Journal article
Photoelectrocatalysis and electrocatalysis on silicon electrodes decorated with cubane-like clusters
Department of Physics, Technical University of Denmark1
Haldor Topsoe AS2
Surface Physics and Catalysis, Department of Physics, Technical University of Denmark3
Computational Atomic-scale Materials Design, Department of Physics, Technical University of Denmark4
Department of Micro- and Nanotechnology, Technical University of Denmark5
Silicon Microtechnology, Department of Micro- and Nanotechnology, Technical University of Denmark6
The influence of the cluster-core unit in cluster-decorated p-Si on photoelectrochemical (PEC) hydrogen evolution has been investigated using a homologous series of cubane-like heterobimetallic sulfide compounds. These compounds stem from the generic cluster structure A3S4 or A3BS4 (A = W, Mo; B = Co, Cu).
We find that the Mo-based (A = Mo) cluster-decorated Si photoelectrodes show higher PEC performance than otherwise equivalent W-based (A = W) cluster-decorated ones. This is consistent with higher electrocatalytic activity of the Mo-based clusters supported on n-Si when measured in the dark. The result of stability tests is that photoelectrodes decorated with clusters without Co (B not equal Co) can exhibit promising stability, whereas clusters of the structure A3CoS4 (A = W, Mo) yield photoelectrodes that are highly unstable upon illumination.
X-ray photoelectron spectroscopy (XPS) results suggest that both oxidation and material loss play a role in deactivation of the A3CoS4 materials. Additionally, we observe that the photocurrent depends linearly on the light intensity in the limiting current region, and the corresponding incident photon to current efficiency (IPCE) may reach approximately 80%.
Density functional theory (DFT) calculations of the clusters adsorbed on the hydrogen-terminated Si surface are used to estimate and compare cluster adsorption energies on the surface as well as the H-binding energies, which is a descriptor for electrocatalytic activity.
Language: | English |
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Year: | 2012 |
Pages: | 026001 |
ISSN: | 19477988 |
Types: | Journal article |
DOI: | 10.1117/1.JPE.2.026001 |
ORCIDs: | Vesborg, Peter Christian Kjærgaard , Seger, Brian , Pedersen, Thomas , Hansen, Ole , Nørskov, Jens Kehlet and Chorkendorff, Ib |