Biomass-derived activated carbon nanocomposites with multicolor photoluminescence

Abstract

In this research work, synthesis, structural, and optical properties of activated carbon (AC) and AC/metal oxide nanocomposites (AC/ZnO and AC/Fe₃O₄) have been studied. Uniformly distributed metal oxide in AC (AC/ZnO and AC/Fe₃O₄) nanocomposites were obtained by a single-step impregnation-carbonization method, using bamboo as the biomass precursor, ZnCl₂, and FeCl₃ as chemical activating agents. The microstructural evolutions and optical characteristics of AC, and the composites have been investigated using X-ray diffraction (XRD), Raman, X-ray photoelectron spectroscopy (XPS), and photoluminescence spectroscopy. Both AC and composites exhibited broad photoluminescence (PL) emissions in the visible region. The PL emissions at 462 and 603 nm by AC were due to the radiative recombination of electron-hole pairs generated by sp² sites embedded in the sp³ matrix. However, two new emission centers in addition to the above appeared at 520 and 560 nm, in both AC/ZnO and AC/Fe₃O₄ nanocomposites. The study suggests that metal oxide formation in composites led to a new sp² cluster formation with a new energy band resulting in two additional emission centers in the green light region. This work provides a simple, cost-effective, and efficient way to develop broadband luminescent materials in visible regions with potential optical and sensing applications.

Graphical Abstract

Keywords:

• Activated carbon (AC)
• activated carbon/metal oxide nanocomposites
• multicolor photoluminescence (PL)
• emissive graphene cluster

Acknowledgments

The authors are thankful to the Central Research Facility (CRF), KIIT, Bhubaneswar, IIT Kanpur, and IIT Guwahati for providing the characterization facilities.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data and code availability statement

Data is available within the article.