Graphene-Based Photocatalytic Systems for Solar Fuel Generation

Graphene, a two-dimensional sheet of sp²-hybridised carbon atoms, has emerged as a versatile platform for photocatalytic systems aiming to convert solar energy into chemical fuels. Its exceptional electrical conductivity, high surface area and tunable electronic structure facilitate efficient light absorption and charge-carrier mobility. By coupling graphene with semiconductors, metal nanoparticles or molecular catalysts, researchers have engineered heterostructures that enhance photogenerated electron–hole separation, extend light harvesting into the visible spectrum and provide active sites for redox reactions. Solar fuel generation employs these composites primarily for two processes: water splitting to produce hydrogen and carbon dioxide reduction to yield hydrocarbons or alcohols. Key strategies include doping graphene with heteroatoms to modulate its band structure, constructing three-dimensional scaffolds to alleviate light-shielding and mass-transport limitations, and decorating the surface with noble metals to exploit plasmonic effects. While fundamental studies have demonstrated high quantum efficiencies under simulated sunlight, challenges remain in scaling up synthesis, improving long-term stability and lowering production costs. Advances in this field hold promise for decentralised fuel production and greenhouse-gas mitigation, situating graphene-based photocatalysts at the forefront of sustainable energy research.

Research from Nature Portfolio

Innovative composites combining facet-oriented noble metal nanostructures with multilayer graphene have achieved overall water splitting under simulated solar illumination without sacrificial donors, attributing enhanced activity to strong metal–graphene interactions and preferential crystal orientations. Nanowire-like hybrids of transition-metal dichalcogenides and graphene have been engineered for photocatalytic CO₂ reduction to methanol, demonstrating that one-dimensional architectures foster charge transport and catalytic turnover. Furthermore, p–n heterojunctions integrating reduced graphene oxide with copper phosphate exhibit markedly improved proton reduction rates, as the intimate p–n interfaces facilitate efficient electron migration and suppress recombination, yielding high hydrogen evolution under visible light.

Graphene-Based Photocatalytic Systems for Solar Fuel Generation publication trend

The graph below shows the total number of articles in graphene-based photocatalytic systems for solar fuel generation across all publications each year (not limited to Nature Index journals).

Technical terms

Photocatalysis: A process in which light energy drives chemical reactions via a catalyst that absorbs photons and mediates redox transformations.

Heterojunction: An interface between two distinct semiconductor materials with differing band structures, promoting charge separation.

Sacrificial agent: A reagent that preferentially donates electrons or holes to prolong catalyst lifetime by mitigating recombination.

Band gap: The energy difference between the valence band and the conduction band in a semiconductor, determining light-absorption threshold.

Solar fuel: A chemical fuel produced directly from solar energy, typically hydrogen or reduced carbon species.

References

1. 111 oriented gold nanoplatelets on multilayer graphene as visible light photocatalyst for overall water splitting. Nature Communications (2016).
2. Preparation of Nanowire like WSe2-Graphene Nanocomposite for Photocatalytic Reduction of CO2 into CH3OH with the Presence of Sacrificial Agents. Scientific Reports (2017).
3. Repercussion of Solid state vs. Liquid state synthesized p-n heterojunction RGO-copper phosphate on proton reduction potential in water. Scientific Reports (2018).
4. Graphene/inorganic nanocomposites: Evolving photocatalysts for solar energy conversion for environmental remediation. Journal of Saudi Chemical Society (2022).
5. Photocatalytic CO2 Conversion into Solar Fuels Using Carbon-Based Materials—A Review. Molecules (2023).
6. Recent Progress of Three-Dimensional Graphene-Based Composites for Photocatalysis. Gels (2024).