ORIGINAL RESEARCH Facile One Pot Synthesis of CuO Nanostructures and Their Effect on Nonenzymatic Glucose Biosensing Mohit Chawla 1 & Veerender Sharma 2 & Jaspreet Kaur Randhawa 3 # Springer Science+Business Media New York 2016 Abstract Morphology of different CuO nanostructures is controlled by changing the precursor counterions. The CuO nanostructures were synthesized using three different precursor salts of copper namely acetate, nitrate, and sulfate via facile chemical precipitation route. The synthesized CuO nanostructures were thoroughly characterized using X-ray diffraction, optical spectroscopy, electron microscopy etc. The nanostructures were studied for catalytic nonenzymatic glucose sensing applications. CuO nanostructures synthesized from copper sulfate having flower-like morphology showed the highest glucose sensitivity of 1830 μAmM -1 cm -2 in a linear range of 0.01–0.2 mM with a detection limit of 8 μM. Keywords Nanostructures . Copper oxide . Morphology . Glucose sensing . Electrocatalysis Introduction Diabetes mellitus has become one of the major health infirmities globally. Therefore, many efforts have been fo- cused on developing various sensors with high sensitivity, high reliability, fast response, good selectivity, and low cost monitoring in the diagnosis of diabetes [1]. As known, glucose sensors can be mainly classified into two categories viz. glucose oxidase-based enzymatic sensors and nonenzy- matic glucose sensors. Electrochemical glucose sensors based on glucose oxidase have been widely explored in the last decade due to their good selectivity and high sensitivity [2]. However, the inadequate stability originating from the inher- ent nature of the enzyme to both pH and temperature poses a challenge on their reliability [3]. Therefore, more and more attempts are being made to construct and develop sensors for glucose detection without enzymes. Recent advances in the development of nonenzymatic glu- cose sensors revolve around the increase in the synthesis of nanomaterials [4]. A wide range of nanomaterials has been used for development of nonenzymatic glucose sensors [5–8]. However, researchers are inclined to use nanostructured metal oxides as artificial mediators between the enzyme and the electrodes [6, 9]. Among the various metal oxides, CuO a p-type metal oxide semiconductor with a narrow band gap (1.2eV) has been extensively investigated for a wide range of potential applications such as lithium ion electrodes, sen- sors, fabrication of photovoltaic devices, heterogeneous catal- ysis, field emission emitter catalysts, high critical temperature super-conductors etc., [10–15]. CuO has also been studied as a unique and attractive monoxide material for glucose sensing due to direct electrooxidation of glucose on CuO enhanced by multi-electronoxidation mediated by the surface oxide layer [ 16–18]. Moreover, in the recent years, morphology- controlled synthesis of CuO has been investigated extensively in order to tune their properties [19]. Singh and coworkers investigated various strategies for the synthesis of CuO nano- tubes [20]. Filipic and Cvelbar reviewed the growth of CuO nanowires [21]. Neupane et al. synthesized flake-like CuO nanoparticles by controlling the precipitation reaction temper- ature via a hydrothermal process [22]. Liu and coworkers undertook the synthesis of CuO honeycombs and flower-like * Jaspreet Kaur Randhawa jaspreet@iitmandi.ac.in 1 School of Basic Sciences, Indian Institute of Technology Mandi, Mandi, Himachal Pradesh, India 2 Centre for Materials Science, National Institute of Technology Hamirpur, Hamirpur, Himachal Pradesh, India 3 School of Engineering, Indian Institute of Technology Mandi, Mandi, Himachal Pradesh, India Electrocatalysis DOI 10.1007/s12678-016-0337-7