Variation Of Calcination Temperature Research Articles

In-depth investigation of microstructure and optical properties of tri-phase TiO2 nanoparticles at varied calcination temperatures for dye sensitized solar cells (DSSCs) applications

Tri-phase TiO2 nanoparticles are synthesized by facile hydrothermal method and calcinated within a temperature range of 450 °C–1050 °C. These nanoparticles are utilized as photoanode material in dye-sensitized solar cell (DSSC) applications. The device fabricated by utilizing TiO2 NPs calcinated at 600 °C reveals a maximum power conversion efficiency (η) of 3.79 %, with a current density (Jsc) of 7.83 mA cm−2 under one sun illumination among all tested devices. This exceptional achievement is related to the synergistic effect of 49 wt % anatase, 39 wt % rutile and 12 wt % brookite content in triphasic TiO2 NPs. The anatase emerges as the most active phase providing a sufficient surface area for dye adsorption, and in parallel rutile phase enhances the scattering of light that potentially boosts mobility and injection of photogenerated electrons (e-s) from the LUMO level (ELUMO = −3.8 eV) of N719 dye to the conduction band (ECB = −4.28 eV). Simultaneously, the presence of the brookite phase reduces the charge-carriers ((e−), (h+)) recombination rate at the TiO2 photoelectrode/electrolyte interfaces because brookite has an inherent resistance to back electron transfer. The effective light-harvesting capabilities of triphasic TiO2 NPs position them as promising contenders for dye-sensitized solar cells (DSSCs).

Evaluation of Impact of Calcination Temperatures on Kola Nut Pod Residue as Catalyst for Biodiesel Synthesis

The research explores the viability of Kola Nut Pod (KNP) residue, derived from kola fruit in West African countries, as a catalyst for biodiesel synthesis. The abundant KNP husk, a byproduct, raises environmental concerns if discarded directly. The study aims to utilize KNP as a biocatalyst to address environmental issues and reduce biodiesel feedstock costs. Applying calcination temperatures from 500 to 900 ℃, the resulting ash undergoes chemical analysis to determine the optimal temperature for catalyst formation. The material undergoes pre-treatment, including drying and grinding, with varied calcination temperatures to obtain ash products. Chemical, elemental, and X-ray Diffraction (XRD) analyses characterize both uncalcined and calcined samples. The uncalcined sample contains SiO2, Al2O3, CaO, MgO, K2O, and other oxides, with CaO as the predominant component. Calcination temperature effects indicate increased SiO2 and Al2O3, while CaO remains stable, presenting KNP as a promising biodiesel catalyst feedstock. Elemental composition analysis identifies potassium as the key catalytic contributor. The CaO content shows an increase from the uncalcined state (29.52%) to 42.81% at 500 and 600°C, and relatively stable at 41% from 700 to 900°C. The elemental composition reveals that potassium is the most abundant element at 31.7%, followed by calcium (17%), and magnesium (7.4%). XRD analysis confirms CaO as the primary compound in calcined KNP ash, with Ca (OH)2 and KCl occurrences. The study offers insights into the optimal calcination temperature for KNP-derived catalysts, underscoring Kola Nut Pod residue's potential as a cost-effective and eco-friendly source for biodiesel production.

Optimizing the photocatalytic performance of SnO2 nanoparticles for methylene blue removal with variation in calcination temperatures

In recent years, numerous studies have been conducted to combine tin oxide (SnO2) with various semiconductor materials to boost its photocatalytic efficiency for water waste treatment, with minimal emphasis placed on intensifying the intrinsic capabilities of pure SnO2. The primary objective of this study is to enhance the photocatalytic efficiency of pure SnO2 nanoparticles (NPs) by modifying their morphology, structural, and optical properties. The SnO2 NPs were synthesized using precipitation method, followed by a calcination process at varying temperatures (non-calcined, 300 °C, and 500 °C). The changes in properties of SnO2 NPs were investigated utilizing X-ray diffraction (XRD), scanning electron microscopy (SEM), particle size analysis (PSA), Brunauer-Emmett-Teller (BET), and ultraviolet-visible (UV-Vis) spectroscopy. The results indicated that elevating the calcination temperature up to 500 °C resulted in an increase in both the average crystallite size (up to 10.50 nm) and crystallinity (up to 85.28 %). However, the highest photocatalytic efficiency for methylene blue degradation of 84.78 % was obtained from the SnO2 NPs calcined at 300 °C sample exhibiting the largest surface area of 83.97 m2g-1. This study affirms that the specific surface area of SnO2 NPs is a critical factor in their efficacy for degrading dye-contaminated water waste.

