Innovative Charge-Tuning for Highly Dispersed Pt Catalysts: Achieving Deep CO Removal in Industrial H2 Purification for Fuel Cells

Proton exchange membrane fuel cells have strict requirements for the CO concentration in H₂-rich fuel gas. Here, from the perspective of industrial practicability, a highly dispersed Pt catalyst (2–4 nm) supported on activated carbon (AC), which was modified by electronic promoters (K⁺) and structural promoters (isopropanol), is studied in detail. Compared with traditional metal oxide supports, the K–Pt/AC catalysts, which benefit from the tuned charge distribution, achieve a significant reduction of CO (from 1% to <0.1 ppb) under H₂-rich conditions and show potential for used in large-scale industrial hydrogen purification. Experimental results and theoretical calculations reveal that the K atom, with its lower electronegativity, contributes to the shift of surface Pt²⁺ to a lower binding energy due to the presence of oxygen species on the AC surface. This facilitates oxygen activation and accelerates desorption of the CO₂ product, thereby accelerating the reaction process and enabling the deep removal of CO in a hydrogen-rich atmosphere.