Enhancement of oxygen reduction on a newly fabricated cathode and its application in the electro-Fenton process. (10th January 2020)

• Record Type: Journal Article
• Authors: Gao, Ying; Zhu, Weihuang; Wang, Chongguang; Zhao, Xiaoli; Shu, Min; Zhang, Jianfeng; Bai, Huiling
• Is Part Of: Electrochimica acta. Volume 330(2019)
• Publication Date: 2020-01-10
• Subjects: Cathode modification -- Anthraquinone -- Graphene oxide -- Two-electron oxygen reduction -- Electro-Fenton; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2019.135206
• Languages: English
• ISSNs: 0013-4686

Abstract

Abstract: High catalytic activity, energy-saving cathodes are desirable for improving the efficiency of the electro-Fenton system. Herein, carbon felt (CF) modified with graphene oxide (GO) and anthraquinone sulfonate (AQS) as a cathode was fabricated. The CF/GO/AQS cathode with excellent catalytic performance for oxygen reduction was further applied in the electro-Fenton process. Surface morphology and structural characteristics of CF/GO/AQS cathode were characterized by scanning electron microscopy (SEM), X-ray spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy. Rhodamine B (RhB) was applied as the target pollutant, and the decolorization rate could reach 95% within 1 h using the CF/GO/AQS cathode, which was 2.3 times higher than that of the unmodified cathode. It was attributed to the prominent capacity to accelerate oxygen reduction reaction (ORR) of CF/GO/AQS cathode. The response current of CF/GO/AQS reached −2.48 mA cm −2, which was about six times higher than that of the bare CF cathode. Electron transfer number determined by linear sweep curves on a rotating disk electrode was calculated to be 1.9–2.2, which indicated the catalytic reduction of molecular oxygen by CF/GO/AQS cathode was dominated by a two-electron reaction pathway. Quinones can catalyze the reduction of molecular oxygen to superoxide radicals. Then the formed superoxide radicals combine with protons to produce hydrogen peroxide (H2 O2 ), which provides a new way of H2 O2 generation applied in the electro-Fenton system. The TOC removal rate arrived at 89.9%, and corresponding energy consumption was 4.23 kWh kg −1 . The catalytic performance of the CF/GO/AQS cathode kept almost stable after six cycles of a repeated experiment. This new CF/GO/AQS cathode can be a promising material applied in the electro-Fenton process for organic pollutant removal. Highlights: CF modified with GO and AQS as a new cathode applied in electro-Fenton. CF/GO/AQS cathode showed excellent catalytic performance for oxygen reduction. Oxygen could be reduced to O2 - by the cathode and subsequently H2 O2 was generated. TOC removal rate could reach 89.9% in electro-Fenton with CF/GO/AQS as the cathode.