Modulating electron density of vacancy site by single Au atom for effective CO2 photoreduction

Abstract

The surface electron density significantly affects the photocatalytic efficiency, especially the photocatalytic CO2 reduction reaction, which involves multi-electron participation in the conversion process. Herein, we propose a conceptually different mechanism for surface electron density modulation based on the model of Au anchored CdS. We firstly manipulate the direction of electron transfer by regulating the vacancy types of CdS. When electrons accumulate on vacancies instead of single Au atoms, the adsorption types of CO2 change from physical adsorption to chemical adsorption. More importantly, the surface electron density is manipulated by controlling the size of Au nanostructures. When Au nanoclusters downsize to single Au atoms, the strong hybridization of Au 5d and S 2p orbits accelerates the photo-electrons transfer onto the surface, resulting in more electrons available for CO2 reduction. As a result, the product generation rate of AuSA/Cd1−xS manifests a remarkable at least 113-fold enhancement compared with pristine Cd1−xS.

Single-atom-based catalysts for photoelectrocatalysis: challenges and opportunities

“…Electronic structures of catalysts are crucial to the overall catalytic process. [28][29][30] The adsorption bond strength of reactants or intermediates, the charge kinetics and the catalyst activity have been proven to be highly related to the characteristics of the surface electronic structure of catalysts. 31,32 Aer the metal SAs are anchored or coordinated with the support, the strong metalsupport interaction can regulate the electronic structures of SAs due to the redistribution of charge density.…”

“…36 For solar-to-chemical energy conversion, Zhou et al found that the deployment of Au SAs in Cd 1Àx S modulated the electronic structures of Au atoms, which could promote the charge transfer and offer sufficient electrons for photocatalytic CO 2 reduction reaction. 30 In another case, band engineering of Pt II -C 3 N 4 photocatalysts by introducing Pt SAs was proven to be an efficient solution to modify the band energy levels and shi the valence band maximum level to promote water oxidation. 37 Similarly, rational design of Ta 3 N 5 photoanodes by gradient Mg doping could improve the PEC water oxidation performance due to band engineering.…”

“…2b. 30 In addition, the isolated singleatom active sites can trap photogenerated charges via chemical bonding in SACs, which reduces undesired charge recombination at the interface toward efficient photocatalysis. 49 Steadystate photoluminescence (PL) spectroscopy and surface photovoltage (SPV) spectroscopy can examine the charge separation, recombination and transfer process.…”

Synthesis of Cu Single Atom with Adjustable Coordination Environment and Its Catalytic Hydrogenation Performance※

“…由于金属原子普遍存在聚集的趋势, 因此, 该领域最关 键的挑战是探索一种有效的方法来牢固地锚定金属单 原子, 从而为所需的催化反应形成高度稳定和反应性的 催化活性中心 [4] . 与贵金属单原子催化材料(如金、铂、 铱、钯等)相比 [5][6][7][8] , 非贵金属催化材料以其丰富的储量, 便宜的价格, 大大降低了成本 [9] . 其中, 铜单原子催化 材料在温和条件下表现出很高的催化性能, 被认为是最 有前途的替代品之一 [10][11][12] , 因而得到了越来越多的关 注.…”

Sulfur Vacancy and Ti3C2Tx Cocatalyst Synergistically Boosting Interfacial Charge Transfer in 2D/2D Ti3C2Tx/ZnIn2S4 Heterostructure for Enhanced Photocatalytic Hydrogen Evolution

“…reported that the direction of photogenerated electron transfer could be controlled by adjusting the vacancy type of CdS. [ 17 ] Gao et al. grew S‐vacancy ZnS vertically on the Zn‐In‐LDH surface, which stimulated the synergistic effect of vacancy and 2D interface and improved the performance of photocatalytic hydrogen production.…”