Hydrogen has become an indispensable aspect of sustainable energy resources due to depleting fossil fuels and increasing pollution. Since hydrogen storage and transport is a major hindrance to expanding its applicability, green ammonia produced by electrochemical method is sourced as an efficient hydrogen carrier. Several heterostructured electrocatalysts are designed to achieve significantly higher electrocatalytic nitrogen reduction (NRR) activity for electrochemical ammonia production. In this study, we controlled the nitrogen reduction performances of Mo2C-Mo2N heterostructure electrocatalyst prepared by a simple one pot synthesis method. The prepared Mo2C-Mo2N0.92 heterostructure nanocomposites show clear phase formation for Mo2C and Mo2N0.92, respectively. The prepared Mo2C-Mo2N0.92 electrocatalysts deliver a maximum ammonia yield of about 9.6 μg h-1 cm-2 and a Faradaic efficiency (FE) of about 10.15%. The study reveals the improved nitrogen reduction performances of Mo2C-Mo2N0.92 electrocatalysts due to the combined activity of the Mo2C and Mo2N0.92 phases. In addition, the ammonia production from Mo2C-Mo2N0.92 electrocatalysts is intended by the associative nitrogen reduction mechanism on Mo2C phase and by Mars-van-Krevelen mechanism on Mo2N0.92 phase, respectively. This study suggests the importance of precisely tuning the electrocatalyst by heterostructure strategy to substantially achieve higher nitrogen reduction electrocatalytic activity.

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The demand for developing high-efficiency multifunctional electrocatalysts with a long-term stability rapidly increases for achieving the commercialization of sustainable hydrogen (H 2 ) production via cost-effective water electrolysis systems. This study describes single-phase metal-rich nickel phosphide (Ni 12 P 5 )-incorporated carbon composites for a highly efficient water-splitting system. The distinct Ni 12 P 5 is anchored in nitrogen (N)-and phosphorus (P)-rich carbon matrices (Ni 12 P 5 @N,P-C); the creation of the matrices entails a facile hydrothermal-followed pyrolysis treatment to explore their bifunctional activities in the water-splitting system. Owing to the superior activity of the rich Ni (δ + ) component for the production of molecular oxygen and that of P (δ − )and N species in the carbon framework for hydrogen adsorption, the optimized Ni 12 P 5 @N,P-C composites contribute effectively toward both high oxygen evolution and hydrogen evolution reactions. Consequently, the Ni 12 P 5 @N,P-C composite-based two-electrode water-splitting system shows a low operating potential of 1.57 V at 10 mA cm −2 and achieves the commercially required high current density of 500 mA cm −2 at a stable potential of 2 V. The functionalization of composite electrocatalysts based on strategical engineering and the intrusion of multiple active sites can help develop enhanced electrochemical energy systems.

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