Hydrogen production from catalytic formic acid ecomposition over Zn based catalysts under room temperature

The depletion of petroleum sources and global warming issues has increased awareness among scientists to produce alternative energy other than the one that we always depend on, which is petroleum. Hydrogen (H2) energy is one of the alternatives that was promising as an efficient and green fuel. Meanwhile, formic acid has been detected as one of the convenient H2 source/storage material. Here, we introduce two heterogeneous catalysts for H2 generation from formic acid. Fe0.1 Zn0.9 and Fe0.5 Zn0.5 were synthesized by a modified microwave method. In this study, we report the result of a detailed study undertaken to investigate the decomposition of formic acid to H2 and carbon dioxide (CO2) using gas chromatography with thermal conductivity detector (GC-TCD). The catalyst used to decompose the formic acid was characterized by x-ray diffraction (XRD) to determine their physicochemical properties. Field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) were also used to determine the surface morphology and the structure of the synthesized catalysts. The result suggested that in the dehydrogenation reaction, 90-96% of H2 was selectively produced from the formic acid with the presence of FeZn catalyst. For Fe0.1Zn0.9 catalyst, FESEM micrograph shows the particle was well dispersed, existing both away from and close proximity to 50-70 nm in size. Both heterogeneous catalysts are able to produce H2 from formic acid at room temperatures (30°C) with no additives added and with high selectivity

The influence of calcination temperature on iron oxide (α-Fe2O3) towards CO2 adsorption prepared by simple mixing method = Kesan suhu pengkalsinan ferum oksida (α-Fe2O3) disediakan melalui kaedah campuran ringkas terhadap penjerapan CO2

Synthesized iron oxide, α-Fe2O3 used for CO2 capturing was prepared by a simple mixing method and calcined at temperatures in a range of 350 – 850 °C. CO2 adsorption isotherms at 25 °C and 1 atm found that the sample namely s450 that calcined at 450 °C gave the highest CO2 adsorption activity with the adsorption capacity of 17.0 mgCO2/gadsorbent. Monodentate carbonate, bidentate carbonate and bicarbonates formation were observed on s450 through the IR spectra. The basicity of s450 was identified by chemisorption of CO-TPD which contains weak, medium and strong basic sites with CO total adsorbed amount of 1.99 cm3/g. It was found that s450 calcined at 450 °C has certain crystallite peaks that abruptly increased through the XRD diffractogram. The texture properties of s450 generated high porosity and more uniform sphere shape particle size with high surface area (50.5 m2/g). Furthermore, it is composed of trimodal distribution for pore size distribution curve desirable for CO2 adsorption. Penjerapan CO2 terhadap ferum oksida, α-Fe2O3 yang disintesis melalui kaedah campuran ringkas dan dikalsin pada suhu 350- 850 °C. Penjerapan isoterma CO2 pada suhu bilik, 25 °C and 1 atm mendapati sampel s450 yang dikalsin pada suhu 450 °C menunjukkan aktiviti penjerapan CO2 paling tinggi dengan keupayaan penjerapan sebanyak 17.0 mgCO2/gpenjerap. Spektrum IR telah membuktikan pembentukan spesis monodentat karbonat, bidentat karbonat dan bikarbonat pada s450. Sifat bes s450 yang dikenalpasti menggunakan jerapan kimia CO-TPD dimana jumlah CO yang dijerap oleh tapak bes lemah, sederhana dan kuat adalah 1.99 cm3 /g. Difraktogram XRD pula menunjukkan terdapat beberapa puncak kekisi yang meningkat. Tekstur s450 pula mempunyai keporosan yang tinggi dan bentuk sfera yang lebih sekata serta luas permukaan yang tinggi (50.5 m2 /g). Tambahan lagi, graf taburan saiz liang s450 juga terdiri daripada taburan jenis trimodal yang menjadi salah satu faktor penting dalam penjerapan CO

Adsorption isotherm and surface analysis for the carbonate formation on nano coral-shaped iron(Iii) oxide

The α-Fe2O3 was synthesized using the hydrolysis method to obtain the nano coral-shaped morphology. The adsorption isotherm and surface analysis upon CO2 adsorption were identified. The adsorption capacity for nano coral-shaped α-Fe2O3 was measured at 8.66 cm3/g (17.00 mg/g). Experimental data from CO2 adsorption isotherm at 25 ℃ best fits with the Freundlich isotherm model which implies the adsorption process is favorable and the multilayer adsorption on the heterogeneous surface. A decrease in the α-Fe2O3 crystallite peaks in the X-ray diffractogram after the CO2 adsorption was associated with the carbonate complexes species formation. IR spectra indicate higher intensities over the CO2 exposure time of 4, 12 and 24 h, especially at absorption bands 1041 and 1627 cm-1 that corresponded to C-O and asymmetry O-C-O stretches, respectively, for carbonate. The morphology of the carbonate formation on nano coral-shaped α-Fe2O3 over the CO2 exposure time was analyzed using FESEM-EDX. Although the carbonate formation was not distinct, the increment in the C element also confirmed the capability of the α-Fe2O3 in adsorbing CO2 for a long adsorption time of 24 h

Comparative adsorption isotherm for Beryllium oxide/Iron (III) Oxide toward CO2 adsorption and desorption studies

Surface modification of Fe2O3 by adding BeO was synthesized and calcined at different temperatures of 200-600 °C. The adsorbents were characterized by using XRD, N2 adsorption-desorption isotherm prior to performing CO2 adsorption and desorption studies. The CO2 adsorption data were analyzed using adsorption isotherm models such as Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich. BeO/Fe2O3-300 that calcined at 300 °C showed the most efficient adsorbent with physisorption and chemisorption were measured at 5.85 and 45.88 mg/g respectively. The CO2 adsorption notably best fitted with Freundlich isotherm with R2 = 0.9897 and calculated adsorption capacity closest to experimental data. This implies the CO2 adsorption process was governed by multilayer adsorption on the heterogeneous surface of the adsorbent. The mean free energy of adsorption (E=3.536 kJ/mol) from Dubinin-Radushkevich and heat of adsorption (bT=3.219 kJ/mol) from the Temkin model support that the adsorption process is physical phenomena

