Title Page
Contents
Abstract 10
1. Introduction 11
2. Experimental 16
2.1. Synthesis of the CoFe-LDH/V₀-Co₃O₄@C 16
2.2. Physical characterization of the CoFe-LDH/V₀-Co₃O₄@C 18
2.3. Electrochemical characterization of the CoFe-LDH/V₀-Co₃O₄@C 19
3. Results and discussion 22
4. Conclusions 47
5. References 48
Table 1. Comparison of Rct, Cdl and ECSA values for the prepared electrocatalysts.[이미지참조] 44
Fig. 1. X-ray diffraction patterns of (a) ZIF-67 and (b) Co₃O₄@C samples. (c) X-ray diffraction (XRD) patterns and (d) Fourier-transform infrared (FT-IR)... 24
Fig. 2. (a) electron paramagnetic resonance (EPR) spectra and (b) zeta potential distribution of CoFe-LDH/V₀-Co₃O₄@C, CoFe-LDH/Co₃O₄@C,... 26
Fig. 3. Thermogravimetric analysis (TGA) results of (a) Co₃O₄@C and (b) V₀-Co₃O₄@C in N₂ (black line) and air (red line) 29
Fig. 4. Scanning electron microscopy (SEM) images of (a) ZIF-67, (b) V₀-Co₃O₄@C, and (c) CoFe-LDH/V₀-Co₃O₄@C. (d) Transmission electron... 30
Fig. 5. High-resolution XPS spectra of (a) Co 2p, (b) O 1s, and (c) C 1s for Co₃O₄@C and V₀-Co₃O₄@C. 33
Fig. 6. High-resolution XPS spectra of (a) Co 2p, (b) Fe 2p, and (c) O 1s for CoFe-LDH, CoFe-LDH/ Co₃O₄@C, and CoFe-LDH/V₀-Co₃O₄@C. Contact... 35
Fig. 7. (a) X-ray diffraction (XRD) patterns of Co₃O₄@C and V₀-Co₃O₄@C synthesized at different reduction temperature of 200°C, 250°C, and... 38
Fig. 8. Electrocatalytic measurements of prepared electrocatalysts toward OER. (a) OER polarization curves obtained using linear scanning voltammetry... 40
Scheme 1. Schematic illustration of preparation for CoFe-LDH/V₀-Co₃O₄@C as an efficient electrocatalyst for OER. 22