The synergistic effects of Pt-OH and Pt 0 enhanced the low-temperature catalytic performance of Pt/CNTs for preferential CO oxidation in a H 2 stream

In the current era of pursuing low carbon, hydrogen energy emerged as a pivotal zero-carbon energy source, but faces a critical challenge in terms of its practical implementation. Trace CO contaminants (~1% CO) in industrial hydrogen streams derived from hydrocarbon reforming can irreversibly poison Pt electrodes of proton-exchange-membrane fuel cells. 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 oxidation. 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.