Selective Transfer Coupling of Nitrobenzene to Azoxybenzene on Rh Nanoparticle Catalyst Promoted by Photoexcited Hot Electrons

Abstract

The reaction rate and product selectivity of nitrobenzene reduction catalyzed on Rh nanocrystals of several nanometers in size are significantly improved under illumination of visible light. Light absorption in the Rh nanocrystals generates hot electrons that are injected into nitrobenzene molecules adsorbed on the Rh surface, accelerating the reduction of nitrobenzene and favoring the transfer coupling of reduced nitrobenzene intermediates into azoxybenzene. The photocatalytic performance is enhanced by loading the Rh nanocrystals on dielectric silica spheres with sizes of hundreds of nanometers, which exhibit strong surface scattering resonances to increase the light absorption power in the Rh nanocrystals. The large size of silica particles also improves the colloidal stability of the small Rh nanocrystals, benefiting the photocatalytic performance. This study highlights the promise of hot electrons in catalyzing hydrogenation reaction with improved kinetics and selectivity.

The role of heat generation and fluid flow in plasmon-enhanced reduction-oxidation reactions

“…Thus, our thermal calculations re-affirm the conclusions in Ref. 52, and support a similar approach adopted earlier 28,36,[58][59][60][61] .…”

Photocatalytic hot-carrier chemistry

“…Small-sized nanoparticles of transition metals that are widely used as catalysts in industry and research could be directly photoexcited to drive efficient hot-electron chemistry, which represents an immediate interest to explore. [20][21][22][23] The light absorption power in the small nanoparticles is usually too low to efficiently harvest photon energy. Integrating the catalyst nanoparticles with light antennae that can concentrate the incident light to generate enhanced local electric fields represents a promising solution to maximize the lightharvesting efficiency and a promising research direction.…”

Light‐Driven Dry Reforming of Methane on Metal Catalysts

“…The most widely explored catalysts are based on nanoparticles of group VIII metals, particularly Ni and Rh, which exhibit strong adsorption of CH x . [ 17,69,83–86 ] These metal nanoparticles exhibit weak optical absorption power in the visible spectral region because of their weak surface plasmon resonances. [ 69 ] The size of metal nanoparticles influences their interaction with the incident light.…”