M1 MoVTeNb Catalyst Surface Area via Protective Agent
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Solution Overview
Problem
Current methods for producing ethylene through oxidative dehydrogenation of ethane face challenges due to low catalyst productivity and specific surface area, limiting industrialization, as existing phase-pure M1 MoVTeNb-oxide catalysts have insufficient space time yield and catalytic activity.
Innovation Solution
A method involving the use of a protective agent in a hydrothermal synthesis process to adjust phase sizes, followed by hydrogen peroxide purification, to achieve a phase-pure M1 MoVTeNb-oxide catalyst with high specific surface area and improved catalytic performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If phase-pure M1 MoVTeNb-oxide catalysts are prepared by hydrothermal or precipitation methods, then high ethane conversion and ethylene selectivity are achieved, but the specific surface area is low which restricts catalytic activity
Solution Approach 1:
The patent applies preliminary action by adding a protective agent (surfactant or small molecule organic acid) to the precursor solution before hydrothermal treatment. This protective agent prevents premature phase transformation and controls crystal growth during the hydrothermal process, enabling the formation of phase-pure M1 catalyst with high specific surface area. The protective agent is removed after catalyst formation, leaving the desired phase structure with enhanced surface area and catalytic activity.
Solution Approach 2:
The patent employs parameter changes by modifying the hydrothermal treatment conditions (temperature, time, pH) in combination with the protective agent to control the phase transformation process. By adjusting these parameters, the catalyst achieves phase-pure M1 structure with optimized specific surface area, resolving the contradiction between phase purity and surface area.
2Stability of the object's composition
If conventional hydrothermal methods are used to prepare M1 catalyst, then phase purity is achieved, but space time yield and catalyst productivity remain far from industrialization requirements
Solution Approach 1:
The protective agent is introduced in advance to control the hydrothermal process, enabling simultaneous achievement of phase purity and high specific surface area. This preliminary action ensures that the catalyst maintains phase-pure M1 structure while possessing the high surface area necessary for high space time yield and industrialization.
3Area of stationary object
If high specific surface area is achieved through conventional methods, then catalytic activity improves, but phase purity is compromised
Solution Approach 1:
The protective agent performs preliminary action during the hydrothermal process to control phase transformation kinetics. This allows the catalyst to form with high specific surface area while maintaining phase-pure M1 structure, as the protective agent prevents unwanted phase transformations during the high-energy hydrothermal treatment.
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 results in a catalyst with high specific surface area, enhanced catalytic activity, and space time yield, overcoming the limitations of existing catalysts and enabling more efficient ethylene production.
Implementation Method 1
subjecting the precursor-protective agent mixed solution to a hydrothermal reaction, and separating out a solid
Implementation Method 2
purifying with hydrogen peroxide, to obtain a phase-pure M1 MoVTeNb-oxide catalyst
Data Source
AI summary
Provided is a method of preparing a pure M1 phase MoVTeNb-oxide catalyst with a high specific surface area, including S1) mixing and dissolving a molybdenum-containing compound, a vanadium-containing compound, a tellurium-containing compound, a niobium-containing compound and a protective agent to obtain a precursor-protective agent mixed solution, in which the protective agent is a surfactant or a small molecule organic acid and a salt thereof; S2) subjecting the precursor-protective agent mixed solution to a hydrothermal reaction to separate out a solid; S3) calcining the solid in an air atmosphere, followed by calcining the same in an inert gas, and then performing a hydrogen peroxide purification treatment to obtain a pure M1 phase MoVTeNb-oxide catalyst. This catalyst exhibits an excellent conversion rate, selectivity, space time yield and stability in the oxidative dehydrogenation reaction of ethane for preparing ethylene.