Zeolite-supported ultra-small nickel as catalyst for selective oxidation of methane to syngas

Abstract

The development of simple catalysts with high performance in the selective oxidation of methane to syngas at low temperature has attracted much attention. Here we report a nickel-based solid catalyst for the oxidation of methane, synthesised by a facile impregnation method. Highly dispersed ultra-small NiO particles of 1.6 nm in size are successfully formed on the MOR-type zeolite. The zeolite–supported nickel catalyst gives continuously 97–98% methane conversion, 91–92% of CO yield with a H2/CO ratio of 2.0, and high durability without serious carbon deposition onto the catalyst at 973 K. DFT calculations demonstrate the effect of NiO particle size on the C-H dissociation process of CH4. A decrease in the NiO particle size enhances the production of oxygen originating from the NiO nanoparticles, which contributes to the oxidation of methane under a reductive environment, effectively producing syngas.

Partial Oxidation of Methane to Syngas via Formate Intermediate Found for a Ruthenium–Rhenium Bimetallic Catalyst

“…Methane (CH 4 ), the main component of natural gas, has attracted increasing attention in the chemical industry, as it can be converted to fundamental chemical products such as methanol, olefins, Fischer–Tropsch (FT) oil, and acetic acid. − Syngas is a mixture of CO and H 2 that is a common intermediate to manufacture the aforementioned chemicals. , Steam reforming of CH 4 (SRM, eq ) and its modified processes have been implemented to produce syngas for a long time. , However, SRM is an endothermic reaction operated at a temperature above 800 °C, which results in large energy consumption and high cost. Alternatively, partial oxidation of methane (POM) to syngas (formally eq ) is a potentially efficient method to reduce energy consumption. − …”

Oxidative Reforming of Methane over Rh-Containing Zeolites: Active Species and Role of Zeolite Framework

“…Various metal supported catalysts for the oxidative reforming of methane have been investigated by many researchers. − Rh is one of the active metal species for the reaction and has been widely utilized. − , In general, thermally stable metal oxides such as Al 2 O 3 , MgO, ZrO 2 , and CeO 2 were used as supports. ,,, Zeolites are also thermally stable materials with large surface areas owing to their porous structures. Metal cations and clusters as active sites can be created by ion-exchange treatment. , In a previous study, Hou et al reported a MOR-type zeolite-supported Rh subnanocluster as a highly active catalyst for the selective oxidation of methane to syngas, and almost equilibrium CO yield at 600 °C was achieved .…”

Synthesis of Ash Derived Co/Zeolite Catalyst for Hydrogen Rich Syngas Production via Partial Oxidation of Methane

“…The main component of natural gas is CH4 which itself is a GHG but can be used in green energy applications which have been a focus of researchers owing to their high efficiency and low emissions [13][14][15][16]. The CH4 is usually converted to syngas using steam methane reforming [17], dry reforming [18][19][20], and partial oxidation of methane (POM) [4, [21][22][23]. Both the reforming processes are very endothermic, i.e.…”

“…A vast number of catalysts have been studied and proposed for POM to syngas [3,4,21,24,[26][27][28]. Kobayashi et al [27] used Rh/zeolite catalyst and were able to obtain conversion of 84% with a H2/CO ratio of 2.0 at 600 °C and the catalytic performance further improved with the addition of cobalt [28].…”

“…Usually this results in Co3O4 having small crystallite size and high specific area, but it can result in strong cobalt-support interactions which can negatively affect the redox properties of cobalt [33,34]. This problem can be dealt with by using zeolite supports which has capability to improve the Co dispersion and provide more active sites [21]. Zeolite can be easily synthesized from a waste coal fly ash.…”