Malaysian Journal of Analytical Sciences Vol 21 No 4 (2017): 914 - 920

DOI: https://doi.org/10.17576/mjas-2017-2104-18

 

 

 

EFFECT OF ANNEALING STRATEGY ON IMPROVED PHOTOACTIVITY OF CUPROUS OXIDE NANOWIRE PREPARED USING FACILE FABRICATION STRATEGY FOR SOLAR WATER SPLITTING

 

(Kesan Strategi Pengkalsinan Terhadap Peningkatan Fotoaktiviti Nanowayar Kuprous Oksida Yang Disediakan Menggunakan Cara Mudah Untuk Pembelahan Air Suria)

 

Mohd Nur Ikhmal Salehmin¹, Lorna Jeffery Minggu¹*, Khuzaimah Arifin¹, Mohammad Bin Kassim^1,2

 

¹Fuel Cell Institute

²School of Chemical Sciences and Food Technology, Faculty of Science and Technology

Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor, Malaysia

 

*Corresponding author:  lorna_jm@ukm.edu.my

 

 

Received: 28 November 2016; Accepted: 27 April 2017

 

 

Abstract

Cu₂O photocathode such as nanowire (NW) have shown to improve photoactivity than that nanoparticle thin film counterpart. This enhancement is attributed to enhanced photocatalytic reaction due to increase in surface active area and effective radial charge diffusion. However, the photoelectrochemical performance of reported work were rather low which need an improvement prior protection. In this study, Cu₂O nanowire photocathode was fabricated using sequential wet chemical oxidation method and annealing under inert condition. Focusing on annealing step, the transformation of precursor Cu(OH)₂ nanowire to Cu₂O nanowire undergone multistep annealing with a different ramping rate under inert condition. The highest photocurrent was then compared with photocurrent generated from Cu₂O NW prepared with direct annealing strategy. With multistep annealing, the best photoelectrochemical performance was obtained from Cu₂O NW prepared at the highest ramping rate which is 1.2 folds better than that obtained with single step annealing. The photocurrent enhancement obtained in this study was attributed to favourable morphology improving light trapping. Overall, the ampleness of material source, non-toxic, simple fabrication and excellent photocatalytic performance are the pre-requisite to realize solar hydrogen production.

 

Keywords:  cuprous oxide nanowire, photocurrent, water-splitting, hydrogen production

 

Abstrak

Fotokatod Cu₂O yang berstrukturkan nano wayar (NW) telah menunjukkan aktiviti foto yang lebih baik berbanding filem nipis. Prestasi fotomangkin yang baik ini disumbang oleh peningkatan luas permukaan yang aktif dan keberkesanan pengaliran cas. Walaubagaimanapun, prestasi fotoelektrokimia yang telah dilaporkan masih lagi rendah dan memerlukan penambahbaikan sebelum penyalutan sebagai perlindungan untuk kestabilan fotokatod. Dalam kajian ini, Cu₂O NW fotokatod telah disintesis menggunakan oksidasi kimia dan pengkalsinan dalam keadaan lengai. Pada peringkat pengkalsinan, transformasi pemula Cu(OH)₂ nanowayar kepada Cu₂O nanowayar telah melalui beberapa langkah pengkalsinan dengan kadar pengkalsinan yang berbeza. Fotoarus yang tertinggi akan dibandingkan dengan fotoarus yang terhasil daripada Cu₂O nanowayar yang disediakan menggunakan pengkalsinan terus. Pada pengkalsinan berperingkat, prestasi fotoelektrokimia yang terbaik didapati daripada Cu₂O NW yang disediakan pada kadar pengkalsinan yang paling tinggi iaitu 1.2 kali ganda lebih baik berbanding yang didapati daripada pengkalsinan terus. Peningkatan fotoarus yang terhasil daripada kajian ini telah disumbangkan oleh kesan morfologi bahan yang berkeupayaan menyerap cahaya secara efektif. Keseluruhannya, keberadaan sumber bahan yang mencukupi, tidak toksik, cara penyediaan yang mudah, serta prestasi fotomangkin yang bagus adalah keperluan untuk merealisasikan penghasilan hidrogen dari tenaga suria.

 

Kata kunci:  nanowayar kuprous oksida, fotoarus, pembelahan air, penghasilan hidrogen

 

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