Bimetallic Cu–Ni catalysts for the WGS reaction – Cooperative or uncooperative effect?

Abstract In this work, bimetallic Cu–Ni catalysts have been studied in the water-gas shift (WGS) reaction, and they have shown different levels of synergy and anti-synergy in terms of catalytic activity and selectivity to the desired products. Cu–Ni interactions alter the physicochemical properties of the prepared materials (i.e. surface chemistry, redox behaviour, etc.) and as a result, the catalytic trends are influenced by the catalysts' composition. Our study reveals that Cu enhances Ni selectivity to CO 2 and H 2 by preventing CO/CO 2 methanation, while Ni does not help to improve Cu catalytic performance by any means. Indeed, the monometallic Cu formulation has shown the best results in this study, yielding high levels of reactants conversion and excellent long-term stability. Interestingly, for medium-high temperatures, the bimetallic 1Cu–1Ni outperforms the stability levels reached with the monometallic formulation and becomes an interesting choice even when start-up/shutdowns operations are considered during the catalytic experiments. Highlights • Comparison of mono and bimetallic Cu–Ni catalysts for clean H 2 production via WGS. • Analysis of the synergy and anti-synergy behaviour of bimetallic Cu–Ni catalysts. • Cu enhanced Ni-based catalysts selectivity to CO 2. • Monometallic Cu catalyst showed high stability and resistance to start/stop cycles. [ABSTRACT FROM AUTHOR]