Z-scheme heterojunction through interface engineering for broad spectrum photocatalytic water splitting

In this paper, we have designed the composite material of black phosphorus/tungsten nitride (BP/WN) with near-infrared light (NIR light) response as a noble-metal free photocatalyst for the first time. Modification of bulk BP by ball milling can control the band gap of the composite material to achieve efficient photocatalytic hydrogen evolution in the near-infrared region. At wider than 420 nm, and with illumination wider than 700 nm, a certain amount of hydrogen can be produced without any hole quencher. The rate of photocatalytic hydrogen evolution from pure water reaches 10.77 mu molg(-1)h(-1) under NIR light without any cocatalyst. The presence of a Z-type heterojunction effectively separates photogenerated carriers and prolongs the lifetime of photogenerated carriers, thereby enhancing the photocatalytic performance. The results indicate that BP/WN photocatalysts can provide a new approach to artificial photosynthesis and renewable energy conversion.