Platinum-Alkali Water Gas Shift Catalyst for Low-Temperature Hydrogen Generation
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Solution Overview
Problem
Existing catalysts for the water gas shift reaction are not sufficiently active at low temperatures (below 450°C) to produce hydrogen-rich gas with thermodynamic equilibrium concentrations, and they often cause unwanted side reactions like methanation, limiting their utility in producing hydrogen-rich syngas for applications such as PEM fuel cells and ammonia synthesis.
Innovation Solution
A platinum-based water gas shift catalyst containing alkali or alkaline-earth metals and additional metals like lithium, sodium, potassium, and transition metals, supported on carriers like alumina or zirconia, which enhances activity and selectivity for hydrogen generation and carbon monoxide oxidation at temperatures up to 450°C, avoiding methanation reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional catalysts are used for water gas shift reaction at low temperatures (below 450°C), then the reaction can proceed, but the catalyst activity is insufficient to produce hydrogen-rich gas with thermodynamic equilibrium concentrations
Solution Approach 1:
The patent employs composite catalyst materials comprising platinum combined with alkali metals (Li, Na, K) and alkaline-earth metals (Ca, Sr, Ba) supported on ceramic carriers. This composite structure synergistically combines the high catalytic activity of platinum with the temperature-promoting effects of alkali/alkaline-earth metals, achieving both high productivity and reliability at low temperatures by preventing methanation side reactions while maintaining equilibrium concentrations.
2Loss of energy
If conventional catalysts operate at low temperatures to preserve thermodynamic equilibrium, then energy consumption is reduced, but unwanted side reactions like methanation occur
Solution Approach 1:
The patent converts the potentially harmful effect of low-temperature operation (which normally promotes methanation) into a benefit by using alkali/alkaline-earth metal promoters that specifically inhibit methanation while maintaining water gas shift activity. The harmful side reaction is transformed into a selective advantage through the unique catalytic properties of the composite material formulation.
3Productivity
If high temperature is used to increase catalyst activity, then hydrogen generation rate improves, but thermodynamic equilibrium concentrations are not achieved and energy consumption increases
Solution Approach 1:
The patent changes the catalytic parameters by introducing alkali and alkaline-earth metal components that modify the electronic and surface properties of the platinum catalyst. This parameter change enables the catalyst to achieve high activity at low temperatures, decoupling the traditional trade-off between temperature, activity, and energy consumption while maintaining thermodynamic equilibrium concentrations.
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 catalyst achieves high activity and selectivity for hydrogen generation and carbon monoxide oxidation at moderate temperatures, producing a hydrogen-rich gas suitable for industrial applications, such as PEM fuel cells and ammonia synthesis, while minimizing unwanted side reactions.
Implementation Method 1
catalysts to generate a hydrogen-rich gas from gas mixtures containing carbon monoxide and water
Implementation Method 2
catalysts of the invention exhibit both high activity and selectivity to hydrogen generation and carbon monoxide oxidation
Data Source
AI summary
A method and catalysts and fuel processing apparatus for producing a hydrogen-rich gas, such as a hydrogen-rich syngas are disclosed. According to the method a CO-containing gas, such as a syngas, contacts a water gas shift catalyst in the presence of water, preferably at a temperature of less than about 450° C. to produce a hydrogen-rich gas, such as a hydrogen-rich syngas. Also disclosed is a water gas shift catalyst comprising:a) Pt, its oxides or mixtures thereof;b) at least one of Li, Na, K, Rb, Cs, Mg, Ca, Sr, Ba, their oxides and mixtures thereof; andc) at least one of Sc, Y, Ti, Zr, V, Nb, Ta, Cr, Mo, W, Mn, Fe, Co, Ir, Ni, Pd, La, Ce, Pr, Nd, Sm, Eu, their oxides and mixtures thereof.The WGS catalyst may be supported on a carrier, such as any one member or a combination of alumina, zirconia, titania, ceria, magnesia, lanthania, niobia, yttria and iron oxide. Fuel processors containing such water gas shift catalysts are also disclosed.