Use of Ni Catalysts Supported on Biomorphic Carbon Derived From Lignocellulosic Biomass Residues in the Decomposition of Methane

Abstract

In this work, we present the results of production of carbonaceous nanomaterials by decomposition of methane on a catalyst of Ni supported on a Biomorphic Carbon. The catalyst was prepared by thermal decomposition in a reductive atmosphere of vine shoots previously impregnated with the Ni precursor. In order to optimize the reaction productivity and selectivity, the effect of the main operational conditions (reaction temperature and feed composition) has been studied in a thermobalance. The main textural properties, BET area of 63 m 2 /g and 56% of microporosity, of the catalyst synthesized indicates that these materials are suitable for gas-phase reactions even in harsh conditions. Thus, the catalyst has proved to be active in the synthesis of carbon nanofibers and graphene related materials at elevated temperatures. The productivity, type, and quality of the carbonaceous nanomaterials obtained are deeply dependent on the operating conditions during the reaction. As an important fact, is has been obtained that the reaction temperature strongly affects the type of the nanomaterial produced. Thus, it is produced CNFs of bamboo type at temperatures until 850 • C. Above this critical temperature, it is mainly obtained nanolayers of graphitic nature. The characterization results indicate that the highest quality graphenic materials were obtained operating at 950 • C with 14.3% of CH 4 and 14.3% of H 2. The kinetic model used to analyze the experimental data is based on the more relevant stages of the mechanism of reaction.

Methane decomposition into CO x ‐free hydrogen over a Ni‐based catalyst: An overview

“…After thermal decomposition, the solid catalyst consists of dispersed metallic nanoparticles supported on the biomorphic carbon material. Azuara et al investigated the production kinetics of the carbonaceous material on Ni supported on biomorphic carbon 122 . The as‐prepared catalyst exhibits a specific surface area of 63 m 2 g −1 and a porosity of 56%, which is suitable for gas‐phase reactions even under harsh conditions.…”

“…The type of carbonaceous materials obtained during the CMD reaction is dependent on the operating temperature. At temperatures less than 850°C, bamboo‐like carbon nanotubes (BLCNTs) are produced, while at a considerably higher temperature, graphitic nanomaterials in the form of a layer are obtained 95,122,140,141 . The effect of reaction temperature on the deactivation mechanism of a 65%Ni‐10%Cu‐25%SiO 2 catalyst was investigated 140,141 .…”

“…However, the catalyst may be encapsulated due to the discrepancy in the methane dissociation rate and carbon transfer rate on the catalyst surface. Moreover, growth of good quality CNTs on the catalyst surface depends on the reaction temperature, 95,122,140,141 catalyst property, and hydrogen formation rate 87,148 . The low catalyst loading and slow hydrogen formation rate favor the formation of high‐quality CNTs, but at the same time, this adjustment affects the hydrogen yield.…”

Performance of AISI 316L-stainless steel foams towards the formation of graphene related nanomaterials by catalytic decomposition of methane at high temperature

“…As it has been mentioned above, the influence of the operating conditions on the CNMs growth kinetics was previously studied in previous works [31][32][33]41,42,44]. Briefly, for the present case, the kinetic model considers the following main steps: i) adsorption and decomposition of CH 4 molecules on the metal nanoparticles segregated during the activation stage to the external surface of the stainless steel substrate [44,45]; ii) formation of a metastable metallic carbide which decomposes into carbon atoms at the metal carbide-metal nanoparticle interface; iii) diffusion of these carbon atoms through the metal nanoparticle and subsequent carbon precipitation at the metal-support interface; iv) formation and growth of the carbonaceous nanomaterial, whose nature (e.g.…”

“…Knowledge the reaction mechanism is crucial to properly control of the production of the CNMs. Based on this mechanism, our group has been working on the modelling of the kinetics of growth of CNMs [31][32][33][40][41][42], in order to quantify the influence of the reaction temperature and feed composition on the rate of carbon formation in the context of the reaction mechanism.…”