Nanometric Cerium Oxide Catalyst for High Reducibility
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Solution Overview
Problem
Current catalysts for treating exhaust gases from internal combustion engines lack high reducibility, especially at low temperatures, which is essential for effective carbon monoxide, hydrocarbon, and nitrogen oxide reduction.
Innovation Solution
A nanometric cerium oxide-based composition supported on silica, alumina, titanium oxide, or zirconium oxide, with particles sized at most 500 nm, exhibiting high reducibility after calcination at 800°C for 6 hours, specifically designed to achieve high catalytic performance in reducing and oxidizing atmospheres.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional catalyst compositions are used, then catalyst structure is maintained, but reducibility is insufficient especially at low temperatures
Solution Approach 1:
The patent changes the particle size parameter of cerium oxide to nanometric dimensions (at most 500 nm), which fundamentally alters the material's reducibility characteristics. This parameter change enables high reducibility (at least 80%) at low temperatures (30-900°C) while maintaining catalytic stability, resolving the contradiction between reliability and productivity
Solution Approach 2:
The patent creates a composite material system where nanometric cerium oxide particles are deposited on a support substrate (silica, alumina, titanium oxide, or zirconium oxide). This composite structure combines the high reducibility of nanometric cerium oxide with the structural stability of the support, achieving both improved reliability and maintained productivity
2Area of stationary object
If particle size is reduced to enhance reducibility, then surface area increases, but particle aggregation may occur
Solution Approach 1:
The patent employs a support substrate that acts as a carrier matrix, distributing nanometric cerium oxide particles throughout its structure. This support framework prevents particle aggregation while maintaining high specific surface area, and the calcination process at 800°C for 6 hours creates a stable composite structure that preserves particle dispersion
Solution Approach 2:
The support substrate provides a porous structure that accommodates nanometric cerium oxide particles, preventing their aggregation through physical separation. The porous architecture maintains high surface area while ensuring stable particle distribution, resolving the contradiction between area and composition stability
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The composition demonstrates high reducibility, measured between 30°C and 900°C, with specific embodiments showing reducibility of at least 80% and high BET specific surface area, effectively addressing the limitations of existing catalysts by enhancing catalytic performance in reducing nitrogen oxides and hydrocarbons at various temperatures.
Implementation Method 1
comprises particles of said supported oxide, deposited on said support
Implementation Method 2
after calcination at a temperature of at least 800° C. for 6 hours
Implementation Method 3
the ability of the catalyst to be reduced in a reducing atmosphere and to be reoxidized in an oxidizing atmosphere
Data Source
AI summary
Catalyst/catalyst support compositions are characterized by a supported cerium oxide, deposited onto a silica, alumina, titanium or zirconium based support, including particles of said supported oxide deposited onto said support, individualized or in the form of aggregates, no greater than 500 nm in size and having, after 6 hours of calcination at a temperature of at least 800° C., a measured reducibility from 30° C. and 900° C. of at least 80%; such compositions are prepared by combining a colloidal dispersion of the supported oxide and a suspension of the support, drying the resulting mixture by atomization and drying the resulting product by calcination.