Well-regulated nickel nanoparticles functional modified ZIF-67 (Co) derived Co_3O_4/CdS p-n heterojunction for efficient photocatalytic hydrogen evolution

摘要

Well-designed functional noble metal-free Ni nanoparticles as co-catalyst to modified ZIF-67(Co) derived Co3O4 framework materials/CdS p-n heterojunction photocatalyst for efficient hydrogen evolution was successfully synthesized via photo-assisted in-situ method. The obtained noble metal-free defect-induced [Co3O4(3 wt %)/CdS/Ni] mesoporous photocatalyst exhibit excellent photocatalytic activity, namely, the maximum amount of hydrogen evolution reaches about 512 mu mol for 5 h over the [Co3O4(3 wt%)/CdS/Ni] photocatalyst under visible light irradiation, which is 14.2 times higher than that of the pure CdS. Deeper further research confirms that the red shift of absorption band edge, the enhancement of light absorption intensity, the short fluorescence lifetime (2.61 ns), the faster electron injection rate (K-ET = 1.17 x 10(8) s(-1)), the larger efficiency of electron injection (eta(inj) = 30.6%), the high photocurrent response and the smaller R-1 (22.3 Omega) and R-2 (16,207 Omega) together accelerate the efficient spatial charges separation and transfer. The deeper characterization study results such as TEM, SEM, XPS, XRD, UV-vis DRS, Transient photocurrent and FT-IR etc. shown that the Ni nanoparticles modified on the Co3O4/CdS provided the more active sites and improved the efficiency of photo-generated charge separation, the results of which were in good agreement with each other.