Stearic Acid Induced Hydrophobization of Pt/Al<sub>2</sub>O<sub>3</sub> Catalysts to Boost the Stability of Preferential\nOxidation of CO in Hydrogen

For\nindustrial hydrogen purification in the methanol-reforming\nprocess, it is crucial to develop catalysts that exhibit excellent\nwater tolerance for preferential CO oxidation (CO-PROX) in the presence\nof a high amount of H<sub>2</sub>O. Herein, the hydrophobic strategy\nwas proposed by bridging stearic acid molecules on the surface of\nthe Pt/Al<sub>2</sub>O<sub>3</sub> catalyst. The stearic acid molecules\nsignificantly enhanced the hydrophobicity of the Pt/Al<sub>2</sub>O<sub>3</sub> catalyst, increasing the water contact angle from 20.1°\nto 150.2°, avoiding the water coverage of active sites, and extending\nthe lifetime of the catalyst. By modulating the stearic acid treatment,\nthe formation of the R–O–Pt structure has been successfully\navoided to a certain extent, maintaining the ability of CO linear\nadsorption on the Pt sites with the high Pt electron density. Compared\nwith the Pt/Al<sub>2</sub>O<sub>3</sub> catalyst with poor stability,\nthe hydrophobic Pt/Al<sub>2</sub>O<sub>3</sub> catalyst achieved a\n100% CO conversion in the presence of CO<sub>2</sub> and H<sub>2</sub>O within the temperature range of 140–200 °C and maintained\ncatalytic stability over 100 h. This work gives a novel approach to\nmitigate the adverse effects of water on the catalyst in realistic\nindustrial CO preferential oxidation.