Role of Zirconia in Indium Oxide-Catalyzed CO₂Hydrogenation to Methanol

Abstract

Monoclinic zirconia has been uncovered as a carrier able to substantially boost the activity of indium oxide for CO2 hydrogenation to methanol. Here, electronic, geometric, and interfacial phenomena associated with this unique effect are investigated. Generating mixed In-Zr oxides by coprecipitation does not improve performance, excluding a primary role of electronic parameters.Since even only 1 mol% of indium stabilizes the metastable tetragonal phase of zirconia, the relevance of its crystalline structure is explored in impregnated solids. Both tetragonal and monoclinic ZrO2 permit epitaxial growth of In2O3, but a delicate lattice mismatching leads to a slightly lower dispersion of the oxide on the second, which is observed in the form of subnanometric islands on the carrier. More importantly, compressive and tensile forces are exerted on In2O3, respectively, which inhibit and foster oxygen vacancy formation, in line with the low and greatly enhanced indium-specific activity of the catalysts prepared with the two polymorphs.Hence, a deposition synthesis method is essential to unlock the role of monoclinic zirconia.According to analyses with reference In2O3-based catalysts supported on alumina and ceria, which display diverse ability to activate CO2 on their surface, the direct participation of monoclinic zirconia in a parallel pathway to methanol is put forward as a second origin of activity boosting.The latter is likely enabled by the abundancy of indium active sites vicinal to the interface and/or by a more favorable CO2 adsorption geometry onto this carrier or onto an alternative bimetallic site possibly produced.

Novel Heterogeneous Catalysts for CO2 Hydrogenation to Liquid Fuels

“… 80 Frei et al also investigated the electronic, geometric, and interfacial phenomena related to the peculiar promotional effects of the monoclinic ZrO 2 carrier on In 2 O 3 . 81 Less-pronounced lattice mismatching between In 2 O 3 and ZrO 2 favors the formation of more surface oxygen vacancies on In 2 O 3 , which is beneficial for methanol synthesis.…”

Indium Oxide Based Nanomaterials: Fabrication Strategies, Properties, Applications, Challenges and Future Prospect

“…Finally, the precipitates are washed and calcined at high temperature to get metal oxide nanomaterials. Several reports are available on synthesis of indium oxide based nanomaterials by this method [55,56].…”

Engineering Heterostructured Nanocatalysts for CO2 Transformation Reactions: Advances and Perspectives

“…[5,6j] For example, In 2 O 3 nanoparticles have been testified as an extremely selective and stable catalyst for CO 2 hydrogenation to green methanol. [40] Recently, Pérez-Ramírez and co-workers [41] prepared a palladium-promoted In 2 O 3 catalyst with palladium atomically embedded in the oxide matrix by using a coprecipitation (CP) method and a reference object embodying palladium nanoparticles on In 2 O 3 by a dry impregnation strategy (DI). Compared to bulk In 2 O 3 , the former (CP) displays a durable activity enhancement for methanol production (space-time yield (STY) = 0.61 g MeOH h À 1 g cat À 1 ), owing to the high stabilization of low-nuclearity palladium clusters (several atoms) on In 2 O 3 nanoparticles, whereas the latter (DI) shows a decaying improvement of both methanol and CO formation owing to the agglomeration of palladium with time on stream.…”

“…Tremendous progress has been made in the exploration of catalytic materials including transition metal and oxide catalysts (e. g., Cu, Pd, Pt, Au, alloy), main group metal and oxide catalysts (i. e. In 2 O 3 , Ga‐based intermetallic compounds), and MOFs‐derived nanostructured catalysts (e. g., ZIF‐8, UiO‐66; ZIF and UiO refer to zeolitic imidazolate framework and the University of Oslo, respectively) [5,6j] . For example, In 2 O 3 nanoparticles have been testified as an extremely selective and stable catalyst for CO 2 hydrogenation to green methanol [40] . Recently, Pérez‐Ramírez and co‐workers [41] prepared a palladium‐promoted In 2 O 3 catalyst with palladium atomically embedded in the oxide matrix by using a coprecipitation (CP) method and a reference object embodying palladium nanoparticles on In 2 O 3 by a dry impregnation strategy (DI).…”