Synthesis of BaTaO2N oxynitride from Ba-rich oxide precursor for construction of visible-light-driven Z-scheme overall water splitting
Synthesis of BaTaO2N oxynitride from Ba-rich oxide precursor for construction of visible-light-driven Z-scheme overall water splitting
复制标题
从富 Ba 氧化物前驱体合成 BaTaO2N 氮氧化物，用于构建可见光驱动的 Z 型整体水分解
DOI：
10.1039/c7dt00854f
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发表时间：
2017-08-28
影响因子：
4
通讯作者：
Li, Can
中科院分区：
文献类型：
--
作者：
Dong, Beibei;Qi, Yu;Li, Can
氧化钽氮化钡（BaTaO2N）吸收边约为660 nm，是最有希望用于太阳能水分解的光催化剂之一，通常是在高温氨流条件下，以Ba/Ta摩尔比为单位的Ba和taca化合物的混合物氮化而合成的，通常会产生高密度的缺陷位点。本文介绍了一种利用通量法制备的富钡LiBa4Ta3O12作为氮化前驱体合成BaTaO2N （BTON）的新方法。作为比较，采用常规固相反应法制备BaTaOx作为前驱体。将氮化态样品分别记为BTON-Flux和BTON-SSR。结果表明，两种方法均可获得结晶良好的氮化硼氧化合物，但与BTON- ssr样品相比，BTON- flux样品的缺陷密度显著降低，比表面积显著增加。由于它们的结构差异，无论是在甲醇存在下的h -2演化半反应还是Z-scheme整体水分解，BTON-Flux样品的光催化水分解性能都远远好于BTON-SSR。本研究为制备低缺陷密度氮化氧光催化剂促进太阳能水分解开辟了一条新途径。
Barium tantalum oxynitride (BaTaO2N) with an absorption edge of ca. 660 nm is one of the most promising photocatalysts for solar water splitting, and is usually synthesized by nitriding a mixture of Ba and Tacontaining compounds with a Ba/Ta molar ratio of unity under ammonia flow at high temperature, usually causing a high density of defect sites. Herein, we introduce a novel synthesis method for BaTaO2N (BTON) by employing Ba-rich LiBa4Ta3O12, prepared by a flux method, as a precursor of nitridation. As a comparison, BaTaOx was prepared by conventional solid state reaction and used as the precursor. The as-nitrided samples were correspondingly denoted as BTON-Flux and BTON-SSR. It was found that well-crystallized BTON oxynitride can be similarly obtained by both methods, but the BTON-Flux sample exhibits significantly decreased defect density and enhanced surface area relative to the BTON-SSR sample. As a result of their structural differences, the photocatalytic water splitting performance of the BTON-Flux sample, regardless of the H-2-evolving half reaction in the presence of methanol or Z-scheme overall water splitting, is much better than that of BTON-SSR. This study may open up a novel strategy for preparing oxynitride photocatalyst with decreased defect density for the promotion of solar water splitting.