Structure and hydrogen generation mechanism of Si-based agent
Structure and hydrogen generation mechanism of Si-based agent
复制标题
DOI：
10.1016/j.apsusc.2020.147398
复制
发表时间：
2021-01-15
影响因子：
6.7
通讯作者：
Kobayashi, Hikaru
中科院分区：
文献类型：
--
作者：
Kobayashi, Yuki;Fujie, Shunta;Kobayashi, Hikaru
由硅粉制成的硅基试剂通过与弱碱性溶液长时间反应可产生大量氢气（例如，在pH值为8.5、36℃条件下反应24小时，产氢量超过500毫升/克）。氢气产生速率随pH值的升高而大幅增加，这表明参与反应的物质是氢氧根离子。在硅基试剂的Si 2p XPS光谱中，出现了由低价氧化物和二氧化硅引起的峰。低价氧化物层位于硅核附近，二氧化硅层在低价氧化物层外侧。光发射引起的荷电效应使二氧化硅的Si 2p峰发生大幅位移，而低价氧化物的峰因荷电产生的位移则小得多。这种现象可以用二氧化硅位于低价氧化物外侧的氧化硅结构很好地解释。
Si-based agent fabricated from Si powder generates a high amount of hydrogen by reactions with weak alkaline solutions for long periods (e.g., more than 500 mL/g hydrogen at pH8.5 and 36 degrees C for 24 h). The hydrogen generation rate greatly increases with pH, indicating that the reacting species is OH- ions. In the Si 2p XPS spectra of Si-based agent, peaks due to suboxide species and SiO2 are present. The suboxide layer is present near the Si core, and the SiO2 layer outside of the suboxide layer. The charging effect caused by photoemission largely shifts the Si 2p peak due to SiO2 while the shifts induced by charging are much lower for suboxide species. This phenomenon is well explained by the silicon oxide structure that SiO2 is present outside of the suboxide species.