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Date palm waste (DPW) is an important waste that is abundantly available in the Middle East. However, this DPW is underutilization in the entire Middle East region. DPW could be a useful source of feedstock to generate sustainable and renewable energy via various thermochemical processes. The core objective of current investigation is to convert the DPW into syngas and the electricity generation from the produced syngas. Furthermore, to configure an integrated system to predict the gas composition and power generation under operating variables of temperature, steam/biomass ratio, compression ratio, and air flowrate. The integrated process simulation model of gasification and power generation model was developed using Aspen Plus V10®. The model consisted of two parts; the production of syngas from steam gasification and the second was the combustion-integrated power turbine system for power generation. The syngas composition at a temperature of 850 °C and steam/biomass of 1.0 was obtained as; H2 37.88 vol%, CO14.24 vol%, CO2 11.29 vol%, CH4 0.001 vol%. The power generation from the gas turbine increased from 3.2 to 3.6 MW with the increase in temperature. Whereas the total power generation was in the range of 3.2 to 5 MW with an increased steam flowrate of 500–2500 kg/h. Energy analysis shows that the process heat integration of the system is able to fulfill the 78 % utilities requirement within the system. This study provides the potential utilization of DPW for renewable fuel gas and electricity generation through a sustainable route and also provides environmentally friendly disposal of DPW in the Middle East and elsewhere in the world.

Energy crises and water pollution have become the key challenges in current era of technology. In this research work, activated carbon modified BiVO4 photocatalysts have been prepared using simple hydrothermal methods for efficient hydrogen evolution through water splitting under visible light irradiation and degradation, simultaneously. The properties of the synthesized photocatalysts were studied through SEM, UV, XRD, BET and PL emission spectroscopy. The 4%AC/BiVO4 exhibited highest degradation efficiency ≈98% in 60 min and production of hydrogen energy ≈510 h−1g−1 which is much higher when compared to pure BiVO4. The enhancement in the efficiency was due to large surface area, large absorption region. High crystallinity, small band gap and synergetic effect between the composites. The activated carbon based BiVO4 composites showed high stability which shows its vital role in practical applications.

We are reporting here a novel antimony doped cobalt oxide based electrode material for supercapacitor application to overcome the current scenario of energy crises by offering excellent capacitive abilities. A facile hydrothermal route was employed to produce this antimony doped cobalt oxide material by varying content value of antimony in the range of 2–6 at. %. The X-ray diffraction results have successfully explored the cubic crystal structure along with phase composition of these as obtained Sb doped Co3O4 materials. The development of sub-micron sized structures-based material was explored by obtaining scanning electron microscopic images. The energy dispersive X-ray spectroscopy results have shown the highly pure nature of as obtained material. Cyclic voltammogram results have exhibited that among the SbCo-0, SbCo-2, SbCo-4 and SbCo-6 materials, SbCo-4 has exhibited higher specific capacitance value i.e 894.15 F/g than remaining, which was obtained by scanning the material at the scan rate of 5 mV/s. More significantly, Galvanostatic charge-discharge profiles obtained at different scan rates ranging from 1 to 10 A/g, for SbCo-4 material has shown even good capacitance retention i.e 75.70% at higher sweep rate, equal to 10 A/g. On the basis of electrochemical impedance spectroscopic analysis, it is concluded that this material has also shown excellent conductive properties. Furthermore, after performing 3000 galvanostatic charge-discharge cycles, it is concluded that this material can possessed an excellent cycling stability equal to 82.02%. All these excellent capacitive properties shown by this material have suggested that it can be proved as a potential applicant in the field of energy storage devices.

In this paper, the bismuth vanadate and the composite of bismuth vanadate BiVO4 with nickel ferrite BiVO4/NiFe2O4 is aimed to be synthesized using hydrothermal method for the effective degradation of methylene blue. The concentration of nickel ferrite is varied from 1 to 5%. The morphological, structural, and the optical properties of the prepared samples are studied using X-ray diffraction (XRD), Scanning electron microscope (SEM), Photoluminescence (PL) spectroscopy, and Ultra-violet (UV) spectroscopy. The photocatalytic activity of the prepared photocatalyst is performed under visible light. The composite of BiVO4/NiFe2O4 4% efficiently degrade 99% of methylene blue after 90 min from 100-ml solution under visible light. This paper explains the synthesis of bismuth vanadate and it is composite with nickel ferrite BiVO4/NiFe2O4 and give information about the structural and morphological of these synthesized materials.

