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

Hydrogenation of CO 2 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, In 2 O 3 has become a promising material for CO 2 hydrogenation. Here we successfully introduced highly dispersed Pt2+ species into three different morphologies In 2 O 3 supports by controllable precipitation method. The dominant exposed crystal facets of In 2 O 3 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/In 2 O 3 whcih mainly exposing (222) or (104) facet, Pt/In 2 O 3 which primarily exposed (211) facet obtained higher catalytic activity, including a CO 2 conversion of 11.7% and methanol selectivity of 74.8% with a space time yield of methanol of 0.63 g MeOH h−1gcat−1 at 300 °C, 5 MPa, and 21,000 cm3 h−1g−1. The highly enhanced activity of 1.5Pt/C-In 2 O 3 -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 In 2 O 3 (211) facet. The special interface structure enabled the activation of CO 2 and hydrogenation of key intermediates effectively. Exposing the highly active crystal face of the In 2 O 3 supports is proved to be an effective strategy to enhance catalytic performance of Pt/In 2 O 3 catalyst for methanol synthesis. The influence of the crystal facets on the 1.5Pt/In 2 O 3 catalyst was explored. Highly dispersed Pt2+ species were successfully introduced into three In 2 O 3 supports that exposed different dominant crystal facets by precipitation method. The highly enhanced activity of the 1.5Pt/C-In 2 O 3 -S catalyst was ascribed to its more abundant oxygen vacancies and well-dispersed Pt2+ species originated from the interface structure of Pt-O-In and the reinforced interaction of Pt2+ with the underlying In 2 O 3 (211) facet, which enabled both CO 2 activation and hydrogenation of key intermediates by effective H 2 dissociation. The synergistic interaction between highly dispersed Pt2+ species and In 2 O 3 crystal facet boosts the rate of methanol formation. Besides, in situ DRIFTS spectra further indicate CH 3 O* and HCOO* species are the key intermediates in the formate route. [Display omitted] • In 2 O 3 with dominant (211) facet shows the highest number of oxygen vacancies and the best Pt dispersion. • 1.5Pt/C-In 2 O 3 -S presents 11.7% CO 2 conversion and 74.8% CH 3 OH selectivity at 300 ℃. • Substitution of In3+ ions by Pt2+ ions generates the special active interface structure of Pt-O-In. • The synergy between highly dispersed Pt2+ and In 2 O 3 boost the rate of methanol formation. • CH 3 O* and HCOO* species are the key intermediates in the formate route. [ABSTRACT FROM AUTHOR]