Wet Impregnation Method Research Articles

β-Cyclodextrin-Stabilized CuO/MXene Nanocomposite as an Electrode Material for High-Performance Supercapacitors.

Supercapacitors are the best energy storage systems due to their high power density, quick charge/discharge rate, and long-term reliability. In this study, β-cyclodextrin-stabilized CuO nanoparticles (CuO@βCD NPs) were synthesized through a simple reduction method and anchored on the surface of MXene nanosheets in three different proportions (1:1, 4:1, and 1:4) to obtain CuO@βCD/MXene nanocomposites through the wet-impregnation method. The formation of CuO@βCD NPs and their physicochemical characteristics were verified by XRD, XPS, FE-SEM, and HR-TEM analysis. The actual focus is on the evaluation of the electrochemical performances of CuO@βCD, MXene, and CuO@βCD/MXene nanocomposites for supercapacitor applications. The cyclic voltammetry and galvanostatic charge-discharge analysis revealed the pseudocapacitance and an improved specific capacitance of 1693.43 F g-1 at 0.90 A g-1 for the CuO@βCD/MXene (1:1) nanocomposite. The electrochemical impedance analysis displays superior electrical conductivity with a low charge transfer resistance value on incorporating CuO@βCD between the MXene layers. Furthermore, the CuO@βCD/MXene (1:1) nanocomposite exhibited improved long-term cycling stability by retaining 86% of its initial specific capacitance even after the 10,000th cycle at the current density of 4.54 A g-1. Based on the electrochemical performance, the CuO@βCD/MXene (1:1) nanocomposite proves its suitability as an electrode material for supercapacitor application with long-term cycling stability and rate capability.

Impact of chelating agents on precursor formation and efficiency of Ni/MgO-Al2O3 catalysts in dry reforming of methane

Using cheap and non-toxic chelating agents during catalyst preparation is considered as an effective tool to control the particle size and to strengthen the metal-support interactions (MSI), while keeping the simplicity of the selected preparation method. The previous properties are useful to improve the catalyst activity, stability, and selectivity in dry reforming of methane (DRM). Therefore, we prepared a series of low Ni loading (2.5 wt%) catalysts supported over MgO-Al2O3 (Mg/Al = 1.3) mixed oxide using the classic wet impregnation method modified with chelating agents (citric acid (CA), tartaric acid (TA) and diethylenetriaminepentaacetic acid (DTPA)) and subsequently evaluated these in DRM. Intensive catalyst characterization (ICP, BET, XRD, XPS, STEM, H2-TPR and O2-TPO) suggested the presence of different structure-activity relationships. Particularly, using chelating agents during catalyst preparation controlled the final particle size range, which in turn played a pivotal role in shaping the strength of the metal support interactions (MSI). These impacts were crucial to improve the activity, stability and to control the formation of coke deposits. Moreover, special focus was put on the catalytic testing of the outperforming sample (Ni(TA)/Mg1.3AlOx) prepared using tartaric acid as chelating agent under severe regimes prone to catalyst deactivation to demonstrate the benefits of the proposed preparation technique.

Graphene with different groups on the interfacial properties of carbon fiber/epoxy composites

To achieve better interfacial adherence of carbon fibers to the epoxy resin, the graphene modified with ammonia and 3-Glycidyloxypropyl trimethoxysilane (GPTMS) was utilized to modify the epoxy resin. Subsequently, a simple two-step method of wet impregnation and the thermoforming process was employed to fabricate the CF/graphene-modified epoxy (CF/EG/EP) composites. The interfacial properties of CF/EP composites were studied using microdroplet debonding and short-beam shear tests on modified graphene (MEG). It is shown that the incorporation of GPTMS-modified graphene into the CF/EP composites strengthened the interfacial and bending properties of CF and matrix, resulting in a 12.5 % growth in interlaminar shear strength (ILSS) and 22.5 % growth in flexural strength of the CF/EP composites, respectively. Meanwhile, scanning electron microscope images confirmed the effectiveness of the GPTMS-modified graphene in improving the interfacial compatibility and adhesion of CF/EP composites.