Hydrothermally assisted Cr@Zn bimetal sulfide nanoparticles with varying calcination temperature as battery grade material for supercapattery

A newly introduced hybrid device, supercapattery has captured the attention of researchers worldwide for its potential to achieve high energy and power density. The performance of this supercapattery depends highly on the materials of the electrodes. Recent research processes: using single transition metal sulfides as electrode materials for their specific capacity and rapid charge transfer processes; however, it suffers from poor electrical conductivity. Therefore, in this work, a novel bimetal Chromium Zinc Sulfide (Cr@ZnS) was synthesized to improve the conductivity via creation of synergistic effect between Cr and Zn ions. During the preparation method, different reducing agents (KOH and NaOH) were used to study the effect of the reducing agents on the electrochemical performance of Cr@ZnS. It was perceived that addition of KOH exhibits better charge storage capacity compared to addition of NaOH as they influence the production of S2- ions during the Cr@ZnS formation. The produced Cr@ZnS was then subjected under different calcination temperatures (100 °C, 200 °C and 300 °C) to investigate its effect on Cr@ZnS performance. From this work, it was revealed that calcination deteriorates the electrochemical performance of Cr@ZnS due to occurrence of morphological evolution in Cr@ZnS. The maximum specific capacitance achieved by Cr@ZnS electrode is 1338.85F g−1 at 3Ag−1. When the optimized Cr@ZnS electrode was coupled with AC, the device exhibited excellent energy and power density value of 29.15 Wh kg−1 and 18.85 kW kg−1, respectively with a decent capacity retention of 82 % over 10,000 cycles.

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.

Calcination temperatures influence the chemo-resistive gas sensing properties of biogenic zinc oxide nanoparticles with antibacterial activity

This study aimed to optimize Garcinia indica leaf extract mediated biogenic synthesis of antibacterial zinc oxide (ZnO) nanoparticles (NPs) and investigate how the calcination temperatures influence the structural and gas sensing properties of ZnO NPs. To study the effects of calcination temperatures, the optimally biosynthesized ZnO NPs were calcined at different temperatures in the range of 350-500 °C, used for the fabrication of thin films and characterized by various spectroscopic and imaging techniques. Characterization techniques confirmed that ZnO NPs were spherical with crystallite size in the range of 20-30 nm, mesoporous (with slit-shaped pores 1-10 nm), and had low band gap energy. Further, calcination temperatures were found to significantly influence the defect energy levels, porosity, surface roughness, and oxygen vacancies. In addition, the variation in calcination temperature was found to influence the gas response (Rg/Ra), relative response (%), sensitivity, response time, recovery time, and reproducibility. A higher gas response (231) was recorded for a thin film of ZnO NPs calcined at 400 °C than other tested temperatures. The average response and recovery time were 1 s and 218 s respectively for differently calcined ZnO NPs. ZnO NPs calcined at 400 °C were also found to exhibit remarkable antibacterial activity against E. coli and B. subtilis.

Life cycle assessment of coal gangue composite cements: From sole OPC towards low-carbon quaternary binder

Cement production is responsible for substantial anthropogenic CO2 emissions, and various solid wastes have been explored as replacements for cement clinker to produce composite cements in lowering the carbon footprint. The composite cements are claimed to be more environmentally friendly than ordinary Portland cement (OPC) in most Life Cycle Assessment (LCA) studies but overlooking the environmental burden from upstream material and strength degradation after replacing the cement may cause significant inequities between LCA models. This paper aims to present a comprehensive LCA, starting from sole OPC through binary and ternary, and followed by a high-volume replacement of OPC with alternative materials, known as quaternary composite cements. The latter incorporated coal gangue, limestone, and ground granulated blast furnace slag as cement replacements. The uncertainty caused by the variation of calcination temperature and kaolinite content of coal gangue were assessed by Monte-Carlo analysis. Results show that ternary composite cement is more recommended in comparison to binary composite cement, considering the very minimal emissions from limestone production, and a calcination temperature of 600 °C is the most recommended owing to the wider selection kaolinite content range of CG. The quaternary composite cement was determined to achieve the most satisfying performance from both mechanical and global warming potential perspectives. However, after considering the environmental burdens of upstream processes as allocation, additional attention should be paid to the deterioration of other environmental impacts, such as freshwater quality and human carcinogenic toxicity.

