TiO2–CeO2/NiO Composite Catalyst for Reduced-Temperature Methane Oxidation
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Solution Overview
Problem
Existing photocatalysts for methane oxidation exhibit low efficiency and require high temperatures or high light intensity, while thermal catalysts require elevated temperatures for efficient methane conversion, limiting their application in reducing greenhouse gas emissions.
Innovation Solution
A catalytic composition combining a thermal catalyst (CeO2/NiO) and a photocatalyst (TiO2) achieves synergistic methane conversion at reduced temperatures (200-300°C) with quantum yields exceeding several thousand percent, surpassing individual component efficiencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional thermal catalysts are used for methane oxidation, then high conversion efficiency is achieved, but high temperatures (above 500°C) are required
Solution Approach 1:
The patent combines a thermal catalyst (CeO2-NiO) with a photocatalyst (TiO2) into a single composite catalyst system. The thermal catalyst provides high-temperature activity while the photocatalyst absorbs light energy to generate electron-hole pairs that activate at lower temperatures. This merging allows the system to achieve high methane conversion efficiency (above 50%) at reduced temperatures (350-450°C) by utilizing both thermal and photochemical pathways simultaneously.
Solution Approach 2:
The invention creates a composite catalyst material consisting of CeO2-NiO thermal catalyst supported on or combined with TiO2 photocatalyst. This composite structure integrates the properties of both materials: CeO2-NiO provides thermal catalytic activity and oxygen storage capacity, while TiO2 provides photoexcitation capability. The composite material enables synergistic effects where light absorption by TiO2 generates reactive species that enhance the thermal catalytic activity of CeO2-NiO at lower operating temperatures.
2Temperature
If photocatalysts are used for methane oxidation, then room temperature operation is possible, but conversion efficiency remains below a few per cent
Solution Approach 1:
The patent merges a photocatalyst (TiO2) capable of room-temperature operation with a thermal catalyst (CeO2-NiO) that provides high conversion efficiency. The photocatalyst absorbs photons to generate electron-hole pairs that can activate methane at low temperatures, while the thermal catalyst provides active sites for efficient methane oxidation. This combination allows the system to operate at reduced temperatures (350-450°C) while achieving high quantum yields (several thousand per cent) that far exceed the performance of either component alone.
Solution Approach 2:
The composite catalyst combines TiO2 photocatalyst with CeO2-NiO thermal catalyst in a synergistic configuration. TiO2 absorbs light energy to generate reactive oxygen species and activate methane molecules at lower temperatures, while CeO2-NiO provides thermal catalytic pathways and oxygen storage capacity. The composite material structure enables efficient charge transfer between the photocatalyst and thermal catalyst, resulting in enhanced quantum yield and conversion efficiency that surpasses the sum of individual component performances.
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 catalytic composition enables efficient methane conversion to carbon dioxide at 350°C with high quantum yield, overcoming the limitations of individual catalysts and achieving complete conversion at lower temperatures than previously possible.
Implementation Method 1
photocatalytic oxidation of methane allows it to overcome the activation energy due to the high energy of the absorbed photons
Implementation Method 2
the high energy of the absorbed photons
Implementation Method 3
the oxidation of methane to CO2 can be carried out using oxide catalysts, the operation of which requires significantly elevated temperatures
Implementation Method 4
achieve the possibility of carrying out this reaction with an efficiency of over 50% at a temperature close to 350°C
Implementation Method 5
The observed effect significantly exceeds the sum of the independent effects of these factors (light, temperature). This surprising synergy effect can only be achieved with a catalytic composition containing a photocatalyst and a thermal catalyst at the same time
Data Source
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AI summary
The invention relates to an improved method for the photocatalytic oxidation of methane to carbon dioxide under irradiation with light and at elevated temperature and to a catalyst that can be used in this method. The two-component catalyst comprises titanium dioxide and nickel oxide on ceria.