3. Results and discussion
3.1 XRD analysis
Fig. 1 depicts the crystal structure and crystallinity of pure MCS, NiSe2 and MCNS composites by XRD analysis. In Fig. 1a , seven distinct diffraction peaks of pure MCS at 24.92o, 26.65o, 28.37o, 36.80o, 43.91o, 48.08o and 52.04o correspond to the crystal planes of (100), (002), (101), (102), (110), (103) and (114) planes, respectively. The diffraction peaks of NiSe2 was corresponded to the cubic NiSe2 with the well matched (200), (210), (211), (311), (023) and (321) crystal planes, respectively. The strong and sharp characteristic peaks of NiSe2suggested high crystallinity of NiSe2 synthesized by hydrothermal method. No other peaks originating by impurities were observed, in the XRD patterns of MCS and NiSe2 alone, implying the successful preparation of MCS solid solution and NiSe2. In theFig. 1b , the diffraction peaks of composite catalyst were actually resembled to pure MCS, indicating that adulteration with a little amount of NiSe2 had not effected on the crystal phase of MCS. Besides, the intensity of diffraction peaks of NiSe2 gradually strengthened with increased of NiSe2, indicating the successfully fabricated of composite catalyst.