Facile preparation of hierarchical CuO–CeO2/Ni metal foam composite for preferential oxidation of CO in hydrogen-rich gas

Abstract

A series of CuO–CeO2/Ni metal foam (MF) composite catalysts with hierarchical structures were prepared using macroporous nickel foams with copper–cerium hydrosols. The catalytic performance of the CuO–CeO2/Ni MF composite was found to be superior to those of CuO/Ni MF and CeO2/Ni MF in terms of the preferential oxidation of CO in excess hydrogen. The molar ratio of Ce to Cu markedly influenced the activity of the CuO–CeO2/Ni MF composite. At a weight hourly space velocity of 90,000 h−1, CuO–CeO2/Ni MF prepared at a Ce/Cu molar ratio of 10 (CuCe110/Ni MF) had the lowest complete CO conversion temperature (130 °C), which was 30 °C lower than that of CuCe110 powder. Moreover, an O2 conversion value of higher than 80% and a CO2 selectivity of about 70% were found for CuCe110/Ni MF at 130 °C. The high activity and excellent stability of CuCe110/Ni MF catalyst can be ascribed to its high surface area, high dispersion of CuO, and interconnected three-dimensional reticular configuration of nickel metal support, which enhance the interaction between CuO and CeO2. This type of CuO–CeO2/Ni MF composite can potentially be used in compact micro-reactors for CO removal.