2. Potentiostatic electrodeposition of Cu. 2. O film. ⫠Synthesis of Ni nanowires: ⢠wet chemical reduction method. ⢠reduction of Ni(OH). 2 under magnetic field.
SYNTHESIS, FABRICATION AND PHOTO-ELECTROCHEMICAL STUDY OF INEXPENSIVE Cu2O FLEXIBLE PHOTOCATHODE COATED WITH A THIN FILM OF Ni NANOWIRES FOR OVERALL WATER SPLITTING Iqra Reyaz Hamdani, and Ashok N. Bhaskarwar Department of Chemical Engineering, IIT Delhi - 110016
INTRODUCTION
RESULTS
Metal oxide semiconductors have aroused great scientific and engineering interest in photocatalytic fields to solve energy and environmental problems. However, their fast electron-hole recombination rates limit their efficiencies, which can be solved by developing a metal-semiconductor heterojunction
improve charge separation at interfaces enhance light absorption increase in light harvesting efficiency
Cu2O environmentally benign ptype direct semiconductor narrow band gap of 2.17eV absorption of large part of the visible light low cost abundance of its raw materials
Cu2O – Ni Nanowires expected reduction in recombination rates Ni – a better alternative to noble metals quasi – 1D nano structures : high surface to volume ratio, Bose-Einstein condensation of excitons at lower light intenisities
Some roughness of wires is noticed Aspect ratio : 12 Both Cu2O and Ni nws are cubic in structure, with Cu2O possessing polycrystalline characteristics
Fig. 4. TEM micrograph of Ni nws
based on solar energy environmentally safe may be used on both small as well as large scale
Fig. 5. a) XRD study of Cu2O b) XRD study of Ni nws
Avg thickness: Cu2O – 1.7µ; Ni nws – 600nm • Visible light (158W/m2) • NaOH solution, pH:13
METHODOLOGY Potentiostatic electrodeposition of Cu2O film on ITO/PET substrate:
Fig. 2. Potentiostatic electrodeposition of Cu2O film Synthesis of Ni nanowires: wet chemical reduction method reduction of Ni(OH)2 under magnetic field Ni2+ + 2OH- → Ni(OH)2↓ 2Ni(OH)2 + N2H4 → 2Ni↓ + N2↑ + 4H2O
Fig .3. Working electrode Fabrication of photocathode
Deposition of Ni nanowires (600nm) on ITO/PET/Cu2O thin film Spin coating : rpm = 2000, t = 45s
Fig. 7. I-V characteristics of photocathode (a) under dark conditions (b) under illumination
DISCUSSION semiconductor- metal based photocathode was successfully fabricated and showed effective photocatalytic activity ten times increase in current density under illumination photocurrent density of 1.18µA/cm2 at 0.551V was observed
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