Hollow CuSe nanocubes as a bifunctional electrocatalyst for energy-saving overall urea–water electrolysis

Abstract

Overall urea–water electrolysis has the potential to be employed in the purification of urea-containing wastewater and the production of hydrogen. However, the lack of cost-effective catalysts currently presents a significant obstacle to the further development of this technology. Through a simple template-directed selenium reaction in a novel type of highly active solution, an interface engineering strategy was designed to synthesize hollow CuSe nanocubes as an efficient bifunctional catalyst. The unique hollow CuSe nanocubes exhibit significant catalytic efficiency because of their larger electrolyte contact area and faster ion transport. In 1 M KOH with a 0.5 M urea electrolyte, CuSe/NF required an overpotential of 199 mV for HER and a potential of 1.38 V for UOR to achieve a current density of 10 mA cm⁻². It can work stably for 24 h without significant degradation of activity at 10 mA cm⁻², showing excellent durability and excellent stability. For overall urea–water electrolysis, it exhibits a remarkable activity with a low cell voltage of 1.61 V at 10 mA cm⁻². Consequently, the design strategy of this unique hollow-structured CuSe provides a new insight to improve electrocatalytic performance and stability.