Simultaneously Promoted Water Resistance and CO Selectivity in Methanol Oxidation Over Pd/CoOOH: Synergy of Co-OH and the Pd-O-Co Interface.

Catalytic purification of industrial oxygenated volatile organic compounds (OVOCs) is hindered by the presence of water vapor that attacks the active sites of conventional noble metal-based catalysts and the insufficient mineralization that leads to the generation of hazardous intermediates. Developing catalysts simultaneously with excellent water resistance and a high intermediate suppression ability is still a great challenge. Herein, we proposed a simple strategy to synthesize a Pd/CoOOH catalyst that contains abundant hydroxyl groups and lattice oxygen species, over which a negligible effect was observed on CHOH conversion with 3 vol % water vapor, while a remarkable conversion reduction of 24% was observed over Pd/CoO. Moreover, the low-temperature CO selectivity over Pd/CoOOH is significantly enhanced in comparison with Pd/Co(OH). The high concentration of surface hydroxyl groups on Pd/CoOOH enhances the water resistance owing to the accelerated activation of HO to generate Co-OH, which replaces the consumed hydroxyl and facilitates the quick dissociation of surface HO through timely desorption. Additionally, the presence of Pd-O-Co promotes electron transport from Co to Pd, leading to improved metal-support interactions and weakened metal-O bonds. This in turn enhances the catalyst's capacity to efficaciously convert intermediates. This study sheds new insights into designing multifunctional catalytic platforms for efficient industrial OVOC purification as well as other heterogeneous oxidation reactions.