Piezocatalytic activities of SnO2/t-BaTiO3 film towards pollutant degradation: Understanding the performance of piezo-current response

[Display omitted] •A piezo-catalytic reactor (PCR) was proposed and constructed.•PCR could degrade pollutant and simultaneously generate piezo-current.•PCR with SnO2/t-BaTiO3 film presented a favorable piezo-current performance.•Electrode processes of PCR was initiated by the piezoelectric effect of t-BaTiO3. A new piezo-catalytic reactor (PCR) was constructed. It was used to investigate the piezocatalytic degradation of pollutants and simultaneous response of current. It was found that PCR with SnO2/t-BaTiO3/ITO film anode possessed a more favourable piezocatalytic degradation and piezo-current response than PCR with only ITO or t-BaTiO3/ITO film anode, individually. For HCOOH, the degradation rate, short circuit current (Isc) and open-circuit voltage (Voc) reached 77.8 mg·L-1·h−1, 5.12 µA, and 0.65 V, respectively, under its optimal condition. Its anodic process predominantly involved the piezocatalytic oxidations of H2O to •OH and HCOOH to CO2, while the cathodic process was mainly related to the reduction of O2 to •O2– or H2O2 and reduction of H+ ion to H2. Although these processes were depended on the energy band structure of t-BaTiO3 and redox potential of cathodic reactions, they were all initiated by the piezoelectric effect of t-BaTiO3, which drove the separation of intrinsic free carries to generate oxidative holes and reductive electrons. These investigation results and findings not only deepened the understanding of its piezo-current response, but also possibly extended the application of piezocatalysis to fuel cell.