Friday, 08 January, 2016

Nanostructured Ternary FeCrAl Oxide Photocathodes for Water Photoelectrolysis

I. Kondofersky, A. Müller, H. K. Dunn, A. Ivanova, G. Štefanić, M. Ehrensperger, C. Scheu, B. A. Parkinson, D. Fattakhova-Rohlfing, and T. Bein -
J. Am. Chem. Soc., 2016, 138 (6), pp 1860–1867, DOI: 10.1021/jacs.5b08040 (2016)

A sol-gel method for the synthesis of semiconducting FeCrAl oxide photocathodes for solar-driven hydrogen production was developed and applied for the production of meso- and macroporous layers with the overall stoichiometry Fe0.84Cr1.0Al0.16O3. Using transmission electron microscopy and energy-dispersive X-ray spectroscopy, phase separation into Fe- and Cr-rich phases was observed for both morphologies. Compared to prior work and to the mesoporous layer, the macroporous FeCrAl oxide photocathode had a significantly enhanced photo electrolysis performance, even at a very early onset potential of 1.1 V vs RHE. By optimizing the macroporous electrodes, the device reached current densities of up to 0.68 mA cm(-2) at 0.5 V vs RHE under AM 1.5 with an incident photon-to-cur-rent efficiency (IPCE) of 28% at 400 nm without the use of catalysts. Based on transient measurements, this performance increase could be attributed to an improved collection efficiency. At a potential of 0.75n V vs RHE, an electron transfer efficiency of 48.5% was determined.

Article on the journal's website