Interface engineering strategy to optimize the electronic structure of CoFe LDH via hybridization with oxygen vacancy-enrich Co3O4 for efficient oxygen evolution reaction

초록

The development of clean and sustainable energy has attracted significant attention due to increasing concerns about global warming and the depletion of fossil fuels. Electrochemical water splitting is considered a promising strategy due to its eco-friendliness and high-purity H2 production. However, the large overpotentials caused by sluggish four-electron reaction during the anodic oxygen evolution reaction limited their large-scale application. Until now, the precious metal-based OER catalysts, such as Ir/Ru based oxide, have been used as state-of-art OER electrocatalyst. Nevertheless, their high cost, scarcity, and low stability have seriously hindered large scale commercialization. Therefore, numerous researchers have been studied about transition metal-based catalysts owing to their low cost, earth-abundance and excellent long-term stability. In this study, we synthesized oxygen defect-rich Co3O4/CoFe-LDH composite on carbon matrix (CoFe-LDH/Vo-Co3O4@C) via co-precipitation, annealing process, and subsequent sonochemistry method. Spinel-structured cobalt oxide is an efficient electrocatalyst due to its high corrosion resistance and rich redox properties. Oxygen defect on the surface of Co3O4 can improve electrical conductivity and modulate the adsorption/dissociation energy states. Furthermore, interfacial junction of Co3O4 with CoFe LDH, which is well known as OER catalyst, can effectively enhance the intimate interaction with oxygen containing intermediates. As expected, the obtained CoFe-LDH/Vo-Co3O4@C showed outstanding OER performance with an overpotential of 298 mV at 10 mA cm-2 and Tafel slope of 60.2 dec-1. In addition, the prepared electrocatalyst exhibited excellent long-term stability for 30 h. This research will provide new insights for preparation of transition metal-based composite materials for future energy storage and conversion system.