Crystal plane induced metal-support interaction in Pd/Pr-CeO2 catalyst boosts H2O-assisted CO oxidation

•H2O promotes the CO oxidation on Pr-CeO2 nanorods supported Pd catalyst.•High dispersed Pd and oxygen vacancy served as the active sites for CO and O2 activation in the presence of H2O.•CO oxidation mainly follows the H2O-mediated L-H mechanism and formate pathway in the presence of H2O.•Pd/Pr-CeO2-NRs catalyst exhibits outstanding SO2 resistance in the presence of 100 ppm SO2.