(499a) SiC Photoanodes for Solar Water Splitting

AIChE 2013 Session: Nanomaterials for Hydrogen Production and Fuel Cells

Title: SiC Photoanodes
for Solar Water Splitting

Authors: C.D. Bohn, M.G. Kang, F. Sharifi, V.A. Szalai

SiC ceramics offer a rich field
for exploration for solar water splitting. 
Polytypes include 4H-SiC with a bandgap of 3.23 eV, 6H-SiC with a
bandgap of 3.05 eV and
3C-SiC with a bandgap of 2.36 eV.  Single crystal substrates of some of these
materials were obtained from commercial vendors.  The effect of nanoscale morphology and the
addition of Pt nanocrystals
at the interface between the SiC and electrolyte were
systematically investigated in a pH=7 potassium phosphate buffer under AM 1.5
illumination.  Gas chromatography
provided insight into the chemical products formed by the n-type SiC photoanodes.  Additionally, linear sweep voltammetry, impedance
spectroscopy and scanning electron microscopy were used to monitor the structural
evolution of the semiconductor surface.  Results
are discussed in the broader context of photoelectrochemical
hydrogen production and recommendations for improving the efficiency of water
splitting with SiC are proposed.

Keywords: solar water splitting, SiC, photoanode