Remarkable Improvement in Photocatalytic Performance for Tannery Wastewater Processing via SnS₂ Modified with N‐Doped Carbon Quantum Dots: Synthesis, Characterization, and 4‐Nitrophenol‐Aided Cr(VI) Photoreduction

Abstract

Photocatalytic pathways are proved crucial for the sustainable production of chemicals and fuels required for a pollution‐free planet. Electron–hole recombination is a critical problem that has, so far, limited the efficiency of the most promising photocatalytic materials. Here, the efficacy of the 0D N doped carbon quantum dots (N‐CQDs) is demonstrated in accelerating the charge separation and transfer and thereby boosting the activity of a narrow‐bandgap SnS2 photocatalytic system. N‐CQDs are in situ loaded onto SnS2 nanosheets in forming N‐CQDs/SnS2 composite via an electrostatic interaction under hydrothermal conditions. Cr(VI) photoreduction rate of N‐CQDs/SnS2 is highly enhanced by engineering the loading contents of N‐CQDs, in which the optimal N‐CQDs/SnS2 with 40 mol% N‐CQDs exhibits a remarkable Cr(VI) photoreduction rate of 0.148 min−1, about 5‐time and 148‐time higher than that of SnS2 and N‐CQDs, respectively. Examining the photoexcited charges via zeta potential, X‐ray photoelectron spectroscopy (XPS), surface photovoltage, and electrochemical impedance spectra indicate that the improved Cr(VI) photodegradation rate is linked to the strong electrostatic attraction between N‐CQDs and SnS2 nanosheets in composite, which favors efficient carrier utilization. To further boost the carrier utilization, 4‐nitrophenol is introduced in this photocatalytic system and the efficiency of Cr(VI) photoreduction is further promoted.

One-pot synthesis of Cu2O/C@H-TiO2 nanocomposites with enhanced visible-light photocatalytic activity

“…The Mott-Schottky (MS) patterns of the nanocomposites are measured to investigate its at band potential and charge density, [44][45][46][47][48][49][50] as shown in Fig. 6c.…”

Immobilization of high concentration hexavalent chromium via core-shell structured lightweight aggregate: A promising soil remediation strategy

“…At a pulverized coal content of 8%, the Cr 6+ peak disappeared completely. Changes in XPS peak intensity can indicate changes in the elemental content in the sample [29,30]. The results of the XPS analysis show that Cr 6+ in LWA appears to be converted into Cr 3+ proportionately with increasing pulverized coal content.…”

A Dual‐Channel Charge Transfer Heterostructure toward Boosting Photocatalytic Hydrogen Evolution

“…The full-range XPS spectrum (Figure S6, Supporting Information) evidences that the Co 9 S 8 /CdIn 2 S 4 /Pt nanocages are composed of Co, S, Cd, In, and Pt elements. As depicted in the Co 2p spectrum of Co 9 S 8 nanocages (Figure S7a, Supporting Information), four peaks at 778.2, 780.8, 793.8, and 795.9 eV, corresponding to Co 3+ 2p 3/2 , Co 2+ 2p 3/2 , Co 3+ 2p 1/2 , and Co 2+ 2p 1/2 , [30,31] respectively. Additional two lower intensities peaks located at higher binding energies are satellite peaks.…”