BACKGROUND: Discovery of the nanometer material-mediated piezoelectric effect has aroused interest in research into harnessing low-frequency vibration energy, because a little vibration energy, even muscle-movement, can generate electrical energy. Recently, much attention has focused on developing new processes of pollutant degradation using in situ application of piezo-generated electrical energy. RESULTS: It was found that the piezoelectric degradation of AO7 could be enhanced by adding ferrous ions. For example, 24.3%, 16.9% and 7.8% degradation of AO7, phenol and 4-chlorophenol, respectively, was observed in a 30 min piezo-process. Meanwhile, it was also found that H2O2 was generated in situ during the piezoelectric process. The maximum concentration of H2O2 reached 5.3 mu mol L-1. It was identified that the enhancement effect of ferrous ions originated from a H2O2-related Fenton reaction. CONCLUSION: The finding of in situ piezo-generated H2O2 and the piezo-Fenton effect led to better understanding of the BaTiO3-mediated piezo-degradation of organic pollutants. It provides a new clue to developing an efficient piezo-process for the degradation of organic pollutants, although the mechanism of piezo-generating H2O2 is still under investigation. (C) 2016 Society of Chemical Industry