Sn-doped BiOCl for photoelectrochemical activities and photocatalytic dye degradation under visible light.

In this work, bismuth oxychloride (BiOCl) and Sn-doped BiOCl (SBCl) with improved visible light photocatalytic activity were synthesized via the co-precipitation method. The XRD analysis determined the tetragonal phase of BiOCl, 1 %, 5 %, and 10 % SBCl. The crystallite sizes were in the range of 20-34 nm. These results confirmed that the Sn ion was successfully incorporated into the BiOCl lattice. This was further confirmed by FT-IR and Raman analysis. The optical properties, such as the band gap energy, were studied using UV-vis DRS. It was found that doping BiOCl with Sn has a minor effect on the band gap tuning. BET shows that the SBCl samples have acquired a larger specific surface area (14.66-42.20 m2/g) than BiOCl (13.49 m2/g). The photocatalytic performance showed that SBCl samples have higher photocatalytic activity than BiOCl in degrading Rhodamine B (RhB) dye under visible light irradiation. Among the SBCl samples, 5 % SBCl exhibited the highest photocatalytic efficiency which degraded 91.2 % of the RhB dye in 60 min. Moreover, the photoelectrochemical activities of the as-synthesized BiOCl and SBCl were investigated using linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS) in the dark and under visible light irradiation. Both studies showed that SBCl exhibits enhanced photoelectrochemical activities than BiOCl. Hence, it can be suggested that SBCl possesses visible light active properties and can be potentially used as a photocatalyst and photoelectrode material.

CO2 Adsorption on Biomass-Derived Carbons from Albizia procera Leaves: Effects of Synthesis Strategies.

CO2 capture is a useful strategy for controlling the risks associated with global warming. The design of an adsorbent is essential for clean and potentially energy-efficient adsorption-based carbon capture processes. This study reports a facile and moderately temperature single-stage combined pyrolysis and activation strategy for the synthesis of nitrogen-doped carbons for high-performance CO2 capture. Using nitrogen-rich Albizia procera leaves as the precursor and carrying out single-stage pyrolysis and activation at temperatures of 500, 600, and 700 °C in the presence NaHCO3 as an activating agent, carbons with different surface characteristics and ultrahigh weight percentage (22-25%) of nitrogen were obtained. The subtle differences in surface characteristics and nitrogen content had a bearing on the CO2 adsorption performance of the resultant adsorbents. Outstanding results were achieved, with a CO2 adsorption capacity of up to 2.5 mmol/g and a CO2 over N2 selectivities reaching 54. The isotherm results were utilized to determine the performance indicators for a practical vacuum swing adsorption process. This study provides a practical strategy for the efficient synthesis of nitrogen-doped carbons for various adsorption applications.

Reticular Chemistry for Optical Sensing of Anions.

In the last few decades, reticular chemistry has grown significantly as a field of porous crystalline molecular materials. Scientists have attempted to create the ideal platform for analyzing distinct anions based on optical sensing techniques (chromogenic and fluorogenic) by assembling different metal-containing units with suitable organic linking molecules and different organic molecules to produce crystalline porous materials. This study presents novel platforms for anion recognition based on reticular chemistry with high selectivity, sensitivity, electronic tunability, structural recognition, strong emission, and thermal and chemical stability. The key materials for reticular chemistry, Metal-Organic Frameworks (MOFs), Zeolitic Imidazolate Frameworks (ZIFs), and Covalent-Organic Frameworks (COFs), and the pre- and post-synthetic modification of the linkers and the metal oxide clusters for the selective detection of the anions, have been discussed. The mechanisms involved in sensing are also discussed.

Facile deposition of FeNi/Ni hybrid nanoflower electrocatalysts for effective and sustained water oxidation.

