A kind of silver-modified titanium dioxide nanotube composite anode and preparation method thereof

Abstract

The invention discloses a silver-modified titanium dioxide nanotube composite anode, which comprises a titanium matrix layer, a titanium dioxide nanotube intermediate layer and an active surface layer; the titanium dioxide nanotube intermediate layer is decorated with metallic silver in a network shape. The preparation method of the present invention: firstly pretreating the titanium substrate; then growing the titanium dioxide nanotube array on the surface of the titanium substrate in situ, after cleaning, decorating the metal silver in the titanium dioxide nanoarray, and finally preparing the salt of the active surface layer The solution is coated on the surface of the titanium dioxide nanotube array modified with metallic silver, and baked to obtain a silver-modified titanium dioxide nanotube composite anode. The service life of the silver-modified titanium dioxide nanotube composite anode of the present invention is much longer than that of ordinary composite electrodes; at the same time, the titanium dioxide nanotube array is modified with metallic silver, which can reduce the ohmic voltage drop of the intermediate layer of the titanium dioxide nanotube, thereby reducing the entire composite anode. the electric potential.

Description

technical field [0001] The invention belongs to the field of electrochemistry, and in particular relates to a silver-modified titanium dioxide nanotube composite anode and a preparation method thereof. Background technique [0002] Metal oxide anodes, also known as shape-stable anodes DSA, were invented by H.B.Beer and were first industrialized by Italian company De Nora (Titanium Electrode Engineering, Beijing: Metallurgical Industry Press, 2003). At present, DSA has been widely used in the electrometallurgical industry , Chlor-alkali industry, electroplating, wastewater treatment. [0003] French scientist Zwilling V et al. first reported the preparation of titanium dioxide nanotubes on titanium plates by anodic oxidation in 1999. Up to now, anodic oxidation has become one of the important methods for preparing titanium dioxide nanotubes. As an inorganic functional material, nano-titanium dioxide has been widely used in the storage and application of solar energy, photoel...

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Problems solved by technology

[0004] Although the preparation methods of titanium-based composite anodes are various, the process is simple, the coating has high catalytic activity and good selectivity, but there is a fatal disadvantage: short service life and easy passivation to form a layer of titanium dioxide with poor conductivity. membrane

In recent years, in order to solve this technical problem, many researchers have mainly proposed the following schemes: The first is to use thermal coating to increase the intermediate layer, usually a tin dioxide intermediate layer, to increase the bonding between the substrate and the coating. The force makes the whole coating dense and increases the resistance to oxygen in the solution, but the addition of the intermediate layer only increases the physical bonding force between the coating layer and the substrate to a certain extent, and fails to fundamentally block the oxygen in the solution from the coating. The corrosion of the substrate in the cracks of the layer; the second is to use titanium and other metals to form titanium alloys, such as titanium-manganese alloys that are widely used in electrolytic manganese dioxide, and the oxide film on the surface is titanium-manganese composite oxide. Corrosion is greatly improved, but the production process of this method is complicated and the consistency is poor; the third method is to introduce a rare metal catalytic layer, but the catalytic effect of rare metals can only be applied to specific fields, and the cost of use is too high, and the introduction of The intermediate layer of titanium dioxide nanotubes is used to increase the corrosion resistance of the electrode. Although this method of introducing a thin and dense intermediate layer on the electrode surface can greatly increase the service life of the titanium anode, the conductivity of the titanium dioxide nanotubes is still poor. This results in a larger pressure drop across the coating and increased energy consumption

Therefore, these current technical solutions cannot fundamentally solve the technical defect of short service life of titanium-based composite anodes

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