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Abstract: Here, the design and synthesis of a multispherical cavity carbon (MSCC) material with in situ silica modification and its application as anode catalyst supporter in proton exchange membrane fuel cells (PEMFC) are reported. The synthetic method involves a template procedure, where 10–30 nm sized silica nanospheres coated with polyvinylpyrrolidone (act as the substrate for aniline polymerization. Pyrolysis of the polymer layer and template etching lead to uniformly distributed MSCC materials. Both the pore sizes and the residue silica content in the inner cavities are controllable during the synthesis. It is further demonstrated that this MSCC material can be used as an anode catalyst supporter in PEMFC systems, where its self‐humidification properties result in enhanced durability. The MSCC‐supported anode exhibits only a 5.4% loss of current density and remains at 860 mA cm−2 after 10 h testing under nonhumidified condition, while commercial catalysts lost 25%. This justifies the promising application of MSCC in PEMFC systems. [ABSTRACT FROM AUTHOR]

Abstract: A novel self-humidifying membrane electrode assembly (MEA) has been successfully prepared by adding both a hydrophilic organic polymer (polyvinyl alcohol, PVA) and an inorganic oxide (silica) to the anode catalyst layer. This MEA shows excellent self-humidification performance under low-humidity conditions. A sample containing 3 wt.% PVA and 3 wt.% silica in the anode catalyst layer achieves a current density as high as 1100 mA cm−2 at 0.6 V, and the highest peak power density is 780 mW cm−2, operating at 60 °C and 15% relative humidity for both anode and cathode. The sample also shows excellent stability at low-humidity: after 30 h of continuous operation under the same conditions, the current density decreases just slightly, from 1100 mA cm−2 to ca. 900 mA cm−2, whereas with MEAs to which only PVA or silica alone had been added, the current densities after 30 h is just 700 mA cm−2 and 800 mA cm−2, respectively. The improved self-humidification performance can be attributed to the synergistic effect of two hygroscopic materials in the anode catalyst layer. [Copyright &y& Elsevier]

Highlights: [•] Mesoporous silica supported Pd-promoted gold catalyst was prepared. [•] Low Pd/Au atomic ratio of 0.05/1 can effectively decrease the gold particles size. [•] Pd0.2Au shows 8 and 3 times higher activity than the Au/MSN and Pd/MSN respectively. [•] Catalysts were characterized by XRD, N2 sorption, DRUV-vis, TPR, XPS and TEM. [Copyright &y& Elsevier]

Abstract: A high-performance, gold-promoted Pd catalyst with mesoporous hollow silica spheres as support, PdAu/MHSS, was prepared using an impregnation–reduction approach. The catalyst showed 10 times higher activity than commercial Pd/C catalyst and 6 times higher activity than Pd/MHSS catalyst. The conversion of phenol was 100% within 30min of reaction at 80°C. The catalyst was characterized by XRD, XPS, and TEM, which revealed that its high performance may result from both the high dispersion of active components on the MHSS, caused by the addition of gold, and the interaction between palladium and gold. [Copyright &y& Elsevier]