Supplementary information files for Identification of structural changes in CaCu3Ti4O12 on high energy ball milling and their effect on photocatalytic performance

Supplementary files for article Identification of structural changes in CaCu3Ti4O12 on high energy ball milling and their effect on photocatalytic performanceThe perovskite CaCu3Ti4O12 is known for its ability to photocatalytically degrade model dye molecules using visible light. The influence of ball milling preformed CaCu3Ti4O12 on the catalysts structure and performance in the degradation of rhodamine B and the antihistamine cetirizine hydrochloride, which does not absorb light in the visible region, was investigated. The surface area of CaCu3Ti4O12 increased from 1 m2 g−1 to >80 m2 g−1 on milling with a retention of 96% CaCu3Ti4O12 phase purity, as determined by X-ray diffraction and extended X-ray absorption fine structure analysis. Multiple characterisation techniques showed an increase in structural defects on milling, including, for the first time, X-ray absorption near edge spectroscopy which showed changes in the local electronic structure from the perspective of Cu and Ti. Photocatalytic degradation was notably higher with the milled sample than that observed for the as-synthesized sample, even after normalisation for surface area, with a doubling of surface normalised rate constant from 4.91 × 10−4 to 9.11 × 10−4 L min−1 m2 for rhodamine B degradation and a tripling for cetirizine hydrochloride degradation from 2.64 × 10−4 to 7.92 × 10−4 L min−1 m−2. The improvement in catalytic performance can be correlated to the defects observed by X-ray absorption spectroscopy.

论文《高能球磨钛酸铜钙（CaCu3Ti4O12）的结构变化及其对光催化性能的影响》补充文件
钙钛矿结构的钛酸铜钙（CaCu3Ti4O12）具备利用可见光光催化降解模型染料分子的能力，该特性已为学界所知。本研究探究了预合成钛酸铜钙经高能球磨处理后，对其催化剂结构及降解罗丹明B（rhodamine B）与不吸收可见光的抗组胺药物盐酸西替利嗪（cetirizine hydrochloride）的性能影响。经X射线衍射（X-ray diffraction, XRD）与扩展X射线吸收精细结构（extended X-ray absorption fine structure, EXAFS）分析证实，球磨后钛酸铜钙的比表面积从1 m²·g⁻¹提升至80 m²·g⁻¹以上，且钛酸铜钙相纯度保持率达96%。多种表征技术均证实，球磨过程中材料的结构缺陷有所增加；其中首次通过X射线吸收近边结构（X-ray absorption near edge spectroscopy, XANES）光谱，从铜（Cu）与钛（Ti）的局域电子结构视角观测到了相应变化。即使经比表面积归一化处理，球磨样品的光催化降解性能仍显著优于原合成样品：罗丹明B降解的表面归一化速率常数从4.91×10⁻⁴ L·min⁻¹·m⁻²升至9.11×10⁻⁴ L·min⁻¹·m⁻²，提升一倍；盐酸西替利嗪降解的表面归一化速率常数从2.64×10⁻⁴ L·min⁻¹·m⁻²升至7.92×10⁻⁴ L·min⁻¹·m⁻²，达到原水平的三倍。催化性能的提升可与X射线吸收光谱观测到的结构缺陷相关联。