Plasmon‐Enhanced Photocatalysis on Anisotropic Gold Nanorod Arrays

Abstract

The field of photocatalysis is an active area owing to the possible contributions to solve some challenging problems such as sustainable energy production, environmental pollution control, and even global warming. Unfortunately, traditional photocatalysts, especially semiconductors, suffer from inherent deficiencies, which include high activation barriers, the low mobility of charge carriers, and poor long‐term stabilities. Herein, we demonstrate a plasmonic photocatalyst based on unidirectional gold nanorod arrays fabricated by using the oblique‐angle deposition (OAD) technique. The fabricated gold nanorod arrays exhibit a remarkable plasmonic anisotropy, which depends on the direction of the incoming light. By employing these arrays as a plasmonic catalyst, a clear improvement and control in the catalytic reduction of o‐nitroaniline to 1,2‐benzenediamine, depending on the directionalities and anisotropic plasmonic properties of the gold nanorods, was obtained. These results suggest that such unique characteristics of directional gold nanorod arrays could greatly impact several technological areas, not only in plasmon‐enhanced photocatalysis but in biosensing and optofluidic applications.

Molding of Plasmonic Resonances in Metallic Nanostructures: Dependence of the Non-Linear Electric Permittivity on System Size and Temperature

“…Plasmonics is the discipline describing the bridging between electromagnetic radiation and electronic oscillations. Recently, the research activity related to plasmonics has undergone a strong acceleration owing to the important role that it can play in different and important fields, such as nanomedicine [ 1 , 2 , 3 , 4 , 5 ], biosensing [ 6 , 7 , 8 , 9 , 10 , 11 , 12 ] nanophotonics [ 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 ], photovoltaic applications [ 29 , 30 , 31 , 32 ] or catalysis [ 33 , 34 , 35 , 36 ].…”

Alkyl-nitrile adlayers as probes of plasmonically induced electric fields

“… 4 – 9 On nanostructure arrays, heterogeneous reactivity has been observed, implicating “hotspots”, areas of intense electric fields, as important for catalysis. 10 The excitation of plasmons has long been associated with nanostructure enhanced spectroscopies, 11 such as surface enhanced (SERS) and tip enhanced (TERS) Raman scattering. The increased electric field promote optical processes by increasing the magnitude of the excitation field ( E exc ) and the emitted electric field ( E emm ) leading to an increased response as shown in eqn (1): where the excitation and emission fields are normalized to the incident electric field ( E 0 ), this equation is known as the E 4 approximation.…”

Light‐Driven Unidirectional Liquid Motion on Anisotropic Gold Nanorod Arrays

“…In this case, tilted AuNRs induce an increment in the photonic light scattering and photonic light trapping correspondingly resulted in the enhancement of the local photon intensity. [ 26 ] These phenomena lead to an increase in the excitation of surface plasmons. The SPR wavelengths shift toward longer wavelengths and become broader at isotropic axis.…”

“…At anisotropic axis, the p-polarization, which possesses an electric fi eld vector oscillating normal to the plane of AuNRs, mainly excites surface plasmons. [ 26 ] However, at isotropic axis, p-polarization cannot excite plasmons enough since it is oriented parallel to AuNRs. In this case, the surface plasmons are mainly excited by s-polarization.…”