Effect of mesoporous nanocrystalline supports on the performance of the Ni–Cu catalysts in the high-temperature water-gas shift reaction

Abstract

Ni–Cu based catalysts supported on different nanocrystalline powders were prepared and investigated in the high-temperature water gas shift (HTWGS) reaction. The supports were synthesized via a simple solid-state method and the prepared support possessed a BET area in the range of 18.6–239.6 m2 g−1. The active metals (Ni and Cu) were deposited on the catalyst supports via the wet impregnation method. The effects of Ni and Cu loadings, calcination and reduction temperatures, GHSV, and steam/gas molar ratio on the catalytic performance of the catalysts were studied. The results indicated that 7 wt%Ni-7.5 wt%Cu/CeO2–Al2O3 catalyst showed higher CO conversion compared to the other prepared catalysts and also produced a low concentration of methane during the reaction. This catalyst also presented higher stability than 7 wt%Ni-12.5 wt% Cu/CeO2–Al2O3 at 400 °C under a high GHSV value (30,000 (mL. h−1. gcat−1)) during HTWGS reaction. It was found that the increment in Cu loading from 5 wt% to 7.5 wt% decreased the CO conversion about 5.61% at 450 °C but methane concentration decreased significantly from 5.95% to 2.65%. The formation of Ni–Cu alloy in nickel-based catalyst improved the selectivity toward HTWGS reaction.