Thick GaN films were grown on the sapphire substrate by hydride vapour phase epitaxy. The properties of GaN films were found to be significantly influenced by the duration of exposing the sapphire substrate to ammonia...Thick GaN films were grown on the sapphire substrate by hydride vapour phase epitaxy. The properties of GaN films were found to be significantly influenced by the duration of exposing the sapphire substrate to ammonia prior to the GaN growth initiation. The crystalline quality of GaN films revealed by high resolution X-ray diffraction were strongly dependent on the nitridation time, which determined substrate surface topography. The different nitridation schemes strongly affected the morphology of GaN overlayers resulting in the blue shift of the main excitonic peak in photoluminescence spectra at room temperature.展开更多
The impregnation method in the preparation of metal cluster catalysts typically inadvertently introduces single atoms(SAs) into the substrate. However, the question of whether the introduction of SAs will further impr...The impregnation method in the preparation of metal cluster catalysts typically inadvertently introduces single atoms(SAs) into the substrate. However, the question of whether the introduction of SAs will further improve the catalytic activity of cluster systems for specific reactions such as the hydrogen oxidation reaction(HOR) remains unraveled. Herein, we demonstrate Ru clusters anchored on WN nanowires(RuC/WN) show a higher alkaline HOR catalytic activity in comparison with Ru SAs and nanoclusters(NCs)-coupled catalyst anchored on WN nanowires system(RuC,S/WN). Notably, the RuC/WN exhibits superb intrinsic catalytic activity with a mass-normalized exchange current density of 890 m A mg^(-1)PGM, which is among the top level of well developed Ru-based HOR catalysts. Both theoretical simulation and experimental investigation suggest that RuC/WN owns an optimized H^(*)and OH^(*) reaction intermediates for the alkaline HOR, therefore resulting in the excellent intrinsic HOR catalytic performance.展开更多
基金National"863"Project of China (2001AA311100 and 2002AA305304) Sino French Cooperation Project:CNRS/ASC Chine 2003 Project(14915)
文摘Thick GaN films were grown on the sapphire substrate by hydride vapour phase epitaxy. The properties of GaN films were found to be significantly influenced by the duration of exposing the sapphire substrate to ammonia prior to the GaN growth initiation. The crystalline quality of GaN films revealed by high resolution X-ray diffraction were strongly dependent on the nitridation time, which determined substrate surface topography. The different nitridation schemes strongly affected the morphology of GaN overlayers resulting in the blue shift of the main excitonic peak in photoluminescence spectra at room temperature.
基金supported by the National Natural Science Foundation of China (22375001, 52203289)the Natural Science Foundation of Anhui Province (2208085Y03)+1 种基金the Youth Innovation Team of Higher Education Institutions in Shandong Province (2023KJ105)the Start-up Grant from Anhui University。
文摘The impregnation method in the preparation of metal cluster catalysts typically inadvertently introduces single atoms(SAs) into the substrate. However, the question of whether the introduction of SAs will further improve the catalytic activity of cluster systems for specific reactions such as the hydrogen oxidation reaction(HOR) remains unraveled. Herein, we demonstrate Ru clusters anchored on WN nanowires(RuC/WN) show a higher alkaline HOR catalytic activity in comparison with Ru SAs and nanoclusters(NCs)-coupled catalyst anchored on WN nanowires system(RuC,S/WN). Notably, the RuC/WN exhibits superb intrinsic catalytic activity with a mass-normalized exchange current density of 890 m A mg^(-1)PGM, which is among the top level of well developed Ru-based HOR catalysts. Both theoretical simulation and experimental investigation suggest that RuC/WN owns an optimized H^(*)and OH^(*) reaction intermediates for the alkaline HOR, therefore resulting in the excellent intrinsic HOR catalytic performance.
