Brightly Fluorescent Zinc-Doped Red-Emitting Carbon Dots for the Sunlight-Induced Photoreduction of Cr(VI) to Cr(III)

Abstract

The present finding deals with a simple and low-cost fabrication of surface-passivated, brightly fluorescent zinc-oxide-decorated, red-emitting excitation-independent ultrafluorescent CDs, denoted as “C ZnO -Dots”. Surface doping of zinc oxide significantly improved the quantum yield by up to ∼72%, and these brightly fluorescent red-emitting C ZnO -Dots have been employed for the aqueous-phase photoreduction of 100 ppm hexavalent chromium(VI) to trivalent chromium(III) under the influence of sunlight irradiation. The overall utility of the prepared C ZnO -Dots can be ascertained by their recyclability over seven cycles.

Sunlight-induced photoreduction of Cr(VI) to Cr(III) in wastewater by nitrogen-phosphorus-doped carbon dots

“…Doping is a well-established method for articulating the optical and electrical properties of semiconductor nanoparticles. 2,4 Many reports are available stating that the doped-CD show remarkable results in terms of better quantum yield over the bluegreen 5 and red 6,7 region of the visible spectrum along with its novel applications. Few groups have reported the doping of nitrogen (N) and phosphorus (P) to form nitrogen-phosphorous doped carbon dots (NP-CD), using hydrothermal, [8][9][10] solvothermal, 11 and microwave [12][13][14][15] assisted methods with the different precursor materials.…”

“…9 Presently, the doping of the CD are used to articulate its potential properties, with a huge expectation of the exploration of its newer prospects. For instance, in the field of water treatment 18,19 via aqueous phase photocatalysis, 6,7,20 which has been barely investigated. As per the general understanding, the heavy-metal-ion contamination in water is a severe threat, which indeed demands a viable, sustainable approach for its efficient sensing followed by its removal.…”

“…21,22 The fabrication of novel nano-structured-materials with unique physical/chemical properties along with high efficiency towards the photocatalysis are the crucial step and required much attention. 6,7,18,23 Beyond the conventional existing applications of CD, the present work investigate a newer perspective of NP-CD, using the natural sunlight for photoreduction of toxic Cr(VI) to Cr(III), followed by precipitation of Cr(III) salt. The toxic nonbiodegradable 24 pollutant Cr(VI) is a well-known by-product of many industrial processes, like electroplating, paint making, leather tanning, and others, was discarded in the wastewater.…”

“…27 So the conversion of Cr(VI) to Cr(III) followed by its simple precipitation is always in high demand. Nevertheless, it could be a sustainable approach, if the same can be performed under the presence of natural sunlight 6,7,18,23 .…”

Synthesis of N-doped carbon dots and application in vanillin detection based on collisional quenching

“…1 CDs exhibit strong and tunable uorescence properties, high photostability, and unique photoluminescence behaviors. 2,3 By virtue of these distinct optical benets, CDs show a variety of applications in uorescent ink, 4 bioimaging, 5 drug delivery 6 as well as sensing. [7][8][9][10] However, the relatively low quantum yield (QY) of nonfunctionalized CDs, usually consisting of carbon and oxygen elements, is usually a limiting factor for their wider applications.…”