Amorphous Iron Molybdate Islands on Rod-Shaped Molybdenum Oxide
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Solution Overview
Problem
Current molybdenum oxide composites used as catalysts have limitations in specific surface area and structural stability, leading to reduced activity and handling difficulties due to the presence of crystalline iron molybdate islands, which are brittle and difficult to preserve.
Innovation Solution
A composite is developed with rod-shaped molybdenum oxide and amorphous iron molybdate islands, where the islands are 10 wt% or less of the composite, with sizes ranging from 10 nm to 50 nm, and a particle ratio of 30:1 to 60:1, achieved through a preparation method involving a mixed solution of iron precursors and solvents with rod-shaped molybdenum oxide, followed by firing at 500°C to 550°C for 3 to 5 hours.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If crystalline iron molybdate islands are used in the composite, then the composite has higher structural stability, but the specific surface area decreases and the islands become brittle and difficult to preserve
Solution Approach 1:
The invention changes the crystal structure parameter from crystalline to amorphous state for the iron molybdate islands. This parameter change resolves the contradiction by eliminating the brittleness and low surface area issues of crystalline structures while maintaining structural stability through the controlled amorphous phase formation during the firing process at 500-550°C for 3-5 hours.
2Stability of the object's composition
If the size of iron molybdate islands is increased, then the composite has higher structural stability, but the catalytic activity decreases due to reduced specific surface area
Solution Approach 1:
The invention changes the size parameter of iron molybdate islands to a specific range (10-50 nm) and maintains them in an amorphous state. This resolves the contradiction by providing sufficiently small particles for high catalytic activity while the amorphous structure and controlled distribution (10 wt% or less) ensure structural stability during the firing process.
3Stability of the object's composition
If crystalline iron molybdate islands are used in the composite, then the composite has defined structure, but the handling becomes difficult due to brittleness
Solution Approach 1:
The invention changes the structural parameter from crystalline to amorphous phase for the iron molybdate islands. This parameter change eliminates the brittleness associated with crystalline structures, making the composite easier to handle while maintaining well-defined structural characteristics through the controlled amorphous phase formation and uniform distribution on rod-shaped molybdenum oxide.
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 composite exhibits a higher specific surface area and improved catalytic activity due to smaller, uniformly distributed amorphous iron molybdate islands, enhancing the catalyst's performance in partial oxidation reactions.
Implementation Method 1
firing after step (c), wherein the firing step (d) is performed in a range of 500°C to 550°C and a range of 3 hours to 5 hours
Data Source
Figure 1
Figure 2(a)~2(b)
Figure 3
AI summary
According to the present invention, a composite including amorphous iron molybdate islands, shows a smaller island size and a uniform distribution of islands compared with a conventional composite including crystalline islands, and thus has a higher specific surface area, thereby exhibiting excellent activity as a catalyst.