Optimizing Active Sites for High CO Selectivity during CO2 Hydrogenation over Supported Nickel Catalysts

Autor(es)

Galhardo, Thalita S. ^[1] ; Braga, Adriano H. ^[1] ; Arpini, Bruno H. ^[1] ; Szanyi, Janos ^[2] ; Goncalves, V, Renato ; Zornio, Bruno F. ^[3] ; Miranda, Caetano R. ^[3] ; Rossi, Liane M. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Dept Quim Fundamental, Inst Quim, BR-05508000 Sao Paulo, SP - Brazil

^[2] Pacific Northwest Natl Lab, Inst Integrated Catalysis, Richland, WA 99352 - USA

^[3] Univ Sao Paulo, Inst Fis, DFMT, BR-05315970 Sao Paulo, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Journal of the American Chemical Society; v. 143, n. 11, p. 4268-4280, MAR 24 2021.
• Citações Web of Science: 0

Resumo

Controlling the selectivity of CO2 hydrogenation catalysts is a fundamental challenge. In this study, the selectivity of supported Ni catalysts prepared by the traditional impregnation method was found to change after a first CO2 hydrogenation reaction cycle from 100 to 800 degrees C. The usually high CH4 formation was suppressed leading to full selectivity toward CO. This behavior was also observed after the catalyst was treated under methane or propane atmospheres at elevated temperatures. In situ spectroscopic studies revealed that the accumulation of carbon species on the catalyst surface at high temperatures leads to a nickel carbide-like phase. The catalyst regains its high selectivity to CH4 production after carbon depletion from the surface of the Ni particles by oxidation. However, the selectivity readily shifts back toward CO formation after exposing the catalysts to a new temperature-programmed CO2 hydrogenation cycle. The fraction of weakly adsorbed CO species increases on the carbide-like surface when compared to a clean nickel surface, explaining the higher selectivity to CO. This easy protocol of changing the surface of a common Ni catalyst to gain selectivity represents an important step for the commercial use of CO2 hydrogenation to CO processes toward high-added-value products. (AU)

• Processo FAPESP: 17/24348-7 - Desenvolvimento de catalisadores híbridos para a conversão de CO2 em produtos químicos e combustíveis
• Beneficiário: Bruno Henrique Arpini
• Modalidade de apoio: Bolsas no Brasil - Doutorado
• Processo FAPESP: 17/02317-2 - Interfaces em materiais: propriedades eletrônicas, magnéticas, estruturais e de transporte
• Beneficiário: Adalberto Fazzio
• Modalidade de apoio: Auxílio à Pesquisa - Temático
• Processo FAPESP: 14/50279-4 - Brasil Research Centre for Gas Innovation
• Beneficiário: Julio Romano Meneghini
• Modalidade de apoio: Auxílio à Pesquisa - Programa Centros de Pesquisa em Engenharia