The conversion of solar energy into hydrogen energy represents a promising and green technique for addressing the energy shortage and reducing fossil fuel emissions. A research team recently developed a lead-free perovskite photocatalyst that delivers highly efficient solar energy-to-hydrogen conversion.The conversion of solar energy into hydrogen energy represents a promising and green technique for addressing the energy shortage and reducing fossil fuel emissions. A research team recently developed a lead-free perovskite photocatalyst that delivers highly efficient solar energy-to-hydrogen conversion.