Tuning the highly dispersed metallic Cu species via manipulating Bronsted acid sites of mesoporous aluminosilicate support for CO2 hydrogenation reactions

Copper-based catalysts have been widely recorded as efficient catalysts of CO2 hydrogenation reaction for producing chemicals and fuels, which not only contributes to decreasing CO2 emissions benefiting for environmental issue, but also alters the industrial concepts for fine chemicals production. CuO-ZnO-ZrO2 (CZZ) composite is intensively investigated for methanol production through CO2 hydrogenation which is due to its high CO2 activation and water tolerance abilities during the reaction. In this work, highly dispersed metallic Cu degrees species from the CuO-ZnO-ZrO2 catalyst have been fabricated with the assistance of the mesoporous aluminosilicate support Al-TUD-1. The amorphous 3D-structured Al-TUD-1 presents extremely high surface areas ( > 600 m(2) g(-1)) and abundant Bronsted acid sites that could play a role for Cu partial incorporation into the siliceous structure and as an anchor for Cu degrees nanoparticles stabilization. As a result, the metallic Cu surface area of the hybrid CZZ@Al-TUD-1 catalyst (Si/Al atomic ratio of 25) could be increased to the maximum value of 49.0 m(2) g(copper)(-1), which is higher than the value for the initial pure CZZ (38.7 m(2) g(copper)(-1)). Theoretical DFT simulation confirms that the Al atoms in the alumino-silicate support's framework form hydroxyl sites for anchoring efficiently metallic Cu species thus creating highly dispersed and stable Cu degrees nanoparticles in the CZZ@Al-TUD-1 hybrid materials. The catalytic results obtained over the hybrid CZZ@Al-TUD-1 (Si/Al atomic ratio of 25) catalyst in the CO2 hydrogenation into methanol are following: the methanol production over 840 g kg(cu)(-1) h(-1) or 180 g kg(cat)(-1) h(-1) at 280 degrees C and 20 bar. Furthermore, the physically mixed composite catalysts obtained from CZZ and Al-TUD-1 could be used as bi-functional catalysts for the direct CO2 hydrogenation into dimethyl ether with relatively high productivity in DME (41 g kg(cat)(-1) h(-1) at 260 degrees C and 20 bar). The results herein provide an understanding of the nature of the strong metal-support interaction and a new insight into designing the Cu-based catalysts for CO2 hydrogenation reactions.