scholarly journals Effects of the Carbon Support Doping with Nitrogen for the Hydrogen Production from Formic Acid over Ni Catalysts

Energies ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 4111 ◽  
Author(s):  
Alina D. Nishchakova ◽  
Dmitri A. Bulushev ◽  
Olga A. Stonkus ◽  
Igor P. Asanov ◽  
Arcady V. Ishchenko ◽  
...  
Keyword(s):  
Formic Acid ◽  
Photoelectron Spectroscopy ◽  
Total Content ◽  
Carbon Support ◽  
Nickel Catalysts ◽  
Synthesis Temperature ◽  
Free Carbon ◽  
Nitrogen Doped ◽  
Surface Areas ◽  
Pyridinic Nitrogen

Porous nitrogen-doped and nitrogen-free carbon materials possessing high specific surface areas (400–1000 m2 g−1) were used for deposition of Ni by impregnation with nickel acetate followed by reduction. The nitrogen-doped materials synthesized by decomposition of acetonitrile at 973, 1073, and 1173 K did not differ much in the total content of incorporated nitrogen (4–5 at%), but differed in the ratio of the chemical forms of nitrogen. An X-ray photoelectron spectroscopy study showed that the rise in the synthesis temperature led to a strong growth of the content of graphitic nitrogen on the support accompanied by a reduction of the content of pyrrolic nitrogen. The content of pyridinic nitrogen did not change significantly. The prepared nickel catalysts supported on nitrogen-doped carbons showed by a factor of up to two higher conversion of formic acid as compared to that of the nickel catalyst supported on the nitrogen-free carbon. This was related to stabilization of Ni in the state of single Ni2+ cations or a few atoms clusters by the pyridinic nitrogen sites. The nitrogen-doped nickel catalysts possessed a high stability in the reaction at least within 5 h and a high selectivity to hydrogen (97%).

scholarly journals Boosting Hydrogen Production from Formic Acid over Pd Catalysts by Deposition of N-Containing Precursors on the Carbon Support

Energies ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3885 ◽  
Author(s):  
Golub ◽  
Beloshapkin ◽  
Gusel’nikov ◽  
Bolotov ◽  
Parmon ◽  
...  
Keyword(s):  
Hydrogen Production ◽  
Formic Acid ◽  
Carbon Support ◽  
Pd Nanoparticles ◽  
High Dispersion ◽  
Pd Catalysts ◽  
Strong Electron ◽  
High Hydrogen ◽  
Hydrogen Carrier ◽  
Pyridinic Nitrogen

Formic acid is a promising liquid organic hydrogen carrier (LOHC) since it has relatively high hydrogen content (4.4 wt%), low inflammability, low toxicity and can be obtained from biomass or from CO2. The aim of the present research was the creation of efficient 1 wt% Pd catalysts supported on mesoporous graphitic carbon (Sibunit) for the hydrogen production from gas-phase formic acid. For this purpose, the carbon support was modified by pyrolysis of deposited precursors containing pyridinic nitrogen such as melamine (Mel), 2,2′-bipyridine (Bpy) or 1,10-phenanthroline (Phen) at 673 K. The following activity trend of the catalysts Pd/Mel/C > Pd/C ~ Pd/Bpy/C > Pd/Phen/C was obtained. The activity of the Pd/Mel/C catalyst was by a factor of 4 higher than the activity of the Pd/C catalyst at about 373 K and the apparent activation energy was significantly lower than those for the other catalysts (32 vs. 42–46 kJ/mol). The high activity of the melamine-based samples was explained by a high dispersion of Pd nanoparticles (~2 nm, HRTEM) and their strong electron-deficient character (XPS) provided by interaction of Pd with pyridinic nitrogen species of the support. The presented results can be used for the development of supported Pd catalysts for hydrogen production from different liquid organic hydrogen carriers.

scholarly journals Effects of Ionic Liquid and Biomass Sources on Carbon Nanotube Physical and Electrochemical Properties

2021 ◽  
Vol 13 (5) ◽  
pp. 2977
Author(s):  
Kudzai Mugadza ◽  
Annegret Stark ◽  
Patrick G. Ndungu ◽  
Vincent O. Nyamori
Keyword(s):  
Ionic Liquid ◽  
Electrochemical Properties ◽  
Photoelectron Spectroscopy ◽  
Nitrogen Doping ◽  
Electrochemical Impedance ◽  
Low Cost ◽  
Doping Content ◽  
Ongoing Research ◽  
Surface Areas ◽  
Pyridinic Nitrogen

