Diamond Particle Dispersion for Visible-Light CO2 Reduction
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Solution Overview
Problem
Existing CO2 reduction technologies face challenges such as high costs due to noble metal catalysts, limited reaction fields, complex production processes, and the need for high-energy inputs like ultraviolet light, while visible light-induced electron emission for reduction reactions has not been effectively applied.
Innovation Solution
A reduction device utilizing a diamond particle dispersion liquid that can be manufactured inexpensively and easily, enabling CO2 and H2O reduction to CO and H2 with visible light without external voltage, leveraging diamond particles with specific surface modifications and dispersal techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If noble metal catalysts are used for CO2 reduction, then catalytic activity is improved, but manufacturing cost increases significantly
Solution Approach 1:
The patent replaces expensive noble metal catalysts with inexpensive diamond particles that can be easily manufactured. The diamond particles are dispersed in a liquid medium to create a disposable or easily replaceable catalytic system that eliminates the need for costly precious metals while maintaining catalytic functionality for CO2 reduction reactions.
Solution Approach 2:
The patent changes the material parameter from noble metals to diamond particles, and changes the physical state from solid electrode catalysts to dispersed liquid-phase catalysts. This parameter change enables the system to achieve similar catalytic activity at much lower cost by utilizing the unique optical and catalytic properties of diamond particles in a dispersed configuration.
2Reliability
If plate-shaped electrode catalysts are used, then catalytic function is achieved, but reaction field is limited
Solution Approach 1:
The patent divides the catalyst into discrete diamond particles dispersed throughout a liquid medium, replacing the single plate-shaped electrode structure. This segmentation creates numerous small catalytic sites distributed throughout the reaction volume, dramatically increasing the effective reaction field and surface area available for CO2 reduction compared to a single planar electrode.
Solution Approach 2:
The patent transitions from a two-dimensional plate-shaped electrode surface to a three-dimensional dispersed particle system. The diamond particles are distributed throughout the liquid volume, creating catalytic activity in multiple spatial dimensions and significantly expanding the reaction field from a flat surface to a volumetric system.
3Productivity
If deep ultraviolet light is used for CO2 reduction, then reaction efficiency is improved, but energy consumption increases
Solution Approach 1:
The patent changes the optical excitation parameter from deep ultraviolet light to visible light for activating the diamond particles. This parameter change reduces the energy input required for the reduction reaction while maintaining productivity, as diamond particles can be excited by lower-energy visible light wavelengths to generate the necessary electrons for CO2 reduction.
Solution Approach 2:
The patent replaces the high-energy ultraviolet light activation mechanism with a visible light activation mechanism. This substitution reduces the energy input from the electromagnetic field while achieving the same electron emission and reduction reaction, effectively lowering energy consumption while maintaining reaction efficiency through the unique optoelectronic properties of diamond particles.
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 device achieves a wide reaction field with high reducibility, long catalyst life, and efficient production of CO and H2 using visible light, which is a low-energy and environmentally friendly energy source.
Implementation Method 1
when a diamond particle dispersion liquid is irradiated with visible light, CO2 and H2O are easily reduced to produce CO and H2 even without application of a voltage from the outside
Implementation Method 2
the diamond particles have a large specific surface area and a wide reaction field. Furthermore, the reduction device can be manufactured by an inexpensive and simple method of dispersing the diamond particles in a solution
Data Source
Figure 1~2
AI summary
Provided is a reduction device that can be manufactured inexpensively and easily, has a wide reaction field, can achieve a reduction reaction even with low energy light such as visible light, and has a long catalyst life. The reduction device of the present disclosure includes diamond particles. It is preferable to contain the diamond particles as a diamond particle dispersion liquid. The diamond particles preferably contain nanodiamond particles having a particle size of 1 µm or less. The diamond particles preferably include detonation nanodiamond particles.