The current research work is to investigate the photocatalytic efficiency and degradation of ciprofloxacin using WO3/TiO2 nanoparticles under visible light irradiation. The nanoparticles of tungsten trioxide (WO3) and its composite with titanium dioxide (TiO2) i.e. WO3/TiO2 was prepared by hydrothermal method. Four basic characterizations were performed to study the prepared sample materials. To study the morphology of the prepared samples, scanning electron microscopy (SEM) was used. The results of SEM clearly showed that tungsten trioxide (WO3) has Rectangular shaped structure. The average size of the pure Tungsten trioxide nanoparticles was about 40–540 nm. The composite of WO3/TiO2 has spherical structure. The reason behind that was the addition of TiO2 in WO3 changes the morphology of pure WO3, and transformed the rectangular structure to a spherical structure. The presence of TiO2 changes the position and orientation of the nanorods in all possible directions. For the detailed analysis of the functional groups present in these samples, band gap, and optical properties of these samples, Fourier transform infrared spectroscopy (FTIR), ultraviolet visible (UV–VIS) spectroscopy and Photoluminescence (PL) emission spectroscopy was used. UV–Vis spectroscopy results showed that the bandgaps of prepared catalysts vary within the range of 2.76 – 2.5 eV. This decrease in bandgap is directly related with the concentration ratio of TiO2 in WO3. The maximum excitation wavelength observed at 440 nm. The maximum degradation efficiency was at 2% of WO3/TiO2 composite catalyst due to unique morphological structure and increase rate of photo absorption.

Recently, photocatalysis has received huge attention in order to overcome energy crisis worldwide. Many semiconductors, potential schemes and hierarchies have come to light during past few decades to fabricate efficient catalysts however, among all these methods heterostructures have taken the world by surprise. With the advancement in post-graphene 2D materials, van der Waals heterostructures have come to light exploring enhancement in photocatalysis. During a very short period a number of ZnO-based van der Waal heterostructures have taken the limelight in the field of photocatalysis. First principles calculations and DFT approach towards the heterostructures of GeC, GaN, WSe2, WS2 and other layered 2D materials unleased a series of properties and facts for the provision of enhanced catalysis. Reduction in bandgap of ZnO has also been observed which widens the pathways towards visible light irradiation. However, energy applications of zinc oxide are also fascinating feature as it can serve as a photoanode to replace TiO2. Whereas the famous hydrogen production, batteries and solar cells have also been fabricated by the use of this semiconductor.

In this study, Mg2+ ions-doped ZnO nanorods were prepared via simple solvothermal method. The prepared samples were characterized by XRD, TEM/SEM, EDX, UV–visible and PL emission spectroscopy to explore the structural, morphological and optical properties, respectively. The XRD results reveal that Mg2+ ions-doped ZnO/MgO nanocomposite exhibited the hexagonal wurtzite structure of ZnO. However, the incorporation of Mg2+ ions into ZnO has shifted the XRD peaks towards lower 2Ө angles which might be due to successful incorporation of Mg2+ ions into ZnO lattice. Moreover, the prepared ZnO, MgO and MgO/ZnO nanocomposites with various Mg to Zn atomic ratios (2–11%) were used as photocatalyst for the degradation of MB and RhB dyes under visible light irradiation. The sample with 8% doping (8%MgO/ZnO) showed excellent photocatalytic performance for both dyes as compared to pure ZnO and other samples. Furthermore, the cyclic stability of 8% MgO/ZnO nanocomposite was also monitored for the degradation of RhB dye, the results show that the prepared nanocomposite has good stability and long-term durability after five consecutive cycles. The current study suggests that ZnO/MgO-based nanocomposites could be proficiently used in numerous applications especially in environmental and energy applications.

Aluminum–nickel ferrite nanostructure with a nominal composition of NiFe2-xAlxO4 (0 < x < 0.9) was synthesized by heat treatment process by employing polyvinylpyrrolidone (PVP) as a capping operator. The effects of Al3+ substitution on structural, morphological, quantitative, qualitative and magnetic properties were characterized via X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray photoelectron microscopy (XPS) and vibrating-sample magnetometry (VSM). Single-phase inverse spinel structure and decrease in average crystal size as Al concentration increases was acknowledged by XRD and EDX characterization. The decrease in average crystal size as Al3+ ions content increases is associated with structural effects of overall crystal size of nanostructure. The development of a thermally stable nickel ferrite above 500 °C was detected by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) measurements. The magnetic hysteresis loop measurements at room temperature (RT) with an ultimate tested magnetic field of 1.8 T shows both saturation and remnant magnetization decreases as content of Al3+ ions substitution increases. The decrease in overall magnetization is due to spin non-collinearity, weakening of magnetocrystalline anisotropy and weak super-exchange interactions.

