Boosting the Dynamic Range for Electrochemical Sensing of Hydrogen Peroxide by Enhanced Integration of Pd Nanoparticles in 3D Porous Si Framework

Three-dimensional porous silicon framework (3D-pSi) integrated with various nanostructures is highly potential for functional devices usage such as micro fuel cells or sensing chips. For noble metal deposition in highly directional Si nanowire array or porous Si with large aspect ratios, one difficulty is the restriction on the depth of deposition available. Herein, we would like to introduce a facile route to enhance the integration of Pd nanoparticles with anisotropic Si porous structure. By converting Si nanowire array into 3D-pSi, the surface coverage of Pd nanoparticles is effectively improved as shown by scanning electron micrographs and cross-sectional element mapping data. The relative electrochemical active surface area is increased by 3.5 folds. In order to demonstrate the merits brought by this morphological evolution, the electrochemical sensing devices are prepared for detecting H₂O₂ in PBS solution. As shown by differential pulse voltammetry, the upper limit of linear range of detection can be raised from 6.30 mM to 14.95 mM. This approach may indicate an alternative for boosting the performance of future sensing chips with progressively limited die area, especially attractive for those scenarios where large dynamic range is favourable.