Cu and Cu/ZnO Carbon-Based Catalysts for the Water-Gas Shift Reaction

In this work, water-gas shift reaction is studied using Cu/ZnO catalysts supported on activated carbons derived from residual olive stone, obtained by physical activation with steam or CO 2 . The steam-activated support, ACH 2 O, exhibits high surface area and broad pore size distribution, which facilitates Cu dispersion. This catalyst displays very high catalytic activity, without the need to incorporate ZnO, showing X CO = 80 %, full selectivity to H 2 , and a promising hydrogen productivity of 120 μmol·(g Cu-ICP ·s) −1 at 300 °C. The CO 2 -activated support shows a lower surface area, mainly dominated by micropores, yielding a lower Cu dispersion. The addition of ZnO enhances Cu dispersion and its catalytic activity, but it remains lower than that of Cu-ACH 2 O. These results are slightly better than those obtained by a commercial catalyst, Cu/ZnO, suggesting that an adequate design of the porosity support can avoid the need for ZnO as promoter, even using a more renewable and sustainable synthesis pathway.