High-Efficiency Concurrent Electrosynthesis of Value-Added Nitrogen-Containing Chemicals by Coupling Nitrate Reduction and Butylamine Oxidation on a Barium-Doped Cobalt Phosphide Bifunctional Catalyst

Integrating the electrooxidation and electroreduction of low-value nitrogen-containing substrates, with water serving as a source of oxygen and hydrogen, is of great significance for the production of high value-added chemicals. Although important progress has been achieved in this field, developing bifunctional catalysts that can effectively accelerate both processes remains a major challenge. In this work, we developed barium-doped cobalt phosphide nanosheets (Ba-CoP NSs) as an effective bifunctional catalyst for the electroreduction of nitrate to ammonia and concurrent electrooxidation of butylamine (BA) to butyronitrile. Compared with pure CoP, barium doping significantly improves the electrochemical performance with Faradaic efficiencies exceeding 96% at the respective optimized potentials of cathodic and anodic reactions. Experimental and theoretical studies reveal that barium doping can modulate the adsorption strength of intermediates and alter the adsorption configuration of *NO to a bridging adsorption mode, thereby reducing the energy barrier and enhancing the electrochemical performance for nitrate reduction. Meanwhile, barium doping can also activate the electrogenerated Co 3+ species and facilitate the dehydrogenation of BA in the anodic electrooxidation reaction. Using Ba-CoP NSs as a bifunctional catalyst, we successfully coupled nitrate reduction and BA oxidation in an electrochemical cell. The economic viability of this system was demonstrated by techno-economic analysis.