Synthesis of Ni nanowires

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 

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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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