Dynamics of Electron Transfer in CdS Photocatalysts Decorated with Various Noble Metals

Abstract

To address charge recombination in photocatalysis, the prevalent approach involves the use of noble metal cocatalysts. However, the precise factors influencing this performance variability based on cocatalyst selection have remained elusive. In this study, CdS hollow spheres loaded with distinct noble metal nanoparticles (Pt, Au, and Ru) are investigated by femtosecond transient absorption (fs‐TA) spectroscopy. A more pronounced internal electric field leads to the creation of a larger Schottky barrier, with the order Pt‐CdS > Au‐CdS > Ru‐CdS. Owing to these varying Schottky barrier heights, the interface electron transfer rate (Ke) and efficiency (ηe) of metal‐CdS in acetonitrile (ACN) exhibit the following trend: Ru‐CdS > Au‐CdS > Pt‐CdS. However, the trends of Ke and ηe for metal‐CdS in water are different (Ru‐CdS > Pt‐CdS > Au‐CdS) due to the influence of water, leading to the consumption of photogenerated electrons and affecting the metal/CdS interface state. Although Ru‐CdS displays the highest Ke and ηe, its overall photocatalytic performance, particularly in H2 production, lags behind that of Pt‐CdS due to the electron backflow from Ru to CdS. This work offers a fresh perspective on the origin of performance differences and provides valuable insights for cocatalyst design and construction.

Spherical 2-acetylene-(copper metal–organic framework) preparation and efficient photocatalytic hydrogen evolution over combined bimetallic sulfides

“…Fig. 4(d-f) show the Zn 2p, Cd 3d, and S 2p spectra, with signal peaks at 1022 and 1045 eV attributed to the Zn 2p 3/2 and 2p 1/2 orbitals, 32,33 405 and 411 eV to the Cd 3d 5/2 and 3d 3/2 orbitals, 34 and 161 and 162 eV to the S 2p 3/2 and 2p 1/2 orbitals, [35][36][37] respectively. By comparing the binding energy shifts, it is found that the introduction of ACu-MOF and Cu-MOF can effectively reduce the charge density on the surface of ZCS compared to ZCS alone.…”