Cu-Mg synergy enhanced synthesis of methyl formate over noble metal-free heterogeneous catalyst systems

To address the challenges associated with storage and transportation of hydrogen, Liquid Organic Hydrogen Carriers (LOHCs) like methyl formate (MF) offer a promising and sustainable solution for storing hydrogen (8.4% wt) under ambient conditions. The conversion of anthropogenic CO<inf>2</inf> to MF in the presence of methanol, under base-free conditions, is attracting significant research attention, as it not only helps to limit the atmospheric CO<inf>2</inf> but also produces MF as an efficient LOHC. In this study, a supported Cu nanocatalyst was synthesized, demonstrating notable activity for CO<inf>2</inf> hydrogenation to MF, achieving a CO<inf>2</inf> conversion of 14.01%, a turnover frequency (TOF) of 186 h⁻¹, and selectivity greater than 99%. These results represent the highest performance reported among noble-metal-free catalyst systems. The Cu-Mg synergy enhanced catalytic activity was thoroughly investigated in the quest for improved activity. Comprehensive characterization studies were conducted to elucidate the structure-activity relationship, and the catalyst exhibited consistent performance in recycling and long-term experiments. Additionally, a plausible reaction mechanism for the catalytic process has been proposed.