APPLICATIONS OF TECHNOLOGY:
- Hydrogen production for clean fuel or chemical reaction feedstock applications
- Biomass oxidation for production of high value products (eg. lactic acid, glyceric acid, dihydroxyacetone, etc.)
- Syngas production for Fischer-Tropsch process
- Reaction can occur without any external energy input other than sunlight
- Suppression of water oxidation for enhanced overall efficiency
- Potential for widespread adoption and scalability due to compatibility with silicon semiconductors
- Versatile and modular due to easy integration of different catalysts
Artificial photosynthesis to produce value-added chemicals and fuels such as hydrogen is an attractive option for expanding the world’s renewable energy supply and building a carbon-free economy. Artificial photosynthesis can be carried out using photochemical diodes in which reactions such as water splitting, biomass oxidation, and carbon dioxide fixation can occur.
While photochemical diode technology offers promising opportunities for solar driven chemical processes, there are still some limitations that exist with current architectures, such as the need for externally applied voltages, high temperatures for thermochemical reactions, and limited scalability. There is a need for development of photoelectrochemical architectures with enhanced efficiencies that do not require external voltage application.
Berkeley Lab scientists have developed a new photochemical diode design architecture that enables unassisted simultaneous oxidation of biomass and hydrogen production or carbon dioxide fixation. The photogenerated holes oxidize biomass at the photoanode and the photogenerated electrons reduce water or carbon dioxide at the photocathode. The scientists have successfully demonstrated over 5 mA/cm2 of simultaneous glycerol oxidation and hydrogen production under 1 sun illumination with no external bias using silicon photoelectrodes.
This design allows for the photochemical reactions to occur solely through the utilization of sunlight under ambient temperatures, without the need for external voltage application, making it highly energy efficient. Additionally, the design suppresses water oxidation. This ensures that all photogenerated holes are utilized for biomass oxidation, enhancing overall efficiency. The design also incorporates silicon based semiconductors, which are well studied and have a highly established industry for fabrication. This aspect can facilitate the widespread adoption and scalability of the design. Furthermore, different catalysts such as Cu, Ag, Au, and Pt, can be simply integrated into the device architecture for tuning of the photochemical reactions.
System validation in laboratory environment
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