Electrochemical oxidation of volatile organic compounds in all-solid cell at ambient temperature

Abstract The catalytic elimination of indoor low-concentration gaseous benzene, toluene and o-xylene (BTX) under ambient conditions remains a challenge. Here, we firstly report a facile gas-solid interface electrochemical oxidation method for the mineralization of BTX at ambient temperature. A membrane electrode assembly (MEA) was used in the all-solid cell. An antimony-doped SnO2 catalyst was coated onto the surface of a porous Ti foam to act as the anode, and reduced graphene oxide/carbon fiber paper-supported Pt (Pt/rGO/CFP) was employed as the cathode. The activity test results showed that 100% BTX conversion to CO2 (85–99%) and CO (15–1%) was achieved within 4–5 h at the optimal cell voltage of 2.0 V at relative humidity 60%. Proton-transfer-reaction time-of-flight mass spectrometry and Fourier transform infrared spectroscopy results showed that no organic byproducts could be detected in the anodic reservoir. OH generated from water vapor discharge was measured directly by laser-induced fluorescence techniques. The electrochemical behavior of the working electrode in benzene solutions with different concentrations revealed that the benzene oxidation process was mainly mediated by OH at the onset potential of OER (2.0 V vs Ag/AgCl, saturated KCl). Our findings provide evidence that the gas-solid interface electrochemical oxidation method can be a potential method for ambient VOC destruction in indoor air environments.