nm) on UPCN nanosheets (NSs). The S-scheme charge transfer route endows UPCN/AMO with fast charge separation and strong redox capability, demonstrated by X-ray photoelectron spectroscopy (XPS), photoelectrochemical tests, steady-state and time-resolved photoluminescence (PL) spectra, and DFT calculations. The UPCN/AMO composite exhibits elevated CO2 photoreduction performance with CO and CH4 yield rates of 6.98 and 0.38 mu mol g(-1) h(-1), which are 3.5 and 2.9 folds higher than that of pristine UPCN, respectively. Finally, the CO2 photoreduction intermediates are analyzed, and the CO2 photoreduction mechanism is discussed. This work provides a reference for various g-C3N4 based composites applied in artificial photosynthesis.

中文翻译：

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用于 CO2 光还原的 S 型多孔 g-C3N4/Ag2MoO4 异质结复合材料

利用太阳能实现化学燃料的人工光合作用在解决二氧化碳过度排放和化石燃料枯竭问题上很普遍。严重的电荷复合和弱的氧化还原能力加剧了 CO2 的光还原性能。工程定制形貌和构建匹配的异质结构是提高 g-C3N4 基复合材料 CO2 光转化效率的两个重要方案。在此，通过在 UPCN 纳米片 (NSs) 上原位生长四方 alpha-AMO 纳米粒子 (NPs) (5-30 nm)，设计了一种新型 S 型超薄多孔 g-C3N4(UPCN)/Ag2MoO4 (AMO) 复合材料。S型电荷转移途径赋予UPCN/AMO快速电荷分离和强氧化还原能力，X射线光电子能谱（XPS）、光电化学测试、稳态和时间分辨光致发光 (PL) 光谱，以及 DFT 计算。UPCN/AMO 复合材料表现出更高的 CO2 光还原性能，CO 和 CH4 产率为 6.98 和 0.38 μ mol g(-1) h(-1)，分别比原始 UPCN 高 3.5 和 2.9 倍。最后，对CO2光还原中间体进行了分析，并对CO2光还原机理进行了探讨。该工作为应用于人工光合作用的各种g-C3N4基复合材料提供了参考。并讨论了CO2光还原机理。该工作为应用于人工光合作用的各种g-C3N4基复合材料提供了参考。并讨论了CO2光还原机理。该工作为应用于人工光合作用的各种g-C3N4基复合材料提供了参考。