Synthesis and Preparation of Mono-Layer h-BN Nanopowders by Using a Combination of CVD Method with Isopropanol-Assisted Exfoliation Process

• Published in: Powder metallurgy and metal ceramics 2017, Vol.55 (9-10), p.530-540
• Main Authors: Moradi, Rasoul, Karimi-Sabet, Javad, Shariaty-Niassar, Mojtaba, Hedayat, Seyed Mahdi
• Format: Article
• Language: English
• Subjects: Anhydrides; Boron nitride; Boron oxides; Ceramics; Characterization and Evaluation of Materials; Chemical synthesis; Chemical vapor deposition; Chemistry and Materials Science; Composites; Exfoliation; Field emission; Field emission microscopy; Fourier transforms; Glass; Guanidine hydrochloride; Infrared spectroscopy; Isopropanol; Materials Science; Metallic Materials; Methods; Molecular chains; Multilayers; Nanostructure; Nanostructured Materials; Natural Materials; Organic chemistry; Platelets; Raman spectroscopy; Scanning electron microscopy; Synthesis; Ultrasonic processing; X-ray diffraction
• ISSN: 1068-1302; 1573-9066
• DOI: 10.1007/s11106-017-9836-1

An experimental study is performed to introduce a new procedure for producing single-layer hexagonal-boron nitride (h-BN) nanopowders. In our modified procedure, synthesis and exfoliation processes are employed to achieve a two-dimensional (2D) h-BN. In the first stage, h-BN nanosheets are successfully synthesized through reacting of boric anhydride (B 2 O 3 ) with guanidine hydrochloride (CH 5 N 3 ∙ HCl) in nitrogen/hydrogen (N 2 /H 2 = 90/10, v/v) atmosphere in the chemical vapor deposition (CVD) furnace. This process results in efficient synthesis of multi-layer h-BN. In fact, the product is significantly cost-effective and applicable for various purposes, such as subsequent exfoliation to obtain single-layer h-BN. In the next step, the prepared h-BN is characterized by using various methods: X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), Fourier transform infrared (FT-IR), and micro-Raman spectroscopy. Finally, the formed multi-layer h-BN nanosheets are converted into single-layer 2D h-BN through a series of solvent-assisted exfoliation experiments. According to our experimental results, the distance between h-BN layers expands through intercalating isopropanol (IP) molecules among them under ultrasonic treatment. As a result of this process, the platelets are completely separated and single-layer h-BN nanosheets are produced. Therefore, this process is recommended for the straight forward production of 2D h-BN.