Sonochemical-Assisted in Situ Electrochemical Synthesis of Ag/α-Fe2O3/TiO2 Nanoarrays to Harness Energy from Photoelectrochemical Water Splitting

Ibrahim Khan, Ahsanulhaq Qurashi

Research output: Contribution to journalArticlepeer-review

56 Scopus citations

Abstract

Numerous protocols in heterostructure engineering hold promise for effectively improving the optical properties of nanomaterials for energy-harvesting applications. In this work, we successfully fabricated Ag/α-Fe2O3/TiO2 heterostructures via electrochemical anodization assisted by pulse sonication. The morphological features of the silver (Ag) deposited on α-Fe2O3/TiO2 showed a layered distribution of the α-Fe2O3 nanoparticles (NPs) over the TiO2 nanotube arrays (NTAs), whereas Ag existed in a pseudocubical form. X-ray diffraction (XRD) patterns and X-ray photoelectron spectrometer (XPS) analysis validated the formation of α-Fe2O3 and anatase TiO2 crystalline phases and Ag/α-Fe2O3/TiO2 heterostructure. The diffuse reflectance spectroscopy (DRS) UV-vis spectroscopy results displayed a gradual decrease in the band gap with enhanced absorption in the visible region of the spectrum due to optically active heterostructure formation in the order Ag/α-Fe2O3/TiO2 (470 nm) > α-Fe2O3/TiO2 (424 nm) > TiO2 (386 nm). The DRS absorption spectrum of Ag/α-Fe2O3/TiO2 also exhibits a characteristic plasmon shoulder of Ag at ∼420 nm. The photocurrent density of Ag/α-Fe2O3/TiO2 (2.59 mA/cm2) is almost 2.5- and 5-fold higher than that of α-Fe2O3/TiO2 (1.05 mA/cm2) and pristine TiO2 (0.54 mA/cm2), respectively, which can be related with the plasmonic behavior of Ag and lower band gap of α-Fe2O3. The results of electron impedance spectroscopy (EIS) analysis also showed facile charge transfer in the same order observed using UV-vis spectroscopy. These results demonstrate the effectiveness of the in situ electrochemical protocol to fabricate tunable heterostructures for efficient solar-driven water splitting.

Original languageBritish English
Pages (from-to)11235-11245
Number of pages11
JournalACS Sustainable Chemistry and Engineering
Volume6
Issue number9
DOIs
StatePublished - 4 Sep 2018

Keywords

  • Ag/α-FeO/TiO
  • Photoanode
  • Photocurrent
  • Plasmonic
  • Water Oxidation

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