H2 oxidation as criterion for PrOx catalyst selection: Examples based on Au–CoOx-supported systems

• A new approach for understanding PrOx reaction over gold- and cobalt-based catalysts.
• Splitting CO and H2 oxidation to study the selectivity of the CO-PrOx reaction.
• Emphasizing the fundamental role of the support in the H2 combustion and its effect in the overall selectivity.
• Fine tune of the oxygen storage capacity of the catalysts to achieve the best activity/selectivity balance.

A new approach for understanding PrOx reaction over gold catalysts is proposed in this work. The competition between H2 and CO oxidation has been studied over a series of Au/MOx/Al2O3 (M = Ce and Co) catalysts in simulated post-reforming gas stream, containing H2O and CO2 for H2 cleanup goals. The catalysts’ behavior is correlated to their oxygen storage capacity, redox behavior, and oxidation ability. The estimation of the reaction rates reveals that in these solids the H2 combustion, the selectivity limiting factor in the PrOx process, is mainly controlled by the support and not by the gold presence. The possible use of the hydrogen oxidation reaction as a catalyst selection criterion is discussed.

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