LED-light-activated photocatalytic performance of metal-free carbon-modified hexagonal boron nitride towards degradation of methylene blue and phenol

Nirmalendu S Mishra; Pichiah Saravanan

doi:10.3762/bjnano.13.114

LED-light-activated photocatalytic performance of metal-free carbon-modified hexagonal boron nitride towards degradation of methylene blue and phenol

Beilstein J Nanotechnol. 2022 Nov 22:13:1380-1392. doi: 10.3762/bjnano.13.114. eCollection 2022.

Authors

Nirmalendu S Mishra¹, Pichiah Saravanan¹

Affiliation

¹ Environmental Nanotechnology Laboratory, Department of Environmental Science and Engineering, Indian Institute of Technology (ISM), Dhanbad-826004, Jharkhand, India.

Abstract

The present study outlines the transformation of non-photoresponsive hexagonal boron nitride (HBN) into a visible-light-responsive material. The carbon modification was achieved through a solid-state reaction procedure inside a tube furnace under nitrogen atmosphere. In comparison to HBN (bandgap of 5.2 eV), the carbon-modified boron nitride could efficiently absorb LED light irradiation with a light harvesting efficiency of ≈90% and a direct bandgap of 2 eV. The introduction of carbon into the HBN lattice led to a significant change in the electronic environment through the formation of C-B and C-N bonds which resulted in improved visible light activity, lower charge transfer resistance, and improved charge carrier density (2.97 × 10¹⁹ cm^-3). This subsequently enhanced the photocurrent density (three times) and decreased the photovoltage decay time (two times) in comparison to those of HBN. The electronic band structure (obtained through Mott-Schottky plots) and charge trapping analysis confirmed the dominance of e^-, O₂ ^-•, and ^•OH as dominant reactive oxygen species. The carbon modification could effectively remove 93.83% of methylene blue (MB, 20 ppm solution) and 48.56% of phenol (10 ppm solution) from the aqueous phase in comparison to HBN which shows zero activity in the visible region.

Keywords: LED light; carbon modification; hexagonal boron nitride (HBN); phenol; photocatalysis.

Grants and funding

Dr P. Saravanan thanks the Science and Engineering Research Board, Department of Science and Technology (DST-SERB) for the financial support received under IMPRINT with the grant code IMP/2019/000286.