Nanoporous Cerium Oxide Single-Step Precipitation Process
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Solution Overview
Problem
Current methods for producing porous cerium oxide catalysts are complex, energy-intensive, and costly, requiring multi-step processes and high-energy fluidized bed reactors, which limit their efficiency and scalability for applications like automobile exhaust treatment and nanowire growth.
Innovation Solution
A cost-effective single-step precipitation process using a cerium nitrate solution and an amine solution in a stirred tank reactor at lower temperatures, eliminating the need for intermediate precursors and steam, resulting in nanoporous cerium oxide with uniformly sized pores arranged in parallel lines on both internal and external surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multi-step heat treatment process with steam atmosphere is used to produce porous cerium oxide, then pore structure and surface area are improved, but process complexity and energy consumption increase
Solution Approach 1:
The invention segments the pore formation mechanism by using a composite precursor system where cerium nitrate and ammonium carbonate react in specific ratios to form cerium carbonate octahydrate with controlled pore structure. This segmentation allows independent optimization of precursor composition and heat treatment conditions to achieve uniform pores without complex multi-step processes
Solution Approach 2:
The invention changes critical process parameters including the molar ratio of cerium nitrate to ammonium carbonate (2:1 to 5:1), heat treatment temperature (130-150°C), and steam atmosphere composition. These parameter changes enable control over pore size, surface area, and distribution while simplifying the overall process to a single heat treatment step
2Manufacturing precision
If multi-step precursor preparation is used to produce cerium carbonate octahydrate, then precursor purity is improved, but manufacturing time and cost increase
Solution Approach 1:
The invention merges multiple precursor preparation steps into a single reaction process where cerium nitrate and ammonium carbonate are mixed in solution and directly form cerium carbonate octahydrate with the desired pore structure. This consolidation eliminates intermediate drying and rehydration steps while maintaining precursor purity through controlled reaction conditions
Solution Approach 2:
The invention performs preliminary action by pre-dissolving cerium nitrate and ammonium carbonate in water before heating, ensuring uniform distribution and complete reaction. This preliminary mixing step prevents formation of unwanted intermediates and ensures consistent precursor composition without requiring multiple sequential processing steps
3Productivity
If fluidized bed reactor with continuous gas pumping is used for heat treatment, then reaction efficiency is improved, but energy consumption and device complexity increase
Solution Approach 1:
The invention replaces the mechanical fluidized bed reactor system with a simpler batch heat treatment process using conventional heating equipment. The reaction is conducted in a closed vessel with controlled atmosphere, eliminating the need for continuous gas pumping and complex mechanical agitation systems while maintaining adequate reaction efficiency
Solution Approach 2:
The invention applies self-service by allowing the reaction system to maintain its own temperature and atmosphere conditions through controlled heating and sealed vessel design. The cerium carbonate octahydrate precursor self-regulates the reaction environment during heat treatment, eliminating the need for external continuous gas flow and complex process control systems
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
This method simplifies the production of nanoporous cerium oxide, reducing energy costs and process complexity while achieving high pore density and uniformity, enhancing catalytic efficiency for applications such as emission control, nanowire growth, and filtration.
Implementation Method 1
mixing a cerium nitrate solution and an amine solution to form a mixture and stirring the mixture thereby forming a nanoporuous cerium oxide precipitate
Implementation Method 2
heat treatment of cerium carbonate octahydrate in an atmosphere controlled to be an air/steam or oxygen/steam mixture
Implementation Method 3
heat treatment of cerium carbonate octahydrate to produce the porous cerium oxide
Data Source
AI summary
Provided herein are a method of making a nanoporous cerium oxide material which can be used for heterogeneous catalysis. The method may include mixing a cerium nitrate solution and an amine solution to form a mixture and stirring the mixture thus forming a nanoporous cerium oxide precipitate. Further, the molar ratio of cerium nitrate and the amine ranges from 2:1 to 5:1.