Photocatalytic Hydrogen Production Using Visible Light

Photocatalytic hydrogen production harnesses semiconductor materials to split water into hydrogen and oxygen under visible‐light irradiation. When photons with energy equal to or greater than the semiconductor bandgap are absorbed, electron–hole pairs are generated. The photogenerated electrons reduce protons to hydrogen at active surface sites, while holes oxidise water to oxygen or other oxidants. Effective visible-light photocatalysis requires a narrow bandgap for solar absorption, efficient charge separation to suppress recombination, suitable band edge positions relative to the water redox potentials and robust surface chemistry. Strategies such as defect engineering, cocatalyst loading and heterojunction construction have been employed to extend light absorption, introduce internal electric fields and accelerate interfacial charge transfer. Advances in materials design—ranging from metal sulfides and oxynitrides to carbon nitride composites—are gradually closing the gap between laboratory performance and practical application. Sustainable photocatalytic systems aim for overall water splitting without sacrificial reagents, long-term stability under continuous irradiation and scalable fabrication methods. The global significance of visible-light photocatalytic hydrogen production lies in its potential to deliver a clean, renewable fuel vector and contribute to a carbon-neutral energy economy.

Research from Nature Portfolio

Recent studies have demonstrated that distortion‐evoked oxygen doping in a metal sulfide photocatalyst can induce significant electronegativity differences between adjacent atomic sites, activating both hydrogen and oxygen evolution reactions and yielding a solar‐to‐hydrogen conversion efficiency of around 0.6% with sustained stability over 120 hours. A superhydrophilic hollow variant of this metal sulfide has been developed to drive unassisted overall water splitting in pure water, maintaining near‐unity stability throughout a full daytime cycle. In parallel, single-atom engineering of platinum protrusions on two‐dimensional sheets has doubled hydrogen evolution rates, reaching over 17 mmol g⁻¹ h⁻¹ under visible illumination with minimal platinum loading, highlighting the synergistic role of atomically precise cocatalysts in suppressing charge recombination and optimising surface reaction kinetics.

Photocatalytic Hydrogen Production Using Visible Light publication trend

The graph below shows the total number of articles in photocatalytic hydrogen production using visible light across all publications each year (not limited to Nature Index journals).

Technical terms

Bandgap: Energy difference between a semiconductor’s valence and conduction bands, determining the wavelengths of light it can absorb.

Heterojunction: Interface between two semiconductors with different band structures, engineered to drive directional charge separation.

Cocatalyst: Auxiliary material deposited on a photocatalyst surface to facilitate redox reactions, often enhancing reaction kinetics.

Apparent quantum yield: Fraction of incident photons that contribute to the desired photochemical reaction at a given wavelength.

Charge recombination: Process by which photogenerated electrons and holes recombine without producing chemical work, reducing efficiency.

Z-scheme: Photocatalytic mechanism that mimics natural photosynthesis by spatially separating oxidation and reduction sites across two coupled semiconductors.

p–n homojunction: Junction within a single semiconductor exhibiting p-type and n-type regions, creating an internal electric field to enhance charge separation.

References

1. Recent advances in photocatalytic hydrogen evolution of AgIn5S8‐based photocatalysts. Interdisciplinary Materials (2023).
2. Non-metal doping induced dual p-n charge properties in a single ZnIn2S4 crystal structure provoking charge transfer behaviors and boosting photocatalytic hydrogen generation. Applied Catalysis B Environment and Energy (2023).
3. Large electronegativity differences between adjacent atomic sites activate and stabilize ZnIn2S4 for efficient photocatalytic overall water splitting. Nature Communications (2024).
4. Protruding Pt single-sites on hexagonal ZnIn2S4 to accelerate photocatalytic hydrogen evolution. Nature Communications (2022).
5. Self-activated superhydrophilic green ZnIn2S4 realizing solar-driven overall water splitting: close-to-unity stability for a full daytime. Nature Communications (2023).