1. (a) XRD patterns of CA, NCS-2, NCS-10 and V3-NCS-1 samples; (b) Total survey, (c) Ni2p, (d) Co2p and (e) S2p XPS spectra of NCS-2

2. SEM images of (a) carbon aerogels, (b) NCS-1, (c, d) NCS-2, (e) NCS-5 and (f) NCS-10

3. (a-b) High-resolution TEM image, (b) HAADF-STEM image and (c) EDS element mappings of NCS-2

4. SEM images of (a) NCS-1 and Vx-NCS-1 (x is (b)3, (c)5 or (d)10)

5. (a) CV curves of CA, NCS-n (n=1, 2, 5, 10) and V3-NCS-n (n=1,2); (b) Comparison of the peak current density and the average load amount of NCS-n (n=1, 2), Vx-NCS-n (x=3, 5, 10; n=1,2); (c) CV curves of V3-NCS-1 in 1 mol/L KOH at 10, 20, 30, 40, 50 mV/s sweep speed with inset showing the relationship between the peak current density and the square root of the sweep speed; (d) Relationship between the methanol concentration and the peak current density of V3-NCS-1

6. (a) Oxidation peak current densities and (b) I-t curves of NCS-2 and V3-NCS-1 electrodes varied within 1000 CV cycles, and (c) XRD patterns of NCS-2 and V3-NCS-1 before and after 1000 cycles; (d) TEM image, (e) HAADF-STEM image and corresponding EDS element mappings of the particles loaded in NCS-2 after 1000 cycles