Constructing amorphous ZnCdS/Bi₄Ti₃O₁₂-Ov heterostructure for enhancing piezocatalytic coupled Fenton-like reaction toward efficient wastewater purification and unraveling the mechanism

Piezocatalysis has emerged as promising technique for production of hydrogen peroxide (H₂O₂) and wastewater treatment; however, slow reaction kinetics significantly hinder its efficiency. This work presents an effective strategy wherein we constructed amorphous ZnCdS and bismuth titanate with oxygen vacancies heterostructure (A-ZnCdS/Bi₄Ti₃O₁₂-Ov, denoted as AZCS/BTO-Ov) to facilitate in-situ H₂O₂ evolution and establish piezocatalytic coupled Fenton (PCF)-like reaction system for efficient wastewater purification. Notably, H₂O₂ evolution rate from AZCS/BTO-Ov catalyst reaches 1172.3 µmol g⁻¹ h⁻¹ in pure water, greatly surpassing the rates observed for pure BTO-Ov and AZCS. Furthermore, evolution rate increases to 2300.2 µmol g⁻¹ h⁻¹ upon addition of ethanol as sacrificial agent, demonstrating excellent activity. Within PCF-like reaction system (AZCS/BTO-Ov/Fe²⁺), particularly degradation efficiency of methyl orange dye reaches 92.9% within 16 min, accompanied by high kinetic coefficient of 0.171 min⁻¹, indicating exceptional catalytic activity that exceeds that of most other piezocatalysts. Relevant experimental results and density functional theory calculations unravel the reaction mechanism, demonstrating that the excellent piezocatalytic performances of AZCS/BTO-Ov are primarily attributed to the construction of heterostructure by significantly modulating electronic structure, improving separation efficiency of charge carriers, facilitating reaction dynamics, and activating both O₂ and H₂O. This research promotes in-situ synthesis of valuable chemicals and provides sustainable and cost-effective pathway to environmental remediation.