Prussian blue analogues-Derived Iron-Cobalt carbon fiber Binder-Free electrodes for electrocatalytic nitrate reduction

Abstract

Developing a highly selective and efficient electrocatalytic system for nitrate reduction reaction (NO3RR) is of great significance but still remains challenging for environmental remediation and energy utilization. Herein, we constructed a binder-free cathode consisted of iron-cobalt Prussian blue analogues-based bimetal derived carbon fiber (FC-PBAFC) to enhance NO3RR performances. Significantly, high NO3−-N removal capacity of 169.1 mgN h−1 gcat-1, excellent ammonia Faradic efficiency (FE) of 83.2 ± 0.7 % and high ammonia selectivity of 99.3 ± 0.6 % were achieved by FC-PBAFC binder-free cathode. The excellent NO3RR performance was attributed to the rational polymer tethering strategy for the binder-free cathode construction. The introduction of polyacrylonitrile for electrospinning shaping essentially regulated the structural and compositional distribution of binder-free electrode during followed pyrolysis. The in-situ infrared spectroscopy and DFT calculation demonstrated that the Fe and Co regulation optimized the adsorption energy of key intermediate products with suppressing the side reactions. The bimetal binder-free cathode offers a promising strategy for selective and effective electroreduction of nitrate for ammonia synthesis.