Development of MgIn₂S₄ Microflower-Embedded Exfoliated B-Doped g-C₃N₄ Nanosheets: p–n Heterojunction Photocatalysts toward Photocatalytic Water Reduction and H₂O₂ Production under Visible-Light Irradiation

Abstract

In recent years, designing a highly efficient, cost-effective, and persistent photocatalyst to annihilate world’s major ongoing challenges has been a hot topic in the research community. Herein, we have developed a microflower-like morphology of MgIn2S4 (MIS) through a simple hydrothermal method without using any surfactants. A series of MIS-modified exfoliated B-doped g-C3N4 (e-BCN) nanocomposites have been synthesized and characterized by powder X-ray diffraction, field emission scanning electron microscopy, high-resolution transmission electron microscopy, UV–vis diffuse reflectance spectroscopy, photoluminescence (PL), electrochemical impedance spectroscopy (EIS), and Mott–Schottky analyses to study their structural, optical, and electrochemical properties. The morphological analyses of MIS/e-BCN composites demonstrated that the MIS microflowers are deposited on the surface of the e-BCN nanosheet, which provides a large number of active sites to the MIS microflowers for the better adsorption of water molecules. XPS and morphological results distinctly evidenced the close interaction between e-BCN and MIS. The results from PL and EIS analyses revealed the deteriorated recombination rate of e–/h+ pairs with reduced charge-transfer resistance of MIS/e-BCN heterojunction photocatalysts. The MIS/e-BCN composite with 10 wt % of MIS (MSBCN-10) exhibited the highest photocatalytic H2 generation rate with an apparent conversion efficiency of 5.27%. A stupendous production efficiency of H2O2 was also observed for the MSBCN-10 composite in the presence of O2-saturated water and ethanol under visible-light illumination. The current study paves an astonishing strategy to design a metal sulfide-modified g-C3N4-based photocatalyst toward photocatalytic applications.

Defect Control via Compositional Engineering of Zn-Cu-In-S Alloyed QDs for Photocatalytic H2O2 Generation and Micropollutant Degradation: Affecting Parameters, Kinetics, and Insightful Mechanism

“…Fundamentally, the photoreduction of O 2 to H 2 O 2 proceeds through two pathways: (i) concerted/direct two-electron reduction process performed by the reduction of dissolved oxygen and (ii) stepwise/indirect one-electron reduction process, which involves the formation of superoxide radical, and oxidation of alcohol (i-PA) in the presence of photogenerated holes producing protons. 13 Further, the CB potential of the as-prepared photocatalysts is suitable for the oxygen reduction reaction (ORR), i.e., generation of H 2 O 2 from dissolved oxygen through both the two-electron single-step (E°= 0.68 V vs NHE) and single-electron two-step reduction processes (E°= −0.33 V vs NHE). Moreover, the featured reduction pathway is discussed in the mechanism section.…”

“…Photocatalytic oxygen reduction is a promising and green approach toward onsite H 2 O 2 generation using earth-abundant O 2 and renewable solar energy as reaction feedstock, which was chosen as the model experiment to determine the catalytic efficacy of the synthesized quantum dots. Fundamentally, the photoreduction of O 2 to H 2 O 2 proceeds through two pathways: (i) concerted/direct two-electron reduction process performed by the reduction of dissolved oxygen and (ii) stepwise/indirect one-electron reduction process, which involves the formation of superoxide radical, and oxidation of alcohol (i-PA) in the presence of photogenerated holes producing protons . Further, the CB potential of the as-prepared photocatalysts is suitable for the oxygen reduction reaction (ORR), i.e., generation of H 2 O 2 from dissolved oxygen through both the two-electron single-step ( E ° = 0.68 V vs NHE) and single-electron two-step reduction processes ( E ° = −0.33 V vs NHE).…”

“…Over the last decade and so, a wide range of photocatalytic materials have been examined toward H 2 O 2 generation, such as ZrS 3 , PEI/C 3 N 4 , Ni 2 P/CD, etc. ; similarly, several catalytic systems were also tested for antibiotic degradation, but the conversion of a laboratory-scale experiment to an industrial-scale one is still ongoing. − In this regard, the authors’ group has also made a tremendous contribution toward both H 2 O 2 production and antibiotic degradation over a wide range of materials like MIS/e-BCN, Au-ZnCr@LDH/RGO, ZnFe 2 O 4 @RGO, ZFCN, e-gCN, Ce 2 Zr 2 O 7 @RGO, TiO 2 /Au/CdS, etc. − …”

MOF-Derived Hollow Tubular In2O3/MIIIn2S4 (MII: Ca, Mn, and Zn) Heterostructures: Synergetic Charge-Transfer Mechanism and Excellent Photocatalytic Performance to Boost Activation of Small Atmospheric Molecules

“…On the other hand, the photogenerated holes gathered at the VB of HT-In 2 O 3 oxidize EtOH to generate protons (H + ), which are further utilized in H 2 O 2 production. The H 2 O 2 production mechanism for the HT-In 2 O 3 /M II In 2 S 4 heterojunction is elucidated as follows in eqs – …”

0D–2D Fe2O3/Boron-Doped g-C3N4 S-Scheme Exciton Engineering for Photocatalytic H2O2 Production and Photo-Fenton Recalcitrant-Pollutant Detoxification: Kinetics, Influencing Factors, and Mechanism

“…BCN was prepared according to the reported literature with minor adjustments. 29 First, 20 g of melamine and 1.24 g of boric acid were taken in 300 mL of distilled water (DW), stirred for nearly 30 min, and then evaporated at 100 °C for 12 h to produce a white crystalline compound, which was then calcined at 550 °C for 4 h, yielding a yellow-colored compound of B-doped g-C 3 N 4 (denoted as BCN). Thereafter, BCN was functionalized upon treatment with HCl for 12 h, and after the completion of the reaction, the slurry was washed continuously with DW until neutral pH was obtained.…”