Li Weihua, Lu Guangxiang, Ding Yanhong, Cong Rihong, Yang Tao
College of Chemistry and Chemical Engineering, Chongqing University, Chongqing 401331, People's Republic of China.
Dalton Trans. 2024 Apr 16;53(15):6747-6757. doi: 10.1039/d4dt00340c.
Developing new photocatalysts and deciphering the structure-property relationship are always the central topics in photocatalysis. In this study, a new photocatalyst BaSnGaO containing two d metal cations was prepared by a high temperature solid state reaction, and its crystal structure was investigated by Rietveld refinements of monochromatic X-ray powder diffraction data for the first time. There are 2 Ba, 4 metal cations and 6 O independent atoms in a unit cell. Sn and Ga co-occupy the octahedral cavities named M1 and M2 sites, and the other two metal sites are fully occupied by Ga. Rational In-to-Ga substitution was performed to reduce the potential of the conduction band minimum and enhance the light absorption ability, which was indeed confirmed using UV-vis diffuse reflectance spectra and Mott-Schottky plots for BaSnGaInO (0 ≤ ≤ 2). Interestingly, In exhibits site selective doping at M1 and M2 sites exclusively. With the light absorption ability enhanced, the photocatalytic overall water splitting activity was also improved, the photocatalytic H generation rate was 1.7(1) μmol h for BaSnGaO, and the optimal catalyst BaSnGaInO loaded with 1.0 wt% Pd exhibited the H generation rate of 27.5(4) μmol h and the apparent quantum yield at 254 nm was estimated to be 2.28% in pure water.
开发新型光催化剂并阐明其结构-性能关系一直是光催化领域的核心课题。在本研究中，通过高温固相反应制备了一种含有两种d金属阳离子的新型光催化剂BaSnGaO，并首次通过对单色X射线粉末衍射数据进行Rietveld精修来研究其晶体结构。一个晶胞中有2个Ba、4个金属阳离子和6个O独立原子。Sn和Ga共同占据名为M1和M2位点的八面体空穴，另外两个金属位点完全被Ga占据。进行了合理的In对Ga的取代以降低导带最小值的电位并增强光吸收能力，这确实通过BaSnGaInO（0≤≤2）的紫外可见漫反射光谱和莫特-肖特基图得到了证实。有趣的是，In仅在M1和M2位点表现出选择性掺杂。随着光吸收能力的增强，光催化全水分解活性也得到提高，BaSnGaO的光催化产氢速率为1.7(1) μmol h，负载1.0 wt% Pd的最佳催化剂BaSnGaInO在纯水中的产氢速率为27.5(4) μmol h，在254 nm处的表观量子产率估计为2.28%。
