钨酸盐
电负性
材料科学
卤化物
光催化
拉曼光谱
钨酸钠
半导体
复合数
带隙
无机化学
化学工程
复合材料
化学
有机化学
冶金
催化作用
光学
钨
光电子学
物理
工程类
作者
István Székely,Endre-Zsolt Kedves,Zsolt Pap,Monica Baia
出处
期刊:Catalysts
[MDPI AG]
日期:2021-06-27
卷期号:11 (7): 779-779
被引量:8
标识
DOI:10.3390/catal11070779
摘要
The design of a semiconductor or a composite semiconductor system—with applications in materials science—is complex because its morphology and structure depend on several parameters. These parameters are the precursor type, solvent, pH of the solution, synthesis approach, or shaping agents. This study gives meaningful insight regarding the synthesis design of such WO3 materials. By systematically alternating the precursor (sodium tungstate dihydrate—NWH, or ammonium tungstate hydrate—AMT), subsequently shaping the agents (halide salts—NaX, KX, or hydrohalic acids—HX; X = F−, Cl−, Br−, I−), we have obtained WO3 semiconductors by hydrothermal treatment, which in composite systems can enhance the commercial TiO2 photocatalytic activity. We investigated three sample series: WO3-NWH-NaX/WO3-NWH-KX and, subsequently, WO3-AMT-HX. The presence of W+5 centers was evidenced by Raman and X-ray photoelectron spectroscopy. W+5 and W+6 species affected the band gap values of the NaX and KX series; a higher percentage of W+5 and, subsequently, W+6 caused a redshift, while, regarding the HX series, it led to a blue shift. Increased electronegativity of the halide anions has an unfavorable effect on the composites’ photoactivity. In contrast, in the case of hydrohalic acids, it had a positive impact.
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