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In this study, we fabricated an efficient and low-cost carbon-doped titania (C–TiO2) counter electrode (CE) as a substitute for platinum (Pt) in dye-sensitized solar cells (DSSCs). By varying different weight ratios, C–TiO2 samples were synthesized through the hydrothermal synthesis method followed by calcination in a tube furnace. The doctor blade coating method was used to deposit thin films of the synthesized samples onto the fluorine-doped tin oxide (FTO) substrates. Structural and morphological properties were studied by using various analytical techniques. Moreover, the electrochemical and photo-conversion characteristics of the fabricated CEs were investigated. Cyclic voltammetry (CV) results of the fabricated CEs showed electrocatalytic activity comparable to the Pt in the DSSCs. Meanwhile, photovoltaic measurement results showed the best-performing 15% C–TiO2 CE having 1.56% power conversion efficiency (PCE) as compared to Pt, which is 2.12%. This study proposed a simple method to fabricate a low-cost and efficient C–TiO2 CE for DSSCs. [ABSTRACT FROM AUTHOR]

Syngas is a valuable entity for downstream liquid fuel production and chemical industries. The efficient production of syngas via catalytic partial oxidation of methane (CPOM) is an important process. In this study, partial oxidation of methane (POM) was carried out using CaO decorated TiO2 catalysts. The catalysts were synthesized employing the sol-gel method, while the decoration of TiO2 with CaO was achieved in an aqueous solution by wetness impregnation method. The prepared catalysts were characterized by employing XRD, Raman, TG-DTG, and SEM-EDX for structural and morphological analysis. On testing for POM, at 750 °C the catalysts demonstrate excellent CH4 conversion of 83.6 and 79.5% for 2% and 3% CaO loaded TiO2, respectively. While the average H2/CO ratio for both 2% and 3% CaO loaded TiO2, 2.25 and 2.28, respectively, remained slightly above the theoretical value (H2/CO = 2.0) of POM. The improved POM performance is attributed to the optimally loaded CaO on the TiO2 surface that promotes the reaction where TiO2 support ensure less agglomerated particles, resulting into a fine distribution of the active catalytic sites. [ABSTRACT FROM AUTHOR]

Summary: In this study, cobalt (Co) loaded Sr2TiFeO6‐δ (STF) double perovskite was synthesized using a modified nitrate combustion method for the application in catalytic decomposition of methane (CH4) for hydrogen (H2) production in a fixed bed reactor. The physicochemical properties of the catalyst were analyzed using X‐ray diffraction (XRD), scanning electron microscopy (SEM), energy‐dispersive X‐ray spectroscopy, N2 adsorption‐desorption, thermogravimetric analysis (TGA), and Fourier transform infrared spectroscopy. The catalyst showed a stable crystalline behavior with a uniform dispersion of Co over STF. The different compositions with varying Co loading were tested for methane decomposition at 850°C and constant flow rate. The 5% Co/STF achieving a maximum CH4 conversion of ~95% with an H2 yield of ~49%. Five percentage Co/STF showed excellent catalytic activity and stability for 46.5 hours time on stream without any indication of performance degradation. The spent catalyst was also analyzed using XRD, SEM, and TGA. The carbon deposited is shaped as carbon nanotubes that are a byproduct and also assist in metal exsolution in high‐temperature processes. The use of STF shows the excellent potential showed by perovskites, which are stable in reducing environments, as support materials for methane decomposition. [ABSTRACT FROM AUTHOR]

Preferential binding of base pair units with metallic ions within deoxyribonucleic acids (DNA) to form metal‐DNA complexes are well studied and understood. Excitingly, such natural processes have been utilized "artificially" for designing and fabricating nanometallic structures and patterns primarily using double stranded DNA. However, little or no effort has been given to ribonucleic acid or RNA in this aspect. Therefore, in this work we study the scaffolding effect of RNA on metalizing silver (Ag) ions and further the diffusion of majority of the Ag‐RNA complexes towards artificially introduced cut or scribed edges as a result of the coffee‐ring effect. Upon removal of the RNA scaffold, metallic nanostructures remain along the line of the cut corresponding to the micrometre scale length of the cut, exercising some amount of control and manipulation of parameter. Other parameters such as the height and diameter may directly be related to the concentration and diffusion of the Ag‐RNA complexes, while gap size related to the cut width. We anticipate that further in‐depth studies will be required before a comprehensive model could be proposed for highly controllable and flexible nanostructure and nanowire fabrication using nucleic acid scaffolding techniques. [ABSTRACT FROM AUTHOR]