Ni-modified MIL-100(Fe) catalysts for CO-SCR of NO and reaction mechanism

To promote the activation of the catalysts in the presence of oxygen and at lower temperatures for the selective catalytic reduction of NO with CO (CO-SCR), iron-based metal-organic frameworks (MOFs) catalysts, called MIL-100 (Fe), were prepared by hydrothermal synthesis and further modified with Ni by wet impregnation method. The CO-SCR of NO was evaluated in a fixed-bed reactor. Results proved that the NO conversion over MIL-100(Fe) and 5.8 %Ni-modified catalysts under oxygen-free conditions was 96.6 % and 100 % at 325 °C, respectively. When 2 vol% oxygen was present, the NO conversions over MIL-100(Fe) and 5.8 %Ni modified catalysts at 250 °C were 37.2 % and 96.6 %, respectively, demonstrating that the Ni-modified MIL-100(Fe) catalyst obviously improved the CO-SCR reactivity under O2 atmosphere. UV–vis DRS, HRTEM, FTIR, TGA, etc., and in situ DRIFTS techniques were used to characterize the physical and chemical properties of the catalysts and study the reaction mechanism. The outcomes demonstrated that the incorporated Ni engaged in interactions with Fe the CO-SCR reaction, resulting in the formation of additional surface or surface synergistic oxygen vacancies (SOV and SSOV), thus improving the redox performance of catalysts. Additionally, the Ni-modified catalyst had better redox performance, which was beneficial to converting the adsorbed NOx substances into active substances. The adsorption behavior of NO, CO, and the reaction intermediates were investigated by in situ DRIFTS and a preliminary reaction path was proposed.

Intensifying levulinic acid hydrogenation using mechanochemically prepared copper on manganese oxide catalysts

A series of copper nanoparticles supported on manganese oxide octahedral molecular sieves (OMS-2) were prepared using mechanochemical (Ball-Mill) and conventional wet-impregnation (Wet-Imp) methods. All catalysts prepared were thoroughly characterized using ICP-OES elemental analysis, X-ray diffraction (XRD), N2 sorption, H2 temperature programmed reduction (TPR) and transmission electron microscopy (TEM) techniques. The catalyst preparation methods greatly affected the size of the Cu nanoparticles. TEM images showed that 5 wt% Cu/OMS-2 (Ball-Mill) catalyst had a narrow particle size distribution with an average Cu nanoparticle size of 2.1 nm, while the corresponding 5 wt% Cu/OMS-2 catalyst prepared using wet-impregnation method had an average Cu nanoparticle size of 19.2 nm. The structural features of the catalysts were corelated with the catalytic activity using the liquid phase hydrogenation of levulinic acid (LA) to γ-valerolactone (GVL), as an exemplar process. In LA hydrogenation at 190 °C and 20 bar H2 pressure, the ball milled catalysts achieved higher LA conversion, and greater GVL yield, as compared to the corresponding catalysts prepared by wet-impregnation method, reinforcing that Cu nanoparticle size and metal dispersion are important tool to intensify the catalytic activity. For instance, 5 wt% Cu/OMS-2 (Ball-Mill) catalyst achieved almost twice the turnover frequency (TOF), 24.7 h−1 as compared to the 5 wt% Cu/OMS-2 (Wet-Imp) catalyst, TOF 11.8 h−1, under identical reaction conditions. The results of this study demonstrate that ball milling is a superior method for Cu/OMS-2 catalyst preparation than wet impregnation.

Direct air CO2 capture using coal fly ash derived SBA-15 supported polyethylenimine

