Efficient decontamination of toxic phenol pollutant using LaCO3OH nanowires decorated Ag3PO4 hierarchical composites mediated by metallic Ag.

With the aim to develop an eco-friendly, efficient and stable photocatalyst, the present work reports the synthesis of Ag3PO4/LaCO3OH (AP/LC) heterojunction photocatalysts. Different weight ratios of AP/(x wt% LC) were tested to find the best composition for superior photocatalytic activity for dye pollutant degradation. AP/LC (20 wt%) revealed a superior photocatalytic activity. Hence it was selected for further analyses. Furthermore, we investigated the influence of distilled water: tetrahydrofuran (DW:TF) solvent system on the morphology as well as photocatalytic activities of AP/LC (20%) heterojunction. FESEM analysis shows that the morphology of AP/LC heterojunctions varied significantly with TF:DW ratio. Sphere-shaped like nanoparticles of LC transformed into nanowires to make intimate contact with AP polyhedras. The increase of TF with respect to DW results increase in the width of wire-like dimension of LC causes loose intimate contact within AP/LC heterojunction. The photocatalytic performance of AP/LC heterojunctions were tested against degradation of toxic phenol contaminant, and the outstanding photocatalytic activity was noticed for the AP/LC-2 photocatalyst (~99% degradation in 120 min) with a rate constant, k of 1.281 × 10-2 min-1. The improved photocatalytic performance can be attributed to the uniform decoration of LC nanowires on the AP microstructure which leads to intimate interface within the heterojunction and effective charge separation. The recyclability of the AP/LC-2 photocatalysts was evaluated via replicated photocatalytic reaction trials.

BiVO4 Fern Architectures: A Competitive Anode for Lithium-Ion Batteries.

The development of high-performance anode materials for lithium-ion batteries (LIBs) is currently subject to much interest. In this study, BiVO4 fern architectures are introduced as a new anode material for LIBs. The BiVO4 fern shows an excellent reversible capacity of 769 mAh g-1 (ultrahigh volumetric capacity of 3984 mAh cm-3 ) at 0.12 A g-1 with large capacity retention. A LIB full cell is then assembled with a BiVO4 fern anode and LiFePO4 (LFP, commercial) as cathode material. The device can achieve a capacity of 140 mAh g-1 at 1C rate, that is, 81 % of the capacity of the cathode and maintained to 104 mAh g-1 at a high rate of 8C, which makes BiVO4 a promising candidate as a high-energy anode material for LIBs.

One-Pot in Situ Hydrothermal Growth of BiVO4/Ag/rGO Hybrid Architectures for Solar Water Splitting and Environmental Remediation.

BiVO4 is ubiquitously known for its potential use as photoanode for PEC-WS due to its well-suited band structure; nevertheless, it suffers from the major drawback of a slow electron hole separation and transportation. We have demonstrated the one-pot synthesis of BiVO4/Ag/rGO hybrid photoanodes on a fluorine-doped tin oxide (FTO)-coated glass substrate using a facile and cost-effective hydrothermal method. The structural, morphological, and optical properties were extensively examined, confirming the formation of hybrid heterostructures. Ternary BiVO4/Ag/rGO hybrid photoanode electrode showed enhanced PEC performance with photocurrent densities (J ph ) of ~2.25 and 5 mA/cm2 for the water and sulfate oxidation, respectively. In addition, the BiVO4/Ag/rGO hybrid photoanode can convert up to 3.5% of the illuminating light into photocurrent, and exhibits a 0.9% solar-to-hydrogen conversion efficiency. Similarly, the photocatalytic methylene blue (MB) degradation afforded the highest degradation rate constant value (k = 1.03 × 10-2 min-1) for the BiVO4/Ag/rGO hybrid sample. It is noteworthy that the PEC/photocatalytic performance of BiVO4/Ag/rGO hybrid architectures is markedly more significant than that of the pristine BiVO4 sample. The enhanced PEC/photocatalytic performance of the synthesized BiVO4/Ag/rGO hybrid sample can be attributed to the combined effects of strong visible light absorption, improved charge separation-transportation and excellent surface properties.

