Cu/REO (RE = La, Pr, Sm, Y, Ce) catalysts for methanol steam reforming: Understanding the interaction between Cu and individual REO supports

With the objective to develop applicable catalysts for methanol steam reforming (MSR) to generate H2, five individual REOs were prepared as supports for Cu/CuO to understand the Cu/CuO-support interaction. Pure REO supports with a cubic phase are successfully fabricated except that monoclinic La2O2CO3 carbonate is formed for La2O3 sample, which has negative effect on the reaction. The reaction performance ranks as 5 % Cu/CeO2 > 5 % Cu/Sm2O3 > 5 % Cu/Pr6O11 > 5 % Cu/Y2O3 > 5 % Cu/La2O3 for the samples. It has been disclosed that the quantities of surface basic sites, active O2– species, Cu+ contents/percentage and active Cu surface area are positively correlated to the reaction performance. Thus, the interaction together of these four factors decides the reaction performance. In addition, In-situ DRIFTS results of CH3OH adsorbing/steam reforming have demonstrated that on the optimal 5 % Cu/CeO2, the reactive monodentate m-HCOO* intermediate is formed, which is absent on 5 % Cu/Y2O3 with worse performance.