Figure 1

Schematic images of Na2SO4 (a), P-2AT (b) and Co9S8/NSPC (c); scanning electron microscopy images of Na2SO4 (d) and P-2AT (e); transmission electron microscopy (TEM) image of P-2AT (f); scan TEM image of Co9S8/NSPC9–45 (g); the corresponding element mapping images of Co (h), S (i), C (j), N (k) and O (l); and high-resolution TEM image of Co9S8/NSPC9–45 (m).