Title Page
Contents
Abstract 10
1. Introduction 11
2. Experimental 15
2.1. Materials and Chemicals 15
2.2. Physicochemical characterization 16
2.3. Electrochemical half-cell test for ORR and OER 17
2.4. Measurement of Zn-air battery 20
2.5. Preparation of PVP-functionalized PS solution 21
2.6. Preparation of PS@ZIF-67 21
2.7. Preparation of hollow-structured Co/CoS₂/NSCNT 22
3. Results and discussion 22
3.1. Synthetic procedure of hollow-structured Co/CoS₂/NSCNT 22
3.2. Physicochemical characterization of electrocatalysts 25
3.3. Electrocatalytic ORR performance of electrocatalysts 38
3.4. Electrocatalytic OER performance of electrocatalysts 43
3.5. Application on rechargeable Zn-air battery 47
4. Conclusions 52
5. References 53
Table 1. Elemental proportion of Co, S, N, and C for Co/NC, CoS₂/NSC, Co/NCNT, and Co/CoS₂/NSCNT measured by TEM-EDS. 31
Fig. 1. (a) X-ray diffraction (XRD) patterns and (b) Raman spectra of Co/NC, CoS₂/NSC, Co/NCNT, and Co/CoS₂/NSCNT. 25
Fig. 2. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images of (a and d) PS@ZIF-67, (b and e) Co/NCNT, and... 28
Fig. 3. (a) N₂ ad/desorption isotherm curves and (b) corresponding pore size distribution of PS@ZIF-67, CoS₂/NSC, and Co/CoS₂/NSCNT. (c) Zeta... 32
Fig. 4. High-resolution XPS spectra of (a) Co 2p, (b) S 2p, (c) N 1s, and (d) C 1s for CoS₂/NSC, Co/NCNT, and Co/CoS₂/NSCNT. Illustration on change of... 35
Fig. 5. Electrocatalytic measurement of prepared electrocatalysts for the ORR. (a) CV curves measured with potential range of 0.2−1.3 V vs. RHE in N₂-... 42
Fig. 6. Electrocatalytic measurement of prepared electrocatalysts for the OER. (a) LSV polarization curves and (b) corresponding Tafel plots. (c) TOF curves... 47
Fig. 7. (a) Schematic illustration of rechargeable ZAB. (b) OCV profiles, (c) discharge polarization curves and corresponding power density curves, (d)... 51
Scheme 1. Schematic illustration of the synthesis of hollow structured Co/CoS₂/NSCNT nanosphere with rational interface engineering and... 24