The synergistic effects of Pt-OH and Pt⁰ enhanced the low-temperature catalytic performance of Pt/CNTs for preferential CO oxidation in a H₂ stream

In current era of pursuing low-carbon, hydrogen energy emerged as a pivotal zero-carbon energy source faces a critical challenge in terms of its practical implementation. Trace CO contaminants (~1% CO) in industrial hydrogen streams derived from hydrocarbons reforming can irreversibly poison Pt electrode of proton-exchange-membrane fuel cells (PEMFCs). The preferential oxidation of CO in H₂-rich stream (PROX) is considered as an effective strategy to eliminate CO. In this work, we synthesized the catalyst of 0.3Pt/CNTs-CIW via a colloidal impregnation method, which achieves unprecedented performance in PROX, delivering 100% CO conversion with 50% CO₂ selectivity across an exceptionally broad operational temperature window from 20 to 200 °C with a minimal Pt content of 0.3 wt%. Various characterizations reveal that the high efficiency derives from the active structures with the synergies of Pt-OH and Pt0. The adsorption of CO is weakened by the construction of Pt-OH and couples with OH in the form of COOH* which is then oxidized by OH* derived from adsorbed O₂ and H₂ on Pt⁰ with a low activation energy, resulting in high efficiency of CO oxidization. Beyond CO-PROX, this bifunction activation paradigm offers transformative potential for diverse catalytic systems involving competitive adsorption and redox coupling, such as low temperature oxidation of methane and volatile organic compounds abatement.