The use of Pd-based catalytic materials as electrocatalysts for formic acid oxidation reaction (FAO), hydrogen evolution reaction (HER) and oxygen reduction reaction (ORR) has been well-established for some time. The incorporation of a second phase can markedly enhance the electronic properties of the composites. The combination of different compounds with superior electronic properties is crucial for the design and preparation of catalysts with optimal catalytic activity and stability. In this study, a novel cauliflower-like Pd/MoC||Mo2C/C composite with heterostructure is synthesised, which exhibits excellent catalytic activity and long-term stability against FAO, HER, and ORR. The high-temperature treatment results in the formation of small-sized Mo₂C and MoC nanoparticles on the carbonaceous substrate, thereby exposing a greater number of Mo and Mo-C active sites. The formation of heterostructures between Mo₂C and MoC optimises the electronic structure of the composite, thereby facilitating enhanced reaction processes. In terms of FAO, the mass activity of Pd/MoC||Mo2C/C is 1.87 A mgPd−1, which is 2.75 times higher than that of Pd/C (0.68 A mgPd−1). As for the HER, a much lower overpotential of 28 mV is required to achieve a current density of 10 mA cm−2 compared to Pd/C (40 mV). Fortunately, Pd/MoC||Mo2C/C also shows excellent ORR activity with a half-wave potential of 0.798 V and the maximum current density of approximately 5.73 mA cm−2 in alkaline electrolyte. These findings may contribute to the development of other noble metal-based materials loaded on intermetallic compounds with stable and effective electrocatalytic performance.
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