Designing an amine modified silica derived from coal fly ash (CFA) towards direct air CO2 capture (DAC) provides an economic way to manage increasing atmospheric CO2 concentration utilizing solid wastes. In this work, rod-like SBA-15 (SBA-15-R) and wheat-like SBA-15 (SBA-15-W) with distinct pore lengths are synthesized from CFA by controlling the synthesis conditions and then modified by PEI via the wet impregnation method. Their CO2 adsorption behaviors under sub-ambient conditions are investigated to explore their feasibility under aggressive conditions. The adsorbents with various silica morphologies exhibit distinctive CO2 adsorption performance under ambient and sub-ambient conditions. At 35°C under dry conditions, the CO2 adsorption capacity increases with amine loading. The CO2 adsorption capacity (qe) of SBA-15-W-PEI with long channels reaches the highest qe of 1.92 mmol/g with 70 wt.% PEI loading due to a large amount of strong chemisorption sites. Under the sub-ambient conditions (-20°C, 400 ppm), SBA-15-R-PEI30 with short channels having weaker CO2 diffusion resistance exhibits promising CO2 uptake of 0.83 mmol/g. These findings indicate that the ultra-dilute CO2 adsorption at ambient temperature requires an adsorbent with large amounts of adsorption sites, whereas the adsorbents for cold temperature application should reconcile amine loading with CO2 diffusion resistance inside pores. The co-adsorption of H2O and CO2 significantly improves CO2 capacity from 0.83 mmol/g and 1.92 mmol/g to 1.81 mmol/g and 3.48 mmol/g for SBA-15-R-PEI30 (-20°C, 400 ppm) and SBA-15-W-PEI70 (35°C, 400 ppm), respectively. Furthermore, the CFA derived SBA-15-PEI shows good cyclic stability during five consecutive TSA cycles. Preparing the amine silica adsorbents from coal fly ash potentially reduces the adsorbent cost of DAC devices. Moreover, the systematic exploration of amine silica adsorbents at a wide range of temperatures guides the design of high-performance CO2 adsorbents employed under various climatic conditions.

Construction of a stable S-scheme NiSnO3/g-C3N4 heterojunction on activated carbon fibre for the degradation of glyphosate in water under flow condition

Creating light-harvesting heterojunctions as a photocatalyst is critical for efficiently treating organics-laden wastewater. Yet the materials stabilization and limited reusability hinder their practical applications. In this study, an S-scheme heterojunction in the Sn-based perovskite and g-C3N4 (gCN) composite, supported on an activated carbon fiber (ACF) substrate, is developed for glyphosate (GLP) degradation under water under flow conditions. The reusable NiSnO3-gCN/ACF photocatalyst was synthesized using a simple wet impregnation and calcination method. The supported photocatalyst achieved 99% GLP-removal at 4 mL/min water flowrate and 1.25 g/m2 of photocatalyst loading in ACF. The photocatalyst showed a stable structure and repeat photocatalytic performance across 5 cycles despite prolonged visible light exposure under flow conditions. The materials stability is attributed to the effective dispersion of NiSnO3-gC3N4 in ACF, preventing the photocatalyst from elution in water flow. Radical trapping experiment revealed the superoxide and hydroxyl radicals as the primary reactive species in the GLP-degradation pathway. A plausible S-scheme mechanism was proposed for heterojunction formation, based on the high resolution deconvoluted spectra of X-ray photoelectron spectroscopy and the radical trapping experimental results. The inexpensive Sn-based perovskite synthesized in this study is indicated as an alternative to Ti-based perovskites for wastewater remediation application.

Nanosized Silica-Supported 12-Tungstophosphoric Acid: A Highly Active and Stable Catalyst for the Alkylation of p-Cresol with tert-Butanol

12-Tungstophosphoric acid supported on nanosilica (TPA/SiO2) was employed as a catalyst for the tertiary butylation of p-cresol using tertiary butanol as an alkylating agent. The TPA/SiO2 catalyst was synthesized using the wet impregnation method followed by steaming at 150 °C for 6 h. The catalysts were characterized by means of X-ray diffraction (XRD) and Transmission Electron Microscopy (TEM) analysis. The surface acidity of the untreated and steamed catalysts was characterized via FTIR and DSC thermal analysis using pyridine as a probe molecule. The fresh and spent catalysts were characterized via TGA analysis. The catalytic activity studies showed that the steamed catalyst displayed higher activity, with a higher desired yield of 2-tert-butyl cresol (2-TBC) compared to the untreated catalyst, and that this activity was related to the presence of stronger Brønsted acid sites in the steamed catalyst. A detailed analysis of the TPA/SiO2 steamed catalyst was performed to study the effects of reactant time-on-stream, reactant feed rate, reaction temperature, and the molar ratio of tert-butanol to p-cresol. The optimum reaction temperature, tert-butanol/p-cresol molar ratio, feed rate, and time-on-stream were 413 K, a molar ratio of 2:1, 6 mL/min, and 2 h, respectively. The present study demonstrates that the TPA/SiO2 catalyst exhibits high activity in terms of % conversion and high % selectivity of 2-TBC under the optimized conditions. The characterization of fresh and spent catalysts confirmed the occurrence of coke deposition after the catalytic reaction. The catalyst was regenerated via heat treatment at 400 °C for 5 h. The regenerated catalyst was reused for subsequent runs for three cycles without showing a loss in its activity.

