CoCu-hydroxyquinoline loaded on copper foam as effective pre-catalytic electrode for oxygen evolution

Abstract

• An effective pre-catalytic electrode composed of CoCu hydroxyquinoline salts was prepared. • The pre-catalytic electrode will be activated during the electrochemical process. • The in situ formed CuO/COOOH would act as the catalytic active phase. • The optimized electrode can afford 20 mA cm −2 with overpotential of 282 mV in 1 M KOH. • The optimized electrode shows excellent stability. Cobalt-copper bimetal hydroxyquinoline salts grown on copper foam substrate are successfully synthesized. The copper foam supported cobalt-copper bimetal hydroxyquinoline salts can act as pre-catalysts for oxygen evolution. The as-obtained electrode presents prominent catalytic performance and stability, showing an overpotential of 282 mV for 20 mA cm −2 in 1 M KOH. Furthermore, the optimized catalytic electrode can maintain the current density of 96.7% after 36 h of catalysis operation at 80 mA cm −2 . The prominent catalytic performance can be attributed to the in situ generated catalytic active species derived from the hydroxyquinoline salt pre-catalysts. Characterizations of the used catalyst after catalysis confirm the formation of cobalt oxyhydroxide and copper oxide, acting as the actual active species for the catalytic process. This convenient but low-cost fabrication method and the favorable catalytic activity make this optimized catalytic electrode a hopeful candidate for electrochemical water splitting.