The design and synthesis of highly efficient and selective catalysts for the CO2 thermal reduction remains a challenging issue of modern catalysis. Molybdenum carbide has attracted great interest in CO2-to-CO conversion (Reverse Water Gas Shift process, RWGS) because of its unique ability to dissociate CO2 and H2. However, single dominant Mo- or C-terminated facets of molybdenum carbide unlikely activate CO2 and H2 molecules simultaneously. Herein we demonstrate how structural diversity of co-generated molybdenum species (i.e., Mon nanoclusters and Mo2C nanoparticles) at the surface of an oxygen-enriched C-carrier, boost synergistically the chemoselective RWGS process with rates up to 581 µmolCO2·gMo-1·s-1 with CO selectivity> 99% already at 400 °C under H2-rich environment. This catalytic outcome ranks among the highest reported so far for molybdenum carbide- or noble metal-based catalysts in the process and it is up to 1.8 times higher than that measured on structurally homogeneous Mo2C-based nanoparticles. The superior activity of the structurally mixed catalyst has been ascribed to a synergistic modulation of geometrical and electronic structure of different Mo sites that reduce the temperature at which CO production starts and facilitates the chemoselective CO desorption pathway. Experimental and in-silico studies have also unveiled the existence of a linear correlation between the percentage of high-valence molybdenum species in the metal active-phase composition (Moδ+ %) and the increase of RWGS rate.
Synergizing Mon Clusters and Mo2C Nanoparticles on Oxidized Carbon Nanotubes Boosting the CO2 Reduction Activity / Cao, Shuo; Guan, Zun; Ma, Ying; Xu, Bing; Ma, Jun; Chu, Wei; Zhang, Riguang; Giambastiani, Giuliano; Liu, Yuefeng. - In: ACS CATALYSIS. - ISSN 2155-5435. - STAMPA. - 14:(2024), pp. 10939-10950. [10.1021/acscatal.4c02069]
Synergizing Mon Clusters and Mo2C Nanoparticles on Oxidized Carbon Nanotubes Boosting the CO2 Reduction Activity
Giambastiani, Giuliano
Conceptualization
;
2024
Abstract
The design and synthesis of highly efficient and selective catalysts for the CO2 thermal reduction remains a challenging issue of modern catalysis. Molybdenum carbide has attracted great interest in CO2-to-CO conversion (Reverse Water Gas Shift process, RWGS) because of its unique ability to dissociate CO2 and H2. However, single dominant Mo- or C-terminated facets of molybdenum carbide unlikely activate CO2 and H2 molecules simultaneously. Herein we demonstrate how structural diversity of co-generated molybdenum species (i.e., Mon nanoclusters and Mo2C nanoparticles) at the surface of an oxygen-enriched C-carrier, boost synergistically the chemoselective RWGS process with rates up to 581 µmolCO2·gMo-1·s-1 with CO selectivity> 99% already at 400 °C under H2-rich environment. This catalytic outcome ranks among the highest reported so far for molybdenum carbide- or noble metal-based catalysts in the process and it is up to 1.8 times higher than that measured on structurally homogeneous Mo2C-based nanoparticles. The superior activity of the structurally mixed catalyst has been ascribed to a synergistic modulation of geometrical and electronic structure of different Mo sites that reduce the temperature at which CO production starts and facilitates the chemoselective CO desorption pathway. Experimental and in-silico studies have also unveiled the existence of a linear correlation between the percentage of high-valence molybdenum species in the metal active-phase composition (Moδ+ %) and the increase of RWGS rate.File | Dimensione | Formato | |
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