Growth study of hierarchical Ag3PO4/LaCO3OH heterostructures and their efficient photocatalytic activity for RhB degradation.

We have demonstrated the synthesis of Ag3PO4/LaCO3OH (APO/LCO) heterostructured photocatalysts by an in situ wet chemical method. From pre-screening evaluations of photocatalysts with APO/(x wt% LCO) composites with mass ratios of x = 5, 10, 15, 20, 25 and 30 wt%, we found that the APO/LCO (20 wt%) exhibited a superior photocatalytic activity for organic pollutant remediation. Therefore, an optimised photocatalyst APO/LCO (20 wt%) is selected for the present study and we investigate the effect of a mixed solvent system (H2O:THF) on the morphology, which has a direct effect on the photocatalytic performance. Interestingly, a profound effect on the morphological features of APO/LCO20 heterostructures was observed with variation in the ratio of the solvent system. From the FESEM study it is observed that the LCO spherical nanoparticles are transformed into nanorods with the variation of THF into the solvent system. Moreover, these LCO nanorods make intimate contact with the APO microstructures which is helpful for the improvement of the photocatalytic activity. The photocatalytic activities of the APO/LCO composites with different solvent ratios were evaluated by the degradation of rhodamine B (RhB) under visible light irradiation. Excellent photocatalytic activity was observed for the APO/LCO-2 (H2O : THF = 60 : 40) sample. This might be due to uniform covering of the APO microstructures by fine LCO rod-like structures offering intimate contact between the APO and LCO and providing proper channels for the degradation reactions. Furthermore, with an increasing THF volume ratio in the reaction system there was an increase of the dimensions of the LCO rod-like structures and also a loose compactness of their uniform intimate contact between the APO/LCO heterostructures. All in all, the enhanced photocatalytic activity of the APO/LCO heterostructures is attributed to the collective co-catalytic effect of LCO, by providing accelerated charge separation through the heterojunction interface, and THF, by helping to tune the unique morphological features which eventually facilitate the photocatalysis process.

Fern-like rGO/BiVO4 Hybrid Nanostructures for High-Energy Symmetric Supercapacitor.

Herein, we demonstrate the synthesis of rGO/BiVO4 hybrid nanostructures by facile hydrothermal method. Morphological studies reveal that rGO sheets are embedded in the special dendritic fern-like structures of BiVO4. The rGO/BiVO4 hybrid architecture shows the way to a rational design of supercapacitor, since these structures enable easy access of electrolyte ions by reducing internal resistance. Considering the unique morphological features of rGO/BiVO4 hybrid nanostructures, their supercapacitive properties were investigated. The rGO/BiVO4 electrode exhibits a specific capacitance of 151 F/g at the current density of 0.15 mA/cm2. Furthermore, we have constructed rGO/BiVO4 symmetric cell which exhibits outstanding volumetric energy density of 1.6 mW h/cm3 (33.7 W h/kg) and ensures rapid energy delivery with power density of 391 mW/cm3 (8.0 kW/kg). The superior properties of symmetric supercapacitor can be attributed to the special dendritic fern-like BiVO4 morphology and intriguing physicochemical properties of rGO.

Magnetically separable Ag3PO4/NiFe2O4 composites with enhanced photocatalytic activity.

Magnetically separable Ag3PO4/NiFe2O4 (APO/NFO) composites were prepared by an in situ precipitation method. The photocatalytic activity of photocatalysts consisting of different APO/NFO mass ratios was evaluated by degradation of methylene blue (MB) under visible light irradiation. The excellent photocatalytic activity was observed using APO/NFO5 (5% NFO) composites with good cycling stability which is higher than that of pure Ag3PO4 and NiFe2O4. All the APO/NFO composites showed good magnetic behavior, which makes them magnetically separable after reaction and reusable for several experiments. Photoconductivities of pure and composite samples were examined to study the photoresponse characteristics. The current intensity greatly enhanced by loading NFO to APO. Furthermore, the photocatalytic performance of the samples is correlated with the conductivity of the samples. The enhancement in the photocatalytic activity of APO/NFO composites for MB degradation is attributed to the excellent conductivity of APO/NFO composites through the co-catalytic effect of NFO by providing accelerated charge separation through the n-n interface.