A novel photo-electrochemical sensor for determination of hydroquinone based on copper hexacyanoferrate and platinum films modified n-silicon electrode

A novel hydroquinone (HQ) sensor was developed by depositing a film of copper hexacyanoferrate (CuHCF) on silicon electrode coated by a platinum layer. The stable film of CuHCF was electrochemically deposited onto a phosphorus heavy doped silicon (n+-Si) with 9 μm epitaxial layer (n-n+-Si) wafers coated with about 40 nm platinum layer (Pt/n-n+-Si). Scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS) and cyclic voltammetry (CV) were used to characterize the morphology, composition and photo-electrochemical behavior of the CuHCF film. A two-electrode cell based on CuHCF/Pt/n-n+-Si electrode was used as sensor for HQ determination by photocurrent measurements at a zero bias. The sensor showed good photocurrent responses by adding different concentrations of HQ with a good stability. The linear range for the detection of HQ was 1.0 × 10−5 to 2.0 × 10−4 M, with a detection limit (S/N = 3) of 2.2 × 10−6 M. This provides a facile way of detecting HQ and succeeds in averting from an inconvenient reference electrode.