Na+-intercalated carbon nanotubes-supported platinum nanoparticles as new highly effective catalysts for preferential CO oxidation in H2-rich stream

Na+-intercalated carbon nanotubes (Na-CNTs) were obtained by impregnation of CNTs with sodium acetate followed by annealing at high temperatures under argon. Stable Na-CNTs-supported Pt catalysts (Pt/Na-CNT catalysts) were then prepared for hydrogen purification via preferential CO oxidation in a H2-rich stream (CO-PROX). Characteristic studies show that the content of Na+ species in CNTs is increased with increased annealing temperature and the Pt nanoparticles with an average size of 2–3 nm are uniformly dispersed on the surfaces of Na-CNTs. An optimized Pt/Na-CNT catalyst with 5 wt% Pt loading can completely remove CO from 40 °C to 200 °C. This catalyst also exhibits long-term stability for 1000 h at 100 °C in feed gas containing 1% CO, 1% O2, 50% H2, 15% CO2, and 10% H2O balanced with N2. The electron transfer between the Pt nanoparticles and Na+ species plays an important role in enhancing the CO-PROX performance of the catalyst.

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► Na+-intercalated CNTs (Na-CNTs) are obtained by annealing NaOAc/CNTs under Ar.
► The content of Na+ species in CNTs is increased with increased annealing temperature.
► 5% Pt/Na-CNTs-500 can completely remove CO in a H2-rich stream at 40−200 °C.
► CO-PROX can be accomplished in a H2 stream containing CO2 and H2O vapor for 1000 h.
► The electronic interactions between Pt and Na+ account for the enhanced performance.