Electro-catalytic steam reforming of methane over Ni-CeO2/γ-Al2O3-MgO catalyst

Abstract

Catalytic steam reforming of methane with Ni-based catalysts is essential for industrial hydrogen production, but the high reforming temperature results in the catalyst deactivation by severe carbon deposition. In this work, a novel electro-catalytic protocol for steam reforming of methane was developed with aims of lowering the reforming temperature and prolonging the catalyst life. Three Ni-based catalysts, i.e., Ni/γ-Al2O3 (Ni/Al2O3), Ni/γ-Al2O3-MgO (Ni/AM) and Ni-CeO2/γ-Al2O3-MgO (Ni-CeO2/AM) were prepared for electro-catalysis to investigate the effects of current intensity, reforming temperature, and steam to carbon ratio on methane conversion, H2 yield and CO selectivity. Moreover, stability tests were performed on the three catalysts. The results indicated that the presence of electric current promoted the methane steam reforming at relatively low temperatures. Among the three catalysts, Ni-CeO2/AM showed the best performance on catalytic efficiency. Under conditions of 600 °C and current of 4.5A, CH4 conversion, H2 yield and CO selectivity achieved 96.4%, 75.3% and 40.1% respectively over Ni-CeO2/AM, which were comparable with those from conventional process at 700 °C. Moreover, after a 9-hour stability test, the CH4 conversion was maintained over 95% under Ni-CeO2/AM. Characterization results of the catalysts from the stability texts showed that the current could help generate more active centers for CH4 activation while inhibit the conversion of coke precursors into carbon on the catalyst surface.