Esmaeil GhasemiKafrudi, N. Mostoufi, Alimorad Rashidi, Reza Zarghami
A novel hybrid Cu(30 %)-ZnO(41 %)/Al 2 O 3 /MWCNT catalyst was developed to enhance hydrogenation of CO 2 to methanol. Multi-walled carbon nanotubes (MWCNTs) were functionalized and incorporated into catalysts with varying carbon contents (0–12 wt%) via co-precipitation. The catalysts were characterized using standard techniques, including XRD, FESEM, TEM, FTIR, Raman spectroscopy, TPR, and CO 2 -TPD, to evaluate their structural, morphological, and chemical properties. The results demonstrated that MWCNTs integration significantly improved metal dispersion, prevented particle agglomeration, and enhanced CO 2 adsorption. The experiments showed that, among all catalyst formulations and the two industrial reference samples, the catalyst with 8 wt% MWCNTs exhibited the highest methanol yield (13.4 %) and a 25 % increase in space–time yield compared to the MWCNT-free catalyst (11.0 %). Furthermore, the catalyst demonstrated excellent long-term stability, preserving its structural integrity and catalytic performance over 60 h of continuous operation. The implementation of this hybrid catalyst as a replacement for the MWCNT-free formulation in the CO 2 hydrogenation process resulted in a 6.1 % reduction in total energy demand, which consequently led to a 7.3 % decrease in greenhouse gas emissions (32.5 kg CO 2 /ton MeOH). These findings confirm that incorporation of MWCNTs constitutes an effective hybrid-support strategy for structural modulation and performance enhancement in CO 2 hydrogenation catalysts. • Novel Cu–ZnO/Al₂O₃/MWCNT catalyst boosts CO₂ hydrogenation to methanol. • MWCNTs enhance Cu dispersion, reduce agglomeration, and improve reducibility. • 8 wt% MWCNTs gives highest methanol yield (13.4 %) and 25 % higher yield. • Catalyst shows excellent 60‑h stability with preserved structure and activity. • Reduces energy use by 6.1 % and GHG emissions by 7.3 % per ton MeOH.