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Electrochemical nitrogen reduction reaction (NRR) is a sustainable alternative to the Haber‒Bosch process for ammonia (NH3) production. However, the significant uphill energy in the multistep NRR pathway is a bottleneck for favorable serial reactions. To overcome this challenge, we designed a vanadium oxide/nitride (V2O3/VN) hybrid electrocatalyst in which V2O3 and VN coexist coherently at the heterogeneous interface. Since single‐phase V2O3 and VN exhibit different surface catalytic kinetics for NRR, the V2O3/VN hybrid electrocatalyst can provide alternating reaction pathways, selecting a lower energy pathway for each material in the serial NRR pathway. As a result, the ammonia yield of the V2O3/VN hybrid electrocatalyst was 219.6 µg h−1 cm−2, and the Faradaic efficiency was 18.9%, which is much higher than that of single‐phase VN, V2O3, and VNxOy solid solution catalysts without heterointerfaces. Density functional theory calculations confirmed that the composition of these hybrid electrocatalysts allows NRR to proceed from a multistep reduction reaction to a low‐energy reaction pathway through the migration and adsorption of intermediate species. Therefore, the design of metal oxide/nitride hybrids with coherent heterointerfaces provides a novel strategy for synthesizing highly efficient electrochemical catalysts that induce steps favorable for the efficient low‐energy progression of NRR. [ABSTRACT FROM AUTHOR]

Tantalum oxynitride (TaOxN1−x) fibers were synthesized and evaluated for their electrocatalytic hydrogen activity using an in‐house developed centrifugal spinning setup. By tailoring the composition of the spinning solution and optimizing collector distance and rotation speed of the spinneret, bead‐free TaOxN1−x fibers with a diameter of 800 nm were obtained. The fibers were structurally characterized through phase and elemental analysis, confirming the formation of monoclinic TaOxN1−x with clear splitting of the X‐ray photoelectron spectroscopy peaks indicating Ta was in +5 oxidation state. The resulting oxynitride fibers exhibited superior electrocatalytic performance with low overpotentials (250 mV) to generate 10 mA/cm2 compared to Ta2O5 oxide fibers. Interestingly, the enhanced activity of oxynitride fibers was observed to be suppressed in basic medium due to the high oxophilicity of tantalum ions and a negative Gibbs adsorption‐free energy, leading to poisoning of the active sites. This work demonstrates a facile pathway for the fabrication of high‐performance electrocatalysts, based on TaOxN1−x fibers, from a cost‐effective and energy‐efficient centrifugal spinning technique. [ABSTRACT FROM AUTHOR]