Piezo-Phototronic Effect Enhanced Photocatalytic Coatings Containing BaTiO3/BiOCl for Cement-Based Materials

Due to its advantages of simple construction and easy combination with the substrate, photocatalytic coating technology is recognized as an effective means to reduce the surface corrosion of cement-based materials and improve environmental pollution. However, the rapid recombination of electrons and holes about the photocatalyst severely limit the photocatalytic degradation efficiency. This problem was solved by successfully preparing BaTiO3/BiOCl heterojunction to accelerate the charge transfer rate in this paper. At the same time, through an external mechanical action, the piezoelectric-photon effect of the material is used to further enhance its degradation ability. Due to the piezo-phototronic effect, the degradation efficiency is 1.33 times higher than the photocatalytic degradation efficiency of BaTiO3/BiOCl-1∶6, which confirmed the effectiveness of the piezo-phototronic effect in enhancing photocatalytic performance. Subsequently, BaTiO3/BiOCl was coated on the cement-based surface with polydimethylsiloxane as the matrix. The hydrophobic properties of the coating are also improved after the incorporation of nanomaterials; however, the bond strengths decrease slightly. More importantly, the coating based on BaTiO3/BiOCl nanomaterials can only degrade 50% of methylene blue in 5 h under light conditions, whereas 98.4% can be degraded in 100 min under ultrasonic and light conditions. Therefore, the piezoelectric enhanced photocatalytic coating based on BaTiO3/BiOCl can improve the degradation efficiency of pollutants on the surface of cement-based materials, which provides an effective method and new protection for the corrosion of cement-based materials.