Hydrogen peroxide (H₂O₂) is a versatile chemical feedstock whose industrial production relies predominantly on an energy-intensive process with a substantial environmental footprint. One alternative is to produce it using a catalyst activated by light. In an international research project involving the Max Planck Institute of Colloids and Interfaces, researchers have now developed a synthesis strategy that allows them to precisely control the spatial arrangement of ions in a carbon nitride. The resulting photocatalyst is three times as efficient as conventional green production methods. The findings have been published in Advanced Materials.