Catalysis of solar hydrogen production by iron atoms on the surface of Fe-doped silicon carbide
The activity of silicon carbide nanowires for light-driven hydrogen production is increased 100-fold by doping with Fe. The surface of the nanowires comprises Si, C, O (OH) and Fe atoms: importantly, selective removal of surface Fe by treatment with HF removes >99% of catalytic H2 evolution activity without altering the bulk electronic properties. Laboratory experiments with an aqueous suspension of nanoparticles at pH 6.4 reveal high stability and a quantum efficiency of 11.6% at 420 nm, when iodide is used as electron donor. The results show that Fe must be a component of surface catalytic sites that include neighbouring OH functionalities, and add further assurance that scalable artificial photosynthesis can be achieved using inexpensive and abundant resources.