Effects of MgO doping in Pd/γ-Al2O3 catalysts forthe hydrogenation of perfluoro olefin

Gamma alumina is widely utilized for preparing the supported noble metal catalysts for the hydrogenation reaction. It is an effective strategy to improve the catalytic performance of catalysts via modifying gamma alumina with alkaline earth metal to regulate its surface acidity and electronic properties. Herein, Pd catalysts supported by Al2O3 and Mg-modified Al2O3 are synthesized via the wet impregnation method, and the effects of MgO doping on the structure, composition, and surface acidity of Pd/γ-Al2O3 catalysts are investigated via X-ray diffraction patterns (XRD), Transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and Temperature programmed desorption (TPD). The results show that Pd/MgO-Al2O3–2 (γ-Al2O3 modified with 2 wt% Mg) has more metallic state palladium and weak acid sites and exhibits the best catalytic performance for the hydrogenation of perfluoro-4-methyl-2-pentene (D1). Density functional theory (DFT) calculations on Pd/Al2O3 and Pd/MgO-Al2O3–2 catalysts are also performed to further explore the mechanism of D1 hydrogenation. The studies for Gibbs free energy of the potential reaction steps and intermediates reveal a complex process to generate the target product C6F12H2, and the rate-determining-step is the addition of the first hydrogen on the second carbon of perfluoro-4-methyl-2-pentene molecule.

Hydrogen-Rich Syngas Production via Dry and Steam Reforming of Methane in Simulated Producer Gas over ZSM-5-Supported Trimetallic Catalysts

This study investigated the production of hydrogen-rich syngas from renewable sources using durable and efficient catalysts. Specifically, the research focused on steam methane reforming (SRM) and dry methane reforming (DRM) of simulated producer gas from biomass steam gasification in a fluidized bed reactor. The catalysts tested are ZSM-5-supported nickel-iron-cobalt-based trimetallic catalysts in different ratios, which were prepared via the wet impregnation method. Synthesized catalysts were characterized using XRD, BET, H2-TPR, and SEM techniques. The results of the SRM with the simulated producer gas showed that the 20%Ni-20%Fe-10%Co/ZSM-5 trimetallic catalyst, at a gas hourly space velocity (GHSV) of 12 L·h−1·g−1 and reaction temperature of 800 °C, achieved the highest CH4 conversion (74.8%) and highest H2 yield (65.59%) with CO2 conversion (36.05%). Comparing the performance of the SRM and DRM of the simulated producer gas with the 20%Ni-20%Fe-10%Co/ZSM5 at a GHSV of 36 L·h−1·g−1 and 800 °C, they achieved a CH4 conversion of 67.18% and 64.43%, a CO2 conversion of 43.01% and 52.1%, and a H2 yield of 55.49% and 42.02%, respectively. This trimetallic catalyst demonstrated effective inhibition of carbon formation and sintering, with only 2.6 wt.% carbon deposition observed from the thermo-gravimetric analysis of the used catalyst from the SRM of the simulated producer gas, thus promoting the potential of the ZSM-5-supported trimetallic catalysts in methane reforming.

Catalytic Oxidation of 1,2-Dichlorobenzene over Metal-Supported on ZrO2 Catalysts

