Propanol formation from CO2 and C2H4 with H2 over Au/TiO2: Effect of support and K doping

•Highly selective propanol synthesis from CO2 with C2H4 and H2 over K–Au/rutile.•Decreased C2H4 hydrogenation with increased temperature due to catalyst design.•Morphological study of different TiO2 structures before and after Au and K deposition.•Two kinds of Au NP on TiO2 in the rutile structure obtained by HAADF-STEM.

The direct conversion of CO2 with C2H4 and H2 into propanol was investigated over K-promoted Au/TiO2_r (rutile) and Au/TiO2_a (anatase) catalysts at 473 K and 523 K. For both catalytic systems, the propanol selectivity increased with rising K loading, while the conversion of CO2 decreased. Both effects of the promoter diminished at 523 K. However, irrespective of K loading and reaction temperature, K–Au/TiO2_r materials showed higher propanol selectivity than K–Au/TiO2_a. In addition, the non-desired conversion of ethylene into ethane over the rutile-based catalysts decreased with rising temperature from 473 K to 523 K, while an increase was observed for the anatase-based materials. Taking into account the results of HAADF-STEM analysis, the metal-support interaction influencing both size and distribution of Au species was assumed to be a reason for the support effect on the target and side reactions.

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