High-Yield Copper Nanosheet Synthesis via Thermal Injection
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Solution Overview
Problem
The synthesis of pure copper nanosheets for catalytic applications is limited by existing methods, which often require aqueous solutions, result in low purity, stability, and yield, and are not well-established for high-yield preparation of two-dimensional Cu nanostructures for CO2 reduction reactions.
Innovation Solution
A high-temperature reduction method using a hydrophobic system with a thermal injection process, involving a reactant solution heated with oleylamine and trioctylphosphine, and injecting a copper-containing precursor to form copper nanosheets with controlled size and purity, allowing for large-scale synthesis and stability in solution for over three months.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If aqueous synthesis methods (hydrothermal route, surfactant-assisted approach, hard template method) are used to prepare Cu nanosheets, then the synthesis can be performed under mild conditions, but the purity, stability, and yield of Cu nanosheets are very limited and their size is more than a few micrometers
Solution Approach 1:
The patent changes the fundamental parameters of the synthesis system by switching from aqueous to non-aqueous solvents (ortho-dichlorobenzene, 1-octadecene) and elevating the temperature to 100-300°C. This parameter transformation enables high-yield synthesis (milligram to gram scale) while producing ultrathin nanosheets (less than 100 nm thickness) with controlled sizes (40 nm to 13 μm), directly resolving the contradiction between mild synthesis conditions and productivity
Solution Approach 2:
The patent utilizes phase transition of solvents from liquid to gas during the synthesis process. The non-aqueous solvents are heated to their boiling points (100-300°C) and maintained in a controlled phase transition state, enabling precise temperature control and high-yield nanosheet formation. This phase transition mechanism allows the reaction to proceed under controlled conditions while achieving high productivity and purity
2Device complexity
If existing methods are used to synthesize Cu nanosheets, then the process can be carried out with simple procedures, but the purity and stability of the resulting nanosheets are very limited
Solution Approach 1:
The patent introduces organic solvents (ortho-dichlorobenzene, 1-octadecene) as intermediary media that mediate between the copper precursors and the final nanosheet product. These intermediaries provide a controlled reaction environment that ensures high purity products with less than 5% aggregation and stability for over three months in solution, while maintaining relatively simple synthesis procedures
Solution Approach 2:
The patent creates an inert non-aqueous environment using organic solvents that prevent unwanted side reactions and oxidation. This inert atmosphere approach ensures the copper nanosheets maintain their purity and stability without degradation, achieving reliability without significantly complicating the synthesis procedure
3Ease of manufacture
If aqueous synthesis methods are used, then the synthesis can be performed with conventional equipment, but the size of Cu nanosheets is more than a few micrometers and their surface area percentage is limited
Solution Approach 1:
By changing the solvent system from aqueous to non-aqueous and increasing temperature to 100-300°C, the patent achieves ultrathin nanosheet formation (less than 100 nm thickness) with high surface area. The parameter changes enable conventional equipment to produce nanosheets with dramatically increased surface area compared to micrometer-scale aqueous synthesis products
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
This method enables the production of stable copper nanosheets with high surface area, enhancing their potential for catalytic applications in CO2 conversion to fuels and chemicals, and providing opportunities for studying plasmonic properties and electronic fabrication under greener conditions.
Implementation Method 1
heating a reactant solution comprising a reducing agent and one or more surfactants to a temperature of about 280° C. to about 330° C.
Implementation Method 2
injecting a hot solution of copper-containing precursor into the heated solution to form the copper nanosheet
Implementation Method 3
a reactant solution comprising oleylamine and trioctylphosphine (TOP)
Data Source
AI summary
Cu-based nanostructures have excellent catalytic, electronic, and plasmonic performance due to their unique chemical and physical properties. A range of Cu materials including foil, spherical nanoparticles, nanowires, and nanocubes have been explored for catalyzing CO2 electroreduction. However, practical application of the CO2 electroreduction reaction requires Cu catalysts hold a high percentage of exposed surface atoms for improved product selectivity. The present disclosure describes a high temperature reduction method to prepare Cu nanosheets with size range from about 40 nm to about 13 μm in a hydrophobic system. The purity of trioctyphosphine (TOP) plays an important role for shape-controlled synthesis of Cu nanosheets. The morphology evolution was investigated by adjusting the feeding molar ratio of TOP/Cu-tetradecylamine complex. The Cu nanosheets formed by the methods of the present disclosure have high surface area and stability in solution for more than three months. These Cu nanosheets have applications in reducing CO2 to fuels.