Grewe Tobias, Tüysüz Harun
Max-Planck-Institute für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany.
ACS Appl Mater Interfaces. 2015 Oct 21;7(41):23153-62. doi: 10.1021/acsami.5b06965. Epub 2015 Oct 12.
A facile hydrothermal synthesis protocol for the fabrication of sodium tantalates for photocatalytic water splitting is presented. Mixtures of tantalum and sodium ethoxide precursors were dispersed in ethanol, and ammonium hydroxide solution was used as mineralizer. By adjusting the amount of mineralizer, a variety of sodium tantalates with various morphologies, textural parameters, band gaps, crystal phases, and degrees of crystallinity were fabricated. The reaction was carefully monitored with a pressure sensor inside the autoclave reactor, and the obtained samples were characterized using X-ray diffraction, transmission electron microscopy, N2-physisorption, and ultraviolet-visible light spectroscopy. Among the series, the amorphous sample and the composite sample that consists of amorphous and crystalline phases showed superior activity toward photocatalytic hydrogen production than highly crystalline samples. Particularly, an amorphous sodium tantalate with a small fraction of crystalline nanoparticles with perovskite structure was found to be the most active sample, reaching a hydrogen rate of 3.6 mmol h(-1) from water/methanol without the use of any cocatalyst. Despite its amorphous nature, this photocatalyst gave an apparent photocatalyst activity of 1200 μmol g(-1) L(-1) h(-1) W(1-), which is 4.5-fold higher than highly crystalline NaTaO3. In addition, the most active sample gave promising activity for overall water splitting with a hydrogen production rate of 94 μmol h(-1), which is superior to highly crystalline NaTaO3 prepared by conventional solid-solid state route.
本文介绍了一种用于制备用于光催化水分解的钽酸钠的简便水热合成方法。将钽和乙醇钠前驱体的混合物分散在乙醇中，并使用氢氧化铵溶液作为矿化剂。通过调节矿化剂的用量，制备了具有各种形态、结构参数、带隙、晶相和结晶度的多种钽酸钠。在高压釜反应器内用压力传感器仔细监测反应，并使用X射线衍射、透射电子显微镜、N2物理吸附和紫外-可见光谱对所得样品进行表征。在该系列中，非晶态样品以及由非晶态和晶态相组成的复合样品对光催化产氢的活性高于高度结晶的样品。特别地，发现具有少量钙钛矿结构结晶纳米颗粒的非晶态钽酸钠是活性最高的样品，在不使用任何助催化剂的情况下，水/甲醇的产氢速率达到3.6 mmol h(-1)。尽管其为非晶态性质，但该光催化剂的表观光催化活性为1200 μmol g(-1) L(-1) h(-1) W(-1)，比高度结晶的NaTaO3高4.5倍。此外，活性最高的样品在全水分解方面表现出良好的活性，产氢速率为94 μmol h(-1)，优于通过传统固-固态路线制备的高度结晶的NaTaO3。
