Carbon nitride-supported CuCeO2 composites derived from bimetal MOF for efficiently electrocatalytic nitrogen fixation

Development of an efficient catalyst for ammonia preparation through electrochemical nitrogen fixation is significant and desirable to relieve the tremendous energy-consumption by the conventional Haber-Bosch process. Herein, the abundant oxygen vacancy-containing CuCeO2@NC composite (denoted as Cu-doped CeO2 nanoparticles supported on carbon nitride) was fabricated by annealing melamine-incorporated metal-organic framework (MOF) of CuCe-BTC (BTC = 1,3,5-benzenetricarboxylic acid) under the reducing atmosphere of 10% H2/Ar. The optimized composite of Cu0·1CeO2@NC achieved a high selectivity and an outstanding electrocatalytic activity with NH3 yield rate of 44.5 μg h−1 mgcat.−1 at −0.5 V versus a reversible hydrogen electrode, surpassing most of the reported electrocatalysts and its analogues without copper and nitrogen atoms as dopants. The favorable performance of Cu0·1CeO2@NC would be ascribed to the synergistic effect of the rich oxygen vacancies and the optimal electrical structure induced by heteroatom doping, further confirmed by X-ray photoelectron spectroscopy (XPS), electron paramagnetic resonance (EPR) spectroscopy, and Raman spectra. Moreover, the great electrochemical selectivity and durability for the longtime electrolysis had been demonstrated. This work offered an insight that the electrocatalytic performance would be regulated by heteroatomic dopants and oxygen vacancy toward MOF-derived materials.