High yield synthesis of boron-based nanosheets

ABSTRACT

We present the chemical exfoliation of magnesium diboride (MgB₂) by employing organic chelating agents for synthesising boron-based nanosheets in high yield. MgB₂ is a promising parent material towards realising quasi-2D forms of boron, owing to its unique layered constitution: graphenic boron planes interleaved with hexagonal arrays of Mg atoms. Chelating agents can selectively extract the interlayer Mg from MgB₂ in water, to form Mg-chelant complexes. The loss of Mg results in delamination of MgB₂ into boron-based nanosheets. This approach is further improved by rational choice of chelants with greater affinity for Mg and tuning the optimal pH for metal complexation, thereby leading to a better yield of nanosheets. These boron-based nanosheets have been explored for their candidacy as a new class of inorganic fillers in a polymeric matrix – polyvinyl alcohol (PVA). The mechanical and thermal properties of these boron-based nanosheet-PVA nanocomposite films have been studied.

KEYWORDS:

• 2D boron
• metal borides
• graphene analogues
• exfoliation
• polymer nanocomposite
• borophene

Acknowledgements

We thank Vikas Patel (SICART, Anand, India) for help with TEM imaging. We are grateful to CIPET, Ahmedabad for providing the mechanical testing facility and Bhimashankar Wangaskar (IIT Kanpur, India) for help with thermal conductivity measurement. We are thankful to IIT Gandhinagar for providing central facilities for conducting various experiments. We also thank Chetan Singh and Narendra Bandaru (with AFM), Rishi Dhawan (with Spin Coating), Sanat Maiti and Sophia Varghese (with DSC) and Pallawi Gupta (with Zeta Potential). We are also thankful to Mr. Supresh Shashikant Thaleshri and Mr. Suvakanta Barik for their help in purchasing and handling out of the chemicals.

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Rohit Saraswat http://orcid.org/0000-0001-5421-0589

Asha Liza James http://orcid.org/0000-0003-2799-0238

Kabeer Jasuja http://orcid.org/0000-0002-4332-0712

Additional information

Funding

This work was supported by Science and Engineering Research Board under Fast Track Research Grant for Young Scientists (SB/FTP/ETA-114/2013) and Core Research Grant (EMR/2017/000730); Department of Science and Technology, India under the INSPIRE Faculty Award Research Grant (DST/INSPIRE/04/2014/001601), and IIT Gandhinagar under Seed Funds.