Confining peroxide to make methanol: In principle, hydrogen peroxide would be an efficient oxidant for the conversion of methane to methanol under mild conditions. In practice, however, it is currently too expensive to produce the peroxide ahead of time for this purpose. Jin et al. report a catalyst system that generates and concentrates hydrogen peroxide for immediate reaction with methane. A hydrophobically coated zeolite keeps the peroxide close to the gold and palladium active site, where incoming methane is then selectively oxidized to methanol. Science , this issue p. 193