Gd3+ Encapsulation on 2D-g-C3N4 Nanostructure for Spintronics and Ultrasound Assisted Photocatalytic Applications: First-Principles and Experimental Studies.

Atomically thin two-dimensional (2D) semiconductors have high potential in optoelectronics and magneto-optics appliances due to their tunable band structures and physicochemical stability. The work demonstrates that Gd3+ incorporated 2D-g-C3N4 nanosheet (Gd3+/2D-g-C3N4 NS) is synthesized through chemisorption methodology for defect enrichment. The material characterizations reveal that the ion decoration enhances the surface area and defect concentration of the 2D sheet. The experimental observations have been further corroborated with the help of density functional theory (DFT) simulation. Spin asymmetry polarizations near the Fermi level, obtained through the partial density of states (PDOS) analyses, reveal the magnetic nature of the synthesized material, validating the room temperature ferromagnetism obtained through a vibrating-sample magnetometer (VSM). Gd3+/2D-g-C3N4 NS shows significant enhancement in saturation magnetization (Ms) experimentally and computationally compared to the pristine one. The magnetic catalyst shows 98% remediation efficiency for ultrasound-assisted visible-light-driven photodegradation of methyl orange (MO). The synergistic approach of liquid chromatography-mass spectrometry (LC-MS) analyses and DFT studies elucidates reaction intermediates and unveils the degradation mechanism. Post-characterization studies assure the stability of the magnetic catalyst through optical, chemical, magnetic, and microscopic analyses. So, the synthesized material can be proficiently used as a magnetic nanocatalyst in wastewater treatments and spin-electronics applications.

Dimensionality effects of g-C3N4 from wettability to solar light assisted self-cleaning and electrocatalytic oxygen evolution reaction.

Unique interfacial properties of 2D materials make them more functional than their bulk counterparts in a catalytic application. In the present study, bulk and 2D graphitic carbon nitride nanosheet (bulk g-C3N4 and 2D-g-C3N4 NS) coated cotton fabrics and nickel foam electrode interfaces have been applied for solar light-driven self-cleaning of methyl orange (MO) dye and electrocatalytic oxygen evolution reaction (OER), respectively. Compared to bulk, 2D-g-C3N4 coated interfaces show higher surface roughness (1.094 > 0.803) and enhanced hydrophilicity (θ âˆ¼ 32° < 62° for cotton fabric and θ âˆ¼ 25° < 54° for Ni foam substrate) due to oxygen defect induction as confirmed from morphological (HR-TEM and AFM) and interfacial (XPS) characterizations. The self-remediation efficiencies for blank and bulk/2D-g-C3N4 coated cotton fabrics are estimated through colorimetric absorbance and average intensity changes. The self-cleaning efficiency for 2D-g-C3N4 NS coated cotton fabric is 87%, whereas the blank and bulk-coated fabric show 31% and 52% efficiency. Liquid Chromatography-Mass Spectrometry (LC-MS) analysis determines the reaction intermediates for MO cleaning. 2D-g-C3N4 shows lower overpotential (108 mV) and onset potential (1.30 V) vs. RHE for 10 mA cm-2 OER current density in 0.1 M KOH. Also, the decreased charge transfer resistance (RCT = 12 Ω) and lower Tafel's slope (24 mV dec-1) of 2D-g-C3N4 make it the most efficient OER catalyst over bulk-g-C3N4 and state-of-the-art material RuO2. The pseudocapacitance behavior of OER governs the kinetics of electrode-electrolyte interaction through the electrical double layer (EDL) mechanism. The 2D electrocatalyst demonstrates long-term stability (retention ∼94%) and efficacy compared to commercial electrocatalysts.

A facile and green synthesis of Mn and P functionalized graphitic carbon nitride nanosheets for spintronics devices and enhanced photocatalytic performance under visible-light.

Manganese and phosphorus co-doped, graphitic carbon nitride (g-C3N4) nanosheet (Mn/P-g-C3N4) is prepared by facile and green calcination process of melamine (C3H6N6), manganese chloride tetrahydrate (MnCl2·4H2O), and ammonium dihydrogen phosphate ((NH4)H2PO4). The Mn/P co-doping significantly enhances magnetic values compared to pristine-g-C3N4, phosphorus-doped g-C3N4 (P-g-C3N4), and manganese-doped g-C3N4 (Mn-g-C3N4). We find that Mn/P-g-C3N4 is a half-metallic ferromagnetic material having a magnetic moment and Curie temperature of 4.51 µB and âˆ¼ 800 K, respectively. The ultraviolet-visible (UV-vis) absorption spectrum of Mn/P-g-C3N4 reveals superior absorption in broader wavelength compared to pristine-g-C3N4, P-g-C3N4, and Mn-g-C3N4. The methyl orange degradation efficiency of Mn/P-g-C3N4 photocatalyst is 94 %, which is three times more than that of pristine-g-C3N4 (29 %) and more significant than the P-g-C3N4 (46 %) and Mn-g-C3N4 (58 %). Furthermore, density functional theory (DFT) calculation explains the origin of high magnetic behavior, the boosted photocatalytic efficiency of Mn/P-g-C3N4, and the essential material properties like structure, bandgap, the density of states (DOS), and atomic level interaction. This work may be helpful for reasonably designing ferromagnetic material for spintronics devices and boosting visible-light (VL) photocatalytic performance for environmental remediation.

Lanthanum ions decorated 2-dimensional g-C3N4 for ciprofloxacin photodegradation.

The low band gap energy and high surface area two-dimensional materials allow it to tune its basic properties using surface decoration. Here, La3+ are decorated on two-dimensional graphitic carbon nitride using a simple and easily scalable chemisorption process with an adsorption capacity of 657.32 mg g-1. In the X-ray diffraction (XRD) study, the positive slope of the W-H plot elucidates the tensile strain generation (0.103) in La3+ ions decorated 2D-g-C3N4 (La3+-2D-g-C3N4). The high-resolution transmission electron microscope (HR-TEM) study and the higher ID/IG ratio (0.82) in the Raman spectroscopy study confirm the more defects intensification in La3+-2D-g-C3N4. The reduction in band gap energy for La3+-2D-g-C3N4 (from 2.83 eV to 2.21 eV) has shown a good correspondence with the band structures study as obtained from the DFT study. In the DFT study, the significant contributions of N atoms in charge transfer validate the N 1s findings from the X-ray photoelectron spectroscopy (XPS) study for La3+-2D-g-C3N4. La3+-2D-g-C3N4 shows the photodegradation efficiency (93%) of ciprofloxacin under UV irradiation, which is superior to pristine 2D-g-C3N4 (82%) as well as other g-C3N4 based nanocatalysts. Also, La3+ decoration results in enhancement (32.3%) in photodegradation kinetics rate. The degradation and kinetics studies in the presence of different scavengers ensure that the O2- and OH- radicals are mostly responsible for the ciprofloxacin photodegradation. The Liquid chromatographic-mass spectroscopy and the high-performance liquid chromatography studies confirm the photodegradation. The reusability of La3+-2D-g-C3N4 is tested up to the fifth cycle. FTIR and UV-visible absorption spectroscopy confirm the stability of the used photocatalyst.