NiFe2O4 Nanofibers with Surface Oxygen Vacancies for Piezo-Catalytic Hydrogen Peroxide Production

Piezoelectric catalysis is a wayof renewable energy conversion,which involves the application of an external mechanical force toa piezoelectric catalyst. In this work, piezoelectric NiFe2O4 nanofibers with surface oxygen vacancies were successfullysynthesized by electrospinning and annealing processes. The introductionof surface oxygen vacancies in NiFe2O4 nanofiberscan effectively increase the piezo-catalytic degradation rates by75% for organic dyes and increase the piezoelectric catalytic hydrogenperoxide generation by 39% in pure water. The piezoelectric catalyticmechanism has been discussed. The oxygen defects enhanced the chargetransfer rate and the activation of molecular oxygen, providing morereaction sites for the catalytic process. It was confirmed that superoxideradicals (O-& BULL;(2) (-)) playedan important role in the whole catalytic process since force-generatedelectrons (e(-)) and holes (h(+)) migratedto the nanofiber surface and redox reactions occurred under the actionof the internal electric field. This work provides a piezoelectriccatalyst to achieve efficient degradation of dyes and produce hydrogenperoxide.