Development of Novel-type of Photocatalyst by Partial Sulfurization of Shape Controlled Composite Oxides Nanoparticles containing Ti or Zr Ion

具有钙钛矿结构的含钛或锆复合氧化物是一种众所周知的具有优异压电、铁电和介电性能的功能材料，广泛用于生产气体传感器、传感器、非易失性存储器、电容器、微波器件和绝缘薄膜。在本研究中，我们开发了一种在凝胶-溶胶体系中制备含钛或含锆复合氧化物纳米粒子如BaTiO_3， SrTiO_3， BaZrO_3和SrZrO_3的有效方法。此外，所制得的含钛或含锆纳米颗粒通过我们所开发的部分硫化技术作为一种新型的可见光响应光催化剂。为了获得在可见光下具有较好光活性的部分硫化的含钛或含锆复合氧化物粉末，必须选择适当的部分硫化温度来研究含钛或含锆复合氧化物的硫化行为。为此，利用石英弹簧式热天平在CS_2气氛中对凝胶-溶胶法制备的含ti或zr复合氧化物纳米颗粒进行了热重研究，并将结果与大粒径SrTiO_3商品粉末的硫化行为进行了比较。对于低温硫化，我们发现羟基的存在起着重要的作用。在可见光下对部分硫化纳米颗粒的光催化活性进行了评价，结果表明硫化增强了纳米颗粒的光催化活性。

Ti or Zr-containing composite oxides with perovskite structures are well known as a functional material of excellent piezoelectric, ferroelectric, and dielectric properties and widely used for the production of gas sensors, transducers, non-volatile memories, capacitors, microwave devices, and insulating films. In the present study, we have developed an efficient procedure for the preparation of Ti-or Zr-containing composite oxides nanoparticles such as BaTiO_3, SrTiO_3, BaZrO_3, and SrZrO_3 in the gel-sol system. Furthermore, the resulting Ti-or Zr-containing nanoparticles were applied as a novel-type of visible light-responsive photocatalyst by the partial sulfurization technique which we have developed. To obtain partially sulfurized Ti-or Zr-containing composite oxides powders with better photoactivity under visible light, the sulfurization behavior of the Ti-or Zr-containing composite oxides is necessary to select an adequate temperature of partial sulfurization. In this regard, the thermogravimetric study of the Ti-or Zr-containing composite oxides nanoparticles prepared by the gel-sol method was carried out by using a quartz spring-type thermobalance in CS_2 atmosphere, and the results were compared with the sulfurization behavior of commercial SrTiO_3 powders with larger particle sizes. For the low-temperature sulfurization, we found that the presence of OH groups plays an important role. Evaluation of the photocatalytic activities of partial sulfurized nanoparticles under visible light revealed that the sulfurization enhances the photocatalytic activities.