Synergistic Enhancement of Electron Dynamics and Optical Properties in Zeolitic Imidazolate Framework-8-Derived Zinc Oxide via Surface Plasmon Resonance Effects of Silver Nanoparticles under UV Irradiation

This study investigates the surface plasmon resonance (SPR)-induced UV photoresponse of zinc oxide (ZnO) derived from zeolitic imidazolate framework-8 (ZIF-8) to assess the influence of silver nanoparticles (Ag NPs) on the photoresponse behavior of metal-organic framework (MOF)-derived ZnO. The initial synthesis involved a thermal treatment in air to convert ZIF-8 into ZnO. We noted enhanced optical absorption both in the UV and visible spectra with the deposition of Ag NPs onto the ZIF-8-derived ZnO. Additionally, the presence of Ag NPs in the ZnO resulted in a substantial increase in current, even without any light exposure. This increase is attributed to the transfer of electrons from the Ag NPs to the ZnO. Photocurrent measurements under UV illumination revealed that the photocurrent with Ag NPs was significantly higher-by two orders of magnitude-compared with that without Ag NPs. This demonstrates that SPR-induced absorption markedly boosted the photocurrent, although the current rise and decay time constants remained comparable to those observed with ZnO alone. Although Ag NPs contribute electrons to ZnO, creating a "pre-doping" effect that heightens baseline conductivity (even in the absence of light), this does not necessarily alter the recombination dynamics of the photogenerated carriers, as indicated by the similar rise and decay time constants. The electron transfer from Ag to ZnO increases the density of charge carriers but does not significantly influence their recombination.

In-situ construction of WS2/ZIF-8 composites with an electron-rich interface for enhancing nitrogen photofixation

Photocatalytic nitrogen reduction reaction (PNRR) is an environmentally friendly synthesis method. It has been regarded as a promising approach for future NH3 preparation, which can reduce the natural fuel consumption and pollution of the Haber Bosch process. Nevertheless, this method exists poor activity for mass production, so it is urgent but challenging to explore highly efficient catalysts. Here, the novel WS2/ZIF-8 composites are reported, DFT and XPS indicate the transfer direction of electrons is from ZIF-8 to WS2, forming an electron-rich interface between WS2 and ZIF-8, thus it endows the more powerful photocatalytic nitrogen reduction ability for 2-WS2/ZIF-8 than monomer material. Meanwhile, 2-WS2/ZIF-8 exhibits admirable photocatalytic nitrogen reduction performance under real and simulated sunlight or in tap water, further attesting its excellent stability and practicability.