Direct S–H Evidence Revealing the Photo-electrocatalytic Hydrogen Evolution Reaction Mechanism on CdS Using Surface-Enhanced Raman Spectroscopy

Abstract

Photoelectrocatalytic water splitting using metal sulfides is a promising method for green hydrogen production. However, in situ probing of the hydrogen evolution reaction (HER) on sulfides with excellent performance remains a challenge. Here, we construct Au@ CdS core−shell nanoparticles to study the HER on CdS, a typical HER catalyst, by surfaceenhanced Raman spectroscopy (SERS) using a "borrowing" strategy. We directly capture the spectroscopic evidence of S−H intermediate under HER condition, further verified by isotopic experiments. Moreover, the population of S−H intermediates is improved by injecting charge carriers through light illumination and the S−H bond is weakened by introducing Pt to form a Au@Pt@CdS structure to change the interfacial electronic structure, both of them resulting in significant HER performance improvement. These findings can deepen the understanding of the HER mechanism and offer strategies for designing of cost-effective HER catalyst with high performance.

Surface Plasmon Field-Enhanced Raman Scattering Co-Excited by P-Polarized and S-Polarized Light Based on Waveguide-Coupled Surface Plasmon Resonance Configuration

“…Raman spectroscopy is a crucial technique for nondestructive, nonlabel analysis of molecular structures and has a wide range of applications in fields such as food safety, medical health, and contraband inspection. − However, a serious disadvantage of Raman spectroscopy is the weak signal, which limits its development and application . The discovery of the surface-enhanced Raman scattering (SERS) phenomenon has greatly improved the signal intensity of Raman spectroscopy and expanded the application field of Raman spectroscopy. ,− SERS has two enhancement mechanisms: an electromagnetic enhancement mechanism and a chemical enhancement mechanism . Based on the electromagnetic enhancement mechanism, researchers have developed various SERS substrates, such as nanoparticles and periodic nanostructures, to improve detection sensitivity and signal uniformity. − However, these structures are complicated, expensive, and difficult to manufacture in large areas.…”