In this study, various nanostructured hematites (α-Fe2O3), including nanorods (α-Fe2O3NR), nanoparticles (α-Fe2O3Np), and nanosheets (α-Fe2O3NS), were synthesized and their electrocatalytic properties towards the reduction of H2O2 were investigated. All nanostructured α-Fe2O3 hematites were synthesized using chemical bath deposition (CBD) under mild conditions, followed by thermal treatment at 500 °C. The nanostructure was controlled simply by adjusting the composition of precursor solution and reaction duration for the CBD process. It was found that iron phosphate (FePO4) was deposited in situ onto the surface of these nanostructured α-Fe2O3 hematites during the electrochemical pretreatment in the phosphate electrolyte, and both FePO4 and α-Fe2O3 showed activity in catalysing the electrochemical reduction of H2O2. In addition, the interaction/compatibility between deposited FePO4 and α-Fe2O3 has a decisive effect on the overall electrocatalytic activity of the resultant electrodes; FePO4 only showed a synergetic effect on the overall electrocatalytic activity with α-Fe2O3NR and α-Fe2O3NS. The rate constant is highest for the electro-reduction of H2O2 on FePO4 modified α-Fe2O3NR (α-Fe2O3NRFePO4), but FePO4 modified α-Fe2O3NS (α-Fe2O3NSFePO4) showed the best overall electrocatalytic activity due to its relatively higher surface area. Furthermore, dissolved oxygen showed negligible interference on the activity of α-Fe2O3NRFePO4 and α-Fe2O3NSFePO4, which makes them promising sensing materials in oxidase-based electrochemical sensors.
All Science Journal Classification (ASJC) codes
- Chemical Engineering(all)