Effect of varying calcination temperature on the structural and optical properties of tin oxide nanoparticles

Tin oxide nanoparticles were synthesized with sol–gel method. The structural, morphological and optical properties of the as-synthesized tin oxide nanoparticles calcined at 400 °C, 600 °C, and 800 °C were studied. The average crystallite size of 7.56 nm, 23.13 nm and 25.01 nm was evaluated through XRD analysis at 400 °C, 600 °C, and 800 °C, respectively, which shows that the average crystallite size of SnO2 nanoparticles increased with the increase in calcinations temperature. UV–Vis spectroscopy revealed that the SnO2 nanoparticles calcined at 400 °C shows larger absorption in the near ultra-violet region as compared to 600 and 800 °C. The band gap energy (Eg) of the synthesized nanoparticles shows a decrease in Eg with the decrease in calcinations temperature, which is 3.030 eV, 3.147 eV, and 4.139 eV at 400 °C, 600 °C and 800 °C, respectively.

Single-Step Synthesis of Graphitic Carbon Nitride Nanomaterials by Directly Calcining the Mixture of Urea and Thiourea: Application for Rhodamine B (RhB) Dye Degradation

Recently, polymeric graphitic carbon nitride (g-C3N4) has been explored as a potential catalytic material for the removal of organic pollutants in wastewater. In this work, graphitic carbon nitride (g-C3N4) photocatalysts were synthesized using mixtures of low-cost, environment-friendly urea and thiourea as precursors by varying calcination temperatures ranging from 500 to 650 °C for 3 h in an air medium. Different analytical methods were used to characterize prepared g-C3N4 samples. The effects of different calcination temperatures on the structural, morphological, optical, and physiochemical properties of g-C3N4 photocatalysts were investigated. The results showed that rhodamine B (RhB) dye removal efficiency of g-C3N4 prepared at a calcination temperature of 600 °C exhibited 94.83% within 180 min visible LED light irradiation. Photocatalytic activity of g-C3N4 was enhanced by calcination at higher temperatures, possibly by increasing crystallinity that ameliorated the separation of photoinduced charge carriers. Thus, controlling the type of precursors and calcination temperatures has a great impact on the photocatalytic performance of g-C3N4 towards the photodegradation of RhB dye. This investigation provides useful information about the synthesis of novel polymeric g-C3N4 photocatalysts using a mixture of two different environmentally benign precursors at high calcination temperatures for the photodegradation of organic pollutants.

Impact of two-step calcination on microstructure, phase, electronic, and dielectric properties of KCa2Nb3O10 bulk layered perovskite

ABSTRACT The effects of varying calcination temperature, K content, and the number of calcination steps in the dielectric performance of KCa2Nb3O10 synthesized via solid-state reaction are investigated. Adding an extra calcination step at 500°C followed by another calcination at 1100°C suppressed the formation of secondary phases while maximizing the relative density (95%) and the average grain area (2.12 μm2). The first calcination at 500°C ensures the formation of intermediate phases (KNbO3 and Ca2Nb2O7), which are prerequisites for single-phase KCa2Nb3O10 synthesis. A significantly high dielectric constant of 352 at 100k Hz is achieved in the two-step calcined sample despite the low sintering temperature of 1250°C. The highest resistivity of the two-step calcined sample (2 × 108 Ω cm) obtained from complex impedance analysis supports its lowest dielectric loss (0.034 at 100k Hz). When the two-step calcined KCa2Nb3O10 powder is exfoliated, much higher dielectric properties of Ca2Nb3O10 nanosheets are expected.

