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The hydrogen oxidation reaction (HOR) has recently attracted great attention, yet the poor performance of HOR over the platinum group metal-free (PGMs-free) catalysts in alkaline conditions strongly impedes the development of hydroxide-exchange membrane fuel cells. Here, we demonstrate that the phase and interface engineering of nickel carbide (Ni3C) nanobranches can significantly enhance the alkaline HOR performance. Specifically, such interface engineering is realized through a facile annealing treatment of a branched Ni3C nanostructure. As a promising PGMs-free HOR catalyst, the strong interfacial synergy of Ni/Ni3C significantly enhances the HOR performance in alkaline media, with the HOR activity being comparable to that of a commercial Pt/C catalyst, and it demonstrates excellent CO tolerance. Mechanism studies show that the interfacial synergy facilitates electron transfer from Ni to Ni3C and thus regulates the absorption strengths of *H and *OH. This work opens up a new avenue for the design of high-performance PGM-free catalysts for electrocatalysis and beyond. [ABSTRACT FROM AUTHOR]

Herein, in-situ Zr 3 [Al(Si)] 4 C 6 -based composites with 10–40 vol% ZrB 2 –SiC (2-to-1 molar ratio) were prepared by hot-pressing sintering at 1850 °C. The simultaneously incorporated ZrB 2 –SiC constitute multicomponent reinforcements and has a synergistic effect on the matrix, which improves the sinterability, mechanical properties, and oxidation resistance of materials. It is found that both of the toughness and strength increase first and then decrease with the increasing content of ZrB 2 –SiC, while the hardness increases near linearly. Zr 3 [Al(Si)] 4 C 6 –ZrB 2 –SiC shows high strength (623 MPa), toughness (7.59 MPa m1/2), and hardness (18.6 GPa), which can be ascribed to the synergistic mechanisms of the binary ZrB 2 –SiC including fine-grained strengthening, particle reinforcement, intragranular microstructure, grain's pull-out and crack bridging, etc. In addition, the oxidation kinetics of as-prepared materials follow the parabolic law, and the composite shows a low oxidation rate of 0.87 × 10−5 kg2 m−4 s−1 when oxidized at 1400 °C. [ABSTRACT FROM AUTHOR]

Pt-SnO 2 catalysts supported on modified carbon fibers were prepared by an electrospinning method with polyacrylonitrile (PAN) as the carrier and polyvinylidene fluoride (PVDF) as the pore-forming agent. The physical-chemical property and catalytic performance of the as-synthesized composites were characterized by XRD, SEM, BET, Chronoamperometry and AC impedance. The results showed that the porous structure in the carbon fibers was formed after calcination at 800 °C in the presence of PVDF. When the weight ratio of PAN/PVDF was 1:0.8, the porous carbon fibers had the largest surface area of 374.85 m2 g−1, which was 3.3 times of carbon fibers prepared without PVDF. The in-situ formed porous structure in carbon fibers can provide more active sites for the catalytic reaction. Therefore, the porous carbon fiber supported Pt-SnO 2 catalysts exhibited the best catalytic performance with the ethanol oxidation peak current value of 140.14 mA cm−2 and the electrochemical active area up to 54.296 m2 g−1. DEFC performance showed that the best potential was 0.7 V and the maximum of power density was 18.1 mW cm−2 when the oxygen flow rate and the temperature were 100 mL min−1 and 80 °C, respectively. Pt-SnO 2 catalysts supported on modified carbon fibers were prepared by an electrospinning method with polyacrylonitrile (PAN) as the carrier and polyvinylidene fluoride (PVDF) as the pore-forming agent. When the weight ratio of PAN/PVDF was 1:0.8, the porous carbon fibers had the largest surface area of 374.85 m2 g−1. The porous carbon fiber supported Pt-SnO 2 catalysts exhibited the best catalytic performance with the ethanol oxidation peak current value of 140.14 mA cm−2 and the electrochemical active area up to 54.296 m2 g−1. Image 1 • Porous carbon fibers were prepared by one-step electrospinning method. • PVDF was used as the pore-forming reagent during the carbonization process. • Porous C/Pt-SnO 2 exhibited the best catalytic activity for the ethanol oxidation. [ABSTRACT FROM AUTHOR]