Sains Malaysiana 54(4)(2025): 1159-1166

jjhttp://doi.org/10.17576/jsm-2025-5404-15

 

 Sintesis dan Mekanisme Pertumbuhan Kepingan NbS₂ yang Dihasilkan Melalui Pemendapan Wap Kimia Dibantu Garam Halida

(Synthesis and Growth Mechanism of NbS₂ Flakes Produced via Halide Salt-Assisted Chemical Vapor Deposition)

 

SYAHIRAH AHINAYADULLAH, MUHAMMAD HILMI JOHARI, MUHAMMAD FARIS MUSAWWI RUSLAN, MEGA FATMASARI, AKRAJAS ALI UMAR & ABDUL RAHMAN MOHMAD*

 

 Institut Kejuruteraan Mikro dan Nanoelektronik, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor, Malaysia

 

Diterima: 20 Ogos 2024/ Diserahkan: 9 Oktober 2024

 

Abstrak

Bahan 2-dimensi berasaskan logam peralihan dwikalkogen (TMD) terutamanya niobium disulfida (NbS₂) berpotensi diaplikasi sebagai mangkin dalam proses elektrolisis air untuk menghasilkan hidrogen. Dalam kajian ini, sintesis dan pencirian kepingan NbS₂ yang dihasilkan menggunakan teknik pemendapan wap kimia dibantu logam alkali halida akan dilaporkan. Bahan pelopor yang digunakan ialah sulfur dan campuran Nb₂O₅ dan garam halida iaitu NaCl. Suhu pertumbuhan yang dikaji ialah 840, 880 dan 920 °C. Kepingan NbS₂ dengan panjang sisi sehingga ~60 µm dan ketebalan 120-180 nm telah diperoleh. Spektrum Raman menunjukkan bahawa kepingan NbS₂ yang diperoleh pada suhu 840 °C terdiri daripada fasa 3R dan campuran 2H dan 3R. Pada suhu >840 °C, fasa yang dominan ialah 3R. Data menunjukkan bahawa kepingan NbS₂ terbentuk melalui mekanisme wap-cecair-pepejal (VLS). Tindak balas antara Nb₂O₅ dan NaCl menghasilkan NaNb_xO_y dalam fasa cecair. Titisan NaNb_xO_y kemudiannya berkumpul di permukaan dan pinggir kepingan dan diikuti proses sulfurisasi untuk menghasilkan NbS₂. Ini menyebabkan pertumbuhan berlaku secara serentak iaitu secara mengufuk dan menegak. Selain itu, data spektroskopi foto-elektron sinar-X (XPS) menunjukkan kehadiran Na₂SO₃ yang berkemungkinan besar adalah hasil sampingan daripada tindak balas antara bahan pelopor.

Kata kunci: Garam halida; logam peralihan dwikalkogen; niobium disulfida; pemendapan wap kimia

 

Abstract

Two-dimensional transition metal dichalcogenides (TMDs), particularly niobium disulfide (NbS₂) is a promising catalyst for water electrolysis to produce hydrogen. This study reports the synthesis and characterization of NbS₂ flakes prepared by metal alkali halide-assisted chemical vapor deposition technique. The precursors used were sulfur and a mixture of Nb₂O₅ and halide salt, NaCl. The growth temperatures were varied at 840, 880, and 920 °C. NbS₂ flakes with side lengths of up to ~60 µm and thicknesses of 120-180 nm were obtained. Raman spectra indicated that NbS₂ flakes prepared at 840 °C are 3R phase and a mixture of 2H and 3R phases. At temperatures >840 °C, the dominant phase is 3R. The data suggests that the NbS₂ flakes are formed via a vapor-liquid-solid (VLS) mechanism. First, the reaction between Nb₂O₅ and NaCl produced NaNb_xO_y in the liquid phase. The NaNb_xO_y droplets then accumulated on the surface and edges of the flakes, followed by a sulfurization process to form NbS₂. This resulted in simultaneous growth in horizontal and vertical directions. X-ray photoelectron spectroscopy (XPS) data showed the presence of Na₂SO₃ which is likely to be the by-product of the reaction between the precursors.

Keywords: Chemical vapor deposition; halide salt; niobium disulfide; transition metal dichalcogenides

 

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