Cu-Ni-Al Spinel Oxide as an Efficient Durable Catalyst for Methanol Steam Reforming

Copper metal catalysts suffer from gradual loss of activity due to the agglomeration and sintering of active metals during the catalytic reaction processes. Herein, we show that enhanced catalytic durability for methanol steam reforming (MSR) can be achieved by using Ni modified Cu-Al spinel solid solution as catalysts without pre-reduction treatment. In so doing, Cu atoms can be gradually released from spinel structure after the initiating of reaction by non-spinel CuO entities. Incorporation of Ni in the spinel structure reveals two positive effects: slowing down the Cu releasing rate and producing even smaller Cu nanoparticles as compared to that of Cu-Al spinel. Since Ni2+ ions in spinel framework cannot be reduced during the catalytic process, we suggest that the remaining defective CuaNib square cAldO4 spinel structure plays a crucial role in stabilizing the formed Cu nanoparticles. The synthesized sample with 0.05 mol Ni per mol Cu shows the best catalytic performance as demonstrated by pretty stable activity during the long-term catalytic testing up to 2000 h. The findings show great commercial application potentials for the production of H-2 from MSR.