Recent Progress and Challenges in Plasmon‐Mediated Reduction of CO₂ to Chemicals and Fuels

Abstract

Meanwhile, global energy demands also continue to rise. In such a situation, inspiration from nature's process of photosynthesis can be taken to target both the challenges, and artificial systems can be employed that recycle atmospheric CO 2 into valuable hydrocarbon fuels. [2,3] At the outset, artificial photosynthesis seems a straightforward and sustainable approach. However, conversion of CO 2 into value-added chemicals such as, carbon monoxide (CO), formic acid (HCOOH), methanol (CH 3 OH), methane (CH 4 ), and other C 2+ products is an endergonic process, involving a significant positive change in Gibbs free energy. [4] Also, kinetics and product selectivity are major challenges to tackle. While the energy barriers might be surpassed by thermal or electrical energy input to catalysts, economic feasibility, product yields, and selectivity are complex factors. A better strategy is to utilize solar energy to drive the thermodynamically uphill reactions and produce chemical fuels in a renewable and sustainable way. Moreover, the light excitation of catalysts allows more controlled CO 2 reduction. Nanotechnology in this scenario provides myriad opportunities to develop photocatalysts that produce electron-hole pairs upon light illumination and carry out the required chemical transformation. Semiconductor materials, mainly titania (TiO 2 ), have dominated the photocatalysis field but pose constraints regarding limited visible light absorption (while visible light constitutes ≈46% of the sunlight) and other factors. [5][6][7][8] As such, the quest to develop an efficient alternative has recently led to the emergence of photocatalysts consisting of plasmonic metal nanoparticles, mainly Au, Ag, Cu, and Al, that can harvest visible light with high optical cross-section and serve as a platform for surface catalyzed reactions. [9][10][11][12][13] Plasmonic nanostructures exhibit strong interaction with the incident electromagnetic radiation and trigger localized surface plasmon resonance (LSPR), leading to enhancement of local electric fields and subsequent generation of energetic charge carriers and heat that can be exploited in tremendous applications of chemical transformation. [14] The energetic charge carriers are generated with a non-equilibrium distribution, and their potential energy depends upon the electronic band structure of the nanomaterial. This regulates their overall contribution to the chemical reaction's free energy and the extent of activation of the reactants. Recent theoretical and experimentalThe realization of the strong interaction of plasmonic nanostructures with electromagnetic radiation, subdiffraction-limit field localization, and unusually high field enhancement enables immense opportunities to harness visible light in the field of photocatalysis. Plasmon-induced energetic charge carriers allow the metal nanostructures to catalyze surface reactions with selective pathways that are rather a holy grail of thermal catalysis. An intriguing application of plasmonic photocatalysis includes sequestr...

Nickel-Laden Dendritic Plasmonic Colloidosomes of Black Gold: Forced Plasmon Mediated Photocatalytic CO2 Hydrogenation

“…Conventional plasmonic nanocatalysts have intense absorptions but are narrow. − In this work, we have designed and synthesized dendritic plasmonic colloidosomes of Au (black gold), based on a nickel photocatalyst that absorbs across the entire visible to NIR range.…”

“…Plasmonic nanocatalysts are a paradigm in heterogeneous photocatalysis. − Localized surface plasmon resonance (LSPR) damping generates hot carriers as well as localized heating in plasmonic nanoparticles, which then interact with reactant molecules and activate their chemical bonds. − A hybrid catalyst design in which plasmonic metal undergoes LSPR and induces optical polarization in a nonplasmonic metal in its vicinity (known as forced plasmon) is another innovative way to broaden the scope of plasmonic catalysis in a variety of reactions. − …”

Plasmonic Photocatalysis for CO2 Reduction: Advances, Understanding and Possibilities

“…Plants can convert CO 2 as a raw material into nutrients through photosynthesis. As being inspired, scientists intend to develop artificial photosynthesis systems mimicking the function of plants to convert CO 2 into fuels, thus not only reducing CO 2 in the air but also alleviating our dependence on fossil fuel [3] . In recent years, photocatalysis as a classic example mimicking natural photosynthesis has been widely explored to reduce CO 2 to value‐added chemicals and has been gaining intensive attention.…”

Investigation of SERS Frequency Fluctuations Relevant to Sensing and Catalysis

“…Hot-carrier generation can be detected in the SERS spectrum, and provide molecular specificity for monitoring catalytic reactions. An example of using SERS in conjunction with hot-carrier formation for catalytic reactions includes inducing oxidation or reduction reactions, such as the reduction of carbon dioxide. , Hot carriers also have the ability to induce additional chemical transformations, such as dimerization or cross-linking, which alter the observed SERS spectrum. The dimerization of para- aminothiophenol (PATP) to 4,4′-dimercaptoazobenzene (DMAB) is a commonly studied example.…”