3.3 XPS analysis
The X-ray photoelectron spectroscopy (XPS) was used to investigate the
surface chemical states of MCNS-10 composite. The Fig. 3aclearly reveals the existence of Mn, Cd, S, Ni and Se elements in
MCNS-10 composite. Fig. 3b was the spectrum of Cd 3d, the
binding energies located at 404.6 and 411.3 eV were respectively
corresponded to Cd
3d5/2 and Cd 3d3/2, which were the
Cd2+ ions [35]. The two binding energy of Mn 2p at
641 and 651.9 eV belong to the Mn 2p3/2 and Mn
2p1/2 respectively as shown in Fig.
3c . According to the S 2p spectra
shown in Fig. 3d , the peaks at 160.9 (S 2p3/2)
and 162.1 (S 2p1/2) eV were the characteristic peaks of
S2- ions [33].
The deconvolution of the overlapped Ni 2p peaks four peaks (Fig.
3e ), the peaks located at 861.9 and 879.5 eV were respectively related
to the satellite peaks of the Ni 2p1/2 and Ni
2p3/2 [37], and the peaks centered at 855.4 and
873.2 eV could be assigned to Ni2+ state [38]. The
XPS spectrum of Se 3d represented in Fig. 3f could divided into
three peaks, the main peaks located at 54.1 and 58.7 eV were
respectively related to Se2- anions and high-valent
oxide [39], and peak at 55 eV were ascribed to Se
3d5/2 of MCNS-10
[40]. These surface bonding
states further proved that composite was composed of MCS and
NiSe2.