The ongoing research toward meeting global energy demands requires novel materials from abundant renewable resources. This work involves an investigation on nitrogen-doped carbon nanotubes (N-CNTs) synthesized from relatively low-cost and readily available biomass as carbon precursors and their use as electrodes for supercapacitors. The influence of the ionic liquid 1-butyl-3-methylimidazolium chloride, or its combination with either sugarcane bagasse or cellulose (IL-CNTs, ILBag-CNTs, and ILCel-CNTs, respectively), in the synthesis of N-CNTs and the resultant effect on their physical and electrochemical properties was studied. Systematic characterizations of the N-CNTs employing transmission electron microscopy (TEM), thermogravimetric analysis, X-ray photoelectron spectroscopy (XPS), elemental analysis, nitrogen sorption analysis, cyclic voltammetry, and electrochemical impedance spectroscopy were performed. TEM data analysis showed that the mean outer diameters decreased, in the order of IL-CNTs > ILBag-CNTs > ILCel-CNTs. The N-CNTs possess only pyridinic and pyrrolic nitrogen-doping moieties. The pyridinic nitrogen-doping content is lowest in IL-CNTs and highest in ILCel-CNTs. The N-CNTs are mesoporous with surface areas in the range of 21–52 m2 g−1. The ILCel-CNTs had the highest specific capacitance of 30 F g−1, while IL-CNTs has the least, 10 F g−1. The source of biomass is beneficial for tuning physicochemical properties such as the size and surface areas of N-CNTs, the pyridinic nitrogen-doping content, and ultimately capacitance, leading to materials with excellent properties for electrochemical applications.

scholarly journals Hydrothermal Synthesis of TiO2 Aggregates and Their Application as Negative Electrodes for Lithium-Ion Batteries: The Conflicting Effects of Specific Surface and Pore Size

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 916
Author(s):  
Saida Mehraz ◽  
Wenpo Luo ◽  
Jolanta Swiatowska ◽  
Boudjema Bezzazi ◽  
Abdelhafed Taleb
Keyword(s):  
Hydrothermal Synthesis ◽  
Specific Surface ◽  
Pore Size ◽  
Lithium Ion Batteries ◽  
Photoelectron Spectroscopy ◽  
Electrode Materials ◽  
Lithium Ion ◽  
Synthesis Temperature ◽  
X Ray ◽  
Surface Areas

TiO2 aggregates of controlled size have been successfully prepared by hydrothermal synthesis using TiO2 nanoparticles of different sizes as a building unit. In this work, different techniques were used to characterize the as-prepared TiO2 aggregates, e.g., X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Brunauer, Emmett and Teller technique (BET), field emission gun scanning electron microscopy (FEGSEM), electrochemical measurements etc. The size of prepared TiO2 aggregates varied from 10–100 nm, and their pore size from around 5–12 nm; this size has been shown to depend on synthesis temperature. The mechanism of the aggregate formations was discussed in terms of efficiency of collision and coalescence processes. These newly synthetized TiO2 aggregates have been investigated as potential negative insertion electrode materials for lithium-ion batteries. The influence of specific surface areas and pore sizes on the improved capacity was discussed—and conflicting effects pointed out.

Dehydrogenation of Formic Acid at Room Temperature: Boosting Palladium Nanoparticle Efficiency by Coupling with Pyridinic-Nitrogen-Doped Carbon

2016 ◽  
Vol 128 (39) ◽  
pp. 12028-12032 ◽  
Author(s):  
Qing-Yuan Bi ◽  
Jian-Dong Lin ◽  
Yong-Mei Liu ◽  
He-Yong He ◽  
Fu-Qiang Huang ◽  
...  
Keyword(s):  
Formic Acid ◽  
Room Temperature ◽  
Palladium Nanoparticle ◽  
Nitrogen Doped ◽  
Nitrogen Doped Carbon ◽  
Pyridinic Nitrogen

Temperature-directed growth of highly pyridinic nitrogen doped, graphitized, ultra-hollow carbon frameworks as an efficient electrocatalyst for the oxygen reduction reaction

2017 ◽  
Vol 5 (34) ◽  
pp. 18064-18070 ◽  
Author(s):  
Bing He ◽  
Fujian Liu ◽  
Shouke Yan
Keyword(s):  
Oxygen Reduction Reaction ◽  
Reduction Reaction ◽  
Nitrogen Doped ◽  
Metal Free ◽  
Surface Areas ◽  
Directed Growth ◽  
Hollow Carbon ◽  
Nitrogen Contents ◽  
Very High ◽  
Pyridinic Nitrogen

