Optimizing Atomic Hydrogen Desorption of Sulfur‐Rich NiS_1+x Cocatalyst for Boosting Photocatalytic H₂ Evolution

Abstract

Low‐cost transition‐metal chalcogenides (MSx) are demonstrated to be potential candidate cocatalyst for photocatalytic H2 generation. However, their H2‐generation performance is limited by insufficient quantities of exposed sulfur (S) sites and their strong bonding with adsorbed hydrogen atoms (SHads). To address these issues, an efficient coupling strategy of active‐site‐enriched regulation and electronic structure modification of active S sites is developed by rational design of core–shell Au@NiS1+x nanostructured cocatalyst. In this case, the Au@NiS1+x cocatalyst can be skillfully fabricated to synthesize the Au@NiS1+x modified TiO2 (denoted as TiO2/Au@NiS1+x) by a two‐step route. Photocatalytic experiments exhibit that the resulting TiO2/Au@NiS1+x(1.7:1.3) displays a boosted H2‐generation rate of 9616 µmol h−1 g−1 with an apparent quantum efficiency of 46.0% at 365 nm, which is 2.9 and 1.7 times the rate over TiO2/NiS1+x and TiO2/Au, respectively. In situ/ex situ XPS characterization and density functional theory calculations reveal that the free‐electrons of Au can transfer to sulfur‐enriched NiS1+x to induce the generation of electron‐enriched Sδ− active centers, which boosts the desorption of Hads for rapid hydrogen formation via weakening the strong SHads bonds. Hence, an electron‐enriched Sδ−‐mediated mechanism is proposed. This work delivers a universal strategy for simultaneously increasing the active site number and optimizing the binding strength between the active sites and hydrogen adsorbates.

Electrocatalytic activity of metal encapsulated, doped, and engineered fullerene-based nanostructured materials towards hydrogen evolution reaction

“…The result obtained also show that the studied C 24 -engineered surfaces also show that the C 24 -engineered encapsulated, doped, and decorated surfaces has much better adsorption energies than graphene-engineered surfaces, which are in most cases comparable with adsorption energies of fullerene (C 24 ) surfaces towards H-molecule. Results obtained from Gao et al 54 , using Moller–Plesset second order perturbation theory (MP2) level of theory with basis sets ranging from 6-31G* to augmented-correlation consistent polarized valence triple zeta (aug-cc-pVTZ) basis set. Without counterpoise correction the results obtained for the studied engineered carbon-based structures (− 0.137 to − 1.965 eV), respectively indicate adsorption properties comparable with carbon-nanotubes, and exhibited better adsorption properties than the graphene and sumanene engineered surfaces.…”

Tailor‐Engineered 2D Cocatalysts: Harnessing Electron–Hole Redox Center of 2D g‐C3N4 Photocatalysts toward Solar‐to‐Chemical Conversion and Environmental Purification

“…Nonetheless, inadequately exposed sulfur (S) sites and the strong chemical bond with the adsorbed hydrogen atoms (S-H ads ) hinder its H 2 gas formation. [250] Henceforth, more efforts should be devoted to inducing electron-enriched active centers, which can weaken the interaction between sulfur and hydrogen atoms, thus boosting the desorption of hydrogen molecules.…”

Enhanced Selective Photooxidation of Toluene to Benzaldehyde over Co3O4‐Modified BiOBr/AgBr S‐Scheme Heterojunction

“…[29][30][31][32][33] Indeed, loading cocatalysts and constructing heterojunction are proved to be the effective strategies to expand the light response region and improve the light absorption as well as expedite electron-hole pairs separation. [34][35][36][37][38] Thanks to the narrow bandgap (%2.6 eV) and high conduction band (CB) position, AgBr can serve as a potent visible-light-responsive semiconductor and has strong reduction ability. [39] However, pristine AgBr suffers from particle agglomeration and severe photochemical corrosion effect.…”