Efficient Production of Segmented Carbon Nanofibers via Catalytic Decomposition of Trichloroethylene over Ni-W Catalyst

Abstract

The catalytic utilization of chlorine-organic wastes remains of extreme importance from an ecological point of view. Depending on the molecular structure of the chlorine-substituted hydrocarbon (presence of unsaturated bonds, intermolecular chlorine-to-hydrogen ratio), the features of its catalytic decomposition can be significantly different. Often, 1,2-dichloroethane is used as a model substrate. In the present work, the catalytic decomposition of trichloroethylene (C2HCl3) over microdispersed 100Ni and 96Ni-4W with the formation of carbon nanofibers (CNF) was studied. Catalysts were obtained by a co-precipitation of complex salts followed by reductive thermolysis. The disintegration of the initial bulk alloy driven by its interaction with the reaction mixture C2HCl3/H2/Ar entails the formation of submicron active particles. It has been established that the optimal activity of the pristine Ni catalyst and the 96Ni-4W alloy is provided in temperature ranges of 500–650 °C and 475–725 °C, respectively. The maximum yield of CNF for 2 h of reaction was 63 g/gcat for 100Ni and 112 g/gcat for 96Ni-4W catalyst. Longevity tests showed that nickel undergoes fast deactivation (after 3 h), whereas the 96Ni-4W catalyst remains active for 7 h of interaction. The effects of the catalyst’s composition and the reaction temperature upon the structural and morphological characteristics of synthesized carbon nanofibers were investigated by X-ray diffraction analysis, Raman spectroscopy, and electron microscopies. The initial stages of the carbon erosion process were precisely examined by transmission electron microscopy coupled with elemental mapping. The segmented structure of CNF was found to be prevailing in a range of 500–650 °C. The textural parameters of carbon product (SBET and Vpore) were shown to reach maximum values (374 m2/g and 0.71 cm3/g, respectively) at the reaction temperature of 550 °C.

Editorial for Special Issue “Advanced Materials in Catalysis and Adsorption”

“…This Special Issue aims to cover the latest research on the design and development of advanced materials for adsorption and catalytic applications. The synthesis of various carbon nanomaterials (CNMs), including carbon nanofibers (CNFs), carbon nanotubes (CNTs), graphene-like materials, and carriers (Sibunit), is of particular interest [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 ]. The functionalization of CNMs with heteroatoms (i.e., nitrogen [ 1 , 6 , 7 , 8 ] and boron [ 3 ]) is an effective method for boosting the applicability of carbon nanomaterials as catalytic substrates.…”

“…Advanced catalytic materials have been developed for diverse types of heterogeneous catalytic reactions, such as the hydrodechlorination of chloroaromatics [ 1 ]; the dehalogenation of halogenated hydrocarbons [ 2 ]; dechlorination via catalytic pyrolysis [ 1 , 2 , 4 ]; the catalytic coupling of CH 4 [ 14 ]; the catalytic processing of hydrocarbons and their mixtures into synthesis gas [ 10 , 11 ] or CNT and CNF materials [ 2 , 5 , 6 , 8 ]; the oxidation of carbon monoxide [ 13 ]; the hydrogenation of organic compounds [ 7 ]; and selective oxidation [ 9 ]. Such advanced materials can be also used for electrocatalytic applications involving the oxygen evolution reaction (OER) [ 12 ] and the electrocatalytic reduction of carbon dioxide (CO 2 RR) [ 15 ].…”

“…Such advanced materials can be also used for electrocatalytic applications involving the oxygen evolution reaction (OER) [ 12 ] and the electrocatalytic reduction of carbon dioxide (CO 2 RR) [ 15 ]. Researchers’ attention has been especially drawn to environmental protection, where advanced materials and adsorbents are highly demanded for the processing of waste components [ 1 , 16 , 17 , 18 ] and pharmaceuticals [ 17 ], the (photo)degradation of dyes [ 16 , 18 ], the catalytic decomposition of chlorinated hydrocarbons [ 1 , 2 , 4 ], wastewater treatment [ 1 , 18 ], and the abatement of CO-containing gases [ 13 ].…”

“…The carbon erosion or metal dusting (MD) of bulk Ni-M and Co-M alloys can be used to produce carbon nanofibers and CNF-based composites [ 1 , 2 , 4 , 5 , 6 ]. The carbon erosion of nickel alloys during the catalytic pyrolysis of organic compounds with the formation of carbon nanofibers in a flow-through reactor and under reaction conditions in a close volume (Reactions under Autogenic Pressure at Elevated Temperature (RAPET)) has been extensively studied in [ 2 ].…”

“…Furthermore, chlorinated hydrocarbons can also serve as a carbon source in catalytic pyrolysis reactions [ 1 , 4 ]. Thus, the research on trichloroethylene (TCE) decomposition over a microdispersed Ni-W alloy (4 wt.% W) revealed that the addition of tungsten results in an enhancement of Ni productivity (1.5–2 times) toward the generation of carbon filaments with a unique segmented structure and a high SSA of 374 m 2 /g [ 4 ]. A similar approach to synthesizing CNFs via the catalytic processing of TCE (a component of organochlorine wastes) over a Ni catalyst was realized in [ 1 ].…”