TiO2-Cu2O Heterojunction Coating for Visible-Light Antibacterial Performance

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Solution Overview

Problem

Conventional antibacterial materials have insufficient persistence of antibacterial performance and are ineffective against viruses, with photocatalysts requiring ultraviolet rays for activation, limiting their use to areas exposed to sunlight.

Innovation Solution

A coating agent composition containing photocatalyst particles with specific band potentials, cuprous oxide particles, a binder resin, and an organic solvent, which provides high antibacterial and antiviral performance even in indoor spaces and persists over time, using a combination of photocatalyst particles like titanium oxide and cuprous oxide to enhance bacterial and viral inactivation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional photocatalysts are used, then antibacterial performance can be achieved under ultraviolet light, but the application is limited to areas exposed to sunlight and cannot provide effective antiviral performance

Engineering Contradiction:
Improveantibacterial performanceVSAvoidapplication scope
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent modifies the band structure parameters of the photocatalyst by constructing a heterojunction between TiO2 and Cu2O, where the conduction band of Cu2O (0.16 V vs SHE) is lower than that of TiO2, enabling visible light absorption while maintaining photocatalytic activity for both antibacterial and antiviral applications

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite photocatalytic system by combining TiO2 particles with Cu2O particles in specific ratios (0.1-5 parts Cu2O per 100 parts non-volatile matter), forming a heterogeneous structure that extends light absorption to visible range while enhancing both antibacterial and antiviral efficacy

Inventive Principle:
Principle #40Composite materials

2Reliability

If silver or zinc-based antibacterial materials are used, then strong antibacterial effect against bacteria can be achieved, but they have no effect on viruses and raise concerns about price and ecotoxicity

Engineering Contradiction:
Improveantibacterial effectVSAvoidecotoxicity and cost
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces expensive precious metals (silver, zinc) with abundant, low-cost TiO2 and Cu2O materials that are environmentally benign, maintaining effective antibacterial performance while eliminating concerns about metal ion toxicity and high material cost

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent utilizes the strong oxidizing capability of photogenerated holes in the TiO2-Cu2O heterojunction system to generate reactive oxygen species that effectively inactivate both bacteria and viruses through oxidation, replacing the ion-release mechanism of silver/zinc with a photocatalytic oxidation mechanism

Inventive Principle:
Principle #38Strong oxidants (Accelerated oxidation)

3Object-affected harmful factors

If titanium oxide photocatalyst is used, then cost-effective and ecologically safe antibacterial material can be obtained, but persistence of antibacterial performance is insufficient

Engineering Contradiction:
ImproveecotoxicityVSAvoidpersistence of antibacterial performance
Core Design Contradiction:
Object-affected harmful factorsVSDuration of action of stationary object

Solution Approach 1:

The patent constructs a TiO2-Cu2O heterojunction composite where Cu2O particles are integrated with TiO2 particles, creating a synergistic effect that enhances charge separation and extends the duration of photocatalytic activity, thereby improving the persistence of antibacterial performance

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent achieves continuous photocatalytic activity by establishing an efficient electron-hole separation mechanism in the TiO2-Cu2O heterojunction, where electrons transfer from Cu2O conduction band to TiO2 conduction band, preventing recombination and maintaining sustained reactive oxygen species generation for long-term antibacterial efficacy

Inventive Principle:
Principle #20Continuity of useful action

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 coating agent composition achieves long-lasting high antibacterial and antiviral performance in indoor environments without the need for ultraviolet light, effectively inactivating bacteria and viruses through visible light-responsive photocatalytic activity.

Implementation Method 1

a coating agent composition capable of obtaining high antibacterial properties and antiviral properties... photocatalyst particles composed of a metal oxide in which an upper end potential of a valence band is 3 V (vs SHE) or more and a lower end potential of a conduction band is 0.16 V (vs SHE) or less

Methodology Applied
Scientific EffectPhotoelectric effect: Photoelectric Effect

Implementation Method 2

Titanium oxide is photocatalytically active, and the antibacterial action using the photocatalytic activity thereof is attracting attention

Methodology Applied
Scientific EffectPhotocatalysis: Photo-oxidation

Data Source

PatentUS10131797B2Coating agent composition and antibacterial/antiviral member
Publication Date: 2018.11.20 PANASONIC HOUSING SOLUTIONS CO LTD

AI summary

A coating agent composition of the present invention contains photocatalyst particles composed of metal oxide in which an upper end potential of a valence band is 3 V (vs SHE) or more and a lower end potential of a conduction band is 0.16 V (vs SHE) or less. Moreover, the coating agent composition contains cuprous oxide particles, metal oxide particles without photocatalytic activity, a binder resin, and an organic solvent. Then, in 100 parts by mass of a non-volatile matter content of the coating agent composition, a content of the photocatalyst particles is 1 to 80 parts by mass, a content of the cuprous oxide particles is 0.1 to 5 parts by mass, and a total content of the photocatalyst particles and the metal oxide particles is 40 to 80 parts by mass.