Graphene Membrane Photocatalytic System for Hydrogen Production

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Solution Overview

Problem

Existing photocatalytic systems using natural resources like sunlight and water to produce fuels face safety concerns due to the formation of diatomic oxygen and hydrogen gases, which inhibit catalytic activity and lead to exothermic reactions when combined, wasting chemical potential energy.

Innovation Solution

A photocatalytic system comprising a graphene layer with a light-absorbing complex and an electron donor, where the graphene layer separates two reservoirs to prevent oxygen and hydrogen gases from mixing, allowing for the efficient catalysis of diatomic hydrogen gas formation and storage of chemical potential energy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If photosystem II is used to produce diatomic hydrogen gas, then fuel production is achieved, but diatomic oxygen gas is also formed causing safety concerns and inhibiting catalytic activity

Engineering Contradiction:

Improvehydrogen production rateVSAvoidoxygen inhibition of catalytic activity

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The system divides the reaction environment into separate compartments using a graphene membrane, isolating the oxygen-evolving photosystem II from the hydrogen-producing catalytic complex. This spatial segmentation prevents oxygen from reaching and inhibiting the hydrogenase enzyme while maintaining high hydrogen production rates.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The graphene membrane acts as an intermediary barrier between the oxygen-containing and hydrogen-containing zones. It selectively transports protons while blocking oxygen and hydrogen gas molecules, enabling continuous catalytic activity by preventing harmful oxygen-hydrogen interactions.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Loss of energy

If diatomic oxygen and hydrogen gases are allowed to mix, then chemical potential energy is stored, but safety hazards increase and catalytic activity is inhibited

Engineering Contradiction:

Improvechemical potential energy storageVSAvoidsystem safety

Core Design Contradiction:

Loss of energyVSReliability

Solution Approach 1:

The system uses a graphene membrane to segment the reaction chamber into distinct oxygen and hydrogen zones, allowing chemical potential energy to be stored in separated gas reservoirs. This physical segmentation eliminates safety hazards associated with mixed oxygen-hydrogen storage while preserving the energy storage function.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The graphene membrane creates an inert barrier environment that prevents direct contact between oxygen and hydrogen gases. By maintaining physically separated zones, the system safely stores chemical potential energy without creating explosive conditions.

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

3Reliability

If a separator is introduced to prevent gas mixing, then catalytic activity is maintained and safety is improved, but device complexity increases

Engineering Contradiction:

Improvecatalytic activity stabilityVSAvoidsystem structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The system employs an atomically thin graphene membrane as the gas separator, which maintains catalytic activity stability and safety without significantly increasing device complexity. The two-dimensional flexible film integrates seamlessly into the photocatalytic system architecture, providing separation functionality with minimal structural addition.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The invention extracts only the essential separation function from complex membrane structures, using pristine graphene's inherent selective permeability properties. This extraction approach achieves effective gas separation with minimal added complexity, leveraging graphene's natural characteristics rather than requiring elaborate engineered structures.

Inventive Principle:

Principle #2Taking out (Extraction)

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 configuration prevents safety hazards and enhances the efficiency of fuel production by separating diatomic oxygen and hydrogen gases, enabling the storage and harnessing of chemical potential energy, which can be converted into electrical energy in a fuel cell.

Implementation Method 1

the graphene layer separates two reservoirs to prevent oxygen and hydrogen gases from mixing

Methodology Applied

Scientific EffectPhysical separation:

Implementation Method 2

a light-absorbing complex coupled to the first surface of the layer

Methodology Applied

Scientific EffectLight absorption: Absorption (EM radiation)

Implementation Method 3

an electron donor

Methodology Applied

Scientific EffectElectron transfer: Redox Reactions

Data Source

PatentUS10625250B2Photocatalytic systems comprising graphene and associated methods

Publication Date: 2020.04.21 PRESIDENT & FELLOWS OF HARVARD COLLEGE

AI summary

The present invention generally relates to photocatalytic systems comprising graphene and associated methods. Some embodiments are directed to systems comprising one or more layers of graphene having a first surface and a second, opposed surface. A light-absorbing complex may be associated with the first surface of the one or more graphene layers, and an electron donor complex may be associated with the light-absorbing complex. A catalytic complex may be associated with the first surface or the second surface of the one or more graphene layers. For example, the catalytic complex may catalyze the formation of hydrogen gas, NADH, and/or NADPH.