“…6a. The reaction has less feasibility with higher hydrocarbons as they readily decompose to H and C 34 .Figure 6Variation of ∆H with temperature for best possible reactions for ( a ) reduction ( b ) carburization.
…”
Carbon coated nano molybdenum carbide (Mo2C) has been synthesized at 800 °C through single step reduction route using molybdenum trioxide (MoO3) as a precursor, polypropylene (P.P) as a carbon source and magnesium (Mg) as a catalyst in an autoclave. The synthesized samples were characterized by X-ray diffraction (XRD), thermal analysis techniques (TG/DTA/DTG), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). Williamson- Hall (W-H) analysis has been done to estimate various parameters like strain, stress and strain energy density. Multi-stage kinetic analysis of the product phase has been studied to establish the nature of the thermal decomposition. Coats-Redfern method applied to determine the mechanism involved in the decomposition of the product phase shows that initial and final stage follow F1 mechanism whereas middle stage follow F3 mechanism. The activation energy (E
a) and pre-exponential factor (A) has also been determined. The morphological studies show that the particles have partially spherical/faceted shape, with carbon coated having wide particle size distribution. The surface chemistry and surface area analysis were studied by X-ray photoelectron spectroscopy (XPS) and Brunauer-Emmet-Teller (BET), respectively. The formation mechanism of carbon coated Mo2C nano particles has been predicted based on the XRD, TG/DTA & DTG and microstructural results.
“…6a. The reaction has less feasibility with higher hydrocarbons as they readily decompose to H and C 34 .Figure 6Variation of ∆H with temperature for best possible reactions for ( a ) reduction ( b ) carburization.
…”
Carbon coated nano molybdenum carbide (Mo2C) has been synthesized at 800 °C through single step reduction route using molybdenum trioxide (MoO3) as a precursor, polypropylene (P.P) as a carbon source and magnesium (Mg) as a catalyst in an autoclave. The synthesized samples were characterized by X-ray diffraction (XRD), thermal analysis techniques (TG/DTA/DTG), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). Williamson- Hall (W-H) analysis has been done to estimate various parameters like strain, stress and strain energy density. Multi-stage kinetic analysis of the product phase has been studied to establish the nature of the thermal decomposition. Coats-Redfern method applied to determine the mechanism involved in the decomposition of the product phase shows that initial and final stage follow F1 mechanism whereas middle stage follow F3 mechanism. The activation energy (E
a) and pre-exponential factor (A) has also been determined. The morphological studies show that the particles have partially spherical/faceted shape, with carbon coated having wide particle size distribution. The surface chemistry and surface area analysis were studied by X-ray photoelectron spectroscopy (XPS) and Brunauer-Emmet-Teller (BET), respectively. The formation mechanism of carbon coated Mo2C nano particles has been predicted based on the XRD, TG/DTA & DTG and microstructural results.
“… 37 and Singla et al . 32 for tungsten carbide NPs which enables these nanomaterials to be used in various electro oxidation reactions 38 .…”
Section: Introductionmentioning
confidence: 99%
“…Various researchers have practiced encapsulation of carbon on NPs through different synthesis techniques and chemical reagents 24 , 25 , 39 – 47 . To overcome the high temperature and time consuming procedures, carbothermal synthesis in an autoclave has been practiced at low temperature 32 , 34 . With the help of an autoclave, various reactants were subjected to carburization of the transition metal (V, Co, W, Ti) source in the presence of a reducing agent to obtain nano TMCs at relatively low temperature 30 , 32 , 34 , 48 .…”
Section: Introductionmentioning
confidence: 99%
“…Although a significant amount of work has been reported on the synthesis of carbon encapsulated TMCs 30 , 32 – 34 , 41 , 49 , 50 , the developing process is not so economical. Zhang et al .…”
A facile carbothermal route was adopted to obtain niobium carbide nanoparticles (NPs) embedded in carbon network from Nb2O5 to study photocatalytic behavior. Optimization of synthesis parameters to obtain single phase NbC NPs has been successfully done. The phase identification, morphology and nature of carbon were determined with the help of X-ray diffraction, transmission electron microscopy (TEM) and Raman spectroscopy. X-ray photoelectron spectroscopy (XPS) suggested the presence of multiple oxidation states of Nb associated to NbC and NbCxOy centers on the surface of NPs. Due to the presence of NbCxOy on the surface of NPs, absorption under visible region of EM spectrum has been observed by UV-visible spectroscopy. Different organic dyes (RhB, MB and MO) were used to study the effect of holding time on the photocatalytic performance of as-synthesized samples. RhB dye was found to be the most sensitive organic molecule among all the considered dyes and degraded 78% in 120 min.
“…The same synergistic effect strategy has also been extended to several other support effects systems. It is critical, therefore, to prepare high-efficiency precious metal-free supports (WC [9,10], MoC [11], and TiO 2 [12,13]), which is an effective way to reduce the Pt particle diameter and also increase the anti-poisoning ability. Tungsten carbide (WC) displays potential applications for Pt-like behavior [14], COtolerance [15], and highly electrical conductivity [16] as support part in anode-catalysts for methanol oxidation reaction (MOR) [17,18].…”
The spray-dried spheres within a W/Pt multi-separation can be used to prepare discrete core-shell WC@C/Pt catalysts through a typical carburization production mechanism at 800 • C. In contrast with previous studies of the WC/Pt synthesis, the reaction observed here proceeds through an indirect annealing mechanism at 600 • C wherein species diffuse, thereby resulting in core-shell structure, and Pt nanoparticles were successfully dispersed in size/shape and randomly scattered across the in situ produced C spheres. Through direct carburization or at higher initial hydrochloroplatinic acid concentrations, however, complete reaction with core-shell spheres was not observed. Indirect carburization reduces the strain felt by the bonds featuring the larger WC particles and allows the motion of carbon around WC and Pt nanoparticles to be reserved, influencing the electrocatalytic performance and stability toward methanol oxidation.
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