Sains Malaysiana 51(10)(2022): 3251-3259

http://doi.org/10.17576/jsm-2022-5110-11

Hydrogen Production from Water Splitting using TiO₂/CoS Composite Photocatalyst

(Penghasilan Hidrogen daripada Pemisahan Air menggunakan Komposit Fotomangkin TiO₂/CoS)

MUTIA AGUSTINA¹, SITI NURUL FALAEIN MORIDON², AMILIA LINGGAWATI¹, KHUZAIMAH ARIFIN^2,*, LORNA JEFFERY MINGGU² & MOHAMMAD B. KASSIM³

¹Department of Chemistry, Faculty of Mathematic and Natural Science, University of Riau, Kampus Binawidya, Km 12.5, Simpang Baru, Pekanbaru Riau, Indonesia

²Fuel Cell Institute, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor Darul Ehsan, Malaysia

³Department of Chemical Sciences, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor Darul Ehsan, Malaysia

Diserahkan: 8 Februari 2022/Diterima: 1 Jun 2022

Abstract

Photocatalytic water splitting reaction has been considered an ideal method for hydrogen generation. In this study, a composite of TiO₂/CoS photocatalyst prepared by hydrothermal synthesis method assisted by ball milling crushing process was used. The TiO₂/CoS composites prepared with three variation compositions of 90/10, 80/20, and 70/30 were named M-10, M-20, and M-30, respectively. Field-emission scanning electron microscopy images showed that the morphologies of the composites were porous and uniform of nanospheres. The X-ray diffraction and energy dispersive spectroscopy analyses confirmed the presence of CoS in the composites. Ultraviolet–visible absorption characterization demonstrated the smallest bandgap value of approximately 2.72 eV presented by sample M-30 with the photocurrent density of 0.32 mA cm⁻² at 0.9 V vs. Ag/AgCl. The presence of CoS in this study could increase the PC hydrogen generation of TiO₂ by nearly 2.5 times. The composites forming a p-n heterojunction between TiO₂ and CoS could prevent electron–hole recombination and increase the overall photoactivity of TiO₂.

Keywords: Composite; hydrogen production; hydrothermal; water splitting

Abstrak

Tindak balas pemisahan air secara fotokatalisis telah dianggap sebagai kaedah yang ideal untuk penjanaan hidrogen dengan menggunakan semikonduktor sebagai fotomangkin. Dalam kajian ini, komposit fotomangkin TiO₂/CoS yang disediakan melalui kaedah sintesis hidroterma dibantu oleh proses penghancuran penggilingan bebola telah digunakan. Komposit TiO₂/CoS yang disediakan dengan tiga komposisi variasi 90/10, 80/20 dan 70/30 masing-masing dinamakan M-10, M-20 dan M-30. Imej mikroskopi elektron pengimbasan pelepasan medan menunjukkan bahawa morfologi komposit adalah berliang dan nanosfera yang seragam. Analisis difraksi sinar-X dan spektroskopi penyebaran tenaga mengesahkan kehadiran CoS dalam komposit. Pencirian penyerapan cahaya ultraungu-nampak menunjukkan nilai celah jalur terkecil kira-kira 2.72 eV yang ditunjukkan oleh sampel M-30 dengan ketumpatan arus foto 0.32 mA cm⁻² pada 0.9 V lwn. Ag/AgCl. Kehadiran CoS dalam kajian ini boleh meningkatkan penjanaan hidrogen PC TiO₂ sebanyak hampir 2.5 kali ganda. Komposit yang membentuk hetero-simpang p-n antara TiO₂ dan CoS boleh mengurangkan penggabungan semula lohong dan elektron serta meningkatkan keseluruhan fotoaktiviti TiO₂.

Kata kunci: Hidroterma; komposit; pemisahan air; pengeluaran hidrogen

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^*Pengarang untuk surat-menyurat; email: khuzaim@ukm.edu.my