NiFeB-assisted adsorption and activation of nitrogen to improve the photooxidation activity of zinc porphyrin.

This study effectively addresses the challenge of nitrogen adsorption and activation in photocatalytic nitrogen fixation by introducing an oxidizing co-catalyst, NiFeB hydroxides. The NiFeB hydroxides could provide reactive active sites and significantly enhance the nitrogen oxidation activity, offering a novel pathway for co-catalysts in nitrogen fixation reactions.

Sonochemical synthesis of graphitic carbon nitride-manganese oxide interfaces for enhanced photocatalytic degradation of tetracycline hydrochloride.

The present study focuses on the sonochemical synthesis of graphitic carbon nitride-manganese oxide (GCN/MnO2) nanocomposite for photocatalytic degradation of an environmentally hazardous pharmaceutical compound, tetracycline hydrochloride (TcH). The sonochemical synthesis aided in tailoring the morphology of GCN/MnO2. The characterization results of SEM/FESEM, XRD, FTIR, UV-Vis spectra, EIS, CV, etc., revealed on the morphology, composition, crystallinity, and other photo-electro-intrinsic properties of the materials. The synergy of GCN and MnO2 results in rapid electron transfer, efficient visible-light absorption, and slower electron-hole pair recombination through its photo-responsive traits against TcH. It was noted that ~ 93% TcH (20 mg L-1) degradation was achieved for 30-mg catalyst dose under light-emitting diode (LED) irradiation (9 W, 220 V) in 135-min duration. The TcH mineralization results were well fit to pseudo-first-order kinetics with a rate constant of 0.02 min-1 (R2 = 0.994). In addition, the composite possessed fair reusability for consequent cycles. Hence, the as-synthesized composite applied for photocatalysis and photoelectrocatalysis fosters a fit-for-purpose and reliable system in the decontamination of TcH in environmental samples. Graphical Abstract.

Bio-inspired honeycomb-like graphitic carbon nitride for enhanced visible light photocatalytic CO2 reduction activity.

Graphitic carbon nitride (g-C3N4) is paying attention lately owing to its interesting characteristics and substantial application in improving environmental and energy concerns. Nevertheless, the photocatalytic activity of g-C3N4 is constrained by the inertness of the surface and particle aggregation during photocatalytic activity. Herein, we report the preparation of g-C3N4 with honeycomb-like morphology (HC-C3N4) via thermal condensation of prepared SiO2 templates and dicyandiamide. The etching out of the SiO2 templates by NH4HF2 created hollow or macropores in the C3N4 matrix resulting in its structural changes. Similar, to the bulk C3N4, the HC-C3N4 exhibited higher photocatalytic CO2 reduction in hydrocarbons. This improved photocatalytic achievement is associated with higher specific surface area, excellent visible light absorption capability, higher electron donor density, easy mass diffusion of materials for surface reaction, and effective segregation of photogenerated charge carriers. Furthermore, the HC-C3N4 honeycomb structure was deposited with Ni(OH)2 clusters which showed remarkable CO2 reduction activity of 1.48 µmolh-1 g-1 of CH4 and 0.73 µmolh-1 g-1 of CH3OH generation which is 3.5 and 4.3 times higher CO2 reduction activity compared with bulk C3N4 clustered with Ni(OH)2 particles. This comprehensive study demonstrated that HC-C3N4 nanostructured polymeric semiconductor is envisaged to have great potential in the application of a variety of fields such as photocatalysis, sensor technology, and nanotechnology.

Fabrication of CdMoO4@CdS core-shell hollow superstructures as high performance visible-light driven photocatalysts.

