Viability of Au/La2O3/HAP catalysts for the CO preferential oxidation reaction under reformate gas conditions

The viability of gold supported on lanthanum-modified HAP catalysts is investigated for CO preferential oxidation (PROX) in H-2-rich stream. All samples comprise small nanoparticles (NPs) of Au (< 4 nm). Addition of La enhances the chemisorption of CO, whereas it lowers that of H-2 and H2O. Moreover, lanthanum improves the reducibility of the catalysts and the mobility of oxygen. FTIR studies show that under CO oxidation conditions Au exists in two distinct forms on La-promoted samples, namely Au sigma+ and Au+ species. The catalytic tests under different PROX conditions show an improvement of the performance with lanthanum addition. The observed improvement is linked to suitable chemical properties, whereas efficiency dependence on Au NP sizes is rather secondary. At 80 degrees C, La-rich catalysts completely eliminate CO and prove to be selective (66%) under realistic PROX conditions (in the presence of H2O and CO2). Moreover, they are exceptionally stable during an extended period (240 h).

Automated summary

The viability of gold supported on lanthanum-modified HAP catalysts for CO preferential oxidation in H-2-rich stream was investigated. Addition of lanthanum enhanced the chemisorption of CO and improved the reducibility and oxygen mobility of the catalysts. Catalytic tests showed an improvement in performance with lanthanum addition, with the size of gold nanoparticles having a secondary effect on efficiency. Lanthanum-rich catalysts completely eliminated CO and exhibited stable selectivity under realistic PROX conditions.