Durable copper–zinc catalysts modified with indium oxide in high temperature steam reforming of methanol for hydrogen production

The catalytic activity of Cu/ZnO decreases gradually in the high temperature steam reforming of methanol to hydrogen and carbon dioxide at 400 °C or above. Addition of indium oxide to Cu/ZnO results in significant deactivation of the Cu surface. The turnover frequency (TOF) of the catalyst containing 4 wt.% of In2O3 is reduced to ca. 1/10, but the activity is stabilized. Partial aggregation of indium oxide takes place during the reaction. Presence of zirconium oxide in the catalytic system greatly mitigates the deactivation with indium oxide. The activity of Cu/ZnO/ZrO2 is also stabilized by the addition of indium oxide, and the by-production of carbon monoxide is significantly suppressed. No aggregation of indium oxide particles occurs in the presence of zirconium oxide. The activity of Cu/ZnO/ZrO2 modified with 2 wt.% of indium oxide is comparable to that of the unmodified Cu/ZnO.

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► Methanol steam reforming was carried out at 400 °C over Cu catalysts.
► In2O3 deactivates Cu/ZnO, but activity is stable.
► Activity of In2O3–Cu/ZnO/ZrO2 is stable and comparable to that of Cu/ZnO.
► In2O3 stabilizes activity of Cu surface and suppresses CO by-production.