In-situ construction of trifunctional boronated CuCo2O4/Co9S8 heterostructure for water splitting and urea electrolysis

The development of robust and cost-effective electrocatalysts is critical for enhancing the catalytic kinetics of the hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and urea oxidation reaction (UOR) in alkaline media. Herein, a heterostructured electrocatalyst comprising boronized CuCo 2 O 4 hexagonal nanosheet clusters and Co 9 S 8 three-dimensional nanoparticles supported on nickel foam (B: CCO-CS/NF) was successfully synthesized via a two-step in situ hydrothermal approach. The resulting architecture features abundant electrochemically active sites and improved charge-transfer efficiency. In 1.0 M KOH, the optimized B: CCO-CS/NF electrode delivers superior bifunctional performance, with low overpotentials of 154 mV for the OER and 189 mV for the HER at 10 mA·cm −2 . For the UOR in 1.0 M KOH containing 0.33 M urea, a low working potential of 1.343 V is required to reach 10 mA·cm −2 , confirming a marked energy-saving advantage over conventional OER. Moreover, the catalyst exhibits satisfactory operational stability. The enhanced electrocatalytic activity is mainly attributed to the synergistic interplay between boron-induced lattice defects in CuCo 2 O 4 and the tight heterointerface with Co 9 S 8 , which collectively facilitate rapid electron transport and strong interfacial coupling effects. This work highlights the promising potential of the B: CCO-CS/NF heterostructure for energy-efficient hydrogen production and urea-containing wastewater treatment.