Bimetallic iron-nickel (FeNi) compounds are widely studied materials for the oxygen evolution reaction (OER) owing to their high electrocatalytic performance and low cost. In this work, we produced thin films of the FeNi alloy on nickel foam (NF) by using an aerosol-assisted chemical deposition (AACVD) method and examined their OER catalytic activity. The hybrid FeNi/Ni catalysts obtained after 1 and 2 h of AACVD deposition show improved charge transfer and kinetics for the OER due to the strong interface between the FeNi alloy and Ni support. The FeNi/Ni-2h catalyst has higher catalytic activity than the FeNi/Ni-1h catalyst because of its nanoflower morphology that provides a large surface area and numerous active sites for the OER. Therefore, the FeNi/Ni-2h catalyst exhibits low overpotentials of 300 and 340 mV at 50 and 500 mA cm-2 respectively, and excellent stability over 100 h, and ∼0% loss after 5000 cycles in 1 M KOH electrolyte. Furthermore, this catalyst has a small Tafel slope, low charge transfer resistance and high current exchange density and thus surpasses the benchmark IrO2 catalyst. The easy, simple, and scalable AACVD method is an effective way to develop thin film electrocatalysts with high activity and stability.

Fabrication of a Novel Co/CoO@Fe2 V4 O13 Composite Catalyst as a Photoanode for Enhanced Photoelectrochemical Water Oxidation.

Herein, the synthesis of a novel composite photocatalyst, Co/CoO@Fe2 V4 O13 , is reported by the deposition of CoO metal oxide nanoparticles on the surface of Fe2 V4 O13 bimetallic oxide. The synthesised photocatalyst exhibited a band gap of roughly 1.8 eV, rendering it responsive to the complete visible light spectrum of the sun, thereby enabling optimal absorption of solar radiation. The Co/CoO@Fe2 V4 O13 composites demonstrated an enhanced photoelectrochemical water oxidation capacity compared to pristine Fe2 V4 O13 when exposed to visible light. The enhanced performance is attributed primarily to the creation of a p-n junction at the interface of Fe2 V4 O13 and Co/CoO, as well as the Z-scheme charge transfer mechanism, which aids in the separation and transfer of photogenerated charge carriers. Light absorption by Co nanoparticles via plasmonic excitation and intra- and inter-band transitions in the composite structure is also likely, resulting in increased composite efficiency. Our findings indicate that Co/CoO@Fe2 V4 O13 composites show promising performance for solar water splitting applications and offer new perspectives for designing effective photocatalysts.

Effect of Synthetic Methodology on the Physicochemical Attributes and Electrocatalytic Activity of NiAl-LDHs for the Oxygen Evolution Reaction.

Layered double hydroxides (LDHs) are promising materials for oxygen evolution reactions (OERs), a key component of water splitting to produce hydrogen and oxygen via water electrolysis. However, the performance of LDHs can be limited by their low surface area and poor accessibility of active sites. In this work, we synthesized highly exfoliated 2D NiAl-LDHs by aqueous miscible solvent treatment method (AMOST) and compared its electrocatalytic efficiency with its analogue synthesised via slow urea hydrolysis. We demonstrate that the exfoliated 2D LDHs prepared by AMOST method have a higher surface area and more active sites than the crystalline LDHs obtained through urea hydrolysis, resulting in a superior OER activity and efficiency. The exfoliated 2D LDHs required a lower overpotential of 280 mV to reach a current density of 50 mA cm-2 and it also outperformed IrO2 , a benchmark OER catalyst, in terms of overpotential and stability. We demonstrate that the physicochemical properties of nanosheets derived from NIAl-LDH-based materials are strongly influenced by the synthetic methodology, which affects the exfoliation degree, surface area and active site density. These factors are crucial for improving the OER catalytic performance of these materials, as shown by our results.

CO2 Adsorption on Pore-Engineered Carbons Derived from Jute Sticks.

CO2 capture is a practical approach to mitigating the impacts of global warming. Adsorption-based carbon capture is a clean and potentially energy-efficient method whose performance greatly depends on adsorbent design. In this study, we explored the use of jute-derived carbon as a high-performance adsorbent for CO2 capture. The carbons were produced by pyrolyzing powdered jute sticks with NaHCO3 as an activating agent at 500-700 °C. Impressive adsorption capacities of up to 2.5 mmol ⋅ g-1 and CO2 /N2 selectivities of up to 54 were achieved by adjusting the pore size distribution and surface functionalization. Based on the isotherm results, the working capacities, regenerabilities, and potentials for CO2 separation were determined for a practical vacuum swing adsorption process. The adsorbent materials were characterized by XRD, FTIR, Raman, FESEM and N2 sorption at 77 K. This study provides a general approach for designing adsorbents for various gas-separation applications.

