Novel Pd0.1Cu0.9Co2O4 nano-flake: A promising multifunctional catalyst for the electrochemical water splitting and photo-degradation reactions at ambient temperature

Abstract

Herein, we report the fabrication of self-assembled Pd0.1Cu0.9Co2O4-nano-flakes via the co-precipitation method. The formation of poly-crystalline cubic spinel phase Pd0.1Cu0.9Co2O4-nano-flake has been identified by powder X-ray diffraction, field emission scanning electron microscopy, and energy dispersive X-ray measurement techniques. The Pd0.1Cu0.9Co2O4 nano-flakes exhibited outstanding activity in the electrochemical water splitting reaction leading to the production of hydrogen and oxygen gas at ambient temperature. Higher current density, lower overpotential, and Tafel slope all are desirable for both HER and OER. Best HER activity (η100 = 628 mV) and capacitive performance in acid was found for Pd-doped electrocatalyst whereas in base the good OER performance (η2 = 434 mV) and capacitive performance was found for CuCo2O4 electrocatalyst. Further, the CPE test demonstrated that Pd0.1Cu0.9Co2O4-nano-flakes are electrochemically stable for 2 h without significant loss in activity. The present catalyst also shows remarkable photocatalytic activity in the degradation of Methylene blue (MB) under visible light at ambient temperature and degrades 100% MB dye in just 1 min. The role of reactive species in the photo-degradation of MB has been established by scavenger tests.