Photocatalytic Plasmon‐Enhanced Nitrogen Reduction to Ammonia

Abstract

Nitrogen reduction to ammonia under ambient conditions is an emerging area of research sparked by the increasing concerns over climate change which is driving the efforts to find alternatives to energy‐intensive Haber–Bosch process. Ammonia is a critical component in the manufacturing of fertilizers and is required to support the global food supply. It can also be used as a fuel source to generate electricity. Many strategies have been used to drive nitrogen reduction under milder conditions including incorporation of plasmonic nanomaterials. The ability of plasmonic nanomaterials to strongly interact with light, resulting in near‐field enhancement, hot charge‐carrier generation and injection, increase in local temperature, has made them attractive candidates for catalysis. This review provides a comprehensive survey of recent developments in photocatalytic, plasmon‐enhanced nitrogen conversion to ammonia and the proposed mechanisms for the increased catalytic activity. A brief outlook on the current challenges and future directions is also provided.

Active Site Engineering on Plasmonic Nanostructures for Efficient Photocatalysis

“…If a sufficient amount of charge carriers is provided (i.e., multielectrons process), the vibrationally excited adsorbate can undergo further excitation (or excitation/de-excitation), 30 resulting in the deposition of more vibrational energy. 55,117 If the vibrationally activated adsorbate is regarded as the initial state of the reaction, the reaction energy barrier for adsorbate activation will be reduced, similar to when the light-excited plasmonic metal is included in the initial state of the reaction (Figure 4f). 118 The role of LSPR in assisting the adsorbate activation explains why some uphill reactions (ΔG > 0, thermodynamically nonspontaneous) can occur under mild conditions in plasmonic photocatalysis.…”

“…The application of plasmonic nanostructures in photocatalysis has gained tremendous attention since the report on direct molecular oxygen activation over Ag nanocubes by Linic and co-workers in 2011. , The related research can be roughly divided into two categories: i) investigating the role of localized surface plasmon resonance in photocatalysis using some model reactions, ,, and ii) developing high-performance photocatalysts for target applications. ,, While these two research directions may have different requirements for photocatalysts (e.g., components and structures), the rational design and engineering of active sites on plasmonic nanostructures is a prerequisite and can be beneficial for both directions . With the tremendous efforts devoted, a variety of active site-engineered plasmonic nanostructures have been developed.…”

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

“…[71] In addition to the strategies mentioned above, the utilization of the localized surface plasmon resonance (LSPR) effect to improve the photocatalytic performance of NRR is recently attracting increasing attention. [72,73] This hybrid approach is the focus of this Perspective and will be discussed in detail in the next sections.…”

Synthesis and Photothermal Properties of UV-Plasmonic Group IV Transition Metal Carbide Nanoparticles

“…6,7 Unlike conventional optics, plasmonic materials enable unrivalled concentration of light beyond the diffraction limit. 8,9 Recent developments into plasmonic nanomaterials have created research interest in using them for sensing, 10,11 data recording and storage, 12 improved energy harvesting, 13,14 solar-vapor conversion, [15][16][17][18][19] photocatalysis 14,20,21 and photothermal therapy. [22][23][24] Traditional plasmonic materials like gold and silver have suffered from thermal instability due to low bulk melting points, chemical instability, and/or high cost.…”