Battery‐Driven N2 Electrolysis Enabled by High‐Entropy Catalysts: From Theoretical Prediction to Prototype Model

Abstract A small‐scale standalone device of nitrogen (N 2 ) splitting holds great promise for producing ammonia (NH 3 ) in a decentralized manner as the compensation or replacement of centralized Haber–Bosch process. However, the design of such a device has been impeded by sluggish kinetics of its half reactions, i.e., cathodic N 2 reduction reaction (NRR) and anodic oxygen evolution reaction (OER). Here, it is predicted from density function theory that high‐entropy oxides (HEOs) are potential catalysts for promoting NRR and OER, and subsequently develop a facile procedure to synthesize HEOs in the morphology of sea urchin‐shaped hollow nanospheres assembled from ultrathin nanosheets. The excellent electrocatalytic activities of HEOs for both NRR (NH 3 yield rate: 47.58 µg h −1 mg −1 and Faradaic efficiency (FE): 10.74%) and OER (215 mV @10 mA cm −2 ) are demonstrated. Consequently, a prototype device of N 2 electrolysis driven by commercial batteries is constructed, which can operate smoothly and deliver remarkable NH 3 yield rate (41.11 µg h −1 mg −1 ) and FE (14.14%). Further mechanism study has attributed the excellent catalytic performances of HEOs to their unique electronic structures originated from multi‐metal synergistic effects and entropy increase effects. The work will provide new clues for designing versatile catalysts and devices for large‐scale industrialization.