Direct photocatalysis making use of plasmonic metals has attracted significant attention due to the light-harnessing capabilities of these materials associated with localized surface plasmon resonance (LSPR) features. Thus far, most reported work has been limited to plasmon-induced chemical transformations. Herein, we demonstrate that electrochemical reactions can also be accelerated by plasmonic nanoparticles upon LSPR excitation. Using glucose electrocatalysis as a model reaction system, the direct plasmon-accelerated electrochemical reaction (PAER) on gold nanoparticles is observed. The wavelength- and solution-pH-dependent electrochemical oxidation rate and the dark-field scattering spectroscopy results confirm that the hot charge carriers generated during plasmon decay are responsible for the enhanced electrocatalysis performance. Based on the proposed PAER mechanism, a plasmon-improved glucose electrochemical sensor is constructed, demonstrating the enhanced performance of the non-enzyme sensor upon LSPR excitation. This plasmon-accelerated electrochemistry promises potential applications in (bio)electrochemical energy conversion, electroanalysis, and electrochemical devices.

Enzyme mimics have been widely used as alternatives to natural enzymes. However, the catalytic performances of enzyme mimics are often decreased due to different spatial structures or absence of functional groups compared to natural enzymes. Here, we report a highly efficient enzyme-like catalytic performance of gold nanoparticles (AuNPs) by visible-light stimulation. The enzyme-like reaction is evaluated by the catalytic reaction of AuNPs oxidizing a typical chromogenic substrate 3,3',5,5'-tetramethylbenzydine (TMB) with hydrogen peroxide as an oxidant. From investigations of the wavelength-dependent reaction rate, radical capture, hole-donor addition, and dark-field scattering spectroscopy experiments, it is revealed that the strong plasmonic absorption of AuNPs facilitates generation of hot electrons, which are transfered from AuNPs to the adsorbed reactant molecule, greatly promoting the catalytic performance of the enzyme-like catalytic reaction. The present work provides a simple method for improving the performance of enzyme mimics, which is expected to find further application in the field of plasmon-enhanced biocatalysis and biosensors.

Recently, the direct utilization of plasmonic metal nanostructures in accelerating the electrochemical reactions reveals the importance of hot charge carriers generated by localized surface plasmon resonance (LSPR). However, the effect of morphological forms of the same metal element on direct plasmon-enhanced electrocatalytic activity has not yet been well documented. Herein, four kinds of Au nanostructures with different morphologies of nanospheres (NSPs), nanorods (NRs), nanostars (NSs), and triangular nanoplates (NPLs) were synthesized. The shape-dependent plasmonic enhancement effect of Au nanostructures toward the electrooxidation of ascorbic acid (AA) was studied. We find that the electrochemistry of AA oxidation on these Au nanostructures can be enhanced upon light irradiation with the higher enhancement effect of the Au NPLs and NSs than the Au NSPs and NRs. This shape-dependent enhancement effect is suggested to be related to the number of “hot spots” in different NP surfaces generated from Au LSPR. Thus, the present work would shed new light on the direct plasmon-enhanced electrochemistry, which helps in widening the potential applications of plasmonic materials in electrochemical sensors and electrochemical energy conversion.