Ke Xiaochun, Wang Ping, Wang Xuefei, Chen Feng, Yu Huogen
School of Materials Science and Engineering, and School of Chemistry, Chemical Engineering and Life Sciences, Wuhan University of Technology, Wuhan, 430070, P. R. China.
Laboratory of Solar Fuel, Faculty of Materials Science and Chemistry, China University of Geosciences, Wuhan, 430074, P. R. China.
Small. 2024 Nov;20(48):e2405378. doi: 10.1002/smll.202405378. Epub 2024 Aug 30.
MoC MXene (MoCT) is one of the most promising noble-metal-free cocatalysts for photocatalytic H production because of its excellent electron transport capacity and abundant Mo sites. However, MoCT typically exhibits a strong Mo─H bond, resulting in that the produced H difficultly desorbs from the Mo surface for the limited activity. To effectively weaken the Mo─H bond, in this paper, a regulation strategy of electron donor Au releasing electrons to the d-orbitals of Mo sites in MoCT is proposed. Herein, the MoCT-Au/CdS photocatalysts are prepared through a two-step process, including the initial loading of Au nanoparticles on the MoCT surface and the subsequent in situ growth of CdS onto the MoCT-Au surface. Photocatalytic measurements indicate that the maximal H-production rate of MoCT-Au/CdS reaches up to 2799.44 µmol g h, which is 30.99 and 3.60 times higher than that of CdS and MoCT/CdS, respectively. Experimental and theoretical data corroborate that metallic Au can transfer free electrons to MoCT to generate electron-enriched Mo sites, thus causing the increased antibonding-orbital occupancy state and the weakened Mo─H bond for the boosted H-production efficiency. This research provides a promising approach for designing MoCT-based cocatalysts by regulating the antibonding-orbital occupancy of Mo sites for improved photocatalytic performance.
碳化钼MXene（MoCT）因其出色的电子传输能力和丰富的钼位点，是最具潜力的无贵金属光催化析氢助催化剂之一。然而，MoCT通常表现出很强的Mo─H键，导致生成的氢因活性受限而难以从钼表面脱附。为有效削弱Mo─H键，本文提出一种电子供体金向MoCT中钼位点的d轨道释放电子的调控策略。在此，通过两步法制备MoCT-Au/CdS光催化剂，包括在MoCT表面初始负载金纳米颗粒以及随后在MoCT-Au表面原位生长硫化镉。光催化测量表明，MoCT-Au/CdS的最大析氢速率达到2799.44 μmol g⁻¹ h⁻¹，分别比硫化镉和MoCT/CdS高30.99倍和3.60倍。实验和理论数据证实，金属金可将自由电子转移至MoCT以生成富电子的钼位点，从而导致反键轨道占据态增加以及Mo─H键减弱，进而提高析氢效率。本研究为通过调控钼位点的反键轨道占据来设计基于MoCT的助催化剂以改善光催化性能提供了一种有前景的方法。
