Synthesis and evaluation of novel Cu-based adsorbent-containing catalysts for CO₂ hydrogenation to methanol and value-added products

In this work, sequential incipient wetness impregnation method was used to synthesize Cu/Al₂O₃, Cu/Na₂O/Al₂O₃ and Cu/CaO/Al₂O₃ catalysts in different compositions for CO₂ conversion to value-added products. Synthesized catalysts were characterized using various analytical techniques and their performances for CO₂ catalytic conversion were tested in a high-pressure packed bed reactor under reaction conditions of P = 60 bars, T = 300 °C, and H₂/CO₂ = 3. The obtained results revealed that the type of adsorbent had a significant impact on CO₂ conversion, with CaO-containing catalyst being more efficient for methanol selectivity. Increased Cu content from 10 wt% to 30 wt% with fixed CaO content of 10 wt% resulted in a small increase in CO₂ conversion where the highest CO₂ conversion of 16.44% and the highest methanol selectivity (17.75%) were obtained for catalyst containing 20 wt% of copper. The best performing catalyst was further promoted using 0.5 wt% Rh promoter which improved both methanol selectivity and space time yield to 23.2% and 0.08 g_MeOHg_cat⁻¹h⁻¹, respectively. The comparative high performance of the Rh-promoted catalyst was attributed to smaller metal oxide particle size with uniform dispersion, presence of effective hydrogen spill over, moderate basic sites, surface defects and presence of induced copper species.

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Published in: Journal of Environmental Chemical Engineering
License: http://creativecommons.org/licenses/by/4.0/
See article on publisher's website: https://dx.doi.org/10.1016/j.jece.2024.112325