Microkinetic Comparison of CO2 Hydrogenation to Methanol over Unsupported and Supported Subnanometer Pdx Clusters

A promising approach to meet rising energy demands while mitigating environmental risks from greenhouse gases is the conversion of carbon dioxide into methanol through CO 2 hydrogenation. Previous studies have demonstrated that unsupported subnanometer Pd x clusters exhibit excellent performance in this conversion. However, the influence of support materials on the activity of Pd clusters remains poorly understood. In this study, we compare the kinetics of CO 2 hydrogenation to methanol using unsupported Pd 7 clusters and those supported by metal oxides, specifically Pd 4 /In 2 O 3 (110) and Pd 3 /TiO 2 (110). Microkinetic simulations, based on available energetic data from the literatures, reveal that Pd 4 /In 2 O 3 (110) delivers superior kinetic performance, followed by Pd 7 and Pd 3 /TiO 2 (110). These findings demonstrate that the choice of support material plays a critical role in dictating the reaction pathway and rate for supported Pd cluster catalysts.