Hollow TiO2-SiO2 Core-Shell Particles for Higher Photocatalytic Surface Area
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Solution Overview
Problem
The catalytic activity of titanium dioxide is adversely affected due to limited surface area and surface contact reactions, necessitating a solution to maintain catalytic activity while preventing the core surface from being covered by a shell.
Innovation Solution
A core-shell hollow structure is formed by modifying titanium dioxide nanospheres to be hydrophobic and aerophilic, allowing them to self-drive into micro-nano bubbles where a silicon dioxide shell is generated, creating a photocatalytic core-shell structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If a core-shell structure is formed to increase surface area, then catalytic activity is improved, but the core surface may be covered by the shell which adversely affects catalytic activity
Solution Approach 1:
The patent employs a porous silicon dioxide shell structure that allows reactants to penetrate through the shell and access the titanium dioxide core. The porous structure maintains high surface area for catalytic reactions while preventing complete surface coverage that would block catalytic activity. The pores enable mass transport while providing structural support for the core-shell architecture.
Solution Approach 2:
The silicon dioxide shell is formed as a thin, flexible layer around the titanium dioxide core through sol-gel process. This thin film structure increases the effective surface area without creating a thick barrier that would impede reactant access to the catalytic core, thus maintaining catalytic activity while expanding reactive surface area.
2Reliability
If titanium dioxide particles are used as photocatalyst, then photocatalytic activity is achieved, but the limited surface area restricts reaction efficiency
Solution Approach 1:
The patent creates a nested core-shell structure where the titanium dioxide core is enclosed by a silicon dioxide shell. This nesting arrangement protects the photocatalytic core while the shell provides additional surface area. The core maintains its photocatalytic function surrounded by the protective and surface-expanding shell structure.
Solution Approach 2:
The patent combines titanium dioxide and silicon dioxide into a composite core-shell material. The titanium dioxide core provides photocatalytic activity while the silicon dioxide shell contributes surface area and structural stability. The composite structure synergistically combines the advantages of both materials to overcome the limited surface area of pure titanium dioxide particles.
3Adaptability or versatility
If hydrophobic modification is applied to titanium dioxide surface, then aerophilic properties are improved, but surface chemistry is altered
Solution Approach 1:
The patent applies preliminary hydrophobic modification to the titanium dioxide surface using tetraoctadecyl orthosilicate before forming the core-shell structure. This preliminary action imparts aerophilic properties that enable the particles to self-drive into micro-nano bubbles during the sol-gel process, facilitating the formation of the hollow core-shell structure with controlled surface properties.
Solution Approach 2:
The patent modifies surface parameters by applying hydrophobic treatment to change the surface energy and wettability characteristics of titanium dioxide. This parameter change enables the particles to exhibit aerophilic behavior and self-assemble into the desired core-shell structure, while the subsequent shell formation stabilizes the modified surface chemistry.
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 enhances catalytic activity by increasing the surface area for reactions and reduces material usage, facilitating large-scale production with improved photocatalytic performance.
Implementation Method 1
tetraoctadecyl orthotitanate is used to modify a surface of a market-available titanium dioxide nanosphere particle to be hydrophobic
Implementation Method 2
the titanium dioxide particle moves into the micro-nano bubble in a self-driven manner due to a difference in surface tensions
Implementation Method 3
a silicon dioxide shell is generated at a water-air interface of the micro-nano bubble
Implementation Method 4
The method enhances catalytic activity by increasing the surface area for reactions
Data Source
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AI summary
The present disclosure provides a method for preparing a core-shell hollow structure with self-driving nucleation of a photocatalytic particle, including: (1) mixing an alcoholic solution of titanium dioxide with tetraoctadecyl orthotitanate to obtain a first solution including modified titanium dioxide nanospheres; (2) injecting air into water through a micro-nano bubble generator to obtain a resultant solution, and shearing and smashing the resultant resolution to obtain a second solution including micro-nano bubbles; (3) mixing the second solution with the first solution at a temperature of 35°C or more, so as to obtain a third solution; (4) adding ammonium hydroxide and a solution of tetraethyl orthosilicate into the third solution, so as to obtain a fourth solution; and (5) separating a precipitate from the fourth solution, and drying and calcining the precipitate, so as to obtain the nanoparticle with the core-shell hollow structure. According to the present disclosure, it is able to improve the catalytic activity through increasing a surface for the catalytic reaction. In addition, the method is relatively simple for large-scale production.