An effective approach to improve catalytic performance of a Cu-based catalyst for the synthesis of dimethyl carbonate (DMC) is to minimize particle size and to increase the dispersion of active Cu species. Here, highly dispersed Cu nanoparticles (NPs) supported on carbon microspheres (CMs) catalyst has been fabricated through a multi-step process involving cationic ion-exchange, high-temperature carbonization and H-2 reduction. The Cu NPs size shows a volcanic curve versus the heat-treatment temperature. Cu/CMs catalyst calcined at 500 degrees C with mean Cu NP size of 5.5 nm, displayed the highest catalytic activity, with a methanol conversion of 5.0%, DMC selectivity of 100% and space time yield of DMC of 3770 mg/(gh). The sulfonic acid groups on the IR 120 resin endows its strong anchoring ability for copper precursors, leading to a decrease in particle size and better dispersion of Cu active species, which plays a key role in promoting the catalytic performance of Cu/CMs catalyst. However, a calcination temperature higher than 500 degrees C was proved to be detrimental because of extensive damage of the sulfonic acid groups. (C) 2019 Elsevier Ltd. All rights reserved.