An organic-inorganic hybrid polyoxoniobate decorated by a Co(III)-amine complex for electrocatalytic urea splitting

The overall energy efficiency of electrochemical systems is significantly reduced by the conventional anodic oxygen evolution reaction (OER). It is feasible to improve energy efficiency by replacing the OER with the urea oxidation reaction (UOR), which has a lower thermodynamic potential. An organic-inorganic hybrid polyoxoniobate decorated by a Co(iii)-amine complex, Na-4(H2O)(15)[Co(en)(3)](2){[Co(en)(Nb6O19)](2)}.34H(2)O (Co2Nb6, en = ethylenediamine) with distinct physicochemical characteristics and well-defined single-crystal structure is reported. The structure of Co2Nb6 contains Lindqvist {[Co(en)(Nb6O19)](2)}(10-) dimer and free [Co(en)(3)](3+) complexes. Co2Nb6 exhibits remarkable catalytic activity for the UOR after being firmly attached to the surface of acetylene black by polyethyleneimine (PEI). To the best of our knowledge, this is the first instance of performing the electrocatalytic UOR based on Lindqvist polyoxoniobate clusters, which will pave the path for innovative concepts in the development of POM-based electrocatalysts.