Cu particles confined in three-dimensional open porous carbon foam monolith as highly efficient electrode for electroreduction of nitrate with significant alleviation of nitrite

Abstract

Electroreduction of nitrate is a promising approach and attracting increasing attention in recent years. However, most studies focus on conventional planar electrodes whose flat structure causes limited mass transfer and low nitrate reduction efficiency. Herein, we prepared a novel Cu-containing particle-embedded 3D open porous carbon foam monolith (3D-PCF) electrode for electroreduction of nitrate. The 3D-PCF was prepared by foaming of molten sucrose, followed by dehydration and carbonization. Then Cu-containing particle was in-situ fabricated on the 3D-PCF using a hydrothermal procedure and a subsequent annealing treatment. Benefitting from the advantages of 3D open porous architecture, highly active interface and excellent electron conductivity of the carbon skeleton, the optimized electrode exhibited 99.9% nitrate removal efficiency in 1 h and 100 % N2 selectivity with the aid of chlorine oxidation in 3 h. The reduction rate of the optimized electrode was about 2.44 times of the 3D Cu foam (15 pieces of Cu foam with the same size as the optimal electrode). Impressively, the catalyst enabled significant alleviation of nitrite because the 3D-PCF substrate could eliminate nitrite rapidly. This work highlights the promise of preparing highly efficient electrocatalyst for efficiently and selectively removing nitrate through supporting of active material onto a 3D monolith substrate.