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

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 SnO 2 / t -BaTiO 3 /ITO film anode possessed a more favourable piezocatalytic degradation and piezo-current response than PCR with only ITO or t -BaTiO 3 /ITO film anode, individually. For HCOOH, the degradation rate, short circuit current (I sc ) and open-circuit voltage (V oc ) 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 H 2 O to •OH and HCOOH to CO 2 , while the cathodic process was mainly related to the reduction of O 2 to •O 2 – or H 2 O 2 and reduction of H + ion to H 2 . Although these processes were depended on the energy band structure of t -BaTiO 3 and redox potential of cathodic reactions, they were all initiated by the piezoelectric effect of t -BaTiO 3 , 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.