Dual‐Shelled CeO2 Hollow Spheres Decorated with MXene Quantum Dots for Efficient Electrocatalytic Nitrogen Oxidation

Abstract Electrocatalytic nitrogen oxidation (NOR) provides a promising alternative strategy for synthesizing nitric acid from widespread N 2 , which overcomes the disadvantages of Haber‐Bosch‐Ostwald process. However, the NOR process suffers from the limitation of high N≡N bonding energy, sluggish kinetics, and low efficiency. It is prerequisite to develop more efficient NOR electrocatalysts. Herein, dual‐shelled CeO 2 hollow spheres (D‐CeO 2 ) are synthesized and modified with Ti 3 C 2 MXene quantum dots (MQDs) for NOR, which exhibited a NO 3 − yield rate of 71.25 µg h −1 mg cat −1 and Faradic Efficiency (FE) of 31.80% at 1.7 V versus RHE. The unique quantum size effect and abundant edge active sites lead to more effective capture of nitrogen. Moreover, the dual‐shelled hollow structure will gather intermediate products in the interlayer of the core‐shell to facilitate N 2 fixation. The in situ Fourier transform infrared (FTIR) spectroscopy confirmed the formation of *NO and NO 3 − species during the NOR, and the kinetics and possible pathways of NOR are calculated by density functional theory (DFT). In addition, a Zn‐N 2 reaction device is assembled with D‐CeO 2 /MQDs as anode and Zn plate as cathode, obtaining an extremely high NO 3 − yield rate of 104.57 µg h −1 mg cat −1 at 1 mA cm −2 .