Green strategy for high-efficiency and high-selectivity catalytic oxidation of alkanes is always a huge challenge for current catalysis chemistry and chemical production. Despite extensive development efforts on new catalysts for cyclohexane oxidation, current commercial processes still suffer from low conversion, poor selectivity, and excessive production of waste. We demonstrate the design and synthesis of composites made from carbon nitride (C₃N₄) and Au nanoparticles for a higher conversion efficiency of 10.54% and 100% selectivity to cyclohexanone photocatalyst systems without any oxidation or initiators under visible light for a total green oxidation of cyclohexane. C₃N₄/Au composites may provide a powerful pathway for the development of high-performance catalysts and production processes for the green chemical industry.