A photoelectrochemical sensor based on nickel hydroxyl-oxide modified n-silicon electrode for hydrogen peroxide detection in an alkaline solution

• We introduce a novel photoelectrochemical sensor for rapid detection of hydrogen peroxide.
• Nickel hydroxyl-oxide double layer coated n-silicon electrode was used as the photoelectrode.
• The flexible sensor lies in its two-electrode system with no reference electrode and no bias voltage.
• The new platform opens new applications in portable sensor of hydrogen peroxide.

A novel photoelectrochemical hydrogen peroxide (H2O2) sensor was constructed with platinum (Pt) and nickel hydroxyl-oxide (NiOOH) double layers modified n-silicon electrode (NiOOH/Pt/n–n+-Si). About 40 nm Pt layer and about 100 nm Ni layer were successively coated on the front surface of n–n+-Si (1 1 1) wafers by vacuum evaporating. A stable layer of NiOOH was formed through oxidation of the Ni layer on the coated silicon wafer by the electrochemical method. The surface of modified electrode was characterized by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The NiOOH/Pt/n–n+-Si electrode has been used for determination of H2O2 with a two-electrode cell in the absence of reference electrode by photocurrent measurement at a zero bias. The photoelectrochemical sensor showed a good linear response to H2O2 concentrations in a range from 1.0×10−5 to 6×10−5 M with a determination limit (S/N=3) of 2.2 μM. The NiOOH/Pt/n–n+-Si electrode exhibited excellent reproducibility and stability. Particularly, the facile measurement requirements made this novel modified electrode promising for the development of outdoor H2O2 sensors.