Silver Catalysts for CO Oxidation in Cigarette Smoke
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Solution Overview
Problem
Smoking articles produce carbon monoxide in both mainstream and sidestream smoke, which is undesirable and not effectively reduced by existing technologies.
Innovation Solution
Incorporating silver-based catalysts, comprising nanoscale particles of silver and/or silver oxide supported on oxide particles of a second metal, into cigarette components like tobacco cut filler and filter material to catalyze the conversion of carbon monoxide to carbon dioxide, reducing its concentration in mainstream smoke.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional cigarette materials are used, then the cigarette structure is simple and easy to manufacture, but carbon monoxide in smoke cannot be effectively reduced
Solution Approach 1:
The patent incorporates silver-based catalysts with specific particle size parameters (nanoscale) and composition ratios (1-70% silver by weight) into cigarette components. These parameter changes enable the catalyst to effectively reduce carbon monoxide through optimized surface area and catalytic activity, resolving the contradiction between CO reduction effectiveness and structural complexity.
Solution Approach 2:
The patent uses composite materials consisting of silver particles supported on metal oxide carriers (such as cerium oxide, aluminum oxide, or titanium oxide). This composite structure combines the high catalytic activity of silver with the stability and surface area provided by the oxide support, enabling effective CO reduction while maintaining a relatively simple cigarette structure that can be manufactured using conventional processes.
2Productivity
If silver-based catalysts are incorporated into cigarette components, then carbon monoxide conversion to carbon dioxide is enhanced, but manufacturing complexity increases
Solution Approach 1:
The silver-based catalyst is pre-incorporated into cigarette components (tobacco filler, paper, or filter) during manufacturing. This preliminary action ensures the catalyst is already in position and activated before the cigarette reaches the consumer, enabling immediate CO conversion efficiency without requiring additional activation steps or complex assembly processes during production.
Solution Approach 2:
The catalyst is distributed locally within specific cigarette components where CO generation occurs (such as in the tobacco filler or near the burning zone). This local placement optimizes CO conversion efficiency at the source while avoiding unnecessary complexity in other parts of the cigarette structure, maintaining ease of manufacture through targeted rather than universal modification.
3Reliability
If nanoscale silver particles are used as catalyst, then catalytic activity for CO oxidation is maximized, but particle aggregation and stability issues arise
Solution Approach 1:
The patent uses metal oxide materials (such as cerium oxide, aluminum oxide, or titanium oxide) as intermediary support structures for the nanoscale silver particles. These oxide supports provide a stable surface that disperses the silver particles, preventing aggregation while maintaining high surface area and catalytic activity. The oxide intermediary ensures both reliability of catalytic function and stability of particle composition throughout the cigarette's usage lifecycle.
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-based catalysts effectively reduce the amount of carbon monoxide and total particulate matter in mainstream smoke during smoking, achieving significant conversion of CO to CO2 at low temperatures.
Implementation Method 1
The silver-based catalysts, which are preferably capable of acting as both an oxidant and as a catalyst for the conversion of carbon monoxide to carbon dioxide
Implementation Method 2
capable of acting as both an oxidant and as a catalyst for the conversion of carbon monoxide to carbon dioxide
Implementation Method 3
the catalyst can be formed by mixing a solution of a silver salt with a colloidal suspension of an oxide of a second metal and then heating the mixture to decompose the silver salt to form particles of silver and/or silver oxide
Implementation Method 4
the catalyst is heated at a temperature of at least 200° C. in an atmosphere comprising an oxygen-containing gas so as to oxidize the silver to form a silver-based catalyst consisting essentially of silver oxide
Data Source
AI summary
A component of a cigarette comprises a silver-based catalyst for the conversion of carbon monoxide to carbon dioxide. The silver-based catalyst comprises particles (e.g., nanoscale or larger sized particles) of metallic silver and/or silver oxide supported in and/or on metal oxide support particles. The silver-based catalyst can be incorporated into a cigarette component such as tobacco cut filler, cigarette paper and cigarette filter material to reduce the concentration of carbon monoxide in the mainstream smoke of a cigarette during smoking. The catalyst can also be used in non-cigarette applications.