Opportunity
The world faces dual crises of environmental pollution and energy scarcity, driven by excessive carbon dioxide (CO₂) emissions from fossil fuel consumption and the accumulation of non-degradable microplastics in ecosystems. Conventional photocatalytic systems for CO₂ reduction suffer from low efficiency due to poor charge separation, competing hydrogen evolution reactions, and the lack of effective hole scavengers. Additionally, existing methods for microplastic degradation are energy-intensive and inefficient. This patent addresses these challenges by proposing a novel photocatalytic system that simultaneously converts CO₂ and microplastics into valuable carbon monoxide (CO) and liquid fuels, leveraging epitaxial noble metal-semiconductor heterostructures to enhance efficiency and stability.
Technology
The patent introduces a wet-chemical method to synthesize noble metal-semiconductor heterostructures (e.g., 4H Au–CdS) with precisely controlled epitaxial interfaces. The process involves forming noble metal seeds (e.g., 4H-phase gold), followed by epitaxial growth of semiconductor structures (e.g., CdS) on these seeds. The heterostructures exhibit high quantum yield (~2.64%) for plasmon-induced charge transfer, enabling efficient light absorption and electron-hole separation. The photocatalytic system utilizes these heterostructures in a strong alkaline solution (e.g., KOH) to enhance CO₂ solubility, while microplastics (e.g., polyethylene) act as hole scavengers, boosting CO production rates by over 1000× compared to traditional systems. The system achieves simultaneous CO₂ reduction and microplastic degradation into formic/acetic acid, addressing both environmental and energy challenges.
Advantages
- High Efficiency: Achieves a CO evolution rate of 1.5 L/g/hour with >24-hour stability.
- Dual-Functionality: Converts CO₂ and microplastics into CO and liquid fuels in one system.
- Superior Charge Separation: Epitaxial interfaces enable high quantum yield (2.64%) for hot-electron transfer.
- Scalable Synthesis: Wet-chemical method allows precise control over heterostructure morphology.
- Environmental Remediation: Degrades persistent microplastics (PE, PVC, PET) into usable chemicals.
Applications
- CO₂ Mitigation: Photocatalytic conversion of industrial CO₂ emissions into CO for syngas production.
- Waste Management: Degradation of microplastics in wastewater or oceanic environments.
- Renewable Energy: Solar-driven fuel production (e.g., formic acid for hydrogen storage).
- Industrial Catalysis: Noble metal-semiconductor heterostructures for other photocatalytic reactions (e.g., water splitting).
