In recent years, mesoporous silicon (mp-Si) nanoparticles (NPs) have been recognized as promising materials for sustainable photocatalytic hydrogen (H₂) generation, which is both an important chemical feedstock and potential clean energy vector. These materials are commonly prepared via magnesiothermic reduction of silica precursors due to the ease, scalability, and tunability of this reaction. In this work, we investigate how the conditions of magnesiothermic reduction (i.e. reaction temperature and time) influence the performance of mp-Si for photocatalytic H₂ generation. The mp-Si NPs were prepared using either the conventional single temperature heating method (650 °C for 3 or 6 h) or a two-temperature method in which the reaction is initially heated to 650 °C for 0.5 h, followed by a second step heating at 100 (mp-Si100), 200 (mp-Si200), or 300 °C (mp-Si300) for 6 h. Of these, mp-Si300 was the best performing photocatalyst and showed the highest H₂ evolution rate (4437 μmol h⁻¹ g⁻¹ Si). Our results suggest that crystallinity has a profound effect on the performance of mp-Si photocatalysts. Additionally, high amounts of oxygen and particle sintering lower H₂ evolution rates by introducing defect states or grain boundaries. It was also discovered that aging mp-Si NPs under ambient conditions result in continued surface oxidation which deleteriously affects its photocatalytic performance.

中文翻译：

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使用介孔硅纳米粒子的光催化氢生成：镁热还原条件和纳米粒子老化对催化活性的影响

近年来，中孔硅（mp-Si）纳米颗粒（NPs）被公认为是可持续产生光催化氢（H ₂）的有前途的材料，氢既是重要的化学原料，又是潜在的清洁能源载体。由于该反应的容易性，可扩展性和可调谐性，通常通过对硅石前体进行镁热还原来制备这些材料。在这项工作中，我们研究了镁热还原的条件（即反应温度和时间）如何影响mp-Si的光催化H ₂性能。代。使用常规的单温度加热方法（650°C 3或6 h）或双温度方法制备mp-Si NP，其中将反应最初加热到650°C 0.5 h，然后再进行第二次加热。在100（mp-Si100），200（mp-Si200）或300°C（mp-Si300）的温度下加热6小时。其中，mp-Si300是性能最好的光催化剂，并显示出最高的H ₂释放速率（4437μmolh ^-1 g ^-1 Si）。我们的结果表明，结晶度对mp-Si光催化剂的性能具有深远的影响。另外，大量的氧气和颗粒烧结降低了H ₂通过引入缺陷状态或晶界来提高演化速率。还发现在环境条件下老化的mp-Si NPs会导致持续的表面氧化，从而对其光催化性能产生有害影响。