The presence of pharmaceutical wastage and their metabolites in the wastewater, even in low absorption concentration has adverse effects on society and the environment. A recyclable and economical-friendly photocatalytic technique is applicable for decontamination and sanitization of the polluted water from the anti-parasitic drugs. Here, activated carbon was synthesized which has become more efficient and suitable for degradation purpose. Peanut shell-based activated carbon (PSAC) and sugarcane bagasse (SBAC) are used for this research. In this research study, results indicate that PSAC was more profitable and energetic as compared to SBAC. XRD demonstrates that PSAC has sharp peaks at 26.8° and 65.6° but SBAC has no specific sharp peaks. SEM analytic pictures visualized that PSAC has a granular nanoporous structure that is efficacious for the Iverzine degradation rather than nano and micro layers based on SBAC. EDX spectrums confessed that PSAC has a high peak of activated carbon and very small impurity peaks of sulphur and oxygen rather than SBAC. By the investigation of FTIR spectra, SBAC and PSAC both have almost the same absorbance bonds but have different percentage transmittance. An analytic study of degradation spectrum, it has been noticed that PSAC degraded 89% of Iverzine drug but SBAC has degraded just about 63%. All the results demonstrated that PSAC was more energetic for the absorption and degradation of pharmaceuticals from water.

The discharge of various textile effluents into water is provoking numerous ecological issues that have become severe threat to human beings and aquatic lives. The removal of the effluents by photodegradation using appropriate nanoparticles (NPs) is the most promising remediation process. In this study, a facile hydrothermal approach is utilized to fabricate pure ZnO and strontium doped ZnO nanoparticles (Sr-ZnO). The fabricated nanoparticles represented hexagonal morphology and structure which was controlled with the strontium doping. The optical properties of fabricated NPs were also controlled and approached to visible light (2.52 eV) instead of the UV light. The fabricated NPs were employed for photodegradation of Rhodamine B (RHB) dye from polluted wastewater and further effect of factors like light irradiation time, pH, photocatalyst dose, dye concentration etc. was also explored to optimize the parameters. Sr-ZnO photocatalyst represent excellent RHB dye degradation as well as cyclic stability with pseudo first order kinetics. The current study proves the suitability of Sr-ZnO photocatalyst under visible light irradiation for treatment of the organic and dye polluted wastewaters.

The concern to reduce global carbon emissions has significantly improved the development of efficient solid sorbents such as activated carbon (AC). In this study, AC is developed from date stones which is one of the abundantly found agricultural waste material in gulf region. The AC was completely characterized in terms of pore volume, surface area, stability test, volatile carbon and fixed carbon contents. Impregnation of AC was performed by three different alkanolamines, namely Diethylene triamine (DETA), Pentaethylene hexamine (PEHA) and Di-ethanol amine (DEA). The alkanolamine impregnated sorbents were utilized for CO2adsorption at temperatures of 25, 30, 40, 50, 60, 70 and 100 °C and carbon dioxide (CO2) concentrations of 10, 30, 50, 70 and 92% in helium. The adsorption phenomenon was evaluated by Langmuir isotherms for all the studied adsorbents. The AC developed from date stones provided high adsorption loading capacity of CO2 i.e., 89.79 mg/g of AC at 25 °C. Thermodynamic parameters showed that the adsorption was endothermic and spontaneous in nature. Moreover, desorption profiles reveal that DETA-AC samples provided most favorable characteristics with respect to the value of desorption constant.

For the first time achieved F modification of titanium dioxide through a plasma method. The F modification of titanium dioxide was achieved by Ar/HF dielectric barrier discharge, including the introduction of Ti-F bonds, interstitial F doping, and substitution of F doping. The characterization results show that the band gap of Ar/HF/DBD-TiO 2 is reduced to 2.78 eV, the fluorescence intensity is greatly reduced, and the electron-hole recombination rate is reduced. The degradation rate of methylene blue by F modified titanium dioxide under visible light reaches 92%.

The waste generated from animal slaughtering increases significantly during the Hajj period due to increased meat consumption as well as performing the religious ritual of animal slaughtering. It is estimated that about 12% of waste per body weight of sheep and goat is generated, while 43% waste of cattle body weight is generated. There are no robust data available about the slaughtering waste generation in KSA. However, it is apparent that huge amounts of waste are generated and disposed of to the landfills without any material and energy recovery. This study estimates that slaughtering activity generated about 0.08 million tons of solid waste in 2016, which will reach up to 0.2 million tons in 2030. The slaughtering activity includes both domestic and international visitors (Umrah and Hajj pilgrims) meat demand along with holly ritual of animal sacrifice on Eid Ul Adha (religious festival). The study assesses the economic feasibility of two scenarios for waste-to-energy production utilizing slaughterhouse waste as input material through sustainable waste management practices. The gross revenue obtained from the waste management facility includes gate fee saving (45 to 114 MSAR) by waste diversion, environmental saving (8 to 20 MSAR) in the form of carbon credits, power generation potential from biogas, biodiesel, glycerol, MBM (scenario I: 14 to 35 MSAR, scenario II: 21 to 52 MSAR) and selling price of the equivalent amount of fossil resources (scenario I: 46 to 117 MSAR; scenario II: 52 to 132 SAR) from 2016 till 2030. In general, the revenue contribution potentials of scenario I and scenario II to the national economic circle will be 288 MSAR and 319 MSAR in 2030, correspondingly. Although preliminary investigations of both scenarios reveal the considerable potential of implementing transesterification and anaerobic digestion for the sustainable management of slaughterhouse waste in Makkah, further in-depth studies in accordance with local geographic, socioeconomic and cultural values are also recommended.

