ZnO nanoflakes as a template for in-situ electrodeposition of nanostructured cobalt electrodes as amperometric phosphate sensors

[Display omitted] •A facile additive free electroplating method was applied to obtain a nanostructured cobalt film.•Cobalt nanoflake/particles were obtained with a sacrificial ZnO nanoflake template.•Limit of detection of phosphate measurements was improved with the nanostructured sensor.•A dominant charge transfer mechanism was proposed to explain the transformation of sensor performance. In this work, a novel method using hydrothermal grown ZnO nanoflakes as a template for nanostructured metal film electroplating was proposed. Compared with the commonly used anodic aluminum oxide (AAO) template, the in-situ grown ZnO nanoflake template can be applied for large area electroplating with a relatively simple process. This method was applied for nanostructured cobalt electrode electroplating. The fabricated electrode was then tested for in situ phosphate detection in aqueous environments. The results showed that the ZnO nanoflake template successfully incorporated nanostructure into a cobalt film, and compared with a planar cobalt film, the sensor’s limit of detection (LOD) was improved by an order of magnitude.