NiFe (Oxy)hydroxide-Incorporated BiVO4 for Sensitive Photoelectrochemical Detection of Catecholamine

Abstract The photoelectrochemical (PEC) detection of catecholamine neurotransmitters has been receiving great attention recently owing to the low cost, fast response, and easy operation. However, the conventional photoactive materials always have relatively low PEC activity, and the PEC signals are prone to interference from the inherent redox reactions at the photoelectrode. Herein, by incorporating the NiFeOOH cocatalyst at the BiVO4 photoelectrode (BiVO4/NiFeOOH), a much higher water oxidation photocurrent was obtained, due to the facilitated hole transport and rapid water oxidation kinetics at the modified ultrathin NiFeOOH layers. Photo-scanning electrochemical microscopy (photo-SECM) was further conducted to reveal the topography and PEC activity of the BiVO4/NiFeOOH, and the local O2 generation rate was inferred by fitting the experimental results. Besides increasing PEC activity, the incorporated NiFeOOH layers would also allow chelating coordination interactions with the catecholamine molecules to achieve sensitive PEC detection. The proposed method would not only offer a new PEC sensing approach for catecholamine detection but also be further expanded to detect other analytes of interest in the biological and environmental fields.