Engineering the crystal facets of Pt/In2O3 catalysts for high-efficiency methanol synthesis from CO2 hydrogenation

Abstract

Hydrogenation of CO2 to methanol is an achievable way for “methanol economy” and “liquid sunshine” visions. Owing to highly tunable properties containing different morphologies, exposed crystal facets and oxygen vacancies, In2O3 has become a promising material for CO2 hydrogenation. Here we successfully introduced highly dispersed Pt2+ species into three different morphologies In2O3 supports by controllable precipitation method. The dominant exposed crystal facets of In2O3 supports during the research are discovered to greatly affect the dispersion of active Pt2+ species and the number of oxygen vacancies, as analyzed by diverse characterization techniques, and closely correlated with the catalytic performance. Compared with Pt/In2O3 whcih mainly exposing (222) or (104) facet, Pt/In2O3 which primarily exposed (211) facet obtained higher catalytic activity, including a CO2 conversion of 11.7% and methanol selectivity of 74.8% with a space time yield of methanol of 0.63 gMeOH h−1gcat−1 at 300 °C, 5 MPa, and 21,000 cm3 h−1g−1. The highly enhanced activity of 1.5Pt/C-In2O3-S catalyst was ascribed to its more abundant oxygen vacancies and well-dispersed Pt2+ species, which derived from the interaction between Pt2+ and the underlying In2O3 (211) facet. The special interface structure enabled the activation of CO2 and hydrogenation of key intermediates effectively. Exposing the highly active crystal face of the In2O3 supports is proved to be an effective strategy to enhance catalytic performance of Pt/In2O3 catalyst for methanol synthesis.