Mg–Fe Layered Double Hydroxide (LDH) with M2+: M3+ 3:1 stoichiometric ratio was synthesized and employed as catalyst precursor for COx-free hydrogen production from ammonia. The resulting catalyst showed good catalytic activity. A series of Mg/Co–Fe layered double hydroxides were synthesized by replacing Mg2+ with Co2+ without disturbing M2+:M3+ ratio. The influence of nature and extent of Co(II) substitution on structure, morphology and surface properties were studied. A systematic study was carried out using these materials as catalyst precursors for ammonia decomposition. BET, XRD, TPR, XPS, CO2-TPD and TEM techniques were used to characterize the synthesized catalysts. These Fe-based catalysts are highly active, highly stable and not promoting any stable surface nitridation during the ammonia decomposition reaction. Among all catalysts, the Mg3Co3Fe2 catalyst showed the highest activity i.e. 100% conversion at 6,000 h−1 and 60% at 50,000 h−1 space velocities at 550 °C. The registered superior catalytic activity was result of the formed specific catalyst's properties like high surface area, high surface Co and Fe atomic concentration and suitable basicity. These Fe-based materials are, cost-effective, easily synthesize and highly stable, thus attractive for large-scale operation.

In this study, the densification of three agriculture waste biomasses (corn cobs, cotton stalks, and sunflower) is investigated using the torrefaction technique. The samples were pyrolyzed under mild temperature conditions (200–320 °C) and at different residence times (10 min–60 min). The thermal properties of the obtained bio-char samples were analyzed via thermo-gravimetric analysis (TGA). Compositional analysis of the torrefied samples was also carried out to determine the presence of hemicellulose, cellulose, and lignin contents. According to the results of this study, optimum temperature conditions were found to be 260 °C–300 °C along with a residence time of 20 min–30 min. Based on the composition analysis, it was found that biochar contains more lignin and celluloses and lower hemicellulose contents than do the original samples. The removal of volatile hemicelluloses broke the interlocking of biomass building blocks, rendering biochar brittle, grindable, and less reactive. The results of this study would be helpful in bettering our understanding of the conversion of agricultural waste residues into valuable, solid biofuels for use in energy recovery schemes. The optimum temperature condition, residence time, and GCV for torrefied corn cobs were found to be 290 °C, 20 min, and 5444 kcal/kg, respectively. The optimum temperature condition, residence time, and GCV for torrefied cotton balls were found to be 270 °C, 30 min, and 4481 Kcal/kg, respectively. In the case of sunflower samples, the mass yield of the torrefied sample decreased from 85% to 71% by increasing the residence time from 10 min to 60 min, respectively.

Silver catalysts supported on ceria-zirconia (CZ) mechanically mixed oxide were synthesized by wet impregnation and chelating methods. Nominal loadings of 5 wt.% of Ag was deposited on the CZ support. These catalysts were tested for the CO2 hydrogenation reaction to methanol with feed gas composition of CO2–H2 = 3:1 at 250 °C, 20 bar total pressure and GHSV of 1800 h−1. The calcined and reduced catalysts were characterized using XRD, BET, TPR, SEM-EDS, XPS and FTIR-DRIFTs techniques. Finely deposited silver crystallites sized in the range of 20–50 nm were observed through SEM and HR-TEM analysis. TPR and XRD studies demonstrated the presence of Ag2O and metallic silver (Ag0) on CZ support. About 10% of CO formation was observed on chelating catalyst (5Ag/CZ CHE). However, only, 5% CO was observed on impregnated (5Ag/CZ IMP) catalyst. The greater CO formation was associated with ease reduction of Ag2O to metallic silver in 5Ag/CZ CHE catalyst. Further, 70% of methanol selectivity was observed on 5Ag/CZ IMP due to the presence of Ag2O on CZ. FTIR-DRIFTs results revealed the methanol formation via formate intermediates and CO formation via RWGS reaction on the studied catalysts.

