Synergistic Effects of Carbon Dots and Palladium Nanoparticles Enhance the Sonocatalytic Performance for Rhodamine B Degradation in the Absence of Light

Abstract

Carbon dot (CD) and palladium nanoparticle (Pd NP) composites are semiconducting materials having tremendous applications in catalysis with suitable band gaps. However, their combination with a suitable polymer matrix in sonophotocatalysis has not been explored. Herein, we have synthesized and characterized a new nanohybrid catalyst from a polyamide cross-linked CD-polymer and subsequent deposition of Pd NPs. A sonocatalytic activity of 99% rhodamine B dye degradation was achieved in mere 5 min in the dark. A model catalyst replacing CDs with benzene and other control studies revealed that the synergistic effects of CDs and Pd NPs enhance the sonocatalytic activity of the nanohybrid catalyst. Interestingly, visible light did not influence the activity significantly. Mechanistic investigations suggest that generation of reactive oxygen species on the surface of the CD–polymer initiated by ultrasound, which is further facilitated by Pd NPs, is the key for remarkable catalytic activity (a rate constant of 0.99 min –1 ). Recyclable heterogeneous catalysts under ambient conditions are promising for exploring sono-assisted dark catalysis for several avenues.

Sulphonated Carbon Dots Synthesized Through a One‐Pot, Facile and Scalable Protocol Facilitates the Preparation of Renewable Precursors Using Glucose/Levulinic Acid

“…Moreover, it is regarded as low toxicity and higher tunability and biocompatibility material [10] . These features further extend its application in photocatalysis, [11] electrocatalysis, [12] sonocatalysis, [13] photo electrocatalysis reactions for degrading organic pollutants, [14] water splitting, [15] CO 2 to CO reduction, [16] and other chemical conversions [9,17] . The key elemental species present in the material are carbon (as sp 2 /sp 3 form), oxygen, and hydrogen; they tend to engage a variety of functional groups, especially hydroxyl and carboxylic, establishing the surface functionalization and fluorescence properties [6,9,14,18] .…”

Recent Progress on Carbon Quantum Dots Based Photocatalysis

“…Selim et al synthesized a Pd-doped hybrid nanocatalyst (Pd@CD-CONH) by cross-linking carbon dots (CDs) with benzene-1,4-diamine (BDA) and doping the resulting polymer with palladium nanoparticles (Pd NPs) ( Selim et al, 2020 ). The mixture of CD-COCl, dry THF, Et 3 N, and BDA was dried at 40°C under vacuum; transferred to a sintered funnel; washed with water, hexane, and diethyl ether; dissolved in methanol, and dried again at 40°C under vacuum to make CD-CONH.…”

“… (A) TEM and (B) HR-TEM images of Pd@CD-CONH and (C) histogram. (Reproduced from Selim et al, 2020 , American Chemical Society). …”

“… (A) TEM images of Pd@CD-CONH, (B) EDAX mapping of some areas of the catalyst, (C) C, (D) O, (E) N, and (F) Pd. (Reproduced from Selim et al, 2020 , American Chemical Society). …”

Realizing Direct Conversion of Glucose to Furfurals with Tunable Selectivity Utilizing a Carbon Dot Catalyst with Dual Acids Controlled by a Biphasic Medium

“…In the past, various functionalized or metal-supported carbonaceous materials, such as graphene oxide, carbon nanotube, g-CN, carbon sphere, and activated carbon, have been exploited as heterogeneous catalysts for various organic transformations because of their cheap and easily available characteristics [34][35][36][37][38]. In recent years, the interest in exploring the applicability of the new class of low-cost carbon nanomaterial, i.e., photoluminescent carbon dots (CD) has increased among scientists because of its wide range of potential applications, including nanotherapeutics, [39] bioimaging, [40] sonocatalysis, [41] energy storage, [42] electronics, [43] and organic transformation reactions [44]. Moreover, it possesses low toxicity, high surface area, good stability, and strong quantum confinement properties.…”