Nitrogen-Doped Catalyst for Methane Oxidative Coupling
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Solution Overview
Problem
The oxidative coupling reaction of methane requires high temperatures and generates hot spots, leading to inefficient catalyst performance and reduced selectivity for C2 hydrocarbons, as existing catalysts like Na2WO4/Mn/SiO2 struggle with activation and conversion ratios.
Innovation Solution
A nitrogen-doped catalyst is produced by doping nitrogen into a Na2WO4/Mn/SiO2 catalyst using pyridine, which induces oxygen vacancies, increasing methane activation and allowing for a lower-temperature oxidative coupling reaction, thereby enhancing conversion ratios and selectivity for C2 hydrocarbons.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high temperature is used to increase methane conversion ratio, then conversion ratio is improved, but selectivity for C2 hydrocarbons deteriorates due to thermodynamically stable reaction path producing CO or CO2
Solution Approach 1:
The patent changes the chemical composition parameters of the catalyst by introducing nitrogen-doped metal oxides with specific ratios (Mn: 0.1-5 wt%, N: 0.01-2 wt%) to modify the reaction pathway and selectivity at lower temperatures
Solution Approach 2:
The patent creates a composite catalyst system combining nitrogen-doped metal oxides (Mn, Fe, Co, Ni, Cu, Zn) with specific support materials (SiO2, Al2O3, TiO2, ZrO2, HfO2) to achieve synergistic effects that improve both conversion and selectivity
2Productivity
If high oxygen partial pressure is used to increase methane conversion ratio, then conversion ratio is improved, but selectivity for C2 product deteriorates as reaction proceeds along thermodynamically stable path
Solution Approach 1:
The patent modifies the catalyst's chemical composition parameters to enable efficient C2 formation at lower oxygen partial pressures, avoiding the thermodynamic trap of CO/CO2 production while maintaining high conversion
3Productivity
If reaction temperature is increased to activate methane, then conversion ratio is improved, but hot spots are generated more severely around catalyst layer
Solution Approach 1:
The patent changes the catalyst's thermal and chemical properties by introducing nitrogen-doped metal oxides that facilitate activation at lower temperatures (600-750°C), thereby reducing hot spot formation while maintaining conversion efficiency
4Reliability
If conventional Na2WO4/Mn/SiO2 catalyst is used for oxidative coupling, then catalyst stability is improved, but activation efficiency and conversion ratio are insufficient
Solution Approach 1:
The patent enhances the conventional catalyst system by introducing nitrogen-doped metal oxides as active components combined with stable support structures, creating a composite that achieves both high stability and improved conversion efficiency
Solution Approach 2:
The patent modifies the catalyst composition parameters by incorporating nitrogen at specific concentrations (0.01-2 wt%) to enhance activation efficiency while preserving the stability of the support structure
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 nitrogen-doped catalyst achieves higher methane conversion and selectivity for C2 hydrocarbons at a lower temperature than traditional methods, improving reaction efficiency and catalyst stability.
Implementation Method 1
doping nitrogen into a Na2WO4/Mn/SiO2 catalyst using pyridine, which induces oxygen vacancies, increasing methane activation
Implementation Method 2
nitrogen-doped catalyst for oxidative coupling reaction of methane, the method including a step of doping nitrogen into a Na2WO4/Mn/SiO2 catalyst using pyridine
Implementation Method 3
oxidative coupling reaction of methane (OCM)... 2CH4+O2→C2H4+2H2O
Implementation Method 4
the oxidative coupling reaction of methane is an exothermic reaction and has a problem in the process, in which hot spots are generated around a catalyst layer
Data Source
AI summary
A nitrogen-doped catalyst for oxidative coupling of methane, which is a catalyst for obtaining a C2 hydrocarbon product with high yield, and a method for manufacturing the catalyst are provided. An embodiment of the present inventive concept relates to a nitrogen-doped catalyst for oxidative coupling of methane having a silica support; and sodium tungstate and manganese supported on the support.