Physico-Chemical Nanomaterials Science

Multilayer N-doped Reduced Graphene Oxide as a Selective Acetylene Hydrogenation Catalyst
Abakumov A.A., Bychko I.B., Strizhak P.E.
Department of catalytic synthesis based on single-carbon molecules, L.V. Pisarzhevskii Institute of Physical chemistry of the NAS of Ukraine.
Prospect Nauki, 31, Kyiv-03028, Ukraine. 
E-mail: abakumov0aa@gmail.com

Basic requirements to acetylene hydrogenation catalyst consist in its selectivity by ethylene and stability. Acetylene hydrogenation catalysts are metal-based materials. Their catalytic activity tends to decrease at high temperatures due to metal particle agglomeration causing instability of the catalyst. Stability and carbonization resistance in hydrocarbon excess atmosphere represent main advantages of carbon nanomaterials, particularly, reduced graphene oxide, over conventional metal-based catalysts. Presented report is dedicated to high selectivity of multilayer N-doped reduced graphene oxide.
Graphene oxide was synthesized following the modified Hummers method and reduced with hydrazine [1]. Obtained black precipitate was filtered, dried and processed under hydrogen flow for 1 hour at 400oC. The multilayer structure of N-RGO particle is maintained by both transmission electron microscopy and X-ray diffraction. Analysis of Raman, infrared and X-ray photoelectron spectra shows that N-RGO is a defect abundant material with the defect distance of 1–3 nm and contains graphenic areas, hydroxyl and carbonyl functionalities as well as, presumably, pyridinic and pyrazole cycles located at the edges of graphene layers. Total molar oxygen and nitrogen percentage are 17 and 3%, respectively