The catalytic oxidation of environmentally unfriendly chlorinated organics is a powerful tool that can be used to completely mineralize these organic compounds. In this study, metals (Mn, Ni, V, and Fe) supported on zirconia have been investigated as catalysts in the oxidation of 1,2-dichlorobenzene. Metal supported on zirconia catalysts were prepared using the wet impregnation method. The catalyst materials were characterized by FT-IR, XRD, SEM–EDX, TEM, BET, and ICP methods. Metals were loaded on ZrO2 support at varied wt%, 2.5, 5, 7.5, and 10 which were confirmed by ICP-OES and EDX analysis. The XRD patterns of all the metals loaded on ZrO2 catalysts showed diffraction peaks that belong to the monoclinic phase of ZrO2 and few that are attributed to the oxides of the metals. The BET surface areas showed a significant decrease as the metal was loaded on ZrO2 support. The BET surface area of ZrO2 was 4.91 m2/g and when 2.5 and 7.5 wt% Fe was loaded on ZrO2 the BET surface areas were 4.48 and 3.09 m2/g, respectively. All the ozonation reactions of 1,2-dichlorobenzene were conducted in an impinger unit for 24 h. The aliquots were collected after 3, 6, 9, 12, 15, 18, and 24 of ozonation and analyzed using FT-IR and GC–MS analyses. The 7.5% Fe/ZrO2 was found to have a relatively high catalytic effect toward the conversion of 1,2-dichlorobenzene into mucochloric acid and 3,4-dichloro-2,5-furandione.

Catalytic Performance of Bimetallic Cobalt–Nickel/Graphene Oxide for Carbon Dioxide Reforming of Methane

The design of economical and robust catalysts is a substantial challenge for the dry reforming of methane (DRM). Monometallic nickel-based catalysts used for DRM reactions had comparable activity to noble metals. However, they turned out to be less stable during the reactions. As a continuation of the interest in synthesizing catalysts for DRM, this paper evaluates the catalytic performance of bimetallic Co–Ni catalysts regarding their synergy effect, with graphene oxide (GO) as support for the first time. The synthesized bimetallic catalysts prepared via the wet-impregnation method were characterized using N2 physisorption analysis, scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and X-ray diffraction (XRD). The catalytic test was performed in a stainless-steel tubular reactor in atmospheric conditions with a reaction temperature of 800 °C, time-on-stream (TOS) of 300 min and CH4: CO2 being fed with a ratio of 1:1. The bimetallic 10 wt%Co–10 wt%Ni/GO and 20 wt%Co–10 wt%Ni/GO catalysts had a similar BET specific surface area in N2 physisorption analysis. The XRD pattern displayed a homogeneous distribution of the Co and Ni on the GO support, which was further validated through SEM–EDX. The conversion of CO2, CH4, and H2 yield decreased with reaction time due to the massive occurrence of side reactions. High conversions for CO2 and CH4 were 94.26% and 95.24%, respectively, attained by the bimetallic 20 wt%Co–10 wt%Ni/GO catalyst after 300 min TOS, meaning it displayed the best performance in terms of activity among all the tested catalysts.

Highly dispersed Ag2O-CuO nanospheres supported on γ-χ-Al2O3 for methanol dehydration to dimethyl ether

In this manuscript, the wet impregnation method was used to support Ag2O, CuO, and Ag2O-CuO nanoparticles on γ-χ-Al2O3 to assess their catalytic capabilities in the methanol dehydration (MD) reaction to produce dimethyl ether (DME); the operation conditions were 1 atm and temperature ranging between 200 and 240 °C. It was found that Ag2O-CuO/γ-χ-Al2O3 catalyst result in MD conversions up to 88 % and selectivities of 100 %, under 240 °C conditions. The catalytic activity of the Ag2O-CuO/γ-χ-Al2O3 catalyst is related to the high dispersion, homogeneity and larger size of the Ag2O-CuO nanoparticles (∼12.6 nm) compared to Ag2O and CuO nanoparticles, which have sizes of ∼ 9.52 and 10 nm, respectively. Additionally, the catalytic activity of the Ag2O-CuO/γ-χ-Al2O3 material is related to its total acidity (weak and moderate), 0.056 mmol/g, showing a difference of 25 %, 28.57 and 5.35 % with respect to the γ-χ-Al2O3, CuO/γ-χ-Al2O3 and Ag2O/γ-χ-Al2O3 materials, respectively. Finally, the catalytic stability measurements of the Ag2O-CuO/γ-χ-Al2O3 catalyst remained relatively constant over time, presenting a conversion value of 79 % after 2.6 h of reaction due to the low apparent activation energy, 112.6 kJ/mol. The results of the exergy analysis indicate that the chemical exergy of the system ranges between 1/6 and 1/3 of the physical exergy, and most of the energy available to produce work is in the form of heat.

