Inducing piezoelectricity in distorted rutile TiO2 for enhanced tetracycline hydrochloride degradation through photopiezocatalysis

A team of material scientists led by Prof. Qi Li from Southwest Jiaotong University in Chengdu, China recently outlined the state of inducing piezoelectricity in distorted rutile TiO₂ for enhanced tetracycline hydrochloride degradation through photopiezocatalysis. Various material design strategies have been developed to enhance photocatalytic performance of TiO₂. However, no report is available on applications of the photopiezocatalysis strategy on TiO₂ due to its lack of piezoelectricity. Here we developed a low-temperature molten salt etching process to create rutile TiO₂ nanoparticles by etching [MgO₆] octahedrons away from MgTiO₃ by molten NH₄Cl, during which a lattice distortion occurred in TiO₂. Lattice distortion leads to a piezoelectric response in the sample, which is then applied in the field of photocatalysis, improving the degradation performance of antibiotics.

The team published their paper in Journal of Advanced Ceramics on March 8, 2024.

In this paper, a low-temperature molten salt etching process was developed with MgTiO₃ as raw materials and NH₄Cl as molten salt. By etching [MgO₆] octahedrons away from MgTiO₃ in this specific synthesis process, rutile TiO₂ nanoparticles (the ER-TiO₂ sample) were created with distorted crystal lattice as demonstrated by the XRD Rietveld refinement analysis. By breaking the structure symmetry of rutile TiO₂ through the lattice distortion, the ER-TiO₂ sample was endowed with an unusual and interesting piezoelectric response for the first time as revealed by the piezoelectric response force microscopy (PFM) analysis.

As one important kind of emerging contaminant, the contamination from pharmaceutical and personal care products (PPCPs) are raising increasing concerns. Tetracycline hydrochloride (TC–HCl) is a commonly used broad-spectrum antibiotic, and its release into water and soil causes serious environmental pollution problems and poses threats to human beings. Through the introduction of piezoelectricity, it was found that the ER-TiO₂ sample had an improved photocatalytic degradation effect on tetracycline hydrochloride (TC–HCl) under visible light illumination than its commercially available rutile TiO₂ nanoparticle counterpart. More significantly, its TC–HCl degradation efficiency was largely enhanced by 71% than its photocatalytic degradation performance when the synergistic photopiezocatalytic effect was present. “The photopiezocatalysis approach could be a novel strategy for the photocatalytic performance enhancement of TiO₂ from the introduction of piezoelectricity into it through the creation of lattice distortion,” said Prof. Qi Li.

Other contributors include Jinghui Wang from Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang, China.

This study was supported by the National Natural Science Foundation of China (Grant Nos. 52272125 and 51902271), the Fundamental Research Funds for the Central Universities (Grant Nos. CX116, 2682020CX07, and 2682020CX08), and Sichuan Science and Technology Program (Grant Nos.2020YJ0259, 2020YJ0072, and 2021YFH0163). We would like to thank Analysis and Testing Center of Southwest Jiaotong University for the assistance on material characterization.

About Prof. Qi Li

Prof. Li graduated with honor from Tsinghua University in 2000, where he got his double bachelor of engineering degree in materials science and engineering (major) and computer technology and application (minor). From 2000 to 2007, he studied in the department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, where he got his MS and Ph.D. degrees. From 2007 to 2009, he worked as a posdoctoral research associate in University of Illinois at Urbana-Champaign. In 2009, he joined the faculty of Institute of Metal Research, Chinese Academy of Sciences as a professor, and led the Environment Functional Materials Division as the deputy director till 2019. Now, he is working as a professor and serving as the deputy dean in School of Materials Science and Engineering, Southwest Jiaotong University. Prof. Li’s research is focused on the development of functional materials for environment remediation, including photocatalytic materials and photocatalysis, adsorbents for the removal of heavy metal ions from water, catalytic materials for environment and energy applications, and 3D/4D printing of functional materials.

About Journal of Advanced Ceramics

Journal of Advanced Ceramics (JAC) is an international journal that presents the state-of-the-art results of theoretical and experimental studies on the processing, structure, and properties of advanced ceramics and ceramic-based composites. JAC is Fully Open Access, monthly published by Tsinghua University Press on behalf of the State Key Laboratory of New Ceramics and Fine Processing (Tsinghua University) and the Advanced Ceramics Division of the Chinese Ceramic Society, and exclusively available via SciOpen. JAC has been indexed in SCIE (IF = 16.9, top 1/28, Q1), Scopus, and Ei Compendex.