Bi2O3/(BiO)2CO3/Bi2MoO6 Composite Photocatalyst for Enhanced Charge Separation
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Solution Overview
Problem
Bi2MoO6 photocatalysts have limited visible light responsiveness, rapid electron-hole pair recombination, and slow migration rates, which hinder their practical application in environmental purification and energy development.
Innovation Solution
A Bi2O3/(BiO)2CO3/Bi2MoO6 composite photocatalyst is developed by introducing Bi2O3 and (BiO)2CO3 nanosheets onto the surface of Bi2MoO6 through a method involving the addition of Na2CO3 and roasting, enhancing visible light response and electron-hole pair separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If Bi2MoO6 photocatalyst is used, then visible light absorption is achieved, but photocatalytic activity remains low due to rapid electron-hole recombination
Solution Approach 1:
The patent constructs a heterostructure composite photocatalyst consisting of Bi2MoO6 coupled with Bi2O3 and (BiO)2CO3 nanosheets. This composite structure creates multiple interfaces that facilitate charge separation while maintaining visible light absorption capability, thereby resolving the contradiction between light absorption and photocatalytic activity
Solution Approach 2:
The Bi2O3 and (BiO)2CO3 nanosheets serve as intermediary components that mediate charge transfer between Bi2MoO6 particles. These intermediate layers provide additional pathways for electron-hole separation and reduce recombination rates, enabling improved photocatalytic performance while preserving visible light responsiveness
2Use of energy by moving object
If Bi2MoO6 photocatalyst is used, then sunlight utilization is improved, but electron-hole pair lifetime is short and migration rate is slow
Solution Approach 1:
The photocatalyst is segmented into a heterostructure with distinct Bi2MoO6 domains and Bi2O3/(BiO)2CO3 nanosheet interfaces. This segmentation creates multiple charge separation sites and extends electron-hole pair lifetime by preventing rapid recombination at interfaces, while maintaining broad sunlight absorption
Solution Approach 2:
The composite heterostructure combines Bi2MoO6 with Bi2O3 and (BiO)2CO3 to create a multi-component system with extended charge carrier lifetime. The different band structures of the composite materials facilitate spatial separation of electrons and holes, reducing recombination and extending effective lifetime for photocatalytic reactions
3Productivity
If composite photocatalyst with multiple components is prepared, then photocatalytic activity is improved, but preparation process becomes more complex
Solution Approach 1:
The patent employs a solvothermal synthesis method where all precursor materials are pre-mixed in a homogeneous solution before a single heating treatment. This preliminary mixing of Bi(NO3)3, Na2MoO4, and Na2CO3 precursors in ethylene glycol ensures uniform distribution of all components, simplifying the preparation process while achieving the desired complex heterostructure
Solution Approach 2:
The preparation process utilizes parameter changes during solvothermal treatment, where temperature and time control the in-situ formation of the heterostructure. By adjusting the solvothermal parameters (160°C for 12 hours), the complex multi-component structure forms automatically from the precursor mixture, simplifying the overall synthesis process
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 photocatalyst exhibits improved catalytic activity, wide visible light responsiveness, and excellent reusability, with a simple and controllable preparation method.
Implementation Method 1
Bi2MoO6 has a band gap of about 2.5-2.8 eV and a maximum absorption wavelength of about 490 nm. It can be excited through absorption of part of visible light.
Implementation Method 2
introducing Bi2O3 and (BiO)2CO3 nanosheets to a surface of the Bi2MoO6 through addition of Na2CO3 and roasting
Data Source
AI summary
The present invention discloses a bismuth oxide (Bi2O3)/bismuth subcarbonate ((BiO)2CO3)/bismuth molybdate (Bi2MoO6) composite photocatalyst, including a Bi2MoO6 photocatalyst, where Bi2O3 and (BiO)2CO3 nanosheets are introduced to a surface of the Bi2MoO6 through addition of Na2CO3 and roasting. The present invention also discloses a preparation method of the Bi2O3/(BiO)2CO3/Bi2MoO6 composite photocatalyst which is specifically implemented by the following steps: step 1: preparing a Bi2MoO6 photocatalyst; step 2: introducing Bi2O3 and (BiO)2CO3 nanosheets to a surface of the Bi2MoO6 photocatalyst obtained in step 1 through addition of Na2CO3 and roasting to obtain the Bi2O3/(BiO)2CO3/Bi2MoO6 composite photocatalyst. The photocatalyst of the present invention has no agglomeration, a wide responsive range of visible light, a significantly improved catalytic activity compared with a Bi2MoO6 alone, and excellent reusability. Moreover, the preparation method is simple with mild conditions, desired controllability and convenient operation.