Synthesis and selenium vacancy-induced catalytic enhancement of CoSe2 for efficient electrocatalytic nitrate reduction

Abstract

The electroreduction of nitrate (NO₃RR) offers an environmentally friendly alternative to the Haber-Bosch process for ammonia (NH₃) synthesis. However, the complex reaction pathway and diverse product distribution pose challenges to achieving efficient NH₃ synthesis. Therefore, the rational design and preparation of high-performance electrocatalysts are crucial for the degradation of NO₃RR. In this study, a selenium vacancy-engineered CoSe₂ supported on carbon felt (CoSe_v/CF) was synthesized via a hydrothermal method. The nanostructure, the interaction between Se and Co, and the formation of selenium vacancies contribute to the generation of abundant active sites, modulation of the electronic structure, and enhancement of substrate adsorption. Consequently, CoSe_v/CF exhibits excellent electrocatalytic performance for NO₃RR. As a result, the CoSe_v/CF catalyst demonstrates a remarkable Faraday efficiency (FE) for ammonia synthesis, achieving a value of 98.62 %, with an exceptionally high ammonia production rate of 4.63 m g·h⁻¹ cm⁻² in a solution comprising 0.1 M Na₂SO₄ and 0.1 M NaNO₃ at a potential of − 0.8 V relative to the reversible hydrogen electrode (RHE).