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Crystal defects are crucially important in semiconductor photocatalysis. To improve the reactivity of photocatalysts and attain desirable solar energy conversion, crystal defect engineering has gained considerable attention in real catalysts. Herein, we engineered crystal defects and mediate oxygen vacancies in host Bi2WO6 crystal lattice via varying content of Ti dopant to fabricate single-unit-cell layered structure, resulting in enhanced visible-light-driven photocatalytic efficiency. Density functional theory (DFT) calculations verified that the substitution of Bi cation in the crystal structure of Bi2WO6 can induce a new defect level, and increase the density of states (DOS) at the valence band maximum, which not only improve the charge dynamic but also the electronic conductivity. Remarkably, the single-unit-cell layers Ti-doped Bi2WO6 structure casts profoundly improved photocatalytic performance towards ceftriaxone sodium degradation, Cr(VI) reduction, and particularly higher photocatalytic H2 production rate, with a 5.8-fold increase compared to bulk Bi2WO6. Furthermore, the photoelectrochemical measurements unveil that the significantly higher charge migration and charge carrier dynamic counts for the elevated photocatalytic performance. After careful examination of experimental results, it was proved that the Ti doping mediated crystal defects, and engendered oxygen vacancies are critically important for controlling the photocatalytic performance of Bi2WO6.

Two-dimensional graphitic carbon nitrides (2D g-C3N4) are promising photocatalysts for water splitting to hydrogen due to their non-toxicity and high stability. However, the bulk g-C3N4 has some intrinsic drawbacks, such as rapid electron–hole recombination and low charge-carrier mobility, resulting in poor photocatalytic activity. Here, 2,4-diamine-6-phenyl-1,3,5-triazine was employed as a precursor to regulating the assembly of melamine and cyanuric acid in water. The resulting g-C3N4 not only improved the visible light absorption and electron–hole separation but also provided more catalytic sites for enhanced photocatalytic hydrogen evolution. The modified g-C3N4 (CNP10-H) showed a hydrogen-releasing rate of 2184 μmol·g−1·h−1, much higher than the bulk g-C3N4.

Crystal defects are crucially important in semiconductor photocatalysis. To improve the reactivity of photocatalysts and attain desirable solar energy conversion, crystal defect engineering has gained considerable attention in real catalysts. Herein, we engineered crystal defects and mediate oxygen vacancies in host Bi

In this study, we reported a novel type-I heterojunction between red phosphorus and graphitic carbon nitride under vacuum condition, which is a novel synthesis process. For preparing the red phosphorus composites, the vacuum condition is appropriate to prevent it from self-ignition. The prepared materials were analyzed with different analytic techniques for the confirmation of their heterojunctions and structure formation. The introduction of red phosphorus into graphitic carbon nitride, reduce the structural defects and increase the charge separation ability. After medication, the synthesized composite shows an enhanced photocatalytic activity against acute toxicity category-III non-color (MTSM, Metsulfuron methyl) and color (RhB), organic pollutants. The photocatalytic degradation mechanism (Mott-Schottky and VB-XPS) study reveal that red phosphorus /graphitic carbon nitride possess type-I heterojunction with enhanced catalytic behavior, due to the effective transformation of photo-generated electrons from CB of GCN to CB of RP with the help of heterojunctions and due to unmoved photo holes on VBs. Synthesized composites also maintained their performance after reused them in three cyclic form.

3-D composite materials containing nanorods of copper–biphenylamines framework at the exterior of Ag doped g-C3N4, to reduce colorless/refractory and colored organic contaminants, with prominent improvement in catalytic action was witnessed for 3-D composite 5% Ag/g-C3N4/Cu(BA), in contrast to original g-C3N4. The improved samples forced electrons colonizing in upper CB and holes colonizing in lower VB, hence improving redox reaction supremacy of the charge carriers. 5% Ag/g-C3N4/Cu(BA) can easily degrade 100% to 99.5% of MO & RhB solutions in 60 min and 73% of phenol and 57% of TCP were degraded. Whereas the degradation efficacies of 5% Ag/g-C3N4/Cu(BN), 5% Ag/g-C3N4/Cu(PD), 5% Ag/g-C3N4 and g-C3N4 are inferior related to 5% Ag/g-C3N4/Cu(BA). The resilient dynamic reactive species (O2−, h+, 1O2, OH), directly caused mineralization of MO, RhB, phenol and TCP. The kapp for 5% Ag/g-C3N4/Cu(BA) also showed superiority over other modified samples. The above results are advantageous for the expansion of a modified catalyst in a wholesale amount and its use. TEM, SEM, EDS elemental mapping, XRD, UV–vis, XPS, and VBXPS studies confirmed that Cu(BA) and 5% Ag/g-C3N4 display close communication with each other. This investigation delivers an innovative approach for extremely worthwhile composite photocatalyst enterprises for environmental remediation.