Improved photocatalytic degradation of rhodamine B by g-C3N4 loaded BiVO4 nanocomposites

Photocatalytic degradation has emerged as one of the most efficient methods to eliminate toxic dyes from wastewater. In this context, graphitic nitride (g-C3N4) loaded BiVO4 nanocomposites (5 wt% g-CN@BiVO4 and 10 wt% g-CN@BiVO4) have been fabricated by the wet impregnation method, and their efficiency towards photocatalytic removal of rhodamine B have been investigated under visible light irradiation. These hybrid composites have been characterized by XRD, FESEM, HRTEM, EDS-mapping, UV-Vis DRS, DLS, XPS and BET, etc. The HRTEM images revealed that BiVO4 has a decagonal shape covered by a layered nanosheet-like structure of g-C3N4. BET measurements suggest increasing the proportion of g-C3N4 results enhancement of the specific surface area. Among different photocatalysts, the 10 wt% g-C3N4@BiVO4 hybrid possesses the best catalytic activity with 86% degradation efficiency after 60 min of reaction time. The LC-MS studies suggest that the degradation reactions follow the de-ethylation pathway. Even after five cycles, the heterostructure shows only a 14% decrease in photocatalytic activity, confirming its stability. As a result, the binary composite can be regarded as a promising catalyst for the degradation of pollutants due to its ease of preparation, high stability and superior catalytic activity.

Photocatalytic Degradation of Methylene Blue Using TiO2/Graphene Photocatalyst

This study focused on the photocatalytic degradation of methylene blue (MB) under ultraviolet light irradiation. The photocatalyst used for methylene blue degradation was the composite of titanium dioxide and graphene, synthesized using the wet-impregnation method. The composition of TiO2/graphene was varied into three different mass ratios to characterize the composite further and identify the best photocatalyst for optimization. For each mass ratio, three affecting parameters, which were photocatalyst dosage, initial MB concentration and irradiation time, were employed to investigate the effects of degradation efficiency. Then, the statistical analysis for the photocatalytic degradation of MB using the most efficient TiO2/graphene photocatalyst was performed by utilizing the Response Surface Methodology.

Copper loading effect on active species formation over Cu/SSZ-13 catalysts for selective catalytic oxidation of high-concentration NH3

Cu/SSZ-13 catalysts not only exhibit superior SCR performance but also possess excellent selective catalytic oxidation (SCO) ability to remove NH3 escaped from engine exhaust gas fueled by NH3. To elucidate the effect of Cu loading on Cu/SSZ-13 catalysts, a series of Cu/SSZ-13 catalysts were prepared through wet impregnation method to remove high-concentration NH3 (5000 ppm). The SCO activity test results showed that when Cu loading increased from 1% to 10%, there was an obvious improvement effect on NH3 conversion performance at low temperature. Cu10/SSZ-13 catalyst reached a high NH3 conversion of 96% at 250 °C, and N2 selectivity was higher than 86% in the whole temperature range. However, when further increasing Cu loading from 10% to 20%, there was no distinctive difference in NH3 conversion and N2 selectivity. The characterization results indicated that there were abundant active species, adsorbed oxygen species, and acid sites on the surface of Cu10/SSZ-13 catalyst. The [Cu(OH)]+ and isolated Cu2+ species in zeolite channels of Cu10/SSZ-13 catalyst rather than CuO species on the surface played a key role in NH3-SCO reactions. Since 20% Cu loading would result in a significant decrease in isolated Cu2+ species, it resulted in both [Cu(OH)]+ species in zeolite channels and superfluous Cu species on zeolite surface being main active species in NH3-SCO reactions. In-situ DRIFTS experiments suggested that NH3-SCO reactions over Cu/SSZ-13 catalysts followed the internal selective catalytic reduction (i-SCR) mechanism.

