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Reduced graphene supported Co-Sn-Pd nanoparticle catalysts(Co 0.2 Sn x Pd y / rGO, x + y = 0.4) were successfully synthesized by reducing the trace amounts of ions (Pd 2+ , Sn 2+ , and Co 2+ ) in the presence of reduced graphene via an ultrasonic irradiation method. Characterization of the Co 0.2 Sn x Pd y /rGO catalysts by X-ray diffraction (XRD) and transmission electron microscopy (TEM) indicates that the Co 0.2 Sn 0.2 Pd 0.2 /rGO catalyst with a mean diameter of $3.8 nm is close to a single-phase solid solution. X-ray photoelectron spectroscopy (XPS) shows the binding energy of metallic Pd shifts to a higher angle in the Co 0.2 Sn x Pd y /rGO (x + y = 0.4) catalysts, indicating a shift of Pd electronic centre upon alloying with Co and Sn. Conventionally, ternary Co-Sn-Pd/rGO catalysts show greater oxygen reduction reaction (ORR) activities and durability than binary Pd-Co/rGO catalyst and 20 wt% Pt/C catalyst even at a very low Pd content. Among of the synthetic catalysts, the Co 0.2 Sn 0.2 Pd 0.2 /rGO catalyst exhibits the best ORR activity (E 1/2 = 0.91 V, k = −57 mV Á dec −1 ) and dominates a 4-electron pathway in the ORR process (n = 3.95 ± 0.09, H 2 O 2 <4%). Also, the Co 0.2 Sn x Pd y /rGO (x + y = 0.4) catalysts display a remarkable advantage of high methanol tolerance compared to that of the commercial 20 wt% Pt/C catalyst, which make them potential candidates for direct methanol fuel cells.

Ni‐P alloys have been successfully electrodeposited in the choline chloride and ethylene glycol with a molar proportion of 1:2(CE) electrolyte and their activities toward hydrogen evolution reaction (HER) have been also evaluated. The electrodeposition of Ni‐P alloy follows a co‐deposition process, and the bulk growth of which depends on an instantaneous nucleation under diffusion control. The morphologies of Ni‐P alloys are significantly influenced by the P content, and low P content can lead to a smooth surface. As expected, Ni‐9.0 wt.% P alloy shows an impressive HER catalytic performance with a Tafel slope (b) of 72.9 mV dec−1 and an overpotential of 105 mV at 50 mA, in agreement with its large ECSA (Cdl = 3.25 mF cm−2) and small interface charge‐transfer resistance. More interestingly, Ni‐9.0 wt.% P alloy exhibits a sustainable catalytic activity toward HER after 1000 cycling test with a tiny potential decline of ~10 mV at 100 mA cm−2. Such a striking HER activity of Ni‐9.0 wt.% P alloy can be attributed to the synergistic effect among the induced active sites from lattice contraction, negatively charged P incorporation, and a mixed nanometre crystal and amorphous structure. Thus, Ni‐P alloy electrodeposited in a CE‐based electrolyte can be used as a promising electrode material with high HER activity in alkaline solutions for hydrogen production.

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