Metal-doped carbon quantum dots for catalytic discoloration of methylene blue in day light

Abstract

Carbon quantum dots (CDs) ingrained form biopolymers as photostable, biocompatible, and nontoxic fluorescence nanostructures, are superiorly applicable in different scientific disciplines. Attributing to their optoelectronic characters, CDs were interestingly exploited in environmental remediation as a catalyst under the effect of UV-light. However, the Current work represents a unique investigation for the superiority of metal-doped CDs (Pd@CDs & Ag@CDs ingrained from xanthan biopolymer) in catalytic discoloration of methylene blue (MB) under the effect of daylight. Geometrical features and mean size of CDs (7.5 nm), Pd@CDs (21.0 nm) & Ag@CDs (11.7 nm) were investigated via microscopic images and Zetasizer data. Additionally, CDs & Ag@CDs & Pd@CDs were exhibited with an observable peak at 220 nm and a broad band at 290 nm, to affirm the conjugative composition for all the nucleated dots. Catalytic performance of the prepared dots for reductive discoloration of MB in day light was followed the order of Pd@CDs > Ag@CDs ≫ CDs. Reduction percent was estimated to be 40 % for CDs, however after metal doping, the reduction percent was greatly enhanced to be 77 % and 83 %, for Ag@CDs & Pd@CDs, respectively. Kinetic studies showed that, the half time for discoloration of MB was decreased from 68.5 min with exploitation of CDs to 30.9 and 22.6 min, using Ag@CDs & Pd@CDs, respectively.