Chemical Reduction Behavior of Zirconia Doped to Nickel at Different Temperature in Carbon Monoxide Atmosphere

The reduction behavior of nickel oxide (NiO) and zirconia (Zr) doped NiO (Zr/NiO) was investigated using temperature programmed reduction (TPR) using carbon monoxide (CO) as a reductant and then characterized using X-ray diffraction (XRD), nitrogen absorption isotherm using BET technique and FESEM-EDX. The reduction characteristics of NiO to Ni were examined up to temperature 700 °C and continued with isothermal reduction by 40 vol. % CO in nitrogen. The studies show that the TPR profile of doped NiO slightly shifts to a higher temperature as compared to the undoped NiO which begins at 387 °C and maximum at 461 °C. The interaction between ZrO2 with Ni leads to this slightly increase by 21 to 56 °C of the reduction temperature. Analysis using XRD confirmed, the increasing percentage of Zr from 5 to 15% speed up the reducibility of NiO to Ni at temperature 550 °C. At this temperature, undoped NiO and 5% Zr/NiO still show some crystallinity present of NiO, but 15% Zr/NiO shows no NiO in crystalline form. Based on the results of physical properties, the surface area for 5% Zr/NiO and 15% Zr/NiO was slightly increased from 6.6 to 16.7 m2/g compared to undoped NiO and for FESEM-EDX, the particles size also increased after doped with Zr on to NiO where 5% Zr/NiO particles were 110 ± 5 nm and 15% Zr/NiO 140 ± 2 nm. This confirmed that the addition of Zr to NiO has a remarkable chemical effect on complete reduction NiO to Ni at low reduction temperature (550 °C). This might be due to the formation of intermetallic between Zr/NiO which have new chemical and physical properties

Preparation and Application of Octadecylsilyl-Silica Adsorbents for Chemical Analysis

Abstract: Octadecylsilylated silica (ODS-Silica) stationary phases were developed and examined for solid phase extraction (SPE) analysis. The ODS-silica phases were endcapped using two different methods, namely by refluxing at 106 °C and stirring at room temperature. The effect of the reaction time was also investigated by performing the reactions for 6 and 16 h. Thermogravimetric analysis performed on the phases indicated that the capped ODS-silicas showed a decrease in weight loss in the temperature range of 25-125 °C, suggesting that the silanol groups decreased with endcapping. The thermograms for all the adsorbents showed a weight loss in the temperature range of 300-600 °C indicating the presence of methyl groups in the adsorbents. Abstrak: Oktadekilsilil-silika (ODS-silika) telah disediakan dan dikaji dalam analisis pengekstrakan fasa pepejal (SPE). Penutupan hujung fasa tersebut telah dilakukan menggunakan dua kaedah yang berbeza: refluks pada 106 °C dan pengacauan pada suhu bilik. Kesan jangka masa tindak balas turut dikaji dengan menjalankan tindak balas selama 6 dan 16 jam. Corak penjerapan bagi bahan yang dihasilkan telah dikaji menggunakan termogravimetri ke atas ODS-silika tertutup-hujung itu, yang menunjukkan pengurangan berat pada julat suhu 25 -125 °C, yang mencadangkan bahawa kumpulan silanol berkurangan dengan penutupan hujung. Termogram bagi semua bahan penjerap pada julat suhu 300 -600 °C menunjukkan pengurangan berat yang maksimum dan terdapat kumpulan metil (ODS) dalam bahan tersebut. __________________________________________________________________________________________

Effect of cobalt on nickel oxide toward reduction behaviour in hydrogen and carbon monoxide atmosphere

The reduction behaviour of cobalt doped with nickel oxide and undoped nickel oxide (NiO) by hydrogen (H2) in nitrogen (20%, v/v) and carbon monoxide (CO) in nitrogen (40%, v/v) atmospheres have been investigated by temperature programmed reduction (TPR). The phases formed of partially and completely reduced samples were characterized by X-ray diffraction spectroscopy (XRD). TPR results indicate that the reduction of Co doped and undoped nickel oxide in both reductants proceed in one step reduction (NiO → Ni) without intermediate. TPR results also suggested that by adding Co metal into NiO, the reduction to metallic Ni by both reductant gaseous give different intensity of the peak. The reduction process of Co and undoped NiO become faster when H2 was used as a reductant. Furthermore, in H2 atmosphere, Co-NiO give complete reduction to metallic Ni at 700 °C. Meanwhile, XRD analysis indicated that NiO without Co composed better crystallite phases of NiO with higher intensity

Carbon dioxide adsorption and desorption study using bimetallic calcium oxide impregnated on iron (III) oxide

Bimetal adsorbent system of calcium oxide impregnated on iron (III) oxide were evaluated as a potential source of basic sites for CO capture. The adsorbents were prepared by impregnation method were calcined at 200 until 600 °C. Several characterizations were carried out using XRD, BET and CO -TPD analysis. The CaO loading increased the basicity of the adsorbent signicantly enhance the CO chemisorption. Furthermore, it drastically reduced the desorption temperature to 310-490 °C, which is important in chemisorption aspect. The CaO/Fe O 200 which calcined at 200 °C was found to be most ecient. The CO chemisorption (81.29 mg CO /g adsorbent) was contributed most compared to physisorption (4.64 mg CO /g adsorbent