DNA templated gold wires (AuWs) were fabricated on Pt sputtered ITO (Pt/ITO) substrates using ‘scribing’ or ‘writing’ method to be used as a modified counter electrode (CE) in Dye sensitized solar cells. The gold nanoparticles (AuNPs) bind to DNA in aqueous solution due to the polyanionic nature of DNA. When a scribe is made on the dropcasted Au-DNA solution, the diffusion of Au-DNA complex occurs towards the edges of the scribe due to the coffee ring effect. Capillary force induces evaporation of water that also forces the Au-DNA complex to migrate towards the scribed edges. Meanwhile, the AuNPs are reduced on the surface of DNA to form active seed for nucleation and growth of AuWs. DNA molecules act as a scaffold to arrange the nanoparticles into well-connected submicron to nanoscale wires. The cyclic voltammetry measurements showed that AuWs/Pt/ITO CE exhibited better electro-catalytic activity and higher conductivity than conventional Pt/ITO CE due to the synergistic effect of Pt and AuWs network on ITO. The DSSC fabricated using TiO2 photoanode, N719 dye, I3−/I− electrolyte and AuWs/Pt/ITO CE showed a 36% increase in efficiency as compared to the cells made under same parameters but using conventional (Pt/ITO) CE. [ABSTRACT FROM AUTHOR]

Ca-doped TiO2 films were synthesized by the modified sol-gel method and employed as the electron transport material of perovskite solar cells (PSCs). Morphological, optoelectronic, thermal, and electrical studies of thin films were investigated through XRD, RAMAN, SEM, AFM, UV-Vis, FTIR, and IV characteristics. Ca doping was detected with the help of structural properties while morphological analysis revealed that thin films based on Ca-doped titania are crack-free, homogenous, and uniformly distributed. Further optoelectronic properties have shown a promising conversion efficiency of 9.79% for 2% Ca-doped titania followed by 1% Ca-doped titania, while 3% have shown the lowest conversion efficiency among these prepared samples. The 2% an optimized doping of Ca has shown an almost two-fold increase in conversion efficiency in comparison to pristine TiO2, along with an increase in current density from 15 mA⋅cm−2 to 19.3 mA⋅cm−2. Improved energy efficiency and higher current density are attributed to faster electron transportation; moreover, the optimized percentage of Ca doping seems to be an effective approach to improve the PSCs' performance. [ABSTRACT FROM AUTHOR]

Methanol electrochemical oxidation in a direct methanol fuel cell (DMFC) is considered to be an efficient pathway for generating renewable energy with low pollutant emissions. NiO−CuO and Ni0.95Cr0.05O2+δ thin films were synthesized using a simple dip-coating method and tested for the electro-oxidation of methanol. These synthesized electrocatalysts were characterized by X-ray diffraction spectroscopy (XRD), X-ray photoelectron spectroscopy (XPS), Scanning electron microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDS), and Raman spectroscopy. Different electrochemical techniques were used to investigate the catalytic activity of these prepared electrocatalysts for methanol oxidation, including linear sweep voltammetry (LSV), electrochemical impedance spectroscopy (EIS), and chronoamperometry (CA). In the presence of 0.3 M methanol, the current densities of NiO−CuO and Ni0.95Cr0.05O2+δ thin films were found to be 12.2 mA·cm−2 and 6.5 mA·cm−2, respectively. The enhanced catalytic activity of NiO−CuO and Ni0.95Cr0.05O2+δ thin films may be a result of the synergistic effect between different metal oxides. The Chronoamperometry (CA) results of the mixed metal oxide thin films confirmed their stability in basic media. Furthermore, the findings of electrochemical impedance spectroscopy (EIS) of mixed metal oxide thin films demonstrated a lower charge transfer resistance as compared to the pure NiO, CuO, and Cr2O3 thin films. [ABSTRACT FROM AUTHOR]

In this work, the biomass fly ash (BFA) was investigated as a potential catalyst for the thermo-catalytic decomposition of methane and attractive approach for hydrogen (H 2) production. The BFA based CeO 2 nanowires promoted cobalt catalyst was synthesized for catalytic methane (CH 4) decomposition and was tested in a fixed bed reactor. The physicochemical properties of the catalyst were investigated using various techniques such as X-ray powder diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, thermal gravimetric analysis, and Fourier transformed infrared. The pure crystalline micro-flake BFA was modified using synthesized CeO 2 nanowires and the resulted micro flakes cross-linked with nanowires shown thermal stability up to 900 °C. The high stability of the catalyst makes it suitable for the thermal catalytic decomposition of methane. The activity of the catalyst was tested at 850 °C to analyze the H 2 production and CH 4 conversion. The obtained results revealed that support and promoter exhibit a strong impact on the CH 4 conversion and H 2 yield in catalyst screening tests. A maximum conversion of 71% for CH 4 with 44.9% H 2 yield was recorded for 34 h on stream activity while using 5% Co/CeO 2 -BFA as the catalyst. While BFA and Co-BFA as catalyst showed 36% and 47% conversion of CH 4 , respectively which indicates that the addition of promoter shows an increase in values of both conversion of CH 4 and H 2 yield. Compared to traditional catalyst support, the use of waste-sourced catalyst support for CH 4 decomposition provides a greener and more economical route for H 2 production. [Display omitted] • Co loaded CeO 2 nanowire promoted biomass fly ash catalyst is synthesized. • CeO 2 nanowire loading enhanced the H 2 production in methane decomposition. • Stability over 34 h is reported with no reduction in activity. [ABSTRACT FROM AUTHOR]

