“…Further, the presence of Zn was apparent in the Zn 2p spectrum of HCF-ZC particles, showing characteristic peaks at 1021.7 and 1044.8 eV (Figure f). We confirmed the uniform distributions of heteroatoms, such as Co, Zn, and N, in the spherical hollow HCF-ZC particles based on the obtained results. ,− For comparative purpose, the surface chemistry of PCF-C and PCF-Z was also investigated as shown in Figure S5. We found effective integrations of Zn and Co, together with N in the HCF-ZC, where the chemical states of each heteroatom are not much different from those of PCF-C and PCF-Z.…”