Pt-modulated Cu/SiO2 catalysts for efficient hydrogenation of CO2-derived ethylene carbonate to methanol and ethylene glycol

Engineered Chemical Utilization of CO2 to Methanol via Direct and Indirect Hydrogenation Pathways: A Review

“…Nevertheless, the precise correlation between copper active sites and methanol selectivity is still controversial. For several works on EC hydrogenation over Cu-based catalysts, the selectivity of methanol increased with an increase in the Cu + /(Cu + + Cu 0 ) ratio, as shown in Figure b. ,,,,,− In some studies, methanol selectivity showed a volcano-like curve with the surface Cu + /(Cu + + Cu 0 ) ratio (Figure c). ,,, In this case, methanol selectivity first increased and declined with a further increase of the Cu + /(Cu + + Cu 0 ) ratio, suggesting that the optimum ratio of the active site increased methanol selectivity. These reports on the relationship between the catalytic activity and surface active site ratio demonstrate the cooperative effect between Cu 0 and Cu + .…”

“…In another recent work, our research group also developed a series of Pt-modulated Cu/SiO 2 catalysts for EC hydrogenation. As a result, it was found that the addition of a suitable amount of Pt dopant could significantly enhance the H 2 adsorption and increase the Cu dispersion and the surface density of Cu + . The optimum 0.2Pt-Cu/SiO 2 catalyst exhibited higher catalytic activity and most importantly 95.8% methanol selectivity at a lower H 2 /EC molar ratio of 60.…”

“…However, the design and development of optimal surface Cu + and Cu 0 sites are still challenging. It is also suggested that when the surface Cu 0 site amount is sufficient to adsorb and activate H 2 , the existence of more Cu + sites and greater Cu + surface area is favorable for methanol formation. , …”

“…Relationship between Cu active sites and catalytic activity for EC hydrogenation: (a) correlation between EC conversion and the Cu + /(Cu + + Cu 0 ) ratio, ,,,,,,− (b) linear correlation between methanol selectivity and the Cu + /(Cu + + Cu 0 ) ratio, ,,,,,− and (c) volcano-like trend between methanol selectivity and the Cu + /(Cu + + Cu 0 ) ratio. ,,,,, …”

“…Doping of the second metal could benefit the evolution, optimization, and stabilization of Cu active sites and promote the metal–support interaction. ,,, Dai et al developed silver-modified copper phyllosilicate nanotubes and evaluated for the hydrogenation of ethylene carbonate. The catalyst prepared by co-ammonia evaporation hydrothermal method obtained >99% EC conversion and 79% methanol yield, and the one with post-impregnated Ag attained 74% methanol yield and 99% EG yield under relatively mild reaction conditions and a liquid hourly space velocity (LHSV) of 0.2 h –1 .…”