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

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/H 2 O 2 mixture and Galvanic displacement, and their electrochemical sensing performance for H 2 O 2 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 H 2 O 2 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 H 2 O 2 is critical, such as fuel cell and other catalytic oxygen reduction reaction systems. [Display omitted] • A general method for improving the electrochemical sensors by morphological optimization of 3D porous electrodes is proposed. • The upper limit of linear range of detection can be boosted by 7.36-fold upon increasing the array height of 3D-pSi. • This approach can be extended to other 3D electrodes, especially for those scenarios where a large dynamic range is favored. [ABSTRACT FROM AUTHOR]