Electroless deposition of Au/Pt/Pd nanoparticles on p-Si(111) for the light-induced hydrogen evolution reaction

• Published in: Catalysis today 2015-04, Vol.244, p.3-9
• Main Authors: Metzler, M., Thorwart, A., Zeller, S., Diemant, T., Behm, R.J., Jacob, T.
• Format: Article
• Language: English
• Subjects: Gold nanoparticles; Hydrogen evolution reaction; Metal deposition; Photoelectrochemistry; Silicon–metal-interface
• ISSN: 0920-5861; 1873-4308
• DOI: 10.1016/j.cattod.2014.10.026

•Fast and facile preparation of electroless deposited metal nanoparticles on p-Si(111).•Au/Pt (Pd) catalysts increase the activity for light-induced HER.•Thin oxide layer decouples metal particles from the silicon substrate.•Complete loss of photoactivity when Au and Pt (Pd) are deposited simultaneously.•Ohmic behavior due to silicide formation at the semiconductor–metal-interface. Electroless deposition of Au nanoparticles and submonolayer equivalents of Pt and/or Pd on p-type silicon are studied with cyclic voltammetry (CV), angle-resolved X-ray photoelectron spectroscopy (AR-XPS) and tapping-mode atomic force microscopy (TM-AFM). The controlled variation of deposition parameters influences the semiconductor/metal interface and the corresponding (photo)electrochemical behavior. The light-induced hydrogen evolution reaction (HER) serves as a model reaction for revealing the distinct changes in the electrode properties dependent on the plating procedure. Improved photoelectrocatalytic activity is observed for Au particles on silicon when decorated with small amounts of Pt (Pd) by means of an additional electroless deposition step, where simultaneous deposition of Pt and Pd leads to the best performance. However, simultaneous deposition of Au and Pt (Pd) results in a complete loss of the photocathode characteristics and therefore yields only dark currents. An interlayer of Pt/Au-silicide, identified with AR-XPS, appears to be responsible for the ohmic behavior.