Elemental bismuth-graphene heterostructures for photocatalysis from ultraviolet to infrared light

Abstract

For an optimized use of solar energy, the fabrication of photocatalysts that are sufficiently stable and responsible for harvesting full-spectrum light from ultraviolet to infrared is required to solve environmental issues and the water shortage crisis but remains a great challenge so far. Here, we show that elemental bismuth-graphene heterostructures synthesized by a solvothermal method followed by calcination have high photocatalytic activity under not only ultraviolet but also visible and even infrared light. These heterostructures are very stable after many photocatalytic cycles, and no leaching of bismuth is observed. Analysis of the morphological structures indicates that the heterostructures remain unchanged after repeated cycling, while displaying no appreciable loss in activity. Furthermore, the experimental and theoretical results demonstrate that the heterostructures have the sufficient band gap energy for simultaneously absorbing across the whole solar spectrum and producing photogenerated electrons which can be shuttled across the elemental bismuth-graphene interface, ultimately turning out to be responsible for the degradation reaction. These findings may help the development of elemental photocatalysts with compatible activities from ultraviolet to infrared regions and hence enable solar energy conversion.