CdS surfaces decorated with sub-nanometer sized noble metal (Au, Pt) clusters have been recently demonstrated to significantly increase the rate of photocatalytic hydrogen production [1-2].To provide a fundamental understanding of the origin of the enhanced photocatalytic activity, we investigated the semiconductor/metal cluster interface using the first-principles density functional theory method. We performed a systematic study of two-dimensional bilayer and three-dimensional structures of unsupported Au and Pt clusters with diameters ranging from 0.7 nm to 1.5 nm and obtained the trends on their structural, energetic and electronic properties. We also investigated the impact of the surface relaxation and reconstruction on the surface energy and the electronic structure of low energy CdS surfaces, including both the nonpolar (101b0) and (112b0) surfaces and the polar S-terminated (0001b) and Cd-terminated (0001) surfaces. We then explored the adsorption geometry and electronic structures of Au and Pt clusters on selected CdS surfaces. Our preliminary results revealed strong bonding between the metal clusters and the substrate, which led to significant deformation of the clusters and modification of the substrate electronic structure. By elucidating the charge transfer and energy level alignment at the semiconductor/metal cluster interface, we have gained insight into the enhanced photocatalytic behavior of such systems.S.X. was supported through a SEED grant between Stony Brook University and Brookhaven National Laboratory under Contract No. 37298. E.B.I. was supported from the U.S. Department of Energy Computational Science Graduate Fellowship under Contract No. DE-FG02-97ER25308.[1] Shen, P.; Zhao, S.; Su, D.; Li, Y.; Orlov, A. Appl. Catal. B 2012  , 126, 153.[2] Shen, P.; Zhao, S.; Wu, Q.; Xiong, S.; Li, Y.; Su, D.; Orlov, A. in preparation.

First-principles study of CdS surfaces decorated with sub-nanometer sized clusters for photocatalytic hydrogen production

247th National Meeting (2014)

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