Gold Nanostars Enable High-Performance Solar Hydrogen Peroxide Production

Star-shaped gold nanoparticles integrated with advanced photocatalysts achieve one of the highest H₂O₂ production rates reported to date.

CPLAS researchers have developed a new photocatalytic system that produces hydrogen peroxide at exceptional rates using sunlight, potentially offering a more sustainable alternative to current industrial methods.

The study, published in EES Catalysis, demonstrates how gold nanostars integrated with poly(heptazine imide) (PHI) achieve a H₂O₂ production rate of 286.95 mM g⁻¹ h⁻¹ under solar irradiation. This represents one of the highest rates reported for photocatalytic H₂O₂ synthesis and showcases the potential of plasmo-catalysis for sustainable chemical production.

Hydrogen peroxide is indispensable across industries, from semiconductor manufacturing to water treatment, yet its production has remained locked in the past. The anthraquinone process, which dominates 95% of global production, relies on fossil fuel-derived hydrogen, requires multiple energy-intensive steps, generates substantial waste, and demands complex infrastructure. Despite H₂O₂ being an environmentally friendly chemical that decomposes only to water and oxygen, its production method is anything but green.

The research team’s approach builds on previous work in plasmonic photocatalysis but introduces an important innovation: using star-shaped rather than spherical or rod-shaped gold nanoparticles. The multiple sharp tips of gold nanostars provide several advantages for photocatalytic applications.

When illuminated, these tips concentrate electromagnetic fields through localised surface plasmon resonance (LSPR), creating regions of enhanced field intensity where reactions are accelerated. The complex geometry also enables broader light absorption across the solar spectrum compared to simpler particle shapes.

The researchers note that “the enhanced performance is primarily attributed to localised surface plasmon resonance effects from the embedded gold nanostars, which significantly boost light absorption and charge separation efficiency.”

The team validated their experimental findings using time-dependent density functional theory (TDDFT) calculations. By modelling a Au₂₀ cluster interacting with PHI, they confirmed that the geometry of the gold nanostars and their electronic coupling with the semiconductor are key factors in the enhanced performance.

This theoretical work provides insights into how the system works at the molecular level:

• Plasmonic excitation generates energetic “hot” electrons
• These electrons transfer efficiently to the PHI semiconductor
• The star geometry minimises charge recombination
• Multiple tips provide numerous active sites for the reaction

The research contributes to several CPLAS objectives, including developing light-driven energy conversion at the nanoscale and creating new materials for applications in sustainable chemical production and environmental remediation.

With global H₂O₂ production exceeding 6.5 million metric tons annually, developing solar-driven alternatives could have significant environmental benefits. The new approach could potentially:

• Reduce dependence on fossil fuel-derived hydrogen
• Lower the energy requirements for H₂O₂ production
• Enable smaller-scale, distributed production facilities
• Decrease the environmental footprint of this important industrial chemical

Conclusion

This research demonstrates how thoughtful nanostructure design can significantly enhance photocatalytic performance. By combining the light-harvesting capabilities of plasmonic gold nanostars with the catalytic properties of PHI, the team has achieved H₂O₂ production rates that bring solar-driven synthesis closer to practical viability.

As efforts to decarbonise chemical manufacturing intensify, such advances in plasmo-catalysis could play an important role in developing more sustainable industrial processes.

Reference: P. Sharma, K. Evers, M. Delarmelina, A. Y. Bykov, M. Wilding, T. He, A. V. Zayats, R. A. Catlow & F. Xie, Plasmonic gold nanostars conjugated poly(heptazine imide) for photocatalytic H₂O₂ production from O₂ reduction, EES Catalysis, 2025. 5. DOI: 10.1039/D5EY00216H

This research highlight showcases work advancing the CPLAS programme grant “New perspectives in photocatalysis and near-surface chemistry: catalysis meets plasmonics”