Photocatalytic CO2 reduction is a potential promising strategy for eliminating the global energy crisis and environmental issue. However, the complex reduction pathway leads to multiple possible products with limited efficiency, representing a great barrier for the further development. Herein, we report a Metal-organic framework (MOF) based heterostructure model for the efficient photoreduction of CO2 with full controllable product selectivity between CO and C2H5OH. Novel core-sheath like MOF@TiO2 heterostructures could be efficiently prepared by the layer-by-layer (LBL) growth of HKUST-1 onto Cu-embedded TiO2 nanofibers (NFs), affording covalent heterointerfaces for efficient S-scheme charge separation and promising potential in photocatalytic activity regulation. By improving the CO2 capture and retention via in situ amino-functionalization of HKUST-1, the photocatalytic CO production rate could be greatly promoted from 8.76 ± 0.84 to 43.46 ± 0.86 μmol g−1h−1 accompanied by an enhancement of selectivity from 91.7 % to 98.3 %. Moreover, the product could be efficiently engineered into ethanol with a C2 product selectivity of 94.2 % by introducing Cu nanoparticles (NPs) as the additional CC coupling site. The in situ FT-IR and DFT calculations reveal the mechanistic process and decisive role of amino-functionalization and Cu NPs deposition in photocatalytic activity engineering. This work highlights the key factors and significance of fabricating MOFs based heterostructures with tunable photocatalytic activity for achieving CO2 neutralization.

中文翻译：

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用于设计 CO2 光还原活性和选择性的多功能 MOF 纳米纤维异质结构：从 CO 到 C2H5OH


光催化二氧化碳减排是消除全球能源危机和环境问题的一种潜在的有前景的策略。然而，复杂的还原途径导致多种可能的产品效率有限，为进一步发展带来了巨大障碍。在此，我们报告了一种基于金属有机框架（MOF）的异质结构模型，用于有效光还原CO2，并且在CO和C2H5OH之间具有完全可控的产物选择性。通过将 HKUST-1 逐层（LBL）生长到嵌入 Cu 的 TiO2 纳米纤维（NFs）上，可以有效地制备像 MOF@TiO2 异质结构这样的新型核-鞘异质结构，为有效的 S 型电荷分离提供共价异质界面，并有希望光催化活性调节的潜力。通过HKUST-1的原位氨基功能化改善CO2捕获和保留，光催化CO产率可以从8.76 ± 0.84大大提高到43.46 ± 0.86 μmol g−1h−1，同时选择性从91.7 %提高至 98.3%。此外，通过引入 Cu 纳米颗粒 (NP) 作为额外的 CC 偶联位点，该产品可以有效地转化为乙醇，C2 产物选择性为 94.2%。原位 FT-IR 和 DFT 计算揭示了氨基功能化和 Cu NPs 沉积在光催化活性工程中的机理过程和决定性作用。这项工作强调了制造具有可调光催化活性的基于 MOF 的异质结构以实现 CO2 中和的关键因素和意义。