Synthesis of nanosize zinc oxide through aqueous sol–gel route in polyol medium

BackgroundThis study is aimed to synthesize nanosize zinc oxide by acid catalyzed sol–gel process using zinc nitrate hexahydrate as precursor, aqueous isopropanol as solvent and glycerin for making polyol system. The polyol mediated procedure was employed in combination with calcination induced synthesis of nanoparticles of numerous sizes obtained with the variation in calcination temperature from 500 to 900 ℃. The crystal structure of the prepared samples was characterized by X-ray diffraction analysis (XRD). Infrared spectroscopy (IR) was used to identify the surface hydroxyl groups. Thermal stability was confirmed by differential scanning calorimetry-thermogravimetric analysis (DSC-TGA) whereas field emission scanning electron microscopy (FESEM) was used to study the surface morphology of nanoparticles.ResultsResults revealed the formation of hexagonal wurtzite structure of irregular shaped nanoparticles having size ranging from 50–100 nm. However, the particles combined to form agglomerates of 200–400 nm with the rise in calcination temperature.ConclusionsThese results indicate that nanosize zinc oxide can be synthesized successfully by a simple process comprising of glycerin as a low-cost, non-toxic and eco-friendly polyol followed by calcination at ambient temperatures.

Effect of Calcination Temperature on Structural, Morphological and Optical Properties of Copper Oxide Nanostructures Derived from Garcinia mangostana L. Leaf Extract.

Synthesis of copper oxide (CuO) nanostructures via biological approach has gained attention to reduce the harmful effects of chemical synthesis. The CuO nanostructures were synthesized through a green approach using the Garcinia mangostana L. leaf extract and copper (II) nitrate trihydrate as a precursor at varying calcination temperatures (200–600 °C). The effect of calcination temperatures on the structural, morphological and optical properties of CuO nanostructures was studied. The red shifting of the green-synthesized CuO nanoparticles’ absorption peak was observed in UV-visible spectrum, and the optical energy bandgap was found to decrease from 3.41 eV to 3.19 eV as the calcination temperatures increased. The PL analysis shown that synthesized CuO NPs calcinated at 500 °C has the maximum charge carriers separation. A peak located at 504–536 cm−1 was shown in FTIR spectrum that indicated the presence of a copper-oxygen vibration band and become sharper and more intense when increasing the calcination temperature. The XRD studies revealed that the CuO nanoparticles’ crystalline size was found to increase from 12.78 nm to 28.17 nm, and dislocation density decreased from 61.26 × 1014 cm−1 to 12.60 × 1014 cm−1, while micro strain decreased from 3.40 × 10−4 to 1.26 × 10–4. From the XPS measurement, only CuO single phase without impurities was detected for the green-mediated NPs calcinated at 500 °C. The morphologies of CuO nanostructures were examined using FESEM and became more spherical in shape at elevated calcination temperature. More or less spherical nanostructure of green-mediated CuO calcinated at 500 °C were also observed using TEM. The purity of the green-synthesized CuO nanoparticles was evaluated by EDX analysis, and results showed that increasing calcination temperature increases the purity of CuO nanoparticles.

Synthesis, growth kinetics and ultra-sensitive performance of electrospun WO3 nanofibers for NO2 detection

WO3 nanofibers are fabricated as NO2 sensing materials by a simple electrospinning technique followed with calcination treatment. The obtained WO3 nanofibers are constructed by nanograins located along the 1 D direction. The growth kinetics of WO3 nanograins in individual nanofibers are studied by varying calcination temperatures and times. The calculated growth exponent value (n = 2.90) suggests that WO3 nanograins growth in nanofibers is developed by lattice diffusion in the pore control scheme. Subsequently, NO2 sensing performance of the as-synthesized WO3 nanofibers is evaluated, which shows excellent performance for NO2 detection at 200 °C, including high response (12.523) and fast response/recovery times (11 s/26 s) to 1 ppm NO2. Moreover, the WO3 sensor displays excellent anti-interference ability toward several interfering gases. The stability of the WO3 sensor is further confirmed by 14 days of continuous testing. Compared with previously reported works, the WO3 sensor still demonstrates outstanding gas sensing properties due to its unique advantages such as 1D nanofibrous structures, high BET surface area, and rich oxygen vacancies.

