One-Step Fabricated Sn0 Particle on S-Vacancies SnS2 to Accelerate Photoelectron Transfer for Sterling Photocatalytic CO2 Reduction in Pure Water Vapor Environment.

Promoting the proton-coupled electron transfer process in order to solve the sluggish carrier migration dynamics is an efficient way to accelerate the photocatalytic CO2 reduction (PCR) process. Herein, through the reduction of Sn4+ by amino and sulfhydryl groups, Sn0 particles are lodged in S-vacancies SnS2 nanosheets. The high conductance of Sn0 particles expedites the collection and transport of photogenerated electrons, activating the surrounding surface of unsaturated sulfur (Sx 2- ) and thus lowering the energy barrier for generation of *COOH. Meanwhile, S-vacancies boost H2 O adsorption while Sx 2- increases CO2 adsorption, as demonstrated by density functional theory (DFT), obtaining a selectivity of 97.88% CO and yield of 295.06 µmol g-1 h-1 without the addition of co-catalysts and sacrificial agents. This work provides a new approach to building a fast electron transfer interface between metal particles and semiconductors, which works in tandem with S-vacancies and Sx 2- to boost the efficiency of photocatalytic CO2 reduction to CO in pure water vapor environment.

Deciphering the Superior Electronic Transmission Induced by the Li-N Ligand Pairs Boosted Photocatalytic Hydrogen Evolution.

Atomic level decoration route is designated as one of the attractive methods to regulate both the charge density and band structure of photocatalysts. Moreover, to enable more efficient separation and transport of photocarriers, the construction of novel active sites can enhance both the reactivity and electrical conductivity of the crystal. Herein, an Li-N ligand is constructed via co-doping lithium and nitrogen atoms into ZnIn2 S4 lattice, which achieves a promoted photocatalytic H2 evolution at 9737 µmol g-1 h-1 . The existence of Li-N ligand pairs and the behaviors of photocarriers on L40 N5 ZIS are determined systematically, which also provides a unique insight into the mechanism of the improved photocarrier migration rate. With the introduction of Li-N dual sites, the vacancy form of ZnIn2 S4 has changed and the photocatalytic stability is significantly improved. Interestingly, the change of charge density around Li-N ligand in ZnIn2 S4 is determined by theoretical simulations, as well as the regulated energy barrier of photocatalytic water splitting caused by Li-N dual sites, which act as both adsorption site for H2 O and stronger reactive sites. This work helps to extend the understanding of ZnIn2 S4 and offers a fresh perspective for the creation of a Li-N co-doped photocatalyst.

Insights into the Operation of Noble-Metal-Free Cocatalyst 1T-WS2 -Decorated Zn0.5 Cd0.5 S for Enhanced Photocatalytic Hydrogen Evolution.

Due to inefficient charge separation and low surface catalytic conversion efficiencies, cocatalysts are required for achieving photocatalytic hydrogen evolution. Being a noble-metal-free cocatalyst, metallic 1T-WS2 with excellent conductivity can function for this reaction. Herein, 1T-WS2 /Zn0.5 Cd0.5 S is constructed via a simple and feasible grinding approach. The composite containing 7.5 % 1T-WS2 in 1T-WS2 /Zn0.5 Cd0.5 S achieves a hydrogen evolution rate of 61.65 mmol g-1 h-1 and an external quantum efficiency of 8.04 % at 420 nm, which is 37 times that of bare Zn0.5 Cd0.5 S (1.67 mmol g-1 h-1 ). The electrical conductivity of metallic 1T-WS2 reduces the transfer impedance at the interface and thus accelerates the non-radiative energy transfer and electron transport rate. The different Fermi levels of 1T-WS2 and Zn0.5 Cd0.5 S form a Schottky junction, which promotes the transfer of photogenerated electrons from Zn0.5 Cd0.5 S to 1T-WS2 . More importantly, the close interface contact between 1T-WS2 and Zn0.5 Cd0.5 S results in strong electron interactions, which is conducive to the spatial separation of photogenerated electrons and holes. This work will further expand the application of 1T-WS2 in the photocatalytic hydrogen evolution process.