Two-dimensional gersiloxenes with tunable bandgap for photocatalytic H ₂ evolution and CO ₂ photoreduction to CO

Abstract

The discovery of graphene and graphene-like two-dimensional materials has brought fresh vitality to the field of photocatalysis. Bandgap engineering has always been an effective way to make semiconductors more suitable for specific applications such as photocatalysis and optoelectronics. Achieving control over the bandgap helps to improve the light absorption capacity of the semiconductor materials, thereby improving the photocatalytic performance. This work reports two-dimensional −H/−OH terminal-substituted siligenes (gersiloxenes) with tunable bandgap. All gersiloxenes are direct-gap semiconductors and have wide range of light absorption and suitable band positions for light driven water reduction into H ₂, and CO ₂ reduction to CO under mild conditions. The gersiloxene with the best performance can provide a maximum CO production of 6.91 mmol g ⁻¹ h ⁻¹, and a high apparent quantum efficiency (AQE) of 5.95% at 420 nm. This work may open up new insights into the discovery, research and application of new two-dimensional materials in photocatalysis.

Abstract

Solar energy conversion may provide a renewable means to store energy as fuels, although there are a limited range of suitable photocatalysts. Here authors develop germanium and silicon based 2D materials with tunable bandgaps for high-performance photocatalytic water and CO ₂ reduction.