A novel and highly efficient ternary mpg-C3N4/BiVO4/TiO2 composite was successfully synthesized and characterized with regard to structure, chemical composition, optical properties and degradation application. The photocatalytic activities of as-prepared samples were evaluated by the photocatalytic decomposition of methylene blue (MB), practical effluent from alkylation and amination steps in 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) production. Compared with TiO2, BiVO4, and mpg-C3N4, the binary composites TiO2/BiVO4 and the ternary mpg-C3N4/BiVO4/TiO2 composites exhibited the higher photocatalytic activity under visible light irradiation. Compared to solo mpg-C3N4 and BiVO4, the photocatalytic efficiency of g-C3N4/TiO2/BiVO4 raised up to 94%. The catalytic activity of g-C3N4/TiO2/BiVO4 against TATB (alkylation and amination) also confirms its efficiency by creating intermediate which were detected by Q-TOF-MS. The thermal stability and photo-stability of the produced composites were investigated. From the view of practical application, mpg-C3N4/BiVO4/TiO2 displayed superior photostability after five times recycle. The mechanism research showed the fitting of band structure among BiVO4, g-C3N4, and TiO2. The presence of mpg-C3N4 and BiVO4 can notably adjust the band gap energy and the synergy effects of them can prolong the lifetime of the charge carrier.

A novel metal free, graphitic carbon nitride self-type heterojunction was successfully created. A self-type heterojunction between two different kind of graphitic carbon nitride with a promote charge separation ability, one was prepared by solvothermal using the dicyandiamide as precursor and other was prepared by direct heating from melamine precursor. This synthesis process is facile, economical and environment friendly. The confirmation of synthesis and heterojunction formation was based on the X-ray-Diffraction, Transmission electron microscopy, Scanning electron microscopy, Fourier transform infrared spectra, X-ray photoelectron spectroscopy and photocurrent. The potential difference in heterojunction between different types of g-C 3 N 4 is the main acting power for the proficient separation and transformation of photo generated charges. Degradation results indicated that, the removal of antibiotic from effluents, graphitic carbon nitride heterojunction (GCN-DM) pointedly enhanced the visible light catalytic activity over solo graphitic carbon nitride (GCN-D, GCN-M). The improved photocatalytic behaviour of heterojunction may be due to charge separation and transfer ability with prolong lifetime of photo-generated charge carrier. The results also indicated that the optical and surface area properties also play a significance role in enhancement of photo-catalytical ability of target photo-catalyst.

Hollow graphitic carbon nitride (HCN) ZrO2/g-C3N4 hybrid composites (HCN–ZR) and the target catalyst Fe/ZrO2/g-C3N4 (HCN–FZR) were prepared successfully by a solvo-thermal method and evaluated for photo-degradation of organic pollutants, i.e. MO, and herbicides, metsulfuron methyl (MTSM). These materials were characterized by a variety of techniques, including Fourier transform infrared spectroscopy, UV-vis spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, HPLC-MS and scanning electron microscopy. The characterization and degradation results showed that FZR particles are well distributed on the surface of HCN to give a photo-catalytically active material. Photodegradation split MTSM completely into a lot of intermediate products, as depicted in the HPLC-MS results. Mooring of FZR on HCN increased the surface-area and light absorption capability of HCN–FZR, due to heterojunction formation between the semiconductors, which retarded electron–hole recombination and enhanced the photo-activity.

This study focused on the fabrication of a peculiar 3D/2D ZnIn2S4/oxygen-doped graphitic carbon nitride (ZnIn2S4/SO-GCN) through a simple hydrothermal method. The flower-like morphology of hexagonal ZnIn2S4 disperse on the SO-GCN nanosheets are evidenced by XRD, scanning and transmission electron microscopy. The as-synthesized nanocomposites were intensively applied for the visible light photocatalytic removal of aqueous phase 2,4-D. The heterojunction creation and the well-developed combined interface between ZnIn2S4 and SO-GCN significantly increases its photogenerated charge separation capability. The photo-degradation mechanism disclose that the heterojunction has improved catalytic degradation activity, due to efficient transferring of photogenerated electron-holes pairs. Under visible-light irradiation, these nanocomposites showed 3–5 times higher degradation rate of 2,4-D (i.e. 0.0112/min, by 30%-ZnIn2S4/SO-GCN), as compared to solo ZnIn2S4 and SO-GCN, attributed to the composite’s synergistic effect in unique 3D/2D heterojunction, that accelerates the electron-hole separation. The h+ and •OH species contribute a noteworthy role in the degradation process of 2,4-D over 30%-ZnIn2S4/SO-GCN. In addition, the synthesized nanocomposites sustained their reusability performance in five cyclic run. Our research have implications of constructing 3D/2D nanocomposites which is beneficial for scalable solution of efficient photocatalysts.