Nanocrystalline aluminum-doped manganese ferrite was synthesized by facile thermal treatment method. Nanostructure-doped ferrite with crystalline size that ranged between 3.71 and 6.35 nm was characterized via X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and vibrating-sample magnetometry (VSM). The Scherrer and Williamson-Hall hypothesis techniques were utilized to determine lattice constants and strain. Various types of structural properties including octahedral and tetrahedral site radius, bond lengths and angles, hopping parameter, oxygen positional parameters, site bonds, and edge lengths were determined from XRD spectrum analysis. Discrepancy in the hypothetically expected angle indicates improvement of A-B superexchange intercommunication. Furthermore, magnetic-hysteresis (M-H) and XPS analysis support the claim of enhancement. The presence of the ionic nature of iron and manganese in ferrite is FeII, FeIII, MnII, and MnIV as revealed by the results of XPS. Moreover, XPS assists in an excellent way to understand the properties such as configuration, chemical nature, and average inversion degree of doped ferrite samples. The spin noncollinearity and exquisite interaction amid the sublattice are responsible for the decrease in the saturation and remnant magnetization determined from the hysteresis loop at ambient temperature with maximum magnetic field of 1.8 T.

The influence of Pd loading was studied for the gas phase catalytic hydrodechlorination of 1,2,4-trichlorobenzene over Pd supported on Mg-Al mixed oxide support with Mg:Al ratio 2:1. The Mg-Al support was prepared from hydrotalcite precursor. A series of catalysts was prepared with different loadings of Pd (1–6 wt%) on Mg-Al mixed oxide support. The performance of catalytic material was evaluated at different temperatures ranging from 425–575K. The fresh and used catalysts were characterized with different analytical techniques such as BET surface area, X-ray diffraction studies, Temperature programmed reduction, X-ray photoelectron spectroscopy and CO-chemisorption studies. H2-Temperature programmed desorption studies was also performed to understand the metal-support interaction and suitable active sites. The 4wt% of Pd on Mg-Al mixed oxide catalyst showed the highest conversion and selectivity among all catalysts and maintained steady activity with 10 h of time-on-stream studies. The main reasons for high activity are suitable metal-support interactions, Pd particle size, high surface area, and high surface Pd atomic concentration. The influence of Pd loading was studied for gas phase catalytic hydrodechlorination of 1,2,4-trichlorobenzene over Pd supported on Mg-Al mixed oxide support with Mg:Al ratio 2:1. The different Pd-loadings in catalyst was studied for hydrodechlorination. The 4wt% of Pd on Mg-Al mixed oxide catalyst showed the highest performance among all the catalysts.

The La based perovskite type LaMO3 (M=Ni, Co) oxides were prepared by combustion synthesis method using citric acid as organic fuel. These catalyst precursors tested for ammonia decomposition. The LaNiO3 and LaCoO3 catalysts showed good activity for NH3 decomposition. The LaNiO3 catalyst displayed greater activity than LaCoO3. This due to high surface area and easily reducibility of Ni species. A 50% of La was substituted by Ce in both LaNiO3 and LaCoO3 catalysts. A remarkable effect on catalytic performance was observed with the partial substitution of La by Ce in perovskite catalyst especially at lower temperatures. The La0.5Ce0.5NiO3 catalyst exhibited highest activity among all prepared samples. The achieved superior activity is due to boost in surface area, reducibility and suitable basicity. The SEM elemental mapping of La0.5Ce0.5NiO3 catalyst concluded that metal oxide constituents dispersed homogeneously. The La0.5Ce0.5NiO3 catalyst showed excellent stable catalytic performance during 50h time on study at 550°C.

Alumina (Al), alumina-boron (Al-15B), alumina-boron-antimony (Al-B-Sb) and alumina-antimony (Al-15Sb) catalysts were synthesized by sol-gel method using ethanol as a solvent and ammonia gas as a gel forming agent. These catalysts were studied for the dehydrogenation of ethylbenzene (EB) to styrene in the presence of oxygen and steam. The reaction was carried out in the temperature range of 450-500 °C with EB contact time 0.54 gcat.s/cm3. The synthesized catalysts were characterized by using N2-physisorption, XRD, XPS, TEM-HRTEM-EDS and NH3-TPD-mass spectral analysis techniques. At 475 °C, only 58% of styrene selectivity with 32% of EB conversion was observed on Al. Addition of 15 mol.% of B to Al significantly enhanced the selectivity of styrene to 94% with 46% EB conversion at 475 °C. Addition of 15 mol.% Sb to Al reduced the EB conversion (38%) and styrene selectivity (75%) compared to Al-15B catalyst. Interestingly, small amount of Sb (5 mol.%) addition to Al-B improved the EB conversion to 52.5% with 92% of styrene selectivity at 475 °C. The acid sites of weak and moderate strength were increased in Al-15B catalyst compared to Al. Boron played a dual role as Al densification suppressing agent and to some extent deposited on the surface of Al which improved the styrene selectivity. However, small amount of Sb addition to Al-15B not only retained weak and moderate strength acid sites of Al-B but also generated acid sites of Sb which led to the formation of N2O and NO during NH3-TPD-mass analysis. Hence, the styrene yield (48.8%) was improved on Al-B-5Sb compared to Al-15B catalyst (43%). It is noteworthy that Al-15B and Al-B-5Sb catalysts were stable for more than 60h of reaction.

