Platinum-rhodium composite electrode for nitrogen-oxygen sensor chip and preparation method of platinum-rhodium composite electrode

Abstract

The invention discloses a platinum-rhodium composite electrode for a nitrogen-oxygen sensor chip and a preparation method of the platinum-rhodium composite electrode. The platinum-rhodium composite electrode comprises a porous platinum-rhodium alloy electrode layer and a porous platinum electrode layer, wherein the porous platinum-rhodium alloy electrode layer and the porous platinum electrode layer are arranged on a double-layer three-dimensional catalytic net; the electrode slurry of the porous platinum-rhodium alloy electrode layer comprises the following components in parts by mass: 30-60 parts of nano platinum powder, 2-6 parts of a rhodium-containing compound, 1-2 parts of a protective agent, 8-20 parts of nano porous carbon powder, 0.1-1 part of a dispersing agent, 3-10 parts of an organic binder, 0.1-0.8 part of an organic zirconium compound, 0.01-0.4 part of an yttrium-containing compound, 0.01-0.6 part of a cerium-containing compound and 12-40 parts of an organic solvent. The platinum-rhodium composite electrode for the nitrogen-oxygen sensor chip and the preparation method of the platinum-rhodium composite electrode have the characteristics of high catalytic activity, good uniformity, excellent mechanical property, reliability, durability, long service life and low cost.

Description

technical field [0001] The invention relates to the technical field of functional electronic materials for sensor chips, in particular to a platinum-rhodium composite electrode for nitrogen and oxygen sensor chips and a preparation method thereof. Background technique [0002] With the rapid development of the automobile industry and stricter emission regulations, electric vehicles currently account for less than 5%, and it will take a long time for electric vehicles to completely replace fuel vehicles. The production and sales of Chinese automobiles have ranked first in the world for 13 consecutive years. In 2019, the National VI emissions will be fully implemented. Automobile lean combustion technology adopts high-temperature combustion with excess air to meet the requirements of energy saving and emission of carbon black fine dust particles; however, under high-temperature and high-pressure environment, the nitrogen in the excess air reacts with oxygen to produce toxic an...

AI Technical Summary

Problems solved by technology

[0013] The preparation of nano-platinum-rhodium composite catalyst particles by colloidal in-situ method and powder particle electroless plating method is a more commonly used technical scheme, but the preparation of nano-platinum-rhodium composite catalyst particles prepared by the above scheme has morphology, composition, Great changes have taken place in the structure, etc., and the catalytic activity has been greatly weakened

[0014] Based on the above, the existing technical solutions have the following defects: (1) The test electrode has only a single layer structure, and the zirconia substrate has a large number of holes inside when the zirconia substrate is at 800°C-1300°C during the sintering process, and the liquid glass glaze and melting The flow and diffusion of the nano-rhodium powder into the zirconia substrate affects the performance of the zirconia solid electrolyte; (2) during the sintering process, although the molten nano-rhodium powder will wrap part of the platinum powder particles and fuse and connect the micron rhodium powder, due to the liquid state Good fluidity will close a large number of pores and form a dense rhodium layer between the catalytic electrode and the zirconia solid electrolyte; greatly reducing the impact of the three-phase interface on catalytic performance and oxygen anions (O 2- ) conduction; (3) due to the use of glass frit as an inorganic binder in the sintering process to promote the sintering of platinum and rhodium powder and the bonding of the alumina diffusion layer and zirconia solid electrolyte layer, but the glass liquid inorganic adhesive The binder will wrap part of the surface of the platinum and rhodium powder particles. Due to the good fluidity of the liquid, a large number of pores will be closed, which will reduce the catalytic efficiency of the electrode.

With long-term high-temperature use, the glass frit will diffuse and flow, causing the sensor chip to fail, reducing the reliability and service life of the product

Images