Regulating the Crystal Facet Differences of In2O3 via Different Precipitants to Affect Methanol Selectivity

Abstract Under the background of “carbon peak and carbon neutrality”, the hydrogenation of carbon dioxide (CO 2 ) to methanol (CH 3 OH) represents a crucial pathway for promoting green and sustainable development. In 2 O 3 has gained attention as a promising material for CH 3 OH production from CO 2 due to its controllable properties including morphologies, particle sizes and oxygen vacancies, along with its excellent selectivity in CO 2 hydrogenation reactions. Herein, by employing various precursors, three distinct indium trioxide (In 2 O 3 ) catalysts with varied morphologies and predominantly exposed crystal facets were synthesized. It is found that the In 2 O 3 catalyst prepared using ammonia monohydrate (NH 3 ⋅H 2 O) as a precipitator exhibits a primarily exposed (211) crystal facet. This catalyst demonstrates a CO 2 conversion rate of 4.7 %, a selectivity of 55 %towards CH 3 OH, and a space velocity of 8000 ml g cat. −1 h −1 , under reaction conditions of 280 °C and 3 MPa. The (211) crystal face of In 2 O 3 is conducive to the generation of oxygen vacancies which shows exceptional active capabilities for CO 2 , and thus showing outstanding advantages in the selectivity towards CH 3 OH. The results underscore the importance of crystal facet engineering in tailoring the properties of catalysts for efficient CO 2 hydrogenation to CH 3 OH.