Herein, supported Ni/MCF-17 catalysts with the size of nickel nanocrystal in the range of 1.5–8.0 nm were synthesized and employed for COx-free hydrogen production for fuel cells via the ammonia decomposition reaction. Characterized by a variety of techniques, the results show that nickel particles are in a highly dispersed state with a uniform particle size for each catalyst. Furthermore, the influence of particle size on the catalytic performance has been investigated. It was later revealed that Ni nanoparticles with different particle sizes exhibited significant differences in catalyzing the COx-free hydrogen production reaction. Moreover, the catalyst with the Ni nanoparticle size around 3.0 nm exhibited highest catalytic activity at each reaction temperature; this could be explained by the presence of high B5 active sites on the Ni-based catalyst surface.

A theoretical study to investigate the electronic, optical and structural properties of sodium-based cubic fluoro-perovskite NaXF3 (where X = Ca, Mg, Sr, Zn), using density functional theory (DFT) based CASTEP (Cambridge Serial Total Energy Package) code with ultra-soft pseudo-potential USP plane wave and Perdew Burke Ernzerhof (PBE) exchange-correlation functional of Generalized Gradient Approximation (GGA), is reported. All of these compounds are found to be in a stable shape with a cubic pm3m structure, according to the findings. The results we discovered are consistent with the data that is already available. Calculations of the electronic band structure show that NaCaF3, NaMgF3 and NaSrF3 have a direct and NaZnF3 has an indirect band gap. Partial density of states (PDOS) and total density of states (TDOS) confirm the degree of electron localization in various bands. All four compounds' optical transitions were investigated by fitting the dispersion relation for the hypothetical dielectric function scale to the corresponding peaks. NaZnF3 is semiconductor while the NaCF3, NaMgF3 and NaSrF3 compounds have insulating behavior. The hypothetical part dispersion of the dielectric function reveals its wide range of energy transparency. As a result, it's possible that these materials may be used in optoelectronics to absorb ultraviolet light.

Water contamination caused by the organic pollutants and microorganism is the serious risk towards the human life and aquatic ecosystem that can be addressed by active and environment-friendly nanoparticles. In current work, Zinc oxide nanoparticles (ZnO-NPs) have been synthesized first time by utilizing leaves extract of Citrus reticulata via facile, cost effective and ecofriendly green approach. Moreover, the influence of leaves extract concentration on properties of synthesized nanoparticles was also inspected. Various characterization techniques results affirmed that the synthesized ZnO-NPs have hexagonal crystalline structure with size range of 43.05–30.67 nm and band gap of 3.26–3.15 eV. Variation in the leaves extract concentration affected the morphology and optical properties of the green synthesized NPs. Further, the synthesized ZnO-NPs were employed as a photocatalyst for photodegradation of Rhodamine B dye. ZnO-NPs were also employed as antibacterial agent against gram-positive (S. aureus) and gram-negative (E. coli) bacteria where they exhibited appreciable antibacterial activity. Therefore, the novel, facile and green synthesized ZnO-NPs are promising for simultaneous removal of organic pollutants and bacteria from polluted water.

The contamination of ammonia in surface water should be given a critical outlook as it easily exceeds the regulated standard limit especially in rivers located in many parts of the world. Several conventional methods for the removal of ammonia have been widely used but its effectiveness in removing ammonia is not impressive. Membrane technology is gaining wider application in removal of nitrogen compounds from water and wastewater. In this study, polyvinylidene fluoride (PVDF) flat sheet membrane incorporated with adsorbent material (zeolite and gypsum) were fabricated to study its efficiency in ammonia removal. The morphology of the blended PVDF membrane by using both additive materials showed that some changes were observed at the bottom layer of the membrane where an extremely wide finger-like structure has been formed. This modified membrane exhibits hydrophobicity properties with contact angle value of 89.0 ± 0.48° and 96.3 ± 0.54° for zeolite and gypsum, respectively. Meanwhile, the crystallinity of the fabricated membrane increases from 20% for pure PVDF to 25.9% and 26.4% for the respective additive of gypsum and zeolite. Furthermore, a comparable separation performance was obtained for the blended membrane with the pure PVDF and the commercial membrane of NF1. Thus, the presence of zeolite or gypsum in the synthesized PVDF membrane could potentially enhance the removal of ammonia by becoming an adsorption material as it commonly functions.

