Electronic effect in PtPd alloy-on-carbon doping with nitrogen bifunctional electrocatalysts for enhancing hydrogen evolution and methanol oxidation

Different atomic ratios of PtPd alloy nanoparticles (NPs) supported on carbon doping with nitrogen-NC (Pt x Pd y /NC) are successfully prepared to simultaneously enhance hydrogen evolution reaction (HER) and methanol oxidation reaction (MOR), in which Pt 5 Pd 5 /NC with an atomic ratio of 5:5 has the best performance. Pt 5 Pd 5 /NC exhibits a significantly reduced HER overpotential (12 mV@10 mA cm −2 ) and the mass activity (MA) for MOR is up to 6.85 A mg −1 PtPd , 11.61 and 34.25 times higher than that of commercial Pt/C (Pt/C-JM) and commercial Pd/C (Pd/C-JM), respectively. Remarkably, coupling boosted HER on the cathode with accelerated MOR on the anode, efficient H 2 generation is achieved. This two-electrode flow cell only requires a cell voltage of 1.100 V at 100 mA cm −2 and can be stably operated for >300 h at 1.960 V with impressive long-life stability. Such performance even outperforms that of (IrO 2 ) OER‖HER (Pt/C-JM) cell. Electrochemical in-situ Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) analysis show that electronic effect is formed between N and PtPd and can oxidize the intermediate HCOO - at a lower potential (0.300 V), promote the desorption of the toxic intermediates and improve the catalytic property.