Theoretical catalytic performance of single-atom catalysts M 1/PW 12O 40 for alkyne hydrogenation materials

Single-atom catalysts (SACs) have provoked significant curiosity in heterogeneous catalysis due to the benefits of maximum metal atoms usage, robust metal-support interaction, single-metal-atom active sites, and high catalytic efficiency.In this study, the electronic structures and catalytic mechanism of ethyne hydrogenation of SACs with the group-9 metal atoms M 1 (M 1 = Co, Rh, Ir) anchored on PTA (phosphotungstic acid) cluster have been explored by using firstprinciples quantum calculations.It is found that the catalytic activity of ethyne (C 2 H 2 ) hydrogenation is determined by two critical parameters: the adsorption energies of the adsorbate (H 2 , C 2 H 2 ) and the activation energy barrier of ethyne hydrogenation.We have shown that the reaction pathway of ethyne hydrogenation reaction on the experimentally characterized Rh 1 /PTA at room temperature consists of three steps: C 2 H 2 and H 2 coadsorption on Rh 1 /PTA, H 2 attacking C 2 H 2 to form C 2 H 4 , then C 2 H 4 desorbing or further reacting with H 2 to produce C 2 H 6 and completing the catalytic cycle.The Rh 1 /PTA possesses fair catalytic activity with a C 2 H 4 desorption energy of 1.46 eV and a 2.59 eV barrier for ethylene hydrogenation.Moreover, micro-kinetics analysis is also carried out to understand the mechanism and catalytic performance further.The work reveals that the PTA-supported SACs can be a promising catalyst for alkyne hydrogenation.