Waste lignocellulosic biomass-derived graphitic carbon encased bimetallic nickel‑palladium oxide nanofibers for efficient organic dye pollutant removal and antibacterial actions.

Abstract

A one-stone-for-three-bird strategy comprising lignocellulose waste management, photocatalytic toxic organic dye degradation, and anti-bacterial activity has been demonstrated using waste coconut coir derived carbon-supported NiO/PdO (NiO/PdO@C) nanocomposite. The formation of interconnected fibrous morphology with intact formation of face-centered cubic NiO and tetragonal PdO within the graphitic carbon shell in NiO/PdO@C was identified from various structural and morphological analyses. Additionally, the elemental mapping and high magnification transmission electron microscopy analyses observed the homogeneous distribution of bimetallic oxides and their complete coverage by multilayered carbon shell. After systematic structural and morphological analyses, the prepared materials were exploited as photocatalysts for the degradation of rhodamine 6G dye. The importance of NiO and PdO heterostructure formation toward overall photocatalytic activity was analyzed by performing catalytic efficiency of individual NiO@C and PdO@C nanostructures and achieving the dye removal efficiencies of 44 % and 34 %, respectively. By integrating NiO and PdO, the electron-hole charge separation was greatly increased while the electron-hole recombination was decreased, and thereby NiO/PdO@C-equipped catalysis degraded 94 % of rhodamine 6G dye within 20 min. Furthermore, similar to photocatalytic activity, the NiO/PdO@C also exhibited exceptional anti-bacterial activity against Klebsiella pneumonia (K. pneumonia), Pseudomonas aeruginosa (P. aeruginosa), and Staphylococcus aureus (S. aureus) bacteria.