Synthesis of Sulfur@g-C(3)N(4) and CuS@g-C(3)N(4) Catalysts for Hydrogen Production from Sodium Borohydride

In this work, the S@g-C(3)N(4) and CuS@g-C(3)N(4) catalysts were prepared via the polycondensation process. The structural properties of these samples were completed on XRD, FTIR and ESEM techniques. The XRD pattern of S@g-C(3)N(4) presents a sharp peak at 27.2° and a weak peak at 13.01° and the reflections of CuS belong to the hexagonal phase. The interplanar distance decreased from 0.328 to 0.319 nm that facilitate charge carrier separation and promoting H(2) generation. FTIR data revealed the structural change according to absorption bands of g-C(3)N(4). ESEM images of S@g-C(3)N(4) exhibited the described layered sheet structure for g-C(3)N(4) materials and CuS@g-C(3)N(4) demonstrated that the sheet materials were fragmented throughout the growth process. The data of BET revealed a higher surface area (55 m(2)/g) for the CuS-g-C(3)N(4) nanosheet. The UV–vis absorption spectrum of S@g-C(3)N(4) showed a strong peak at 322 nm, which weakened after the growth of CuS at g-C(3)N(4). The PL emission data showed a peak at 441 nm, which correlated with electron–hole pair recombination. The data of hydrogen evolution showed improved performance for the CuS@g-C(3)N(4) catalyst (5227 mL/g·min). Moreover, the activation energy was determined for S@g-C(3)N(4) and CuS@g-C(3)N(4), which showed a lowering from 47.33 ± 0.02 to 41.15 ± 0.02 KJ/mol.