A theoretical study to investigate the electronic, optical and structural properties of sodium-based cubic fluoro-perovskite NaXF3 (where X = Sr, Zn), using density functional theory (DFT) based CASTEP (Cambridge Serial Total Energy Package) code with ultra-soft pseudo-potential USP plane wave and Perdew Burke Ernzerhof (PBE) exchange-correlation functional of Generalized Gradient Approximation (GGA), is reported. The findings show that both compounds are in a stable form with a cubic structure. The calculated elastic constants also meet the mechanical stability criteria. NaSrF3 is brittle, while NaZnF3 is ductile, according to Pugh's criteria. The electronic band structure calculations reveal that NaSrF3 has a direct and NaZnF3 has an indirect band gap. The finding of band gap is agreed well with the data that is already available. The degree of localized electrons in different bands is confirmed by partial density of states (PDOS) and total density of states (TDOS). By fitting the dispersion relation for the hypothetical dielectric function scale to the corresponding peaks, the optical transitions in both compounds were investigated. Both materials are insulators at 0 K and semiconductor at high temperature. However, the dielectric function's imaginary component dispersion exposes its broad range of energy transparency. As a result, it can be inferred that these materials could be used to capture the ultraviolet region in optoelectronics.

This work deals with the effect of catalyst preparation method of the mixed Co, Mg and La oxide catalysts on their structure and catalytic properties for ammonia decomposition. Two methods are used for catalysts preparations impregnation and co-precipitation (in air and in pure O2 atmosphere), The Mg/La = 2 molar ratio and 5 wt% of cobalt content was maintained same in all catalysts. The catalyst performance was evaluated in the temperature range 300–550 °C at atmospheric pressure. The prepared catalysts were characterized by BET, XRD, TPR, XPS, CO2-TPD and SEM techniques. No pronounced differences were observed in BET among the catalysts. It was found that the 5CML-OXY (5 wt%Co over Mg La catalyst prepared by co-precipitation method in oxygen atmosphere) has superior activity among the other catalysts. This could be attributed to availability of easily reducible cobalt species determined by TPR studies and enhanced interaction between Mg and La determined by SEM and XPS. The moderate basic site density determined by CO2-TPD results was also increased in 5CML–OXY catalysts compared with other catalysts. These consequences are might be one of the reasons for enhanced activity of 5CML–OXY catalyst compared to other catalysts. Hence catalyst preparation by co-precipitation in oxygen atmosphere is the best method which might be one of the parameters that influenced on catalytic properties of the cobalt on MgO La2O3 system, for ammonia decomposition.

The study presents the deposition of nanostructured indium tin oxide thin films with thicknesses of 10, 30 and 50 nm on the polylactic acid (PLA) substrate by sputtering at $$30{^{\circ }}\hbox {C}$$. The absence of ITO peaks on the X-ray diffraction patterns confirms the amorphous state of ITO films and the X-ray photoelectron spectroscopy spectrum validates the deposition of ITO films on the PLA substrate. The results of atomic force microscopy of films exhibit variation in the average roughness of 0.3–1.5 nm when the thickness is increased. It was examined that optical transmission is dependent on the thickness of films which varies from 78 to 87% in the visible spectrum of 400–700 nm and the energy band gap varies from 3.95 to 4.02 eV. The films exhibit the low sheet resistance which is due to the formation of oxygen vacancies and dangling bonds. An increase in transmittance enhances the FOM of the ITO films on the PLA substrate.

Rh@UIO-66, prepared by using the double-solvent host–guest strategy and excess reduction methods, exhibited a higher catalytic activity in AB hydrolysis compared with Rh/UIO-66 because the ultrafine Rh nanoparticles were confined to UIO-66 channels. This confinement effect played a key role in enhancing the catalytic activity for AB hydrolysis.

