PdCu/C Catalyst with Electricity Self-Generation via a Fuel Cell for Electroreduction of Nitrate

Abstract

This research aims to use nitrate as an electron acceptor in the cathode of ethanol fuel cells. Nitrate was electroreduced to nitrogen gas at the cathode and removed from water. Carbon-supported PdCu was prepared as a cathode catalyst for nitrate reduction and was characterized by electrochemical methods, scanning electron microscopy, and X-ray diffraction. The results show that PdCu/C is vital to the evolution of nitrate to nitrite and then to N2 gas. A nitrogen selectivity of approximately 93% is obtained under acidic conditions, in which protons facilitate the electroreduction of nitrate to N2. A maximum power density of 2.90 W m–2 with an open-circuit voltage of 1.6 V is achieved at 20 °C using 300 ppm N-NO3 −. After 24 h of discharge, approximately 56% of the nitrate is eliminated with an initial N-NO3 − concentration of 150 ppm. The undesirable products of ammonia and nitrite are not observed in the catholyte. The technique developed in this work provides a sustainable solution for either nitrate removal by electroreduction or electricity generation for net energy recovery.

Short Review of Self-Powered Nitrogen Removal via Abiotic Electrochemical Catalysis

“…Compared to the ethanol-O 2 fuel cell, the ethanol-nitrate fuel cell exhibited improved the performance of OCV and the maximal power density owing to the low activation energy required for the NRR. Wei Xu et al investigated the nitrogen removal process in ethanol-nitrate [46]. In order to improve the NRR rate and electrochemical selectivity of nitrate to N 2 gas, carbon-supported PdCu was synthesized as a cathode catalyst.…”