Cu-MOR Catalyst Methane Oxidation Selectivity
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Solution Overview
Problem
Current methods for converting methane to methanol are limited by high reactivity of products leading to over-oxidation, necessitating new strategies to enhance methanol selectivity.
Innovation Solution
A method involving a copper-loaded mordenite zeolite (Cu-MOR) catalyst, where an oxygen-containing feed gas stream is introduced to activate the catalyst, followed by a methane-containing feed gas stream to convert methane to methanol, with specific temperature and gas composition controls to optimize methanol yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional catalysts are used for methane oxidation, then methane conversion can be achieved, but over-oxidation occurs leading to low methanol selectivity
Solution Approach 1:
The patent applies local quality by creating specific copper active sites with defined coordination environments (Cu2O)2+ species with specific oxygen coordination within the zeolite framework. These localized active sites with precise geometric and electronic properties enable selective methane oxidation to methanol while preventing over-oxidation, as the specific local structure controls the reaction pathway.
Solution Approach 2:
The patent employs parameter changes by optimizing copper loading amounts (0.5-5 wt%), controlling calcination temperatures (300-500°C), and adjusting oxygen treatment conditions to generate the desired (Cu2O)2+ active sites. These parameter optimizations transform the catalyst properties to achieve high methanol selectivity while minimizing over-oxidation.
2Productivity
If high copper loading is used to increase active sites, then activity improves, but metal aggregation occurs reducing dispersion
Solution Approach 1:
The patent applies preliminary action by pre-treating the copper-loaded zeolite with controlled oxygen exposure and calcination before the main methane oxidation reaction. This preliminary treatment stabilizes the copper species in the desired (Cu2O)2+ form and prevents aggregation during subsequent reactions, maintaining high dispersion while ensuring sufficient catalytic activity.
Solution Approach 2:
The patent uses composite materials by combining copper species with the zeolite framework to form a structured composite catalyst. The zeolite support provides confinement effects that prevent copper aggregation, while the integrated Cu-zeolite composite structure maintains both high metal dispersion and catalytic activity through synergistic interactions between the metal species and framework.
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 achieves a significant methanol production yield of 10 to 30 μmol per gram of catalyst within the first 5 to 20 minutes, with the Cu-MOR-WI catalyst exhibiting the highest performance due to high metal dispersion and methane adsorption.
Implementation Method 1
passing the oxygen-containing feed gas stream through the reactor in contact with the Cu-MOR catalyst particles at a temperature of 100 to 500° C. to form an oxidized Cu-MOR catalyst
Implementation Method 2
introducing and passing a CH4-containing feed gas stream through the reactor in contact with the oxidized Cu-MOR catalyst at a temperature of 50 to 200° C. thereby converting at least a portion of the CH4 to CH3OH
Implementation Method 3
the CH3OH is adsorbed on surfaces and pores of the regenerated Cu-MOR catalyst
Data Source
AI summary
A method for direct methane (CH4) oxidation (DMTM) to methanol (CH3OH) includes passing an oxygen-containing feed gas stream into a reactor containing a copper-loaded mordenite zeolite (Cu-MOR) catalyst particles such that the oxygen-containing feed gas stream is in contact with the Cu-MOR catalyst particles, at a temperature of 100 to 500° C., to form an oxidized Cu-MOR catalyst. The method further includes displacing oxygen in the reactor by nitrogen purging, and further passing a CH4-containing feed gas stream through the reactor in contact with the oxidized Cu-MOR catalyst at a temperature of 50 to 200° C., thereby converting at least a portion of the CH4 to CH3OH. The method further includes regenerating the Cu-MOR catalyst particles to form a regenerated Cu-MOR catalyst. The CH3OH is adsorbed on surfaces and pores of the regenerated Cu-MOR catalyst.