CdMoO4@CdS core-shell hollow microspheres with the diameter of 2-3 µm were synthesized through a simple ion exchange hydrothermal method by using CdMoO4 solid microspheres as the sacrificial template in the presence of thioacetamide (TAA). Based on the detailed investigation it was found that the concentration of TAA in the starting solution affects the size of the CdS nanosheets and the hollowing process. At the TAA concentration of 0.1 M, CdMoO4@CdS core-shell hollow spheres with a CdS nanosheet thickness of 50-100 nm were obtained. The formed CdS nanosheets have a hexagonal wurtzite structure and exhibit good size uniformity and regularity. Furthermore, the photocatalytic activity of the as-prepared samples was evaluated towards degradation of Rhodomine B (RhB) aqueous dye solution under visible-light. Compared to CdMoO4 microspheres, CdMoO4@CdS core-shell hollow microspheres show enhanced photocatalytic activity. The observed photocatalytic performance was attributed to the synergetic effects of composite morphology, pore structure, and exposed two-dimensional (2D) CdS nanosheets with dominant 001 facets in CdMoO4@CdS core-shell hollow microspheres. Furthermore, the growth mechanism of CdMoO4@CdS hollow microspheres was discussed in detail.

Hydrothermal synthesis of meso/macroporous BiVO4 hierarchical particles and their photocatalytic degradation properties under visible light irradiation.

An ordered hierarchical meso/macroporous monoclinic bismuth vanadate (BiVO4) particle was fabricated for the first time by a simple two-step melamine template hydrothermal method followed by calcination. The physiochemical parameters of as-prepared porous materials were characterized by means of X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy, Raman, Barrett-Emmett-Teller, and UV-vis techniques. The nitrogen adsorption-desorption measurement and pore size distribution curve suggest that meso/macropores exist in these hierarchical microarchitectures. Further, it is found that melamine plays a significant role in the formation of porous BiVO4 particles, and when a known amount of melamine was added, the surface area and pore size of such porous BiVO4 particles were increased. The photocatalytic activities of the as-prepared hierarchical BiVO4 samples were measured for the photodegradation of Congo red aqueous dye solution under visible light irradiation. Surprisingly, the porous BiVO4 particles showed outstanding photocatalytic activities than polycrystalline BiVO4 sample. The possible enhancement of such catalytic performance has also been further discussed.

Long phosphorescent Ca2SnO4 with minuscule rare earth dopant concentration.

Rare-earth doped Ca2SnO4 phosphors were synthesized using a conventional solid state reaction method. The red phosphorescence of Eu(3+) was observed in this system with persistence time. In the as-prepared samples, the doped rare earth ions occupied both Ca and Sn sites in the host lattice. The longest phosphorescent persistence property can be achieved for the Ca2SnO4 phosphors with a 0.1% Eu dopant. Depending on the doped rare earth ions, afterglow emissions of various colors were observed.

Facile synthesis of novel hierarchical graphene-Bi2O2CO3 composites with enhanced photocatalytic performance under visible light.

A facile template-free hydrothermal approach is developed to synthesize hierarchical flower-like graphene-Bi(2)O(2)CO(3) microcomposites. The as-prepared samples were systematically characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, Fourier transform infrared spectroscopy, N(2) adsorption-desorption and UV-visible diffuse reflectance spectroscopy. The photocatalytic activity of the as-prepared samples was evaluated towards degradation of Rhodamine B (RhB) under visible light. Compared to hierarchical Bi(2)O(2)CO(3), hierarchical flower-like graphene-Bi(2)O(2)CO(3) microcomposites show enhanced photocatalytic activity. In addition, our results indicate that both the physico-chemical properties and associated photocatalytic activity of graphene-Bi(2)O(2)CO(3) composites are shown to be dependent on graphene loadings. The highest photocatalytic performance can be achieved for the graphene-Bi(2)O(2)CO(3) microcomposites with 1.0 wt% graphene. The underlying mechanism responsible for the formation of graphene-Bi(2)O(2)CO(3) composites and enhanced photoreactivity was discussed. Results from this study illustrate an entirely new approach to fabricate semiconductor composites containing graphene-bismuth with high visible-responsive photocatalytic performance.