Low-Pt anodes with gradient molybdenum isomorphism for high performance and anti-CO poisoning PEMFCs

The development of low Pt-loading hydrogen oxidation reaction electrocatalysts with high catalytic activity, durability, and resistance to CO poisoning is essential for the commercialization of proton exchange membrane fuel cells. Herein, two hybrid catalysts coupled with single atoms are prepared. Electrochemical tests show that PtMo1/KB (Ketjen Black) (1.85 wt.% Pt) exhibits extraordinary HOR activity and durability, with the mass activity in electrochemical cells and even PEMFCs are 8.36 and 2.71 times higher than that of commercial Pt/C, respectively. In addition, PtMo10/KB with novel configuration performed super high CO resistance (1000 ppm) in both three electrode and PEMFC measurement with an ultra-low Pt loading of 1.56 wt.%, demonstrating the high application value in the next generation highly efficient PEMFC. DFT calculations also show that the adsorption energy of the intermediates H⁎ and CO is optimized by tuning the d-band center of Pt, thus enhancing the HOR activity and CO tolerance of the catalyst. Meanwhile, in situ CO-adsorption surface-enhanced infrared adsorption spectroscopy also confirms that the weakening of the Pt-CO bond strength and the adsorption energy of CO contributes to the improvement of CO tolerance in PtMo10/KB.