Catalytic mechanism and bonding analyses of Au-Pd single atom alloy (SAA): CO oxidation reaction

Abstract

Single-atom catalysts (SACs), including metalmetal-bonded bimetallic ones named single-atom alloys (SAAs), have aroused significant interest in catalysis. In this article, the catalytic mechanism and bonding analysis of CO oxidation reaction on bimetallic gold-palladium (Au-Pd) model of single atom alloy Au 37 Pd 1 are investigated by using quantum chemical calculations. The molecular geometries and adsorbate/substrate binding energies of CO@Au-Pd, O 2 @Au-Pd and CO/O 2 @Au-Pd configurations are identified. The core-shell structure is confirmed to be the most stable structure for Au-Pd SAA, where the Pd atom prefers to situate at the core site. Charge transfer from the Pd atom to the Au atoms has been confirmed to stabilize the structure. According to the binding energy and chemical bonding analysis, both CO and O 2 prefer to bind to the Pd atom at the hex site with low coordination number. The formation of new co-adsorption species is identified, in which vertical and parallel bridging adsorptions of CO and O 2 on the Au-Pd bonds are observed. CO oxidation on Au-Pd SAA is found to be feasible with low energy barriers and follows the Langmuir-Hinshewood (L-H) mechanism. Our work offers insights into the significant role of single atom of the SAAs in catalytic reactions and can provide evidence for designing new SAAs with high-performance catalytic activities.

Atomic-level-designed copper atoms on hierarchically porous gold architectures for high-efficiency electrochemical CO2 reduction

“…Significantly, one of the effective ways is to stabilize isolated metal atoms on the surface of another host metal (e.g., single-atom alloys (SAAs)), which possess peculiar electronic and geometric features rather different from their constituent metals, thus providing unique active centers and consequently altering the adsorption energy of intermediates [19][20][21][22][23]. Interestingly, SAA catalysts have been proved to possess remarkable catalytic activity in various chemical reactions including hydrogenation/dehydrogenations, C-C and C-O coupling reactions [24][25][26]. However, during ECR to CO, the SAA strategy is rarely reported to optimize the *COOH and *CO binding strength on the surface of catalyst.…”

Theoretical studies of MXene-supported single-atom catalysts: Os1/Ti2CS2 for low-temperature CO oxidation

“…Over the past decade, SAC has expanded rapidly and the concept of SAC has been further developed into dynamic SACs [24] and single-cluster catalysts (SCCs) [25,26]. Many studies [27][28][29][30][31][32][33][34][35][36] have been devoted to obtaining SACs with high stability, high selectivity and high reactivity [37][38][39] for thermocatalysis, photocatalysis, electrocatalysis, and photoelectrocatalysis reactions [15,[40][41][42][43], such as CO oxidation, water gas shift reaction, activation of C-H bonds, photo-and electro-catalytic water splitting, and CO 2 reduction reaction, oxygen reduction reaction, hydrogen evolution reaction, oxygen evolution reaction, hydrogenation reactions, and nitrogen reduction reaction [5,15,[43][44][45][46][47][48][49][50][51][52][53][54].…”

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.…”