Search

Mixed zinc‐zirconium oxides, ZnZrOx, are highly selective and stable catalysts for CO2 hydrogenation to methanol, a pivotal energy vector. However, their activity remains moderate, and descriptors to design improved systems are lacking. This work applies flame spray pyrolysis (FSP), a one‐step and scalable method, to synthesize a series of ZnZrOx catalysts, and systematically compares them to coprecipitated (CP) analogs to establish deeper synthesis–structure–performance relationships. FSP systems (up to 5 mol%) generally display a threefold higher methanol productivity compared to their CP counterparts. In‐depth characterization and theoretical simulations show that, unlike CP, FSP maximizes the surface area and formation of atomically dispersed Zn2+ sites incorporated in lattice positions within the ZrO2 surface, which is key to improving performance. Analysis by in situ electron paramagnetic resonance (EPR) spectroscopy reveals that the specific architecture of the flame‐made catalyst markedly fosters the generation of oxygen vacancies. Together with surrounding Zn and Zr‐O atoms, the oxygen vacancies create active ensembles that favor methanol formation through the formate path while suppressing undesired CO production, as confirmed by kinetic modeling. This study elucidates the nature of active sites and their working mechanism, pushing forward ZnZrOx‐catalyzed methanol synthesis by providing a new benchmark for this cost‐effective and earth‐abundant catalyst family. [ABSTRACT FROM AUTHOR]

A plethora of metal promoters have been applied to enhance the performance of In2O3 in CO2 hydrogenation to methanol, a prospective energy carrier. However, the lack of systematic catalyst preparation and evaluation precludes a direct comparison of their speciation and promotional effects, and consequently, the design of an optimal system. Herein, flame spray pyrolysis (FSP) is employed as a standardized synthesis method to introduce nine metal promoters (0.5 wt.%) into In2O3. Methanol productivity generally increased on M‐In2O3 with selectivity following Pd ≈ Pt > Rh ≈ Ru ≈ Ir > Ni ≈ Co > Ag ≈ In2O3 > Au. In‐depth characterization, kinetic analyses, and theoretical calculations reveal a range of metal‐dependent speciation which dictate catalyst architecture and degree of promotion. Atomically‐dispersed promoters (Pd, Pt, Rh, Ru, and Ir) grant the highest improvement in performance, particularly Pd and Pt, which markedly promote hydrogen activation while hindering undesired CO formation. In contrast, metals in clustered (Ni and Co) and nanoparticle (Ag and Au) forms display moderate and no promotion, respectively. This study provides an atomic‐level understanding of In2O3 promotion based on a unified protocol, and highlights the potential of FSP to engineer complex catalytic systems toward more efficient energy transformations. [ABSTRACT FROM AUTHOR]

Keywords: CO2 hydrogenation; flame spray pyrolysis; oxygen vacancies; sustainable methanol; ZnZrOx catalysts EN CO2 hydrogenation flame spray pyrolysis oxygen vacancies sustainable methanol ZnZrOx catalysts 1 1 1 04/17/23 20230413 NES 230413 B Methanol Synthesis b In article number 2204122, Javier Pérez-Ramírez and co-workers apply flame spray pyrolysis to design superior ZnZrO SB I x i sb catalysts for methanol synthesis from CO SB 2 sb . Design of Flame-Made ZnZrOx Catalysts for Sustainable Methanol Synthesis from CO2 (Adv. CO2 hydrogenation, flame spray pyrolysis, oxygen vacancies, sustainable methanol, ZnZrOx catalysts. [Extracted from the article]

CO 2 hydrogenation, green methanol, indium oxide, metal speciation, promotion Flame Spray Pyrolysis as a Synthesis Platform to Assess Metal Promotion in In2O3-Catalyzed CO2 Hydrogenation (Adv. Keywords: CO 2 hydrogenation; green methanol; indium oxide; metal speciation; promotion EN CO 2 hydrogenation green methanol indium oxide metal speciation promotion 1 1 1 04/18/22 20220414 NES 220414 B Flame Spray Pyrolysis b In article number 2103707, Núria López, Javier Pérez-Ramírez and co-workers apply flame spray pyrolysis as a standardized synthesis method to investigate promotional effects of nine transition metals in In SB 2 sb O SB 3 sb -catalyzed CO SB 2 sb hydrogenation to methanol, revealing that catalyst architecture (single atoms, clusters, and nanoparticles) and corresponding reactivity are dictated by the nature of the promoter. [Extracted from the article]