*Article* **Synergistic Piezo-Photocatalysis of BiOCl/NaNbO3 Heterojunction Piezoelectric Composite for High-Efficient Organic Pollutant Degradation**

**Li Li 1, Wenjun Cao 1, Jiahao Yao 1, Wei Liu 1, Feng Li 2,\* and Chunchang Wang 1,\***


**Abstract:** Piezo-photocatalytic technique is a new-emerging strategy to alleviate photoinduced charge recombination and thus enhance catalytic performance. The heterojunction construction engineering is a powerful approach to improve photocatalytic performance. Herein, the BiOCl/NaNbO3 with different molar ratios piezoelectric composites were successfully synthesized by hydrothermal methods. The piezo/photodegradation rate (k value) of Rhodamine B (RhB) for BiOCl/NaNbO3 (BN-3, 0.0192 min−1) is 2.2 and 5.2 times higher than that of BiOCl (0.0089 min−1) and NaNbO3 (0.0037 min<sup>−</sup>1), respectively. The enhanced performance of BN-3 composite can be attributed to the heterojunction construction between BiOCl and NaNbO3. In addition, the piezo/photodecomposition ratio of RhB for BN-3 (87.4%) is 8.8 and 2.2 times higher than that of piezocatalysis (9.9%) and photocatalysis (40.4%), respectively. We further investigated the mechanism of piezocatalysis, photocatalysis, and their synergy effect of BN-3 composite. This study favors an in-depth understanding of piezo-photocatalysis, providing a new strategy to improve the environmental pollutant remediation efficiency of piezoelectric composites.

**Keywords:** BiOCl/NaNbO3; heterojunction; piezocatalysis; photocatalysis; degradation
