Metal–Organic Framework Membranes Encapsulating Gold Nanoparticles for Direct Plasmonic Photocatalytic Nitrogen Fixation

Abstract

Photocatalytic nitrogen fixation reaction can harvest the solar energy to convert the abundant but inert N2 into NH3. Here, utilizing metal–organic framework (MOF) membranes as the ideal assembly of nanoreactors to disperse and confine gold nanoparticles (AuNPs), we realize the direct plasmonic photocatalytic nitrogen fixation under ambient conditions. Upon visible irradiation, the hot electrons generated on the AuNPs can be directly injected into the N2 molecules adsorbed on Au surfaces. Such N2 molecules can be additionally activated by the strong but evanescently localized surface plasmon resonance field, resulting in a supralinear intensity dependence of the ammonia evolution rate with much higher apparent quantum efficiency and lower apparent activation energy under stronger irradiation. Moreover, the gas-permeable Au@MOF membranes, consisting of numerous interconnected nanoreactors, can ensure the dispersity and stability of AuNPs, further facilitate the mass transfer of N2 molecules and (hydrated) protons, and boost the plasmonic photocatalytic reactions 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 (>400 nm, 100 mW cm–2) with an apparent quantum efficiency of 1.54% at 520 nm.

Subnanometric alkaline-earth oxide clusters for sustainable nitrate to ammonia photosynthesis

“…c Calculated activation energy for NO 3 − RR for NH 4 + synthesis and water splitting for H 2 generation. d Long-term stability of BaO NCs -TNS and comparison of total NH 4 + yield with different NH 4 + synthesis routes 11 , 16 , 25 , 42 , 59 , 68 – 75 . The detailed comparison lists of b and d are provided in Supplementary Table 2 .…”

Construction of Heterostructured Sn/TiO2/Si Photocathode for Efficient Photoelectrochemical CO2Reduction

“…As previously reported, hot electrons generated by Sn plasmon resonance could enhance the adsorption of formate intermediates (*OCHO) under light irradiation and promote the subsequent proton‐coupled electron transfer pathways [32] . In this work, the hot electrons generated by Sn plasmon resonance and the coupled electrons provided by the applied electric field can further improve the carbon dioxide conversion efficiency compared to the electronic field alone [15c] . Meanwhile, the energy barrier of HER was much higher compared with EC performance, indicating more sluggish HER kinetics under light field [33] …”

Challenges and Opportunities for Renewable Ammonia Production via Plasmon‐Assisted Photocatalysis

“…Reproduced with permission. [ 124 ] Copyright 2021, American Chemical Society. c) Schematic illustration of solar thermal NH 3 synthesis on Ru/TiO 2‐x H x .…”