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Nanotextured spikes of α-Fe2O3/NiFe2O4 composite for efficient photoelectrochemical oxidation of water

Hussain, S ; Sharif University of Technology | 2018

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  1. Type of Document: Article
  2. DOI: 10.1021/acs.langmuir.7b02786
  3. Publisher: American Chemical Society , 2018
  4. Abstract:
  5. We demonstrate for the first time the application of p-NiFe2O4/n-Fe2O3 composite thin films as anode materials for light-assisted electrolysis of water. The p-NiFe2O4/n-Fe2O3 composite thin films were deposited on planar fluorinated tin oxide (FTO)-coated glass as well as on 3D array of nanospike (NSP) substrates. The effect of substrate (planar FTO and 3D-NSP) and percentage change of each component (i.e., NiFe2O4 and Fe2O3) of composite was studied on photoelectrochemical (PEC) water oxidation reaction. This work also includes the performance comparison of p-NiFe2O4/n-Fe2O3 composite (planar and NSP) devices with pure hematite for PEC water oxidation. Overall, the nanostructured p-NiFe2O4/n-Fe2O3 device with equal molar 1:1 ratio of NiFe2O4 and Fe2O3 was found to be highly efficient for PEC water oxidation as compared with pure hematite, 1:2 and 1:3 molar ratios of composite. The photocurrent density of 1:1 composite thin film on planar substrate was equal to 1.07 mA/cm2 at 1.23 VRHE, which was 1.7 times higher current density as compared with pure hematite device (0.63 mA/cm2 at 1.23 VRHE). The performance of p-NiFe2O4/n-Fe2O3 composites in PEC water oxidation was further enhanced by their deposition over 3D-NSP substrate. The highest photocurrent density of 2.1 mA/cm2 at 1.23 VRHE was obtained for the 1:1 molar ratio p-NiFe2O4/n-Fe2O3 composite on NSP (NF1-NSP), which was 3.3 times more photocurrent density than pure hematite. The measured applied bias photon-to-current efficiency (ABPE) value of NF1-NSP (0.206%) was found to be 1.87 times higher than that of NF1-P (0.11%) and 4.7 times higher than that of pure hematite deposited on FTO-coated glass (0.044%). The higher PEC water oxidation activity of p-NiFe2O4/n-Fe2O3 composite thin film as compared with pure hematite is attributed to the Z-path scheme and better separation of electrons and holes. The increased surface area and greater light absorption capabilities of 3D-NSP devices result in further improvement in catalytic activities. © 2018 American Chemical Society
  6. Keywords:
  7. Anodes ; Catalyst activity ; Electrochemistry ; Glass ; Hematite ; Light absorption ; Nanocomposite films ; Oxidation ; Oxide films ; Photocurrents ; Photoelectrochemical cells ; Substrates ; Thin films ; Tin oxides ; Absorption capability ; Composite thin films ; Electrolysis of waters ; Fluorinated tin oxides ; Performance comparison ; Photo-electrochemical oxidations ; Photoelectrochemicals ; Photon-to-current efficiencies ; Nickel compounds
  8. Source: Langmuir ; Volume 34, Issue 12 , 2018 , Pages 3555-3564 ; 07437463 (ISSN)
  9. URL: https://pubs.acs.org/doi/10.1021/acs.langmuir.7b02786