Exchange bias of ordered α-Fe2O3 nanowires: A first-order reversal curve analysis

Ordered α-Fe2O3 nanowires with different gap sizes and diameters were fabricated using SBA-15 as template through varying calcination temperature. The composition, microstructure and morphology of the samples were characterized by XRD, TEM and N2 adsorption–desorption isotherms. The results showed that the α-Fe2O3 replicated the pore channels of SBA-15. The nanowire diameter and wire spacing were controllably changed at different calcination temperatures. ZFC-FC, hysteresis lines and First-order reversal curve (FORC) of the samples were tested at 10 K, 50 K, 100 K, 200 K and 300 K. Exchange bias (EB) was observed under low-temperature field cooling conditions due to the increase of spin disorder on the surface of small size α-Fe2O3 which was freezen into a spin-glass-like phase at low temperature. The influence of the domain states and interactions on EB of α-Fe2O3 were investigated using FORC. The mixed domain states were observed for small size samples at low temperatures. The excitation of EB at low temperatures was proven to be influenced by magnetic interactions.

Highly active MnOx supported on the MgAlOx oxides derived from LDHs for low temperature NH3-SCR

A series of novel highly dispersed MnOx on the MgAlOx support derived from layered double hydroxides (LDHs) were successfully prepared by incipient wetness impregnation method for low-temperature selective catalytic reduction of NOx with ammonia (NH3-SCR). The physicochemical properties and the catalytic performance of the prepared samples with different Mn precursor salt (acetate, nitrate and sulfate) and varying calcination temperatures of MgAlOx support were systematically investigated. The optimal catalyst, MgAlOx calcined at 800 °C with impregnating manganese acetate (denoted as MnA/MgAlOx-800), exhibited superior denitration performance, with NOx conversion over 80 % in the temperature range of 100–300 °C as well as remarkable resistance against H2O. The proper supports MgAlOx not only provided large specific area for the dispersion of the Mn, but also supplied more adsorption sites for reactant molecules. It was also found that the interaction between Mn species and MgAlOx support induced the higher concentration of Mn4+ and chemisorbed oxygen species. As suggested from in situ DRIFTs analysis, Lewis acid sites promoted the adsorption and activation of NH3, which facilitated the NH3-SCR reaction to proceed. Furthermore, E-R mechanism was proposed in the SCR reaction, evidenced by in situ DRIFTS study.

Synthesis, characterization, and thermoluminescence‐based high‐dose neutron and gamma dosimetry study of Al5BO9: Mn, Li nanophosphor

AbstractA near tissue equivalent (Zeff = 10.8) and wide bandgap (Eg = 5.95 eV) Al5BO9: Mn, Li nanophosphor was synthesized by facile gel‐combustion (GC) method, and structural characterizations were performed by XRD, infra‐red, transmission electron microscopy, energy‐dispersive spectra, diffuse reflectance UV–visible spectra, and PL studies. Thermoluminescence (TL) study of Al5BO9: Mn, Li revealed the dosimetry glow peak at 542 K, which was absent in undoped Al5BO9 indicating the importance of Mn dopant. The highest TL response was obtained for the lowest studied dopant concentration (0.1 mol% Mn) that was attributed to the concentration quenching phenomenon. The material is highly reusable with low fading (<10%) up to 110 days. TL response for both thermal neutron and gamma radiations showed excellent linearity within 5 × 109–3 × 1011 n/cm2 and 30–5000 Gy, respectively. These studies suggested promising potential of Al5BO9: Mn, Li nanophosphor in clinical neutron dosimetry and food irradiation dosimetry applications. Based on the variation of calcination temperature, strategy toward dual application, namely, radiation dosimeter and red‐light emitting phosphor of the material was established. For a better understanding of the TL process, various kinetic parameters like activation energy (E), order of kinetics (b), and frequency factor (s) were evaluated using different methodologies, and the results were found to be in good agreement.

EFFECT OF CALCINATION TEMPERATURE AND CA:EG RATIO ON TL AND OSL CURVE COMPONENTS OF NEIGHBORITE

This study reveals the differences created by varying calcination temperature and citric acid/ethylene glycol ratio (CA:EG) in thermoluminescence (TL) and optically stimulated luminescence (OSL) curves so that the Neighborite (NaMgF3) compound synthesized using sol-gel can be used as a radiation dosimeter. While producing NaMgF3 phosphors, four different calcination temperatures (700, 800, 900 and 1000 °C) were applied for the calcination process. Characterization analyzes of the samples were performed using X-ray diffraction (XRD) and Scanning electron microscopy (SEM). It was observed that the oxide phases in the crystal structure of the sample increased gradually with increasing calcination temperature. At 1000 °C, it was observed that the crystal structure of the sample was deformed and moved away from the aimed structure. Considering the signal intensities in the TL and OSL glow curves obtained after radiation exposure and the data in the characterization analyzes, the calcination temperature of 800 °C was determined as the optimum temperature. This calcination temperature was kept constant and the samples were reproduced by changing the CA:EG ratio in four different ways (2:4, 4:4, 8:4 and 16:4). By comparing all the sample, the samples with the best crystallization and the most suitable surface morphology were determined. In TL glow curves, it was observed that deep traps could be formed only in samples calcined at 800 °C. Likewise, it was observed from the OSL glow curves that the samples calcined at 800 °C had higher sensitivity. It has been stated that the low sensitivity of the samples calcined at high temperatures is due to the density of the oxide phases formed in the calcination process.

