Preferential Oxidation of CO in H2 on Pure Co3O4−x and Pt/Co3O4−x

Abstract

AbstractDriven by the development of a catalyst made of earth‐abundant elements for on‐board purification of H2 of this energy conversion technology, preferential oxidation (PROX) on pure Co3O4 nanorods and Co3O4 nanorods with supported Pt nanoparticles was explored with the aid of in situ studies. This catalyst remains its 100 % conversion of CO in H2 at a gas hourly space velocity of 42 857 mL h−1 g−1 at 120 °C for at least 96 h. In situ studies showed that the active surface phase during PROX is nonstoichiometric Co3O4−x. A correlation between density of surface oxygen vacancies and conversion of CO to CO2 suggest that oxygen vacancy is a necessary component of a catalytic site for PROX on Co3O4−x. Compared to pure Co3O4 nanorods, anchoring Pt nanoparticles on Co3O4 nanorods unfortunately increases selectivity for oxidation of H2 owing to the low dissociation barrier of molecular H2 on Pt. Co3O4−x exhibits much higher selectivity for CO oxidation in PROX than Pt/Co3O4−x at a temperature lower than 140 °C.