pH-modulated wet chemical synthesis of copper oxide nanostructures

As an effective tool to monitor the glucose level in the human body and to diagnose diabetes, glucose sensors are widely applied in medical practice and the daily life of patients. Cupric oxide (CuO) is a promising material for fabricating non-enzymatic glucose sensors. While CuO shows very good sensing performance and is easy to synthesise, the common wet chemical routes can result in varying nanostructures depending on various parameters, including temperature and pH. The present work explores the influence of the solution pH and base/acid addition order on the physico-chemical characteristics and sensing behaviour of CuO formed following a simple solution synthesis route. Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and Raman and IR spectroscopy were used to characterise the nanostructures. Although the synthesis route is robust with respect to the acid/base concentration, it is clear that an overall alkaline environment is needed for the successful formation of CuO nanostructures.