Nanoparticles (NPs) are extensively being used in state-of-the-art nano-based therapies, modern electronics, and consumer products, so can be released into the environment with enhancement interaction with humans. Hence, the exposures to these multifunctional NPs lead to changes in protein structure and functionality, raising serious health issues. This study thoroughly investigated the interaction and adsorption of catalase (CAT) with HfO2-NPs by circular dichroism (CD), Fourier transform infrared (FTIR), absorption, and fluorescence spectroscopic techniques. The results indicate that HfO2 NPs cause fluorescence quenching in CAT by a static quenching mechanism. The negative values of Vant Hoff thermodynamic expressions (ΔH o , ΔS o , and ΔG o ) corroborate the spontaneity and exothermic nature of static quenching driven by van der Waals forces and hydrogen bonding. Also, FTIR, UV-CD, and UV–visible spectroscopy techniques confirmed that HfO2 NPs binding could induce microenvironment perturbations leading to secondary and tertiary conformation changes in CAT. Furthermore, synchronous fluorescence spectroscopy confirmed the significant changes in the microenvironment around tryptophan (Trp) residue caused by HfO2 NPs. The time depending denaturing of CAT biochemistry through HfO2-NPs was investigated by assaying catalase activity elucidates the potential toxic action of HfO2-NPs at the macromolecular level. Briefly, this provides an empathetic knowledge of the nanotoxicity and likely health effects of HfO2 NPs exposure.

Superfine paramagnetic nickel particles were synthesized by using different anionic and cation surfactants in the presence of propylene glycol. Surfactants including gum arabic, gelatin, PVP and tri-sodium citrate were used. SEM analysis proved that the morphology of nickel particles was perfectly spherical with little agglomeration. The morphology of microspheres was changed with variation of anionic and cationic surfactants, but majorly the spherical shape of nickel particles was retained. The purity of superfine nickel particles was also confirmed with EDS results which confirmed the presence of superfine nickel particles. The XRD analysis results also indicated the presence of "fcc" crystal in the superfine particles. The magnetic field analysis designated the existence of magnetic properties in synthesized superfine nickel particles. Surface area properties were also measured with the help of BET analysis which determined the enhanced catalytic property of these particles. Overall the synthesized nickel superfine microspheres possesses improved morphology and magnetic properties with the addition of PVP as surfactant as compared to gum arabic, gelatin, and tri-sodium citrate.

The flower like microrods (MR) of α-Bi2O3 defined as (MR-Bi2O3) and ultrathin g-C3N4(UT-C3N4) p-n junction was successfully prepared by loading different concentrations of UT-C3N4 over MR-Bi2O3. Their morphology and structure were thoroughly studied by XRD, SEM, XPS, TEM, UV–vis diffuse reflectance spectra, FT-IR and PL spectra. The results showed that the UT-C3N4 has been wrapped in the flower like MR-Bi2O3. The designing of the p-n junction of UT- C3N4 and MR-Bi2O3 can enhance the separation efficiency of the electron-hole pairs. The photocatalytic degradation of RhB was drastically increased by designing of the p-n junction that is due to the photogenerated electron–hole pair's separation efficiency.

Exfoliation of porous g-C3N4 has been proved a very effective way to prepare g-C3N4 nanosheets (2D layered materials). Here, we present an environment-friendly, high-efficiency and easy scale-up preparation method of curly leaf-like g-C3N4 nanosheets (CL-CN) by liquid-phase exfoliation of honeycomb-like porous g-C3N4 (HP-CN). Two-dimensional curly nanosheets have induced excellent physicochemical properties, i.e. large surface area, high fluorescence quantum efficiency, wide band gap and good water-dispersibility. The photocatalytic performance of CL-CN in degradation of RhB under visible light is much better than that of honeycomb-like porous g-C3N4 and bulk g-C3N4. The improved photocatalytic performance of CL-CN is well explained by the improved physicochemical properties and photocatalytic mechanism. In addition, CL-CN being a 2D layered material with excellent photoluminescence characteristic and non-toxic behavior can be widely applied in bio-medicine, bio-imaging and biosensors field.

In the title compound, C17H19NO4S, the terminal ethyl group is disordered over two sets of sites, with refined site occupancies of 0.536 (7) and 0.464 (7). The dihedral angle between the two aromatic rings is 81.92 (12)°. The molecular conformation is stabilized by intramolecular N—H...O and C—H...O hydrogen bonds, which generate S(6) motifs. In the crystal, molecules are linked by C—H...O hydrogen bonds, forming chains along the b axis.

The title molecule, C16H14N2O4S, adopts an L-shaped conformation, with the central C—S—N—C torsion angle being −69.1 (3)°. The two benzene rings form a dihedral angle of 89.94 (15)°. The molecular conformation may be influenced by a weak intramolecular C—H...O hydrogen bond which generates an S(6) ring motif. In the crystal, molecules are linked by N—H...O and weak C—H...O hydrogen bonds, forming chains propagating along the b axis. Weak C—H...N hydrogen bonds connect the chains into a two-dimensional network parallel to (011). The crystal studied was an inversion twin, the ratio of components being 0.7 (1):0.3 (1).