In a quiet but consequential step forward, researchers in China have coaxed sunlight and water into producing hydrogen peroxide — one of chemistry's most versatile and widely needed compounds — without drawing a single watt from the electrical grid. The work resolves a cluster of longstanding obstacles that had kept solar-driven chemical synthesis largely theoretical: competing reactions, rapid degradation, and insufficient yield. By designing two electrodes that each guide their half of the reaction with remarkable precision, the team has demonstrated that useful molecules can be harvested fr