Nitrogen-Doped TiO2 Photocatalyst Synthesis
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Solution Overview
Problem
Current TiO2-based photocatalysts face challenges such as instability in the liquid phase, high synthesis complexity, and high costs due to the use of noble metals, along with limited light absorption in the visible spectrum, making them inefficient for pollutant degradation and water cracking applications.
Innovation Solution
A process for preparing macro and mesoporous crystalline titanium dioxide (TiO2) is developed, involving an acidified mixture with a poly(ethylene glycol) separator and nitrogen doping, resulting in a material with enhanced visible light absorption and stability, eliminating the need for noble metals and simplifying synthesis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If TiO2 nanotubes are grown on titanium sheets to achieve high photocatalytic activity in visible spectrum, then photocatalytic efficiency is improved, but stability in liquid phase deteriorates
Solution Approach 1:
The patent employs a porous silica support structure with controlled pore sizes to accommodate TiO2 nanoparticles. The porous architecture provides high surface area for catalyst deposition while maintaining structural integrity in liquid environments, resolving the stability issue of nanotube-on-sheet configurations.
Solution Approach 2:
The invention creates a composite material system combining TiO2 photocatalytic particles with a stable porous silica support matrix. This composite structure integrates the high photocatalytic activity of TiO2 with the chemical and mechanical stability of silica, enabling both high productivity and reliability in liquid phase applications.
2Use of energy by moving object
If noble metal particles are added to TiO2 to improve visible light absorption, then light absorption capability is improved, but manufacturing cost increases
Solution Approach 1:
The patent replaces expensive noble metal particles with cost-effective carbon-based materials (such as carbon dots, carbon nanotubes, or graphitic carbon) that can be synthesized from inexpensive precursors. These carbon materials provide comparable or superior visible light absorption and photocatalytic activity without the high manufacturing costs associated with noble metals.
Solution Approach 2:
The invention modifies the optical and electronic parameters of TiO2 by introducing carbon dopants or carbon-based composites. This changes the band structure and light absorption characteristics of TiO2, enabling efficient visible light utilization through chemical composition modification rather than expensive metal particle addition.
3Productivity
If TiO2 particles are made at nanoscale to increase surface area, then photocatalytic activity is improved, but separation from solution becomes difficult
Solution Approach 1:
The patent introduces magnetic nanoparticles (such as Fe3O4 or other magnetic materials) as intermediary components within the TiO2 composite structure. These magnetic particles enable easy separation of the nanoscale photocatalyst from solution through external magnetic field application, while the nanoscale TiO2 maintains its high surface area and photocatalytic 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 resulting TiO2 exhibits exceptional visible light absorption and stability, enabling efficient pollutant degradation and water cracking, with improved handling and cost-effectiveness compared to previous materials.
Implementation Method 1
addition in two stages to a source of titanium of the acidified mixture comprising a separator and of a source of nitrogen
Implementation Method 2
obtaining a titanium dioxide gel from the nitrogen-doped titanium solution
Implementation Method 3
dissolving of a separator in a hydrated acid; the mixture being acidified to at least 25% by weight
Implementation Method 4
washing the titanium dioxide gel with an alcohol
Implementation Method 5
obtaining macro and mesoporous crystalline titanium dioxide from the gel of washed titanium dioxide
Implementation Method 6
obtaining macro and mesoporous crystalline titanium dioxide from the gel of washed titanium dioxide
Data Source
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AI summary
The present invention concerns a method for preparing crystalline macro- and mesoporous titanium dioxide (TiO2), in particular comprising the steps of preparing an acidified mixture comprising a separator, the mixture being acidified to at least 25% by mass in acid; - adding the acidified mixture comprising a separator and a source of nitrogen to a source of titanium, in two stages; - obtaining a titanium dioxide gel from the nitrogen-doped titanium solution; - washing the titanium dioxide gel with an alcohol; - obtaining a crystalline macro- and mesoporous titanium dioxide from the washed titanium dioxide gel. The invention also concerns a crystalline macro- and mesoporous titanium dioxide that can be obtained by the above method.