The heterojunction regulated by Au nanoparticles efficient removal of NO through the synergistic effects of SPR and the electron bridge.

The elimination of low-concentration (ppb) nitrogen oxides (NOx) in city and indoor environments, particularly the selective removal of NO while preventing toxic NO2 formation is a significant challenge. Photocatalytic technology offers a promising solution, but its effectiveness is limited by high carrier recombination rates and insufficient active sites. This study introduces a photocatalyst (Au@NM/ZIF) that forms a Z-type heterojunction structure by precisely positioning gold nanoparticles within the NM/ZIF framework. The catalyst consists of amino-functionalized NH2-MIL-125 and ZIF-8, with gold nanoparticles serving dual roles: UV-Vis analysis shows that their surface plasmon resonance (SPR) enhances visible light absorption, promoting the generation of charge carriers that drive the oxidation of NO to NO3-. Additionally, X-ray photoelectron spectroscopy (XPS) and work function analysis indicate that gold nanoparticles function as an electronic bridge, optimizing charge transfer between NM and ZIF-8, improving electron-hole separation and increasing active site utilization, thereby significantly enhancing NO conversion efficiency. In situ Fourier-transform infrared spectroscopy (FT-IR), electron spin resonance (ESR), and radical capture experiments further clarify the formation pathways of preliminary products and completed outputs, emphasizing the important roles of active radicals (such as •OH and •O2-) in the deep oxidation of NO. This research offers a valuable solution for effectively removing low-concentration NOx.