Comparative performance of M-MCM-41 (M: Cu, Co, Ni, Pd, Zn and Sn) catalysts for steam reforming of methanol

One-pot hydrothermal procedure was used to synthesize high surface area M-MCM-41 (M: Cu, Co, Ni, Pd, Zn, and Sn) nanocatalysts. The M-MCM-41 catalysts containing 10 wt% of different metals were examined to evaluate the performance of individual metals in steam reforming of methanol (SRM) in terms of activity, selectivity and long term stability under similar operating conditions. The fresh and spent catalysts were characterized using BET, XRD, TGA-DSC, TEM, TPR, ICP-OES, EDX, Raman, and FTIR analytical techniques. Cu-MCM-41 showed the best performance in terms of activity and selectivity among the different catalysts investigated in this study. The overall SRM reactivity trend for different metals based on methanol conversion followed the order: Cu-MCM-41 > Pd-MCM-41 > Sn-MCM-41 > Ni-MCM-41 ≈ Zn-MCM-41 > Co-MCM-41. The catalytic performance of Cu-MCM-41 at 250 °C using 1:3 methanol-water mole ratios showed 100% H2 selectivity, ∼6% CO, and no methane formation. The time-on-stream studies conducted continuously for 40 h at 300 °C revealed that Cu-MCM-41 was the most stable catalysts and displayed consistent steady state conversion (up to74%). The SRM activity of Pd, Sn and Zn was comparatively better; however, they deactivated steadily with time. Although coking was a major factor in deactivation of the catalysts, degradation of the mesoporous structure and thermal sintering appeared to play an influential role in deactivation, particularly in the case of Sn-MCM-41.