MOF derived porous Ni/Co@C nanocomposite as electromagnetic wave absorber with optimized impedance matching

The performance and effective absorbing bandwidth (EAB) of electromagnetic wave (EMW) absorbers depend largely on electromagnetic impedance matching. Herein an efficient strategy for tuning impedance matching is reported. Porous Ni/Co@C nanocomposites with adjustable pore sizes were synthesized by varying calcination temperature. The obtained Ni/Co@C have EMW absorption capacity, adjusted impedance matching, and multiple scattering. Impedance matching is optimized to achieve super reflection loss (RL) of Ni/Co@C-600, while broaden the EBA of Ni/Co@C-650. Ni/Co@C-650 nanocomposite has the optimum RL of −66.3 dB with a thickness of 2.0 mm, and the EAB reaches 6.0 GHz at 2.3 mm thickness. Ni/Co@C-600 has an optimum RL of −71.9 dB at 8.9 GHz. This work provided a facile strategy for the design of porous nanocomposite with improving impedance matching.

High current density electroreduction of CO2 into formate with tin oxide nanospheres

In this study, we demonstrate three-dimensional (3D) hollow nanosphere electrocatalysts for CO2 conversion into formate with excellent H-Cell performance and industrially-relevant current density in a 25 cm2 membrane electrode assembly electrolyzer device. Varying calcination temperature maximized formate production via optimizing the crystallinity and particle size of the constituent SnO2 nanoparticles. The best performing SnO2 nanosphere catalysts contained ~ 7.5 nm nanocrystals and produced 71–81% formate Faradaic efficiency (FE) between −0.9 V and −1.3 V vs. the reversible hydrogen electrode (RHE) at a maximum formate partial current density of 73 ± 2 mA cmgeo−2 at −1.3 V vs. RHE. The higher performance of nanosphere catalysts over SnO2 nanoparticles and commercially-available catalyst could be ascribed to their initial structure providing higher electrochemical surface area and preventing extensive nanocrystal growth during CO2 reduction. Our results are among the highest performance reported for SnO2 electrocatalysts in aqueous H-cells. We observed an average 68 ± 8% FE over 35 h of operation with multiple on/off cycles. In situ Raman and time-dependent X-ray diffraction measurements identified metallic Sn as electrocatalytic active sites during long-term operation. Further evaluation in a 25 cm2 electrolyzer cell demonstrated impressive performance with a sustained current density of 500 mA cmgeo−2 and an average 75 ± 6% formate FE over 24 h of operation. Our results provide additional design concepts for boosting the performance of formate-producing catalysts.

Phase-dependent electrocatalytic activities of Pt-anchored rutile, anatase and mixed anatase-rutile TiO2 nano-composites for methanol oxidation in alkali

Anatase, rutile and mixed anatase-rutile TiO2 are synthesized using a single pot sol-gel technique followed by variation of calcination temperature. The Pt decorated synthesized catalysts have been characterized by diffraction, spectroscopic and microscopic analyses. The cyclic voltammetry (CV) study reveals the increase of forward peak current density of methanol oxidation in alkali on Pt-anchored mixed-phase TiO2 (Pt/ARTiO2) (324.8 A g−1) by 4 and 2.5 times than that on Pt-containing rutile and anatase phases. The charge transfer conductance of the former electrode (1/184 Ω−1) is 5.7 and 8.7 times greater compare to that of the laters. The phase-dependent electrocatalytic activity of the electrodes and large retention (95%) of maximum peak current density at 500th CV cycle for the best electrode, are analyzed by different product selectivity of the electrodes. Pt/ARTiO2 is found to be the best current provider and reliable as it accelerates the formation of formate instead of carbonate.