Precisely detecting the concentration of glucose in the human body is an attractive way to prevent or treat diabetes. Portable glucose sensors with non-enzymatic catalytic materials have received great attention in recent years. Herein, a facile strategy for fabricating a high-performance electrochemical sensor is proposed. A non-enzymatic three-electrode integrated glucose sensor device based on CuO nano-coral arrays/nanoporous Cu (NCA/NPC) is designed and fabricated. The portable NCA/NPC glucose sensor device exhibits high catalytic activity for glucose. The great performance of the NCA/NPC glucose sensor device derives from the excellent conductivity of the NPC substrate and the high electrocatalytic activity of CuO nano-coral arrays. This device exhibits a high sensitivity of 1621 μA mM−1 cm−2 in the linear range of 0.0005–5.0 mM, low detection limit of 200 nM (S/N = 3), fast response time of 3 s, good anti-interference performance, excellent repeatability and considerable stability for glucose detection. This work will certainly provide an efficient structure and proper catalytic material choices for future non-enzymatic glucose sensors.
Although reverse osmosis (RO) has been widely used in the recycling of metal plating wastewater, organic compounds and heavy metals in the RO concentrate are difficult to remove by conventional treatment. A combination process including Fenton oxidation and a biological aerated filter was used to treat RO concentrate containing complex Cu and Ni from metal plating. During the Fenton treatment, Cu and Ni ions were released due to degradation of organic compounds and then removed by pH adjustment and coagulation. The concentrate was further treated using by a biological aerated filter. Optimum conditions were as follows: initial pH of influent of 4.0; dosage of H2O2 of 5.0 mmol l−1; ratio of n(Fe2+)/n(H2O2) of 0.8; precipitation pH of Cu and Ni ions of 8.0; and a hydraulic retention time of the biological aerated filter of 2.5 h. The results showed that concentrations of effluent COD, Cu and Ni ions were less than 40 mg l−1, 0.5 mg l−1 and 0.3 mg l−1, respectively; this means the treated effluent meets the emission standards for pollutants from electroplating set by China's Environmental Protection Agency.
Flexible physiological medical devices have gradually spread to the lives of people, especially the elderly. Here, a flexible integrated sensor based on Au nanoparticle modified copper hydroxide nanograss arrays on flexible carbon fiber cloth (Au@Cu(OH)2/CFC) is fabricated by a facile electrochemical method. The sensor possesses ultrahigh sensitivity of 7.35 mA mM−1 cm−2 in the linear concentration range of 0.10 to 3.30 mM and an ultralow detection limit down to 26.97 nM. The fantastic sensing properties can be ascribed to the collective effect of the superior electrochemical catalytic activity of nanograss arrays with dramatically enhanced electrochemically active surface area as well as mass transfer ability when modified with Au and intimate contact between the active material (Au@Cu(OH)2) and current collector (CFC), concurrently supplying good conductivity for electron/ion transport during glucose biosensing. Furthermore, the device also exhibits excellent anti-interference and stability for glucose detection. Owing to the distinguished performances, the novel sensor shows extreme reliability for practical glucose testing in human serum and juice samples. Significantly, these unique properties and the soft structure of silk fabric can provide a promising structure design for a flexible micro-device and a great potential material candidate of electrochemical glucose sensor.
A three-dimensional bi-continuous nanoporous gold (NPG)/nickel foam is developed though the electrodeposition of a gold–tin alloy on Ni foam and subsequent chemical dealloying of tin. The newly-designed 3D metal structure is used to anchor MnO2nanosheets for high-performance supercapacitors. The formed ternary composite electrodes exhibit significantly-enhanced capacitance performance, rate capability, and excellent cycling stability. A specific capacitance of 442 Fg−1is achieved at a scan rate of 5 mV s−1and a relatively high mass loading of 865 μg cm−2. After 2500 cycles, only a 1% decay is found at a scan rate of 50 mV s−1. A high power density of 3513 W kg−1and an energy density of 25.73 Wh kg−1are realized for potential energy storage devices. The results demonstrate that the NPG/nickel foam hybrid structure significantly improves the dispersibility of MnO2and makes it promising for practical energy storage applications.