Highly pyridinic nitrogen doped hollow carbon frameworks (N-HCFs) with large BET surface areas, ultra large pore volumes and very high pyridinic nitrogen contents were prepared, which could be used as highly efficient and stable metal-free electrocatalysts for the ORR.

scholarly journals Ruling Factors in Cinnamaldehyde Hydrogenation: Activity and Selectivity of Pt-Mo Catalysts

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 362
Author(s):  
Marta Stucchi ◽  
Maela Manzoli ◽  
Filippo Bossola ◽  
Alberto Villa ◽  
Laura Prati
Keyword(s):  
Photoelectron Spectroscopy ◽  
Pt Nanoparticles ◽  
Carbon Support ◽  
Catalytic Performance ◽  
Acid Sites ◽  
Hydrogenation Catalysts ◽  
Cinnamaldehyde Hydrogenation ◽  
Transmission Electron ◽  
Heat Treated ◽  
Heating Treatment

To obtain selective hydrogenation catalysts with low noble metal content, two carbon-supported Mo-Pt bimetallic catalysts have been synthesized from two different molybdenum precursors, i.e., Na2MoO4 and (NH4)6Mo7O24. The results obtained by X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) combined with the presence and strength of acid sites clarified the different catalytic behavior toward cinnamaldehyde hydrogenation. After impregnating the carbon support with Mo precursors, each sample was used either as is or treated at 400 °C in N2 flow, as support for Pt nanoparticles (NPs). The heating treatment before Pt deposition had a positive effect on the catalytic performance. Indeed, TEM analyses showed very homogeneously dispersed Pt NPs only when they were deposited on the heat-treated Mo/C supports, and XPS analyses revealed an increase in both the exposure and reduction of Pt, which was probably tuned by different MoO3/MoO2 ratios. Moreover, the different acid properties of the catalysts resulted in different selectivity.

Levulinic acid hydrogenation to γ-valerolactone over single Ru atoms on a TiO2@nitrogen doped carbon support

2021 ◽  
Author(s):  
Kaili Zhang ◽  
Qinglei Meng ◽  
Haihong Wu ◽  
Tongying Yuan ◽  
Shitao Han ◽  
...  
Keyword(s):  
Porous Carbon ◽  
Levulinic Acid ◽  
Room Temperature ◽  
Carbon Support ◽  
Complete Conversion ◽  
Turnover Frequency ◽  
Nitrogen Doped ◽  
Nitrogen Doped Carbon

TiO2@nitrogen doped porous carbon dispersed single Ru atom catalyst (Ru/TiO2@CN) efficiently transforms levulinic acid into γ-valerolactone at room temperature in water with a turnover frequency of 278 molGVL molRu−1 h−1 at complete conversion.

scholarly journals One-step chemical vapor deposition synthesis and supercapacitor performance of nitrogen-doped porous carbon–carbon nanotube hybrids

2017 ◽  
Vol 8 ◽  
pp. 2669-2679 ◽  
Author(s):  
Egor V Lobiak ◽  
Lyubov G Bulusheva ◽  
Ekaterina O Fedorovskaya ◽  
Yury V Shubin ◽  
Pavel E Plyusnin ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Hybrid Materials ◽  
Vapor Deposition ◽  
Porous Carbon ◽  
Photoelectron Spectroscopy ◽  
Electrochemical Impedance ◽  
Chemical Vapor ◽  
Carbon Surface ◽  
Simultaneous Formation ◽  
Nitrogen Doped

Novel nitrogen-doped carbon hybrid materials consisting of multiwalled nanotubes and porous graphitic layers have been produced by chemical vapor deposition over magnesium-oxide-supported metal catalysts. CN x nanotubes were grown on Co/Mo, Ni/Mo, or Fe/Mo alloy nanoparticles, and MgO grains served as a template for the porous carbon. The simultaneous formation of morphologically different carbon structures was due to the slow activation of catalysts for the nanotube growth in a carbon-containing gas environment. An analysis of the obtained products by means of transmission electron microscopy, thermogravimetry and X-ray photoelectron spectroscopy methods revealed that the catalyst's composition influences the nanotube/porous carbon ratio and concentration of incorporated nitrogen. The hybrid materials were tested as electrodes in a 1M H2SO4 electrolyte and the best performance was found for a nitrogen-enriched material produced using the Fe/Mo catalyst. From the electrochemical impedance spectroscopy data, it was concluded that the nitrogen doping reduces the resistance at the carbon surface/electrolyte interface and the nanotubes permeating the porous carbon provide fast charge transport in the cell.

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