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

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/MO_x/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.