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

Abstract

Despite its severe operating conditions, associated energy consumption, and environmental concerns, the manufacture of nitrogen‐rich fertilizers still relies heavily on producing ammonia in centralized chemical plants via the Haber–Bosch process. A distributed and more sustainable scheme considers the on‐site production of carbon‐neutral fertilizers at ambient conditions in photocatalytic reactors powered by sunlight. Among the different strategies proposed to boost the nitrogen reduction ability of conventional catalysts, the incorporation of plasmonic nanomaterials is gaining widespread interest owing to their unique optical tunability and their potential to improve the efficiency and selectivity of many chemical transformations. This Perspective examines the state‐of‐the‐art for the nitrogen reduction reaction via plasmon‐driven photocatalysis and discusses design principles for advancing it. The different physical mechanisms underlying the operation of plasmonic materials in a catalytic setting, and the dimensions along which the catalysts can be tuned to harness them are detailed. Paths to overcome current frontiers in the field, including design strategies of plasmonic photocatalysts, the development of complementary characterization techniques, the standardization of the reaction conditions and ammonia quantification methods, and the possibilities offered by theoretical methods to drive material discovery, identifying fundamental bottlenecks, and proposing directions for the advancement of this emerging field are outlined.

Direct Bottom-Up In Situ Growth: A Paradigm Shift for Studies in Wet-Chemical Synthesis of Gold Nanoparticles

“…While for these applications top-down nanofabrication of the nanostructures is common, the relatively simple and high-throughput synthesis of in situ grown nanostructures opens a wealth of possible applications in both photocatalysis and surface-enhanced sensing. Thus far, significant developments have been made toward applying plasmonic materials toward directing catalyst driven reactions, such as H 2 and O 2 dissociation , or reactions relevant to environmental remediation. , Plasmonic nanocrystals ,,, and substrates/electrodes functionalized with plasmonic nanostructures or nanoantennas prepared by top-down nanofabrication, such as those explored by the groups of Halas and Nordlander, ,, Cortés, , Atwater, and others , are some popular examples of platforms for probing and optimizing plasmon-enhanced catalysis. Metamaterials have recently emerged as a step forward toward translating the potential of plasmonic nanostructures into practical, large-scale, photocatalytic applications. , Narang and co-workers have explored plasmonically enhanced chemistry in a number of configurations and reactions. ,,, Two-dimensional metamaterials ( i.e.…”

“…Thus far, significant developments have been made toward applying plasmonic materials toward directing catalyst driven reactions, such as H 2 and O 2 dissociation 75,396 or reactions relevant to environmental remediation. 397,398 Plasmonic nanocrystals 27,28,399,400 and substrates/electrodes functionalized with plasmonic nanostructures or nanoantennas prepared by top-down nanofabrication, such as those explored by the groups of Halas and Nordlander, 396,401,402 Corteś, 403,404 Atwater, 405 and others 406,407 are some popular examples of platforms for probing and optimizing plasmonenhanced catalysis. Metamaterials have recently emerged as a step forward toward translating the potential of plasmonic nanostructures into practical, large-scale, photocatalytic applications.…”

Rational construction of ZnO/CuS heterostructures-modified PVDF nanofiber photocatalysts with enhanced photocatalytic activity

“…[3][4][5] TiO 2 and ZnO are claimed to have comparable wide band gap (∼3.3 eV), but the better photocatalytic degradation efficiency of low-cost ZnO for a variety of organic dyes in acidic and alkaline environments has piqued the interest of a large number of researchers. [6][7][8][9] However, the low quantum efficiency of ZnO as a result of the quick photogenerated electron/hole recombination drastically lowers photocatalytic performance. Meanwhile, the extremely limited range of its spectral response results in a low visible-light photocatalytic activity.…”

Photocatalytic Synthesis of Ammonia from Pinecone Graphite-Phase Carbon Nitride Loaded with MoS2 Nanosheets as Co-catalysts

“…It is widely known that ammonia is an essential industrial raw material and also serves as a green energy transporter. , N 2 in the atmosphere is the primary source of ammonia, yet N 2 molecules are stable and resistant to chemical reactions. , Currently, ammonia is usually synthesized in industry by the Haber–Bosch process, which requires high pressure and temperature . Additionally, the Haber–Bosch reaction also requires large amounts of gray hydrogen from fossil fuels, which belong to industries with high energy consumption and carbon emissions. , Therefore, researchers are seeking environmentally friendly alternatives to replace the Haber–Bosch reaction …”

“…5 Additionally, the Haber−Bosch reaction also requires large amounts of gray hydrogen from fossil fuels, which belong to industries with high energy consumption and carbon emissions. 6,7 Therefore, researchers are seeking environmentally friendly alternatives to replace the Haber− Bosch reaction. 8 In nature, water could be used as a source of protons for N 2 fixation, which inspired scientists to investigate the use of photocatalysis for N 2 fixation.…”