Efficient and robust CO2 hydrogenation to methanol achieved by copper nanoparticles anchored in copper phyllosilicate core-shell nanoreactor

Abstract

Methanol synthesis by CO2 hydrogenation is a key process in a sustainable methanol-based economy. Copper silicate (CuSiO3) is considered as efficient for hydrogenation of C-O/CO bonds due to the synergistic effect from its unique dual-sites of Cu0-Cu+. However, it still confronts great obstacles of poor CO2 conversion and low methanol selectivity. Herein, we designed a core-shell CuSiO3 nanoreactor by hydrothermal method, the cavity of which between core and shell provided the reaction space for CO2 and H2 in CO2 hydrogenation. Interestingly, the cavity of the nanoreactor could be tuned by the hydrothermal time, and the product selectivity altered accordingly. Intrinsically, because of the spatial restriction effect of reactants, the reactant especially hydrogen can be enriched on the concave surface of nanotubes and hollow spheres, leading to a favorable activity. Furthermore, the longer diffusion path derived from the increased cavity volume would cause a deep hydrogenation to CH4. Based on this, we chose the nanoreactor with suitable cavity volume to impregnate copper nanoparticles to increased the active sites and regulate the ratio of Cu0/Cu+, achieving remarkable catalytic activity (the conversion of CO2 is 19.7% and yield of methanol reaches up to ∼18%). Moreover, the copper nanoparticles could be anchored by the core and shells, contributed to an excellent stability of the catalytic system (>120 h).