Silicon is not only the most important material for photovoltaics but also a potential photocatalyst for solar hydrogen production because of its ability to generate strong photovoltages under visible light illumination. Here we evaluate the potential of nanostructured silicon particles for photocatalytic water reduction, in the presence of sacrificial electron donors. P-type silicon nanowires were synthesized by chemical etching from Al-doped silicon wafers, followed by ultrasonication. With the modification of 1% MoS2 nanosheets,the photocatalytic water reduction activity of nanowire suspension in 20 vol% aqueous formaldehyde was improved from 34 to 62 �mol�g-1h-1 under visible light. Photoelectrochemical and surface photovoltage spectroscopy data show that the MoS2 cocatalyst improves the proton reduction kinetics, and charge separation in the Si-MoS2 system. The activity of this system appears to be limited by slow hole extraction from the silicon nanoparticles. These results illustrate the promise of suspended silicon structures as components for Tandem based photocatalysts and suggest ways to improve their activity.

Suspended silicon nanowires as photocatalysts for hydrogen evolution from water under visible light

248th National Meeting (2014)

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