Low-pressure hydrogenation of CO2 to methanol over Ni-Ga alloys synthesized by a surfactant-assisted co-precipitation method and a proposed mechanism by DRIFTS analysis
| Autor: | Marco Antonio Rossi, José Mansur Assaf, Elisabete Moreira Assaf, Letícia F. Rasteiro |
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| Rok vydání: | 2021 |
| Předmět: |
Inorganic chemistry
02 engineering and technology General Chemistry 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences Catalysis 0104 chemical sciences chemistry.chemical_compound chemistry Pulmonary surfactant METANOL Phase (matter) Formate Methanol Particle size 0210 nano-technology Space velocity Ambient pressure |
| Zdroj: | Repositório Institucional da USP (Biblioteca Digital da Produção Intelectual) Universidade de São Paulo (USP) instacron:USP |
| Popis: | Ni-Ga alloy catalysts were synthesized by a surfactant-assisted co-precipitation method and were tested in CO2 hydrogenation to methanol at 10 bar and at ambient pressure. The presence of surfactant in the synthesis led to a decrease in particle size, with the catalyst produced using 1% of surfactant (C_1%) presenting the smallest and most homogeneous particle size. A difference between the catalysts was also observed in the change of the crystalline phase after the reaction, where the C_1% catalyst presented the lowest loss of the Ni5Ga3 active phase. Methanol productivity showed positive relations with smaller particle size and higher quantity of Ni5Ga3 crystalline phase remaining after the reaction, with the C_1% catalyst presenting the highest methanol productivity. Catalytic evaluation under different conditions showed that higher temperature and GHSV values led to poorer selectivity to methanol. The C_1% catalyst also presented good activity at ambient pressure and remained stable after 5 h, with no deactivation. A mechanistic study employing DRIFTS analyses found that the reaction pathway on Ni-Ga alloy involved both the RWGS and formate routes, as shown by the presence of formate, methoxy, and CO intermediates. |
| Databáze: | OpenAIRE |
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