Sabir Muhammad, Sayed Mahmoud, Riaz Iram, Qiu Guogen, Tahir Muhammad, Alibrahim Khuloud A, Wang Wang
State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070, China.
Laboratory of Solar Fuel, Faculty of Materials Science and Chemistry, China University of Geosciences, Wuhan 430078, China.
Materials (Basel). 2025 Jul 21;18(14):3419. doi: 10.3390/ma18143419.
The rapid recombination of photoinduced charge carriers in semiconductors remains a significant challenge for their practical application in photocatalysis. This study presents the design of a step-scheme (S-scheme) heterojunction composed of carbon nitride (g-CN) and nickel-based metal-organic framework (Ni-MOF) to achieve enhanced charge separation. The establishment of an S-scheme charge transfer configuration at the interface of the Ni-MOF/g-CN heterostructure plays a pivotal role in enabling efficient charge carrier separation, and hence, high CO photoreduction efficiency with a CO evolution rate of 1014.6 µmol g h and selectivity of 95% under simulated solar illumination. CO evolution represents an approximately 3.7-fold enhancement compared to pristine Ni-MOF. Density functional theory (DFT) calculations, supported by in situ irradiated X-ray photoelectron spectroscopy (XPS) and electron paramagnetic resonance (EPR) experimental results, confirmed the establishment of a well-defined and strongly bonded interface, which improves the charge transfer and separation following the S-scheme mechanism. This study sheds light on MOF-based S-scheme heterojunctions as fruitful and selective alternatives for practical CO photoreduction.
半导体中光生载流子的快速复合仍然是其在光催化实际应用中的一个重大挑战。本研究提出了一种由氮化碳（g-CN）和镍基金属有机框架（Ni-MOF）组成的阶梯型（S型）异质结设计，以实现增强的电荷分离。在Ni-MOF/g-CN异质结构界面处建立S型电荷转移构型在实现高效载流子分离方面起着关键作用，因此，在模拟太阳光照射下，具有1014.6 μmol g⁻¹ h⁻¹的CO析出速率和95%的选择性，实现了高CO光还原效率。与原始Ni-MOF相比，CO析出提高了约3.7倍。密度泛函理论（DFT）计算，得到原位辐照X射线光电子能谱（XPS）和电子顺磁共振（EPR）实验结果的支持，证实了明确且强键合界面的建立，这按照S型机制改善了电荷转移和分离。本研究揭示了基于MOF的S型异质结是实际CO光还原的有效且选择性的替代方案。
