An advanced electro-Fenton degradation system with triboelectric nanogenerator as electric supply and biomass-derived carbon materials as cathode catalyst

Abstract

On the basis of the advantages of electro-Fenton (EF) and the flexible design of triboelectric nanogenerator (TENG) and biomass carbon materials, a self-powered EF system is conceived, which is self-driven by a flexible multilayered TENG (FM-TENG) using carbon materials derived from long bean as the cathode catalyst for oxygen reduction. The synthesized carbon material is promising electrocatalyst due to its macro-/meso-porous structure, large surface area (2270m2g−1), high nitrogen content and superhydrophilicity, which can facilitate dissolved O2 mass transfer and promote the oxygen reduction. The instantaneous short-circuit current, transferred charge and open-circuit voltage of FM-TENG could reach 650μA, 1.7μC and 750V, respectively, corresponding to an instantaneous power density of 2.6Wm−2 (500kΩ). Driven by FM-TENG, 4-dimethylaminoazobenzene can be decomposed to CO2 and inorganic ions by hydroxyl radical (•OH) generated via EF process. Cyclic voltammogram, gas chromatograph-mass spectrometer, UV–vis spectra and the H2O2 measurement together disclose such degradation mechanism in single-compartment cell (S-cell) and double-compartment cell (D-cell). Here, S-cell is preferable owing to the high efficiency, simple setup and low voltage. This provides a proof-of-concept of an innovative EF process using biomass-derived carbon materials as oxygen reduction electrocatalyst and FM-TENG as the electric supply to power the degradation of organic pollutants.