Dynamic range boosting for electrochemical sensing by morphological optimization of three-dimensional silicon porous framework@Au nanoparticles

Abstract

Herein we would like to introduce a general method for improving the dynamic range for electrochemical sensing devices based on 3D porous electrodes by morphological optimization. As a showcase, a series of Au nanoparticles integrated three-dimensional silicon-based porous frameworks working electrodes (3D-pSi@AuNP) with the array height ranging between 20 µm and 120 µm are prepared by a combination of metal-assisted chemical etching and surface defects induced isotropic etching in HF/H2O2 mixture and Galvanic displacement, and their electrochemical sensing performance for H2O2 are investigated by voltametric and amperometric methods in detail. The experimental results show that, as the array height of 3D-pSi was increased from 20 µm to 120 µm, the electrochemical active surface area (EASA) was raised by nearly 6 folds, and the upper limit of linear range of detection of H2O2 can be boosted from 4.39 mM to 32.30 mM. With the optimization of Au deposition, it could be further increased to 56.57 mM. We expect this approach to be one of the general methodologies for the improvement of electrochemical sensing devices, especially for those scenarios where the fast detection of high concentration of H2O2 is critical, such as fuel cell and other catalytic oxygen reduction reaction systems.