Probe Binding Mode and Structure of the Photocatalytic Center: Hydrogen Generation by Quantum Dots and Nickel Ions
journal contributionposted on 22.09.2021, 17:04 by Yang Wang, Xiang-Bing Fan, Xu-Bing Li, Chen-Ho Tung, Li-Zhu Wu
Artificial photosystems consisting of colloidal semiconductor quantum dots (QDs) and non-noble metal salts (e.g., Ni2+) show exceptional photocatalytic H2 activity. Recent studies have found the structure of the catalysts distorted during the photocatalytic H2 evolution reaction, which significantly influences the reaction kinetics. However, the in situ binding form between QDs and the catalytic center is still ambiguous. Herein, we reveal that, in the high-efficiency H2 evolution photosystem based on CdS–S2– QDs and water-soluble Ni2+ salts (pH 6.0), the Ni0 clusters formed in situ bind on the surface of QDs via a Ni–S bond to work as the real catalytic species for H2 photogeneration, manifested by a combination of X-ray photoelectron spectroscopy, electron paramagnetic resonance, X-ray absorption spectroscopy, and a set of control experiments.
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