Study On Fabrication And Catalytic Properties Of Nano Copper Based Materials For Nitrate Sensors

Nitrate (N03) widely existing in water and food in nature has a great influence on ecological environment and human health. Electrochemical detection of NO3- has attracted considerable attention due to the simple operation, fast detection and other advantages. However, the wide application of electrochemical method has been limited by the high cost of the noble metals which have high catalytic activity towards the reduction of NO3-.Recently, it was found that nanostructured none-noble metals exhibited high catalytic activity towards NO3- when compared with the bulk samples. The study focuses on the preparation of 3D porous Cu and CuNi with good catalytic performance by via hydrogen bubble templated electrodeposition. The effect of deposition current density, deposition time and solution concentration on the composition, morphology and catalytic properties of the 3D porous Cu and CuNi were studied. The conclusions are as follows:1、 Nano-structured copper with different morphologies were deposited on copper substrate by hydrogen bubble templated electrodeposition at different current density and deposition time. The results showed that the deposition current density and deposition time are key factors which determine both the morphology and the catalytic activity of the copper. Regular polyhedron structure was obtained at low current density of 0.01 A/cm2; tetrahedron structure was obtained at a current density of 0.025 A/cm2; dendrite copper was obtained at a deposition current density of 0.25 A/cm2. Dendrite structure copper shows the greatest catalytic activity towards the oxidation of nitrate.2、3D porous CuNi alloy was obtained by constant current deposition using hydrogen bubble template method at the deposition current density of 1.25 A/cm2. The content of Ni in CuNi alloy was changed by changing the concentration of Cu2+ and Ni2+ in the deposition solution. The results showed that with the increase of the Ni2+/Cu2+ ratio, the morphology was maintained as dendrite structure, but the content of Ni increases in the alloy. The elemental distribution in the dendrite is not uniform, Ni content decreased along the direction of dendrite stem and increased along the direction of branch. With the increase of Ni content in the alloy, the lattice constant of CuNi alloy showed a decreasing tendency, which indicated that CuNi alloy is a single phase solid solution. The addition of Ni can effectively promote the catalytic effect of Cu on nitrate ions.