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Tungsten carbide (WC)-based materials are widely considered as the hydrogen evolution reaction (HER) process catalysts due to their “Pt-like” electronic structure. Nonetheless, traditional powder electrodes have a high cost, and display problems related to the process itself and the poor stability over operation time. This paper presented a self-supported asymmetric porous ceramic electrode with WO3−x whiskers formed in situ on the walls of the finger-like holes and membrane surface, which was prepared by combining phase inversion tape-casting, pressureless sintering, and thermal treatment in a CO2 atmosphere. The optimized ceramic electrode displayed good catalytic HER activity and outstanding stability at high current densities. More specifically, it demonstrated the lowest overpotentials of 107 and 123 mV and the lowest Tafel slopes of 59.3 and 72.4 mV·dec−1 at 10 mA·cm−2 in acidic and alkaline media, respectively. This superior performance was ascribed to the structure of the ceramic membrane and the charge transfer efficiency, which was favored by the in situ developed WC/WO3−x heterostructure and the oxygen vacancies.

Li

A novel green-yellow emitting Ca1.5Mg0.5Si1-xLixO4-δ:Ce3+ phosphor with high quantum efficiency and thermal stability was discovered for applications in near ultraviolet pumped white light-emitting diodes. Its crystal structure was determined with a single-particle diagnosis approach. The Si sites in the SiO4 tetrahedra are reported for the first time to accommodate Li+ ions. This substitution, confirmed by 6Li solid-state NMR and T.O.F. neutron powder diffraction, causes a disordered occupation of Ca/Mg in the Ca3MgSi2O8 host and favors a phase transformation at ∼330 °C, which results in the formation of the novel phosphor. The produced phosphor was efficiently excited by near UV light peaking at 365 and 410 nm and produced broad green-yellow emission with peaks at 500 and 560 nm, respectively. Its quantum efficiency reached 88.4% (internal) and 55.7% (external) under excitation at 365 nm, and 80.5% (internal) and 42.7% (external) under excitation at 410 nm, while the decrease of luminescence intensity at 200 °C was small (∼26%). A WLED lamp with a high color rendering index of Ra = 92.8 was produced with the combination of a 365 nm emitting chip with blue emitting BaMgAl10O17:Eu2+, green-yellow emitting CMSL:0.01Ce, and red emitting Sr2Si5N8:Eu2+ phosphors.