Zr, La-dual doped silver niobate for photocatalytic degradation of dyes under visible light irradiation.

Sol-gel-assisted synthesis of silver niobate, 1%, 5%, and 10% Zr, La-dual doped silver niobates were carried out. Analysis done using XRD showed that increasing Zr and La dual doping caused the synthesized materials to adopt an AgNbO3-like structure. This is also supported by FT-IR results. FESEM revealed that the silver niobate has a prism-like morphology while Zr, La-dual doped samples are irregular in shape. EDX mapping of the 10% Zr, La dual silver niobate confirmed the presence of Nb, Ag, Zr, and La metals. When compared with the silver niobate, the band gap energy of Zr, La-dual doped silver niobates are narrower, as shown by UV-Vis DRS measurements. It was revealed that dual doping of silver niobates with Zr and La has significantly improved the photocatalytic degradation of methylene blue (MB) and Rhodamine B (RhB) dyes. The 1% Zr, La-dual doped silver niobate showed the best photocatalytic results in terms of degrading MB while 10% Zr, La-dual doped silver niobate achieved the best performance when degrading RhB.

ZSM-5 Catalysts for MTO: Effect and Optimization of the Tetrapropylammonium Hydroxide Concentration on Synthesis and Performance.

Light olefin production from methanol using various zeolite catalysts has industrial and economic importance considering the growth of the petrochemical market. Zeolites are generally synthesized using various organic templates as structure-directing agents (SDAs). In this study, synthesis of a series of ZSM-5 zeolites was performed systematically using the microwave-assisted crystallization method, and these samples were analyzed in detail to understand the effect of the SDA concentration. Powder diffraction, N2 adsorption, scanning electron microscopy, ammonia adsorption desorption, and 27Al and 29Si NMR spectroscopies were used for the characterization. The organic SDA tetrapropyl ammonium hydroxide (TPAOH/SiO2 mole ratio = 0.0500) is found to have an optimum concentration against the silica precursor for achieving the highest crystallinity, suitable morphology, ideal pore size, effective pore volume, and tuned microporous/mesoporous area. For samples with a template concentration ratio of 0.050 or higher, 29Si and 27Al NMR data revealed the presence of an intact ZSM-5 structure. Using a fixed bed reactor at 500 °C and atmospheric pressure, the catalytic performance of the selected catalysts from the series is investigated for the methanol-to-olefin conversion reaction. The sample with the highest crystallinity showed the best conversion, selectivity toward light olefins, and time on stream stability. It is also worth noting that the highest crystallinity, micropore area, and micropore volume are reached for the optimum value rather than the highest template concentration. This allows for a reduction in the template concentration and a move closer to a synthesis pathway benign to environment and economics.

Catalytic Cracking of n-Dodecane to Chemicals: Effect of Variable-Morphological ZSM-5 Zeolites Synthesized Using Various Silica Sources.

This study emphasizes tuning the synthesis conditions of MFI zeolites to achieve better catalytic properties by optimizing the mesoporosity, the balance between Brønsted and Lewis sites, and the zeolite particle sizes. The MFI zeolites were hydrothermally synthesized at various temperatures employing different silica sources. The synthesis temperature was varied between 110 to 180 °C at constant synthesis time (15 h). Different silicon sources led to variations in structure, morphology, and size of the MFI zeolite along with tuned Lewis and Brønsted acid sites in parallel correlation with shape selectivity of the reaction. The catalytic activities of synthesized zeolites were investigated in the catalytic cracking of n-dodecane to produce value-added chemicals. The zeolite synthesized at 180 °C using fumed silica presented the highest catalytic conversion (96.6%), while maximum light olefin gaseous products (73.1%) were obtained for the sample synthesized at 140 °C using tetraethyl orthosilicate as the silica source. The MFI zeolite synthesized at 180 °C employing tetraethyl orthosilicate as a silica source facilitated the formation of both naphthenes and aromatics (71.3%) as major liquid products.

Clinical Investigation on the Impact of Cannabis Abuse on Thyroid Hormones and Associated Psychiatric Manifestations in the Male Population.

