Copper Dimer on Carbon Nitride for Methane Oxidation
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Solution Overview
Problem
Current industrial processes for converting methane to liquid hydrocarbons are energy-intensive and economically nonviable, particularly for distributed sources like flare gas, necessitating the development of more robust technologies for direct methane conversion.
Innovation Solution
A catalyst composite comprising a copper dimer with two copper atoms bridged by an oxygen atom, coordinated to two nitrogen atoms of a carbon nitride substrate, is used for the selective oxidation of methane, achieving high selectivity and activity under both thermocatalytic and photocatalytic conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional two-step reforming process is used to convert methane to liquid hydrocarbons, then conversion efficiency is improved, but energy consumption increases significantly
Solution Approach 1:
The patent extracts and eliminates the high-temperature reforming step from the traditional two-step process. By using a copper-dimer catalyst on carbon nitride support, the system directly converts methane to liquid hydrocarbons in a single step at much lower temperatures, removing the energy-intensive synthesis gas generation stage while maintaining conversion efficiency.
Solution Approach 2:
The invention changes the operating parameters from high temperature (>500°C) reforming conditions to low temperature direct conversion conditions. The copper-dimer catalyst enables the reaction to proceed at temperatures where energy consumption is dramatically reduced, while the carbon nitride support stabilizes the catalyst structure for sustained activity.
2Use of energy by moving object
If direct conversion of methane is implemented, then energy consumption is reduced, but conversion selectivity and activity decrease
Solution Approach 1:
The patent employs a composite material system consisting of copper dimers anchored on carbon nitride support. The copper dimer active sites provide high selectivity for methane activation and C-H bond cleavage, while the carbon nitride support enhances catalyst stability and prevents copper aggregation. This composite structure achieves both low energy consumption and high conversion selectivity simultaneously.
Solution Approach 2:
The carbon nitride support acts as an intermediary that facilitates the interaction between methane and the copper-dimer catalyst. It stabilizes the copper species in the appropriate oxidation state, promotes methane activation, and directs the reaction pathway toward liquid hydrocarbon products, thereby improving selectivity without requiring high energy input.
3Productivity
If copper loading is increased to improve activity, then catalytic activity increases, but catalyst stability and selectivity deteriorate
Solution Approach 1:
Instead of uniformly distributing copper throughout the catalyst, the patent creates localized copper-dimer sites on the carbon nitride support. Each copper dimer unit consists of two copper atoms in a specific configuration that provides optimal activity. This localized arrangement maintains high activity per copper atom while preventing the aggregation and deactivation that occur with higher overall copper loading.
Solution Approach 2:
The copper phase is segmented into discrete dimer units rather than forming continuous metal particles or high-loading aggregates. This segmentation into small, isolated active sites (each containing only two copper atoms) prevents catalyst deactivation pathways associated with bulk metal formation, thereby maintaining stability while preserving high specific activity.
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 composite demonstrates enhanced selectivity and activity for the partial oxidation of methane, achieving greater than 10% conversion and greater than 98% selectivity toward methyl oxygenates, with a mass-specific activity of 1399.3 mmol gCu−1 h−1, significantly improving upon existing catalysts.
Implementation Method 1
A catalyst composite comprising a copper dimer with two copper atoms bridged by an oxygen atom, coordinated to two nitrogen atoms of a carbon nitride substrate, is used for the selective oxidation of methane
Implementation Method 2
achieving high selectivity and activity under both thermocatalytic and photocatalytic conditions
Implementation Method 3
photocatalytic oxidation of methane with O2 achieves greater than 10% conversion and greater than 98% selectivity toward methyl oxygenates
Data Source
AI summary
Disclosed are dimeric copper centers supported on graphitic carbon nitride (denoted herein as Cu2@C3N4) and their use as advanced catalysts for partial oxidation of CH4.