Enhancing effect of MgO modification of Cu–Al spinel oxide catalyst for methanol steam reforming

Cu–Al spinel oxide (CA) as a sustained release catalyst has been successfully used in methanol steam reforming and it is highly required to improve its catalytic performance. Here, surface modification of the CA with various MgO loadings was performed. Characterization results showed that MgO dopant had strong interaction with the CA, resulting in a substantial change of the surface microstructure. Importantly, a small portion of lattice Cu²⁺ was phased out while partial Mg²⁺ cations incorporated into the spinel structure, giving rise to a variation of the cation distribution. Consequently, the change of the Cu²⁺ surrounding environment made it become hard to be reducible, thus the doped catalysts showed a lower copper releasing rate and smaller copper particles. Then, the activity and stability were enhanced when a suitable amount of MgO was highly dispersed. Excess amount of crystalline MgO gave rise to easy coking that resulted in an inferior catalytic performance.