Enhanced catalytic performance of Au/CuO-ZnO catalysts containing low CuO content for preferential oxidation of carbon monoxide in hydrogen-rich streams for PEMFC

In this study, effects of Au and CuO loadings in Au/CuO-ZnO nanocatalysts for preferential oxidation of carbon monoxide in H2-rich streams (PROX) are investigated. CuO-ZnO supports were synthesized by a co-precipitation method. Au was also incorporated into the catalysts by a deposition-precipitation procedure. The catalysts were characterized by XRD, BET surface area, FESEM, HRTEM, H2-TPR, FTIR, and CO-TPD. 2-10 nm Au nanoparticles are dispersed on CuO-ZnO support and significantly enhance the reducibility of CuO. The Au/CuO-ZnO catalysts containing low amount of CuO were found to be more active for PROX compared to the Au/ZnO catalyst. Moreover, as more CuO is added to Au/ZnO, the CO2 selectivity increases in the whole PROX temperature range. The catalyst containing 2 wt% Au and 1 wt% CuO on ZnO exhibited the highest activity and selectivity in the operating temperature range of PEM fuel cells. The activity of this catalyst also remained almost intact during 900 min of PROX time on stream at 80 °C.