Defect-engineered Co-SnS₂ nanosheets for superior piezocatalytic pollutant degradation: synergizing piezoelectricity and surface catalysis

Piezocatalysis is an attractive technology for wastewater purification, yet its efficacy is primarily constrained by the inherently weak piezoelectric response and sluggish surface-catalyzed reactions of catalysts. Simultaneously boosting both parameters remains an enticing but largely unexplored route to a genuine performance leap. Herein, we validate this strategy with defect-engineered Co-SnS₂ nanosheets, enabling superior performance for organic pollutants degradation. Specifically, lattice distortion induced by heterovalent substitution of Sn⁴⁺ with Co²⁺ enhanced the piezoelectric response of SnS₂. Moreover, the generated S_v served as catalytic active centers that facilitated the adsorption and activation of H₂O and O₂ molecules. The significantly enhanced piezo-response and surface catalyzed kinetic synergistically boost the generation of key reactive oxygen species (i.e., •OH). As a result, the defect-engineered SnS₂ nanosheets (i.e., 5%Co-SnS₂) removed 93.3% of carbamazepine (CBZ) pollutant in 60 min, exhibiting a 5.9-fold enhancement in the degradation rate constant compared with SnS₂. This work provides fundamental insights into how defect engineering synergistically enhances both the piezoelectricity and the surface catalysis process, inspiring the rational design of advanced piezocatalysts.