Photocatalytic nitrogen fixation reaction can harvest solar energy to convert the abundant but inert N2 into NH3, which, however, has been prevented by multiple challenges, including the high kinetic barriers for activating N2 molecules, the low photoelectric conversion efficiency, and the sluggish mass transfer of N2 molecules at the gas-liquid-solid reaction interface. Here, employing metal-organic framework (MOF) membranes, resembling the assembly of numerous interconnected nanoreactors, to disperse and confine plasmonic gold nanoparticles (AuNPs), we realize direct plasmonic photocatalytic nitrogen fixation under ambient conditions. Upon visible irradiation, the hot electrons generated on the AuNPs can be directly injected into the adsorbed N2 molecules, which can be simultaneously activated by the strong but evanescently localized surface plasmon resonance (LSPR) field. Due to the additional activation from LSPR, a supralinear intensity dependence of the ammonia evolution rate was observed, with a significant increase in the apparent quantum efficiency (AQE) and a decrease in the apparent activation energy for N2 reduction under stronger irradiation. Moreover, the gas-permeable Au@MOF membranes not only ensure the dispersity and stability of AuNPs, but also facilitate the mass transfer of N2 molecules and (hydrated) protons to the surfaces of AuNPs at the designed gas–membrane–solution interface. As a result, an ammonia evolution rate of 18.9 mmol gAu–1 h–1 was achieved under visible light (&gt;400 nm, 100 mW cm–2) with an AQE of 1.54% at 520 nm.

Metal-organic framework membranes encapsulating gold nanoparticles for direct plasmonic photocatalytic nitrogen fixation

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