Waveguide-Coupled Photocatalyst for Deep Light Penetration

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Solution Overview

Problem

Conventional catalytic converters and fuel cells have limited light irradiation depth, typically to the top 1% of the catalyst volume due to the dispersive nature of catalyst materials, restricting efficiency and selectivity in chemical and electrochemical processes.

Innovation Solution

A catalyst with photocatalytic sites and a waveguide system that optically couples light to semiconductor nanoparticles, allowing for precise control and enhanced efficiency and selectivity by confining light at the catalyst interface.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If conventional catalyst material is used with dispersive nature, then catalyst loading can be distributed, but light irradiation depth is limited to top 1% of total volume

Engineering Contradiction:
Improvelight irradiation depthVSAvoidcatalyst volume utilization
Core Design Contradiction:
Illumination intensityVSQuantity of substance

Solution Approach 1:

The patent introduces a waveguide as an intermediary structure that channels light directly to photocatalytic sites. The waveguide acts as a mediator between the light source and the catalyst particles, enabling deep light penetration into the catalyst layer by confining and guiding light along the waveguide structure, thus overcoming the limited irradiation depth of conventional dispersive catalysts.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent transitions from conventional bulk catalyst loading to a structured approach where photocatalytic sites are positioned on or near waveguide surfaces. This dimensional reorganization allows light to propagate along the waveguide length, illuminating catalyst sites distributed over a larger effective volume and surface area, thereby increasing overall catalyst utilization.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Productivity

If light is used to activate photocatalytic sites, then reaction efficiency and selectivity improve, but device complexity increases due to waveguide integration

Engineering Contradiction:
Improvereaction efficiencyVSAvoidwaveguide integration
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The waveguide structure serves multiple functions: it guides light to photocatalytic sites, provides a support structure for catalyst particles, and can be integrated into existing reactor designs. This multi-functionality reduces the need for separate light delivery and catalyst support systems, thereby mitigating the increase in device complexity while maintaining improved reaction efficiency.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent employs porous or structured waveguide materials that allow light penetration and catalyst particle attachment while maintaining structural integrity. The porous nature of the waveguide enables efficient light-catalyst interaction without requiring complex sealing or isolation mechanisms, thus improving productivity with moderate complexity increase.

Inventive Principle:
Principle #31Porous materials

3Use of energy by moving object

If photocatalytic sites are arranged for optical coupling with waveguide, then light utilization efficiency increases, but manufacturing precision requirements increase

Engineering Contradiction:
Improvelight utilization efficiencyVSAvoidphotocatalytic site positioning
Core Design Contradiction:
Use of energy by moving objectVSManufacturing precision

Solution Approach 1:

The patent optimizes parameters such as waveguide dimensions, catalyst particle size, and spacing to achieve effective optical coupling. By carefully selecting and adjusting these parameters, the system achieves high light utilization efficiency through enhanced light confinement and catalyst proximity, while maintaining manufacturability through standardized parameter ranges.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent achieves effective optical coupling by positioning photocatalytic sites in close proximity to the waveguide surface, where the evanescent field extends. This partial coupling approach, where not all catalyst sites need perfect alignment, achieves sufficient light utilization efficiency while reducing the stringency of manufacturing precision requirements.

Inventive Principle:
Principle #16Partial or excessive 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 system achieves efficient light utilization and reaction control, increasing the catalytic activity and selectivity in catalytic converters and fuel cells, particularly for exhaust gas treatment and hydrogen oxidation/reduction reactions.

Implementation Method 1

the photocatalytic sites are arranged for an optical coupling and for receiving the light from the waveguide

Methodology Applied
Scientific EffectOptical coupling:

Implementation Method 2

a waveguide for the light at the at least one excitation wavelength

Methodology Applied
Scientific EffectWaveguide: Waveguide (optics)

Implementation Method 3

the photocatalytic sites comprise a semiconductor material for absorbing the light at the at least one excitation wavelength

Methodology Applied
Scientific EffectLight absorption: Absorption (EM radiation)

Implementation Method 4

Catalysts of a semiconductor or metallic material are known. In photocatalysis, a catalyst is activated by light to accelerate the chemical reaction

Methodology Applied
Scientific EffectPhotocatalysis:

Data Source

PatentEP4678287A1Catalyst with photocatalytic sites and a device with the catalyst
Publication Date: 2026.01.14 TOYOTA JIDOSHA KK
  • EP4678287A1 patent drawingFigure 1~2
  • EP4678287A1 patent drawingFigure 3~4B
  • EP4678287A1 patent drawingFigure 4C~4E

AI summary

A catalyst, comprising photocatalytic sites responsive to light at at least one excitation wavelength, and a waveguide for the light at the at least one excitation wavelength, wherein the photocatalytic sites are arranged for an optical coupling and for receiving the light from the waveguide (1).