Nanoengineering of ZnCo2O4@CoMoO4 heterogeneous structures for supercapacitor and water splitting applications

A hybrid ZnCo2O4@CoMoO4 heterogeneous structure deposited onto nickel foam was synthesized via a two-step hydrothermal process. The results demonstrate that the hybrid architecture exhibits excellent electrochemical performance, including the specific capacitance of 1040C g−1 at 1 A g−1 for hybrid structures, high energy density of 87.3 Wh kg−1 at a power density of 2700 W kg−1 for an as-assembled supercapacitor and excellent cycle stability with a capacity retention of 99% undergoing 8000 charge-discharge for the device. Moreover, it also shows favorable electrocatalytic activity with low overpotentials of 237 mV at 20 mA cm−2 for oxygen evolution reaction and 114 mV at 10 mA cm−2 for hydrogen evolution reaction, and low cell voltage of 1.54 V at 10 mA cm−2 for overall water splitting. In addition, the stability maintains well for the long-term use of 13 h. We believe that this hybrid ZnCo2O4@CoMoO4 heterogeneous structure could be a promising candidate for future energy storage and conversion.