“…The XPS survey spectra proved the presence of C, N, O, P, and S elements in DCAs, N-DCAs, N-P-DCAs, N-S-DCAs, and N-P-S-DCAs in Figure S3. As shown in Figure b, the N 1s spectra of N-P-S-DCAs show four characteristic peaks centered at approximately 397.38, 398.08, 399.38, and 400.48 eV, which are assigned to pyridinic N (N-6), pyrrolic N (N-5), graphitic N (N-Q), and oxidized N, respectively Figure c shows the high-resolution C 1s XPS spectra, which exhibit two main peaks at 283.98 eV (CC) and 284.58 eV (C–C).…”