Cannabis abuse is a common public health issue and may lead to considerable adverse effects. Along with other effects, the dependence on cannabis consumption is a serious problem which has significant consequences on biochemical and clinical symptoms. This study intends to evaluate the harmful effects of the use of cannabis on thyroid hormonal levels, cardiovascular indicators, and psychotic symptoms in the included patients. This prospective multicenter study was conducted on cannabis-dependent patients with psychotic symptoms (n = 40) vs. healthy control subjects (n = 40). All participants were evaluated for psychiatric, biochemical, and cardiovascular physiological effects. Patients were selected through Diagnostic and Statistical Manual of Mental Disorders (DSM)-IV criteria and urine samples, exclusively for the evaluation of cannabis presence. Serum thyroid stimulating hormone (TSH), T3, and T4 levels were measured using the immunoassay technique. Patients were assessed for severity of depressive, schizophrenic, and manic symptoms using international ranking scales. Various quantifiable factors were also measured for the development of tolerance by cannabis. Among the patients of cannabis abuse, 47.5% were found with schizophrenia, 20% with schizoaffective symptoms, 10% with manic symptoms, and 22.5% with both manic and psychotic symptoms. In the group-group and within-group statistical analysis, the results of thyroid hormones and cardiovascular parameters were non-significant. The psychiatric assessment has shown highly significant (p < 0.001) difference of positive, negative, general psychopathology, and total scores [through Positive and Negative Syndrome Scale (PANSS) rating scales] in patients vs. the healthy control subjects. The study revealed that cannabis abuse did not significantly alter thyroid hormones and cardiovascular parameters due to the development of tolerance. However, the cannabis abuse might have a significant contributing role in the positive, negative, and manic symptoms in different psychiatric disorders.

Aerosol-Assisted Chemical Vapor Deposition Growth of NiMoO4 Nanoflowers on Nickel Foam as Effective Electrocatalysts toward Water Oxidation.

The fabrication of active and durable catalysts derived from transition metals is highly desired for the realization of efficient water oxidation reactions. This is particularly important to address the slow oxygen evolution reaction (OER) kinetics and hence can contribute to the conversion and storage of sustainable energy. In this study, the deposition of crystalline flowerlike 2D nanosheets of nickel molybdate (NiMoO4) directly on nickel foam (NF) through an aerosol-assisted chemical vapor deposition process is reported. The NiMoO4 nanosheets were developed on NF by altering the deposition time for 60 and 120 min at a fixed temperature of 480 °C. The structural determination by XRD and XPS analyses revealed a highly crystalline single phase NiMoO4. The micrographs of NiMoO4 show that the surface consisted of vertically aligned 2D nanosheets assembled into flowerlike structures. The nanosheets produced after 60 min deposition time on a network of NF is found to perform better for OER as compared to the one developed for 120 min. A reference current density of 10 mA cm-2 was achieved at an overpotential (η) of 320 mV, which was better as compared to that reported for the benchmark OER catalyst in 1.0 M KOH. Moreover, a small Tafel value (75 mV dec-1) and good OER stability for >15 h were also observed.

Sulfone-containing Conjugated Polyimide 2D Nanosheets for Efficient Water Oxidation.

Water oxidation is a bottleneck in artificial photosynthesis that impedes its practicality for solar energy conversion and utilization. It is highly desired to significantly improve the efficacy of the existing catalysts or to rationally design new catalysts with improved performance. We report a novel conjugated and sulfone containing polyimide as a metal-free photocatalyst synthesized via a two-step method: (i) synthesis of precursor poly(amic acid) (PAA) (ii) solvothermal synthesis of polyimide through thermal imidization. The synthesis of the polyimide photocatalyst was demonstrated by the amide linkage in the FTIR spectrum. The obtained photocatalyst was semicrystalline in nature and possessed sheet-like morphology as illustrated by the diffraction pattern and the electron micrographic images, respectively. The thermogravimetric analysis of the polyimide nanosheets validated a thermally stable structure. The DFT calculations were performed which showed a suitable HOMO band position, favorable for water oxidation. The photoelectrocatalytic (PEC) performance of the polyimide nanosheets evaluated by studying water oxidation reaction without any sacrificial agent under 1-SUN showed enhanced PEC performance and good stability towards water oxidation at 0 V versus SCE.