Co/TiO2–MgAl2O4 was investigated in a fixed bed reactor for the dry reforming of methane (DRM) process. Co/TiO2–MgAl2O4 was prepared by modified co-precipitation, followed by the hydrothermal method. The active metal Co was loaded via the wetness impregnation method. The prepared catalyst was characterized by XRD, SEM, TGA, and FTIR. The performance of Co/TiO2–MgAl2O4 for the DRM process was investigated in a reactor with a temperature of 750 °C, a feed ratio (CO2/CH4) of 1, a catalyst loading of 0.5 g, and a feed flow rate of 20 mL min−1. The effect of support interaction with metal and the composite were studied for catalytic activity, the composite showing significantly improved results. Moreover, among the tested Co loadings, 5 wt% Co over the TiO2–MgAl2O4 composite shows the best catalytic performance. The 5%Co/TiO2–MgAl2O4 improved the CH4 and CO2 conversion by up to 70% and 80%, respectively, while the selectivity of H2 and CO improved to 43% and 46.5%, respectively. The achieved H2/CO ratio of 0.9 was due to the excess amount of CO produced because of the higher conversion rate of CO2 and the surface carbon reaction with oxygen species. Furthermore, in a time on stream (TOS) test, the catalyst exhibited 75 h of stability with significant catalytic activity. Catalyst potential lies in catalyst stability and performance results, thus encouraging the further investigation and use of the catalyst for the long-run DRM process. [ABSTRACT FROM AUTHOR]

TiO 2 is a wide bandgap semiconductor commonly used as a photoanode material in dye sensitized solar cells (DSSCs). However, low absorption of TiO 2 in visible range of solar spectrum limits its performance in DSSCs. A multistep electrophoretic deposition (EPD) process was used to improve the morphology of the mesoporous films and high quality TiO 2 films were fabricated. Meanwhile, the optical absorbance was enhanced by a convenient and simple surface modification method using tin (Sn). The prepared films were subjected to morphological, optical, elemental, and phase analyses. It was observed that multistep EPD produced high quality films at various electric fields. Moreover, the surface modification was achieved using sonochemical deposition of Sn+ on the film which enhanced its photo-absorption. The current density (J) versus voltage (V) characteristics of Sn/TiO 2 film deposited at 20 V based DSSC showed approximately twofold increase in the efficiency of the solar cells. Improved open-circuit voltage (V oc), short-circuit current density (J sc) and efficiency (η) of the DSSCs as well as significantly high fill factor indicated that the surface modified EPD film is a potential candidate as a photoanode film in DSSCs. • A multiple step electrophoretic deposition method for TiO 2 film. • Effective enhancement in TiO 2 light absorption towards visible region using surface modification. • Fabrication of porous thin films without compromising the surface area of the films. • Enhancement in photovoltaic performance of the dye sensitized solar cells due to effective surface modification using tin. [ABSTRACT FROM AUTHOR]

In this study, various energy conservation techniques and clean energy utilization prospects are investigated for the residential buildings of Saudi Arabia. A base case study of a distinctive residential building in Saudi Arabia is performed using simulation packages and its energy performance is optimized by incorporating the design standards of International Energy Conservation Code (IECC). The optimized results show that the energy consumed by the IECC standardized building is less by 56% for space cooling, 37% for space heating, 46% for lighting, and 27% for appliances. The IECC standardized building is integrated with a passive solar water heating system and a grid-connected solar PV system to meet the water heating load and lighting load, respectively. The use of solar water heating system shows 76% reduction in energy consumption as compared to the electric water heater. The feasibility of integrating a grid-connected solar PV system in the residential buildings is justified in terms of subsidy provided by the government and eco-environmental benefits. Finally, the prospects of utilizing solar energy in buildings are discussed with their economic and environmental benefits. [ABSTRACT FROM AUTHOR]