The rapid depletion of fossil fuel resources and climatic changes has triggered the researchers' attention to find an alternative and renewable energy source. Thus, biodiesel has been recognized as a potential alternative to petrodiesel for its biodegradability, non-toxicity, and environment-friendly attributes. In this study, an efficient and recyclable Cu–Ni doped ZrO2 catalyst was synthesized and used to produce biodiesel from a novel non-edible caper (Capparis spinosa L.) seed oil. The synthesized catalyst was characterized by x-ray diffraction, fourier-transform infrared spectroscopy, scanning electron microscopy, and energy dispersive x-ray analysis. The catalyst was reused in four consecutive transesterification reactions without losing any significant catalytic efficiency. Transesterification reaction conditions were optimized via response surface methodology based on Box-Behnken design for predicting optimum biodiesel yields by drawing 3D surface plots. Maximum biodiesel yield of 90.2% was obtained under optimal operating conditions of 1:6 M ratio of oil to methanol, reaction temperature of 70 °C, reaction time of 1.5 h, and 2.5% catalyst loading. Fourier-transform infrared spectroscopy, gas chromatography–mass spectrometry, and nuclear magnetic resonance (1H and 13C) analysis confirmed the high quality of biodiesel produced from non-edible caper (Capparis spinosa L.) seed oil. The fuel properties of the produced biodiesel were also found, such as kinematic viscosity (4.17 cS T), density (0.8312 kg/L), flash point (72 °C), acid no (0.21 mgKOH/g) and sulphur content (0.00042 wt%). These properties were matched and are in close agreement with the International Biodiesel Standards of European Union (EU-14214), China GB/T 20,828 (2007), and American (ASTM6751). Thus, non-edible Capparis spinosa L. seed oil and Cu–Ni doped ZrO2 catalyst appeared to be highly active, stable, and cheap candidates to boost the future biodiesel industry.

This study is aimed to understand the role of alkaline earth elements (AEE) to the catalytic performance of PtSnM1/γ-Al2O3catalystfor the direct propane dehydrogenation (where M1 = Mg, Ca, Sr, Ba). All the catalysts were prepared by using wet impregnation.The overall catalytic performance of all the catalysts was studied at different reaction temperatures, feed composition ratios and GHSV. The best operating reaction conditions were575and#186;C, feed composition ratio of C3H8:H2:N2 = 1.0:0.5:5.5 and GHSV of 3800h-1. An optimal addition of “Ca” to PtSn//γ-Al2O3 catalyst, enhanced the catalytic activity of PtSnM1/γ-Al2O3 catalyst in comparison to other studied AEE. This catalyst had shown the highest propane conversion (~ 55.8 %) with 95.7 % propylene selectivity and least coke formation (7.11 mg.g-1h-1). In general, the increased catalytic activity of PtSnM1/γ-Al2O3 is attributed to the reduced coking extent during the reaction. In addition, the enhanced thermal stability of the PtSnCa/γ-Al2O3catalystis because of the protective layer betweenγ-Al2O3 and active metal, which allows the formation of active species such as PtSn, PtCa2 and Pt2Al phases?

Magnesium hydride (MgH 2 )–carbon nanotubes (CNT) composite has been prepared by high-energy ball milling method and their experimental and kinetic hydrogen adsorption studies was assessed. Hydrogen adsorption studies were performed by Sievert’s volumetric apparatus and kinetic evaluation was conducted by surface chemistry and Langmuir–Hinshelwood–Hougen–Watson (LHHW) type mode. Powder X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM) were performed. Hydrogen adsorption capacity of commercial MgH 2 , milled MgH 2 , and MgH 2 /CNT composite are found to be 0.04, 0.057, and 0.059 g (H 2 )/g (MgH 2 ) at 673 K and hydrogen pressure of 4.6 MPa. Addition of 5 wt% of CNTs to MgH 2 proved to be very critical to enhance hydrogen adsorption as well as to improve its kinetics. It was observed that hydrogen adsorption is not in quasi-state equilibrium and is modeled using kinetic rate laws.

Template-free fabrication of graphitic carbon nitride nanotubes modified with lanthanum (La/g-CNT) for dynamic photo-catalytic CO2 reduction with CH4 has been investigated. Successful fabrication of g-C3N4 nanosheets and nanotubes were obtained with enhanced photo-activity under visible-light. Using 5 wt% La/g-CNT, CO yield of 491 µmole g-cat−1 h−1 was obtained which is 3.6 and 5.9 folds higher than g-CNS and g-CN samples. Similarly, production of H2 was highest over La/g-CNT which was 2.95 folds more than g-CNT and 5.1 times higher than using g-CN. Although, pristine g-CN has more basic sites and larger BET surface area but enhanced photo-activity over La/g-CNT can be attributed to efficient transfer of electrons over 1D structure and separation of charge carriers by La. More interestingly, effect of CH4/CO2 feed ratios was obvious, whereas, highest CO was produced at CH4/CO2 ratio of 1.0 but H2 was maximum with ratio of 2.0. Among the different reaction systems, highest CO was obtained using DRM, while CO2 reduction by H2/H2O promoted both CO and CH4 production. This was obviously due to basic characteristics, sorption competition over the catalyst surface and favorable reverse water gas shift (RWSG) reaction. The stability test further confirmed the suitability of this material which prevailed until three cycles without obvious deactivation. This work will open new opportunities to develop structured nanocalaysts for solar energy based reutilization of CO2 and CH4 for the production of renewable fuels.