Nanobubbles-assisted piezoelectric effect enhances interfacial reactivity and accelerates water decontamination

Piezocatalysis integrated with advanced oxidation processes (AOPs) represents a promising strategy for sustainable water treatment, offering potential solutions to water pollution and energy scarcity. However, conventional piezocatalytic systems rely strongly on intense external mechanical energy, leading to substantial energy consumption. In this study, we propose a nanobubbles (NBs)-enabled piezocatalytic system by integrating with molybdenum disulfide (MoS₂) to activate peroxymonosulfate (PMS), which enables efficient contaminants degradation. Kinetic experiments reveal selective removal of target pollutants in NB/MoS₂/PMS system with k_obs of 0.95-1.60 times those in MoS₂/PMS system, which correlates with hydrophobicity of contaminants. Experimental results and modeling simulations demonstrate that NBs can serve as a localized and continuous mechanical energy input, effectively enhancing the piezoelectric response of MoS₂ and promoting PMS activation. Theoretical calculations further clarify the underlying mechanism of the selective removal, where NBs act as an interfacial microreactor and induce the enrichment of hydrophobic pollutants and reactive species at the gas-liquid interface. Particularly, the reaction energy barrier is calculated to reduce at the gas-liquid interface, theoretically resulting in a 100-fold acceleration in reaction kinetics. This work provides a new paradigm for low-energy piezocatalysis and offers a viable strategy for developing sustainable AOPs driven by naturally available mechanical energy.