Various fillers such as zeolites, metal-organic framework, carbon, metal framework, graphene, and covalent organic framework have been incorporated into the polymers. However, these materials are facing issues such as incompatibility with the polymer matrix, which leads to the formation of non-selective voids and thus, reduces the gas separation properties. Recent studies show that hexagonal boron nitride (h-BN) possesses attractive characteristics such as high aspect ratio, good compatibility with polymer materials, enhanced gas barrier performance, and improved mechanical properties, which could make h-BN the potential candidate to replace conventional fillers. The synthesis of materials and membranes is the subject of this review, which focuses on recent developments and ongoing problems. Additionally, a summary of the mathematical models that were utilised to forecast how well polymer composites would perform in gas separation is provided. It was found in the previous studies that tortuosity is the governing factor for the determination of the effectiveness of a nanofiller as a gas barrier enhancer in polymer matrices. The shape of the nanofiller particles and sheets, disorientation and distribution of the nanofillers within the polymer matrix, state of aggregation and rate of reaggregation of the nanofiller particles, as well as the compatibility of the nanofiller with the polymer matrix all played a significant role in determining how well a particular nanofiller will perform in enhancing the gas barrier properties of the nanocomposites. For this purpose, this review has been focused not only on the experimentation work but also on the effect of tortuosity, exfoliation quality, compatibility, disorientation, and reaggregation of nanofillers. [Display omitted] • Experimental results acquired from h-BN based nanocomposites are summarized. • Mathematical models explaining the experimental results have been studied. • Recommendations are given to improve performance of gas barrier coatings. • Novel methods for environmental remediation are critically explained. [ABSTRACT FROM AUTHOR]

The massive increase in the use of PET plastic bottles has raised the challenge of accumulated waste plastics disposal and its related environmental concerns. Reusing this plastic waste through a solvent-based recycling process seems to be an eco-friendly solution for eliminating waste plastic and converting them into high quality products. The selection of solvent with its temperature requirement for the dissolution of polymeric materials is crucial in the solvent-based recycling process. Therefore, an innovative MATLAB program named HSPs-TPT was designed and constructed in this work to evaluate the dissolving power of solvents. Through this program, the solubility of the waste PET polymer was examined in thirteen (13) different solvents at different temperatures. As a results, the degree of waste PET polymer dissolution in the solvents was presented as the polymer-solvent solubility diagram, which provided the information about the relative energy difference (RED) change with the temperature rise. The program also provided the temperature range effective for the dissolution of PET by indicating the minimum and maximum solubility point for each solvent, which was further validated by the experimental data found in the literature. The proposed MATLAB program can numerically analyse the solubility of a polymer in different solvents in a short time for the recycling process and fabrication of different value-added plastic products such as polymer monoliths and membrane filters. [Display omitted] • The solubility of waste PET was examined in 13 solvents at different temperatures. • A MATLAB program for temperature based solubility analysis has been developed. • The RED changes with the temperature rise was studied for each solvent. • The temperature range for the PET dissolution for each solvent was determined. • The miscibility order at minima and maxima solubility points were discussed. [ABSTRACT FROM AUTHOR]

In this study, the current situation and future prospects of cleaner energy production through concentrated solar power (CSP) plants in Pakistan are analyzed. The assessment of required resources, evaluation of techno-economic feasibility, analysis of existing policy framework, and potential barriers in adopting the concentrated solar thermal technologies in Pakistan are presented. Six potential sites for installing solar thermal power plants are selected on the basis of solar resource assessment, land availability, and feasible infrastructure. A case study of a 100 MW parabolic trough collector (PTC) solar thermal power plant is simulated for these potential sites by using the System Advisor Model (SAM) software. The optimization of solar field size and thermal energy storage is performed to obtain the minimum Levelized cost of electricity (LCOE) for each potential site. Results indicate that the LCOE under the optimized configuration of the PTC solar thermal power plant in Pishin and Quetta can be minimized to 14.7 cents/kWh and 15.3 cents/kWh, respectively. Although the LCOE is the lowest in Pishin, the better availability of the desired infrastructure including transmission lines, water facility, and grid stations in Quetta makes it a more favorable site for installing the PTC solar thermal power plant. Furthermore, a discussion of government policies, along with major barriers (financial, political, infrastructural, technical, and social) that hinder the development of concentrated solar thermal technologies in Pakistan, is presented in detail. In order to overcome these barriers, several recommendations, including the introduction of financial incentives to investors, promoting private stakeholders, the establishment of research facilities in the country, and educating the general population regarding the benefits of clean energy are also outlined. • Potential and viability of CSP generation in Pakistan is evaluated. • Solar, infrastructural, and land resource assessment for CSP generation is presented. • Techno-economic evaluation of 100 MW PTC solar thermal power plant is performed. • Pishin and Quetta are techno-economically favorable regions for CSP generation. • Policy framework and potential barriers for CSP generation in Pakistan are presented. [ABSTRACT FROM AUTHOR]