Dodecahedron ZIF-67 anchoring ZnCdS particles for photocatalytic hydrogen evolution

The exposure of rich active sites and the rapid transfer of photo-induced electron-hole pairs are important prerequisites for a photocatalyst with good performance. In this work, a low cost and high active composite Zn0.5Cd0.5S/ZIF-67 was successfully prepared by a hybrid growth method. The dodecahedron ZIF-67 with a very regular surface provides sufficient area for the dispersion of Zn0.5Cd0.5S (ZCS) nanoparticles, which greatly decreases the serious aggregation effect of ZCS particles, and is conductive to further exposing more active sites in the photocatalysis hydrogen evolution process. Moreover, compared with pure ZCS, Zn0.5Cd0.5S/ZIF-67 composite shows more significant ability of capture visible light in the range of 515–600 nm. The highest hydrogen production rate can reached 23264.6 μmol g−1 h-1 under visible light irradiation and the apparent quantum efficiency can reached 6.95 % at 420 nm visible light irradiation. Because of the matched valence band position for ZIF-67 and ZCS, photo-generated carrier recombination rate is greatly inhibited and photo-excited electron-hole pair separation and transfer is accelerated. By analyzing a series of characterization results (SEM, TEM, XPS, PL, UV and DFT), the possible mechanism of photocatalytic water-spitting of the composite to produce hydrogen is proposed.