Platinum Catalyst for Water-Gas Shift
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Solution Overview
Problem
Current catalysts for the water-gas shift reaction face challenges due to moderate activity, deactivation issues, and contamination from sodium, particularly in high-temperature applications, and the need for high dispersion of noble metals like platinum with minimal content and small particle sizes.
Innovation Solution
A method involving coprecipitation of soluble salts using ammonium hydroxide to produce catalysts with platinum, zirconia, ceria, or iron oxides, achieving high dispersion and small particle sizes (<1 nm) while eliminating sodium contamination, thus enhancing activity and stability for dehydrogenation and water-gas shift reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional catalysts with high noble metal content are used, then high activity for water-gas shift reaction is achieved, but cost increases and noble metal availability becomes a limiting factor
Solution Approach 1:
The invention changes the particle size parameter of platinum from conventional larger sizes to ultra-fine particles with diameter of 1 nm or less. This parameter change increases the surface area to volume ratio, providing more active sites per unit mass of noble metal, thereby achieving high catalytic activity with reduced platinum content (0.05-5% by weight).
Solution Approach 2:
The invention segments the platinum phase into discrete ultra-fine particles rather than using bulk or large aggregated forms. This segmentation into numerous small particles increases the dispersion of the active phase on the support, maximizing the utilization of noble metal and achieving high activity with minimal platinum content.
2Reliability
If catalysts with reduced metallic particle size are used, then catalyst activity increases due to increased dispersion, but manufacturing precision and control become more challenging
Solution Approach 1:
The invention performs preliminary action by incorporating the platinum precursor into the support matrix during the formation stage, before final calcination. This preliminary incorporation ensures uniform distribution of platinum species throughout the support, which after calcination results in uniform ultra-fine particles with controlled size of 1 nm or less, achieving both high activity and manufacturing precision.
Solution Approach 2:
The invention uses the support material as an intermediary that controls the formation and size of platinum particles. The support acts as a template or confining structure that limits particle growth during preparation and calcination, ensuring that platinum forms ultra-fine particles of controlled size rather than uncontrolled aggregates, thereby achieving precise particle size control.
3Reliability
If copper-based catalysts are used for low temperature shift, then activity is improved, but deactivation occurs due to operating temperature and contamination from chloride or sulfur compounds
Solution Approach 1:
The invention replaces copper-based catalysts that are susceptible to deactivation with platinum-based catalysts that exhibit superior stability and resistance to poisoning by chloride or sulfur compounds. Although platinum is more expensive per unit mass, the reduced quantity needed (due to ultra-fine particle size) combined with extended catalyst life and resistance to deactivation provides economic and operational advantages.
Solution Approach 2:
The invention uses a composite structure consisting of platinum dispersed on an oxide support (such as Al2O3, SiO2, TiO2, ZrO2, or CeO2). This composite material combines the high activity of platinum with the stability and resistance to poisoning provided by the oxide support, achieving both high activity and long-term stability without deactivation issues.
4Reliability
If copper oxide phases are reduced to activate the catalyst, then activity is achieved, but exothermicity of the activation reaction can cause damage to the reactor or loss of activity
Solution Approach 1:
The invention eliminates the need for high-temperature reduction activation step that causes exothermic reactions by using platinum on an oxide support that is inherently active or can be activated under milder conditions. This avoids the exothermic reduction of copper oxide phases that can damage reactors or cause loss of activity, ensuring both catalyst activity and reactor integrity.
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 method results in catalysts with high activity and efficiency for CO conversion to CO2 and H2, reducing energy consumption and minimizing chromium handling risks, while maintaining catalyst performance and extending its operational life.
Implementation Method 1
coprecipitation of soluble salts using ammonium hydroxide to produce catalysts with platinum, zirconia, ceria, or iron oxides
Implementation Method 2
The reaction of carbon monoxide and water to produce carbon dioxide and hydrogen is known as the water-gas shift reaction
Implementation Method 3
method results in catalysts with high activity and efficiency for CO conversion to CO2 and H2
Data Source
AI summary
The present invention addresses to catalysts applicable to the conversion of CO to CO2 and H2 by the water-gas shift reaction. Such catalysts are made up of iron oxides, zirconium oxides, cerium oxides or a mixture of the same, promoted by platinum (Pt) contents between 0.1 and 0.4% m/m and with a sodium (Na) content below 0.01% m/m, based on the oxidized material. The present invention makes it possible to obtain catalysts with a high dispersion of Pt, with metallic particles of the order of 1 nm and methods of preparation by coprecipitation of soluble salts in aqueous medium using ammonium hydroxide as a precipitating agent.