Palladium-Containing Catalysts Based on Functionalized CNFs for the Dehydrogenation of Methylcyclohexane

The activity of palladium-containing catalysts based on functionalized carbon nanofibers prepared by an incipient wetness impregnation method in the dehydrogenation reaction of methylcyclohexane was investigated. Methylcyclohexane is considered as one of the most promising liquid hydrogen carriers. The dependence of the catalytic characteristics of the samples on the functionalization conditions of carbon nanofibers has been studied. By temperature-programmed desorption, it was shown that an increase in the treatment time of carbon nanofibers in concentrated nitric acid from 1 to 3 h increases the number of hydroxyl groups on their surface, and treatment for 6 h contributes to a rise in the concentration of carboxyl groups and their derivatives (esters and anhydrides). Additional calcination of the functionalized nanofibers in an inert atmosphere at 530°C yielded a sample containing predominantly hydroxyl groups. The presence of hydroxyl groups on the surface of the carbon material has a positive effect on the performance of the catalysts, while the presence of carboxyl groups leads to a decrease in the yield of toluene. It is assumed that the observed differences in catalyst activity are due to differences in dispersion and localization of palladium particles.

Process optimization of rice husk ash supported catalyst in biodiesel synthesis using response surface methodology approach

Biodiesel is sustainable and biodegradable energy that is synthesized from renewable material consisting of a high capability to replace energy from fossil fuels. This research focused on biodiesel synthesis from waste cooking oil utilizing rice husk ash (RHA) supported catalysts. A series of alkaline earth metal oxide, calcium oxide, and strontium oxide supported on RHA catalyst; CaO/RHA and SrO/RHA catalysts were synthesized via wetness impregnation method with varied calcination temperatures and ratios. It was found that the 10SrO/90RHA (900 °C) catalyst produced maximum biodiesel yield (89.97%) over the transesterification process from waste cooking oil, while the catalytic activity of 10CaO/90RHA (800 °C) catalyst demonstrated the 83.09% of biodiesel yield. Further analysis on optimization of parameters for transesterification reaction using 10SrO/90RHA (10:90) catalyst revealed that higher biodiesel produced at a reaction temperature of 65 °C, catalytic loading of 6 wt%, oil-to-methanol of 1:18 mol ratio and reaction time of 1 h. The optimization for the 10SrO/90RHA (900 °C) catalyzed reaction was then verified using response surface methodology (RSM) throughout Box-Behnken design (BBD). The characteristics of the produced biodiesel, under optimal process conditions, comply with the standards set by ASTM D6751 and EN 14214 for fuel quality.

Silver Nanoparticles/Titanium Dioxide Nanowires Photocatalyst Formation for Microplastic Removal Using Ultraviolet Radiation

Microplastic is the most problematic persistent pollutants in the environment despite of its unique properties for various life application. The objective is to investigate the feasibility and practicability of the nanostructured TiO2 coupling with noble metal in removal polypropylene (PP) microplastics. The TiO2 nanowires (NWs) were synthesized by thermal oxidation of Ti foil under various mixed oxidation environments. TiO2 NWs were successfully grown uniformly and with full coverage over the foil under the condition of ramping in KOH mist and soaking in water vapour at 700 °C for 120 minutes. Heterojunction photocatalyst of Ag/TiO2 NWs was formed using wet impregnation method. Small quantity of Ag nanoparticles (NPs) was attached onto the TiO2 nanowires. The photocatalytic efficiency of the synthesized Ag/TiO2 NWs photocatalyst was tested upon removal of PP microplastic from non-static water bodies under UV irradiation. Coupling Ag NPs with TiO2 NWs have better photocatalytic performance than those without Ag NPs from the reduction of weight loss and the possibility of presence of carbonyl group.

Catalytic co-pyrolysis of plastic pyrolyzed and biooil over Ni-modified ZSM-5 hierarchical structures

Hierarchical designing of (10 wt% - 70 wt%) nickel over HZSM-5 zeolite was done using wet-impregnation method. The material formation was established by XRD, BET, TPD and TEM studies. Optimization of reaction parameters for mixture of LDPE derived oil and waste cooking oil was found to be 450 °C, 4.6 h−1, 1:1, and 2nd h. The oxygenated and aliphatic molecules from catalytic co-pyrolysis were effectively transformed, resulting in an elevated selectivity to BTX (as high as 29.7%) and an increased relative selectivity of aromatics to the highest of 97.3%. Despite the comparatively short carbon chains of LBF components, activating the co-pyrolysis products with Ni/HZSM-5 (50 wt %) was found to be helpful in improving subsequent aromatization reactions with biomass pyrolysis intermediates. This work offers a new technique for the co-utilization of abundant biooil and most unused PPL with additional value, which helps to produce renewable chemicals while lowering environmental pollution.