Silver-Carbon Composite via Carbon Nanodot Reduction

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing methods for manufacturing silver nanoparticles, such as surface modification, electrochemical synthesis, and wet grinding, use toxic reducing agents like sodium borohydride and long-chain polymers like PVP, leading to environmental pollution and poor stability of the nanoparticles, making it difficult to preserve their antibacterial properties.

Innovation Solution

A method involving the creation of a silver-carbon composite by mixing a carbon-containing solution with silver ions, where carbon nanodots act as both protecting and reducing agents, eliminating the need for external agents and enhancing stability and environmental compatibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional reducing agents (sodium borohydride) and protecting agents (PVP) are used to manufacture silver nanoparticles, then silver nanoparticles can be produced with small particle sizes and antibacterial ability, but environmental pollution occurs and the nanoparticles have poor stability

Engineering Contradiction:

Improvestability of silver nanoparticlesVSAvoidenvironmental pollution from reducing agent and protecting agent

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The carbon nanodots serve as both reducing agent and protecting agent simultaneously, eliminating the need for external sodium borohydride and PVP. The carbon nanodots self-reduce silver ions to silver nanoparticles and self-protect the nanoparticles from aggregation, achieving environmental compatibility and improved stability without harmful chemicals

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The carbon nanodots perform multiple functions: they act as reducing agents to convert silver ions to silver nanoparticles, and simultaneously serve as protecting agents to prevent nanoparticle aggregation. This multi-functionality replaces the conventional separate reducing and protecting agents, resolving the contradiction between effectiveness and environmental harm

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Stability of the object's composition

If PVP is used as a protecting agent to prevent silver nanoparticle aggregation, then dispersibility is enhanced, but the long chain polymer cannot be decomposed easily in nature

Engineering Contradiction:

Improvedispersibility of silver nanoparticlesVSAvoidpersistence of PVP in environment

Core Design Contradiction:

Stability of the object's compositionVSObject-generated harmful factors

Solution Approach 1:

The carbon nanodots are derived from natural carbon-containing materials through calcination, creating environmentally benign protecting agents that can decompose in nature. Unlike persistent PVP polymers, the carbon-based protecting agents offer temporary protection during storage and then degrade harmlessly, resolving the contradiction between stability and environmental persistence

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Ease of manufacture

If sodium borohydride is used as a reducing agent to reduce silver ions to silver metal, then silver nanoparticles are formed, but the reducing agent is toxic

Engineering Contradiction:

Improveefficiency of silver nanoparticle formationVSAvoidtoxicity of sodium borohydride

Core Design Contradiction:

Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The patent changes the chemical nature of the reducing agent from toxic sodium borohydride to non-toxic carbon nanodots. The carbon nanodots possess reducing capability due to their carbon structure and surface properties, enabling silver ion reduction without introducing toxicity. This parameter change in the reducing agent's chemical composition resolves the contradiction between manufacturing efficiency and safety

Inventive Principle:

Principle #35Parameter changes

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 silver-carbon composite exhibits improved stability and antibacterial properties, allowing for the production of an effective antibacterial liquid with enhanced environmental and biocompatibility, capable of broad applications including disinfection of living items.

Implementation Method 1

at least one of the silver ions is reduced on at least one of the carbon nanodots

Methodology Applied

Scientific EffectReduction: Reduction

Implementation Method 2

The mixed solution is heated, such that at least one of the silver ions is reduced on at least one of the carbon nanodots

Methodology Applied

Scientific EffectHeating: Heating

Data Source

PatentUS11466035B2Method for manufacturing silver-carbon composite

Publication Date: 2022.10.11 NAT CHENG KUNG UNIV

AI summary

A method for manufacturing a silver-carbon composite includes steps as follows. A carbon-containing solution is provided, wherein a carbon-containing material is subjected to a calcination step and is dissolved by a solvent to obtain the carbon-containing solution. The carbon-containing solution includes a plurality of carbon nanodots, and the carbon nanodots are negatively charged. A silver ion-containing solution is provided, wherein the silver ion-containing solution includes a plurality of silver ions. The carbon-containing solution and the silver ion-containing solution are mixed to obtain a mixed solution. The mixed solution is heated, such that at least one of the silver ions is reduced on at least one of the carbon nanodots to obtain the silver-carbon composite.