Mixed Dimensional Nanostructure (UiO-66-Decorated MWCNT) as a Nanofiller in Mixed-Matrix Membranes for Enhanced CO2 /CH4 Separation.

Mixed-matrix membranes (MMMs) with combination of two distinct dimensional nanofillers (such as 1D-3D, 2D-3D, or 3D-3D, etc.) have drawn special attention for gas separation applications due to their concerted effects on gas permeation and mechanical properties. An amine-functionalized 1D multiwalled carbon nanotube (NH2 -MWCNT) with exceptional mechanical strength and rapid gas transport was crosslinked with an amine-functionalized 3D metal-organic framework (UiO-66-NH2 ) with high CO2 affinity in a Schiff base reaction. The resultant crosslinked mixed-dimensional nanostructure was used as a nanofiller in a polysulfone (PSf) polymer matrix to explore the underlying synergy between 1D and 3D nanostructures on the gas separation performance of MMMs. Cross-sectional scanning electron microscopy and mapping revealed the homogenous dispersion of UiO-66@MWCNT in the polymer matrix. The MMM containing 5.0 wt. % UiO-66@MWCNT demonstrated a superior permeability 8.3 Barrer as compared to the 4.2 Barrer of pure PSf membrane for CO2 . Moreover, the selectivity (CO2 /CH4 ) of this MMM was enhanced to 39.5 from the 28.0 observed for pure PSf under similar conditions of pressure and temperature.

A 2D Graphitic-Polytriaminopyrimidine (g-PTAP)/Poly(ether-block-amide) Mixed Matrix Membrane for CO2 Separation.

Poly(ether-block-amide)/g-PTAP mixed matrix membranes (MMMs) were developed by incorporating different wt.% (1-10%) of a novel 2D g-PTAP nanofiller and its effects on membrane structure and gas permeability were studied. The novel 2D material g-PTAP was synthesized and characterized by various analytical techniques including field-emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and Raman spectroscopy. The fabricated MMMs were investigated to study the interaction and compatibility between Pebax and g-PTAP. The MMMs showed an effective integration of g-PTAP nanofiller into the Pebax matrix without affecting its thermal stability. Gas permeation experiments with MMMs showed improved CO2 permeability and selectivity (CO2 /N2 ) upon incorporation of g-PTAP in the Pebax polymer matrix. The maximum CO2 permeability enhancement from 82.3 to 154.6 Barrer with highest CO2 /N2 selectivity from 49.5 to 83.5 were found with 2.5 wt.% of nanofiller compared to neat Pebax membranes.

Frontiers and Challenges in Electrochemical Corrosion Monitoring; Surface and Downhole Applications.

Corrosion sensing is essential to monitor and safeguard the materials' health and control the maintenance cost of corrosion-prone materials used in various industries. The petroleum industry is a major sufferer of corrosion costs among various industries due to pipelines and downhole applications. This review article encompasses an overview of various technologies used in early detection stages for more reliable corrosion sensing and warnings. This review provides a summary of corrosion types, corrosion causing chemical species, different destructive and non-destructive technologies used in monitoring corrosion and a comprehensive overview of the state-of-the-art of various electrochemical techniques used for surface and downhole corrosion monitoring. Finally, the existing challenges for corrosion monitoring in surface and downhole conditions and prospects are discussed.

Laser Induced Anchoring of Nickel Oxide Nanoparticles on Polymeric Graphitic Carbon Nitride Sheets Using Pulsed Laser Ablation for Efficient Water Splitting under Visible Light.

A visible-light-active nickel oxide-graphitic carbon nitride (NiO@g-CN) hetero-structured nanocomposite was synthesized for the first time by pulsed laser ablation in liquid and used as a photoanode material in photoelectrochemical water-splitting reaction with a solar simulator. It was found that the photoelectrochemical performance of PLAL synthesized NiO@g-CN nanocomposite as photoanode, compared to g-CN as photoanode showed fourfold enhancements in photocurrent density under visible light. FT-IR, XRD, FE-SEM, and EDX consistently showed the proper anchoring of nano-sized NiO on g-CN. UV-DRS and the band gap estimation showed the narrowing down of the band gap energy and consequent enhancement in the visible-light absorption, whereas photoluminescence spectroscopy confirmed the reduction of the recombination of photo-excited electron hole pairs as a result of the anchoring of NiO on g-CN. The photoelectrochemical performance of g-CN and the NiO@g-CN nanocomposite photoanodes was compared by linear sweep voltammetry (LSV), Chronoamperometry (I-t), and Electrochemical Impedance Spectroscopy (EIS). All of these results of the characterization studies account for the observed fourfold enhancement of photocurrent density of NiO@g-CN nanocomposite as photoanode in the photoelectrochemical reaction.

Ultrasonically controlled growth of monodispersed octahedral BiVO4 microcrystals for improved photoelectrochemical water oxidation.

The synthesis of facet-controlled structures with precise morphology and exposed reactive surface is one of the key research challenges. We effectively endeavoured to obtain the monodisperse octahedral bismuth vanadate microcrystals with exposed {101},{200},{312} and {021} dominant facets through an optimized sonochemical assisted hydrothermal process. A pulse sonication (5-s ON and 2-s OFF cycle, 21 W ultrasonic power and 20 kHz ultrasonic frequency) for 30 mins followed by 1 h hydrothermal treatment was found to yield the preferred octahedral morphology. The microscopic and X-ray analysis suggested a potent role of ultrasonic waves for the initial seed growth and its evolution into a well-defined monodisperse microcrystals. The density functional theory (DFT) calculations revealed strongly localized bandgap states with a bandgap of ~2.47 eV. The PEC measurements for water oxidation demonstrated the efficacy of these microcrystals as photoanode. Notably, the optimized octahedral BiVO4 microstructure exhibited a superior performance as evident from photocurrent density ~0.9 mAcm-2 at 1.23 V vs. RHE and %IPCE value of ~22% compared to analogous photoanodes under visible light irradiation.

Hematite and Magnetite Nanostructures for Green and Sustainable Energy Harnessing and Environmental Pollution Control: A Review.

The optoelectrical and magnetic characteristics of naturally existing iron-based nanostructures, especially hematite and magnetite nanoparticles (H-NPs and M-NPs), gained significant research interest in various applications, recently. The main purpose of this Review is to provide an overview of the utilization of H-NPs and M-NPs in various environmental remediation. Iron-based NPs are extensively explored to generate green energy from environmental friendly processes such as water splitting and CO2 conversion to hydrogen and low molecular weight hydrocarbons, respectively. The latter part of the Review provided a critical overview to use H-NPs and M-NPs for the detection and decontamination of inorganic and organic contaminants to counter the environmental pollution and toxicity challenge, which could ensure environmental sustainability and hygiene. Some of the future perspectives are comprehensively presented in the final portion of the script, optimiztically, and it is supported by some relevant literature surveys to predict the possible routes of H-NPs and M-NPs modifications that could enable researchers to use these NPs in more advanced environmental applications. The literature collection and discussion on the critical assessment of reserving the environmental sustainability challenges provided in this Review will be useful not only for experienced researchers but also for novices in the field.

Report: Antibacterial and antifungal activities of leaf extract of Achyranthes aspera (Amaranthaceae) from Pakistan.

Alcoholic extract and various fractions of Achyranthes aspera leaves, traditionally used in Pakistan for treatment of infectious diseases was screened for in vitro antibacterial and antifungal activity. The chloroform and butanol fractions were found to be the most active among the fractions, showing considerable antibacterial activity against Shigella flexneri and Escherichia coli. The highest activity was found in the ethylacetate fraction (17 mm zone of inhibition) against gram-negative (Salmonella typhi) bacteria, with MIC value as 0.29 mg/mL. In antifungal screening, moderate activity was shown by the chloroform fraction (50 % inhibition) against Microsporum canis, with MIC value as 0.25mg/mL. Considerable level of antifungal activity was depicted by crude extract, hexane and butanol fractions against Aspergillus flavus and Microsporum canis. The ability of various extracts of Achyranthes aspera to inhibit different strains of fungi and bacteria indicates its potential use for the treatment of microbial infections.