Diethylenetriamine assisted synthesis of mesoporous Co and Ni-Co spinel oxides as an electrocatalysts for methanol and water oxidation

The electrocatalytic oxidation of small molecules such as methanol and water is the crucial part of energy storage/generation technologies such as fuel cell and metal-air batteries. However, the high overpotential, sluggish reaction dynamics and low stability of electrode materials are the main barriers in developing an excellent catalyst for the anodic electro-oxidation process. To overcome such problems, we developed an easy synthesis root for the preparation of novel mesoporous (MP) Co3O4 and NiCo2O4 using a template-free hydrothermal and subsequent annealing method. In which, we used diethylenetriamine as a complexing agent, which was able to control crystal growth of corresponding metal hydroxide, leading to the formation of a mesoporous structure. Results show that the MP-NiCo2O4 exhibits a current density of 10.0 mA cm−2 even at a lower potential (286 mV vs. Ag/AgCl) for methanol oxidation reaction compared to that of MP-Co3O4. On the other hand, both MP-Co3O4 and MP-NiCo2O4 display excellent electrocatalytic activity towards water oxidation with lower onset potential and overpotential (MP-Co3O4 ɳ10 = 302 mV and MP-NiCo2O4 ɳ10 = 322 mV). The excellent electrochemical performance suggests that this mesoporous MP-NiCo2O4 and MP-Co3O4 could be potential candidates for energy and environmentally related applications.