CuO/CoZn-Layered Double-Hydroxide Nanowires on Carbon Cloth as an Enzyme-Free H2O2 Sensor

Transition metal layered double hydroxides (LDHs) have attracted much attention as catalysts due to their multiple valence states and high electrocatalytic activity. Traditional enzyme-based electrochemical H2O2 sensor is limited by short lifetime, instability, and complicated fabrication procedure, making it difficult to be widely used. Instead of natural enzymes, transition metal based LDHs can be applied as electrocatalysts for enzyme-free H2O2 sensor. In this work, CoZn-LDH nanosheets grown on CuO nanowires (NWs) were synthesized on carbon cloth (CC) by electrodeposition and hydrothermal methods for the electrochemical enzyme-free detection of H2O2. For this purpose, CuO NWs were first electrodeposited on CC substrate, on which CoZn bimetal LDH nanosheets were synthesized by the hydrothermal technique. Herein, CC provides an ideal conductive substrate for the growth of CuO NWs and CoZn-LDH, so that the sythesized CuO/CoZn-LDH NWs can be evenly dispersed, exposing more active sites for the enhancement of their electrocatalytic activity. As a result, CuO/CoZn-LDH NWs display excellent electrocatalytic activity for the reduction of H2O2. The fabricated sensor has a good linear response in the concentration range of 0.01–16 mM for the electrochemical detection of H2O2, with low detection limit of 0.46 μM and high sensitivity of 760.64 μA mM–1 cm–2. In real sample mouthwash detection, the proposed sensor demonstrates the efficient recovery of H2O2, indicating the ability of CuO/CoZn-LDH NWs to quantitatively detect real samples.