g-C3N4/CuFeO2 Photocatalyst Composite for Plastic-to-Hydrogen Reforming
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Solution Overview
Problem
Existing photocatalytic methods for producing hydrogen from plastic waste use highly toxic or precious metal-based catalysts, which are unsustainable and costly.
Innovation Solution
A photocatalyst composite composed of non-toxic and earth-abundant elements, specifically g-C3N4/CuFeO2, is synthesized through a simple and low-cost method, utilizing an alkaline environment to produce hydrogen from hydrolyzed polyester plastics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If highly toxic photocatalysts (e.g., cadmium sulfide) or precious metal-based co-catalysts (e.g., platinum) are used, then photocatalytic hydrogen production from plastic waste can be achieved, but the technology becomes unsustainable and costly
Solution Approach 1:
The patent replaces expensive and toxic photocatalysts with low-cost, non-toxic alternatives made from abundant elements. The photocatalyst composite uses carbon nitride (g-C3N4) combined with metal oxides or hydroxides (such as TiO2, ZnO, Fe2O3, Al2O3, SiO2, or their hydroxide forms), which are earth-abundant, inexpensive, and environmentally benign materials that can be easily synthesized and discarded without harmful impact
Solution Approach 2:
The patent creates a composite photocatalyst structure by combining carbon nitride (g-C3N4) with metal oxides or hydroxides. This composite approach enhances the photocatalytic activity compared to individual components, achieving efficient hydrogen production from plastic waste while maintaining low cost and non-toxicity. The synergistic effect between g-C3N4 and the metal oxide/hydroxide components improves overall performance
2Productivity
If a photocatalyst composite is designed to work in alkaline environments with polyester plastics, then hydrogen production efficiency is enhanced, but the system complexity and preparation difficulty increase
Solution Approach 1:
The patent optimizes the photocatalyst composite by controlling the weight ratio of g-C3N4 to metal oxide/hydroxide components within 1:1 to 7:1, with 5:1 being optimal. The preparation involves simple thermal processing of melamine at 500-600°C for 2-5 hours, followed by mixing with metal salt solutions and drying. These parameter optimizations enhance hydrogen production efficiency while keeping the preparation process straightforward and avoiding excessive structural complexity
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 photocatalyst composite exhibits enhanced hydrogen production efficiency, outperforming individual components, and can oxidize plastics into valuable chemicals, demonstrating versatility in various water sources and plastic types.
Implementation Method 1
the photocatalyst composite (herein represented as photocatalyst I/photocatalyst II) can perform photocatalysis to produce hydrogen in an alkaline environment containing polyester plastics
Implementation Method 2
the photocatalyst composite can produce hydrogen under light irradiation
Implementation Method 3
uses hydrolyzed plastic as a raw material to generate hydrogen under sunlight irradiation
Implementation Method 4
the hydrolyzed plastic is degraded into economically valuable chemicals
Implementation Method 5
photocatalyst composite can perform photocatalysis to produce hydrogen
Data Source
AI summary
The present invention provides a photocatalyst composite, a method of preparing the same, and a method of producing hydrogen. The method of preparing the photocatalyst composite includes a step of preparing g-C3N4, a step of preparing CuFeO2 and a step of synthesizing g-C3N4/CuFeO2. Preparing g-C3N4 includes heating a predetermined weight of melamine at a predetermined heating rate for a predetermined time to obtain g-C3N4 powder. Preparing CuFeO2 includes hydrothermal synthesis followed by drying to obtain CuFeO2 powder. Synthesizing g-C3N4/CuFeO2 includes mixing the g-C3N4 powder and the CuFeO2 powder obtained in the previous steps with a predetermined ratio to obtain a photocatalyst composite of g-C3N4/CuFeO2 in which the photocatalyst composite has a heterogeneous structure. The method of producing hydrogen includes adding plastic to an alkaline solution to form a pretreatment solution and performing hydrogen production through a photoreforming reaction in the plastic pretreatment solution using the aforementioned photocatalyst composite.