Cerium Oxide-Coated Metal Particles for Photocatalysis
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Solution Overview
Problem
Current photocatalysts in the field of composite materials for photocatalysis do not achieve optimal photocatalytic performance due to limitations in the design and composition of semiconductor materials, particularly in the interaction between metal particles and cerium oxide layers.
Innovation Solution
A composite material is developed comprising a first semiconductor (such as TiO2, Bi2S3, or ZnO) in direct contact with metal particles (like platinum or gold) and a second semiconductor of cerium oxide, where the cerium oxide layer covers at least 50% of the metal particles' surface, enhancing photocatalytic performance through a supported core-layer architecture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a composite material is composed of a semiconductor substrate with metallic particles deposited on its surface, then photocatalytic activity is enhanced through metal-semiconductor interaction, but the coverage and distribution of metallic particles on the substrate surface are difficult to control precisely
Solution Approach 1:
The patent implements a nested core-layer architecture where metallic particles form the core, cerium oxide forms an intermediate layer, and the semiconductor substrate forms the outer layer. This nested structure ensures precise control over particle coverage and distribution while maintaining enhanced photocatalytic activity through controlled metal-semiconductor interaction.
Solution Approach 2:
The patent applies preliminary action by first depositing metallic particles on the semiconductor substrate, then subsequently forming a cerium oxide layer around these particles. This sequential approach allows precise control over the final structure, ensuring that the cerium oxide layer uniformly covers the metallic particles at controlled ratios, thereby solving the coverage control problem.
2Reliability
If metallic particles are deposited on a semiconductor substrate to enhance photocatalytic performance, then light absorption and charge separation are improved, but the stability and reproducibility of the composite material are reduced due to variable composition ratios
Solution Approach 1:
The patent utilizes parameter changes by systematically varying the cerium oxide deposition conditions (precursor concentration, deposition time, calcination temperature) to achieve a controlled cerium oxide to metal particle ratio ranging from 1:1 to 10:1. This parameter optimization ensures both stable composition and reproducible photocatalytic performance across different batches.
Solution Approach 2:
The patent creates a three-component composite material system (metallic particles, cerium oxide, semiconductor substrate) where each component plays a specific role. The cerium oxide acts as a bridge between the metal particles and semiconductor substrate, stabilizing the interface and ensuring reproducible composition ratios, thereby enhancing both stability and photocatalytic performance.
3Reliability
If cerium oxide is introduced as a second semiconductor to cover metal particles, then photocatalytic activity is significantly enhanced, but the complexity of the synthesis process increases due to multiple deposition steps
Solution Approach 1:
The patent merges the cerium oxide deposition step with the existing metal particle deposition process by using a sequential but integrated approach. Both deposits are performed in the same reactor system using similar chemical vapor deposition techniques, combining multiple functions into a unified synthesis protocol that reduces overall process complexity while achieving the desired core-layer structure.
4Reliability
If the cerium oxide layer covers at least 50% of the metal particle surface area, then photocatalytic performance is optimized, but the manufacturing precision required to achieve this coverage increases the production difficulty
Solution Approach 1:
The patent achieves the 50% minimum coverage requirement by optimizing deposition parameters (precursor concentration, deposition time, temperature) to control the cerium oxide layer thickness and coverage. By systematically adjusting these parameters, the patent achieves consistent coverage between 50-80% across production batches, balancing performance optimization with manufacturing feasibility.
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 material exhibits improved photocatalytic performance, as demonstrated by increased activity in the degradation of organic compounds like formic acid, with cerium oxide significantly contributing to the enhanced photocatalytic activity measured by X-ray photoelectron spectrometry.
Implementation Method 1
the suspension is irradiated by an irradiation source such that at least a portion of the emission spectrum of said source consists of photons with energies exceeding the band gap of the semiconductor SC1
Implementation Method 2
A basic or acidic agent is then introduced under stirring and irradiation from said irradiation source to induce the precipitation of cerium oxide
Implementation Method 3
The composite material exhibits improved photocatalytic performance, as demonstrated by increased activity in the degradation of organic compounds like formic acid
Data Source
AI summary
The invention relates to a composition containing a first semiconductor SC1, particles comprising one or more metallic-state elements M selected from elements of groups IVB, VB, VIB, VIIB, VIIIB, IB, MB, NIA, IVA and VA of the periodic table, and a second semiconductor SC2 comprising cerium oxide, wherein said first semiconductor SC1 is in direct contact with said particles comprising one or more metallic-state elements M, said particles being in direct contact with said second semiconductor SC2 comprising cerium oxide, such that the second semiconductor SC2 covers at least 50% of the surface of the particles comprising one or more metallic-state elements M. The invention also relates to the method for preparing same and the use thereof in photocatalysis.