Effect of Cu loading on CeO2CeO2 for hydrogen production by oxidative steam reforming of methanol

Catalytic performance of Cu/CeO2Cu/CeO2 catalysts was studied as a function of Cu loading in the oxidative steam reforming of methanol (OSRM) reaction. The reduction of CuO/CeO2CuO/CeO2 catalysts evidenced the existence of different kinds of CuO species. Their reduction peaks shift to higher temperatures as a function of the CuO loading. The catalyst which exhibited a reduction peak at 242∘C showed low activity on the OSRM reaction and poor H2H2 selectivity. SEM, XRD and TPR analyses of this sample revealed the strong influence of the large crystallites of Cu on the catalyst performance. Catalysts with 2 and 6 wt% of copper showed a similar activity in the OSRM reaction. However, the highest H2H2 selectivity was observed on the 2Cu/CeO22Cu/CeO2 catalyst in the range of 210–230∘C. Above 230∘C, H2H2 selectivity was improved on the 6Cu/CeO26Cu/CeO2 sample and decreased in the 2Cu catalyst. A diminished H2H2 selectivity is attributed to the loss of the active copper phase by oxidation during catalytic reaction, as confirmed by TPR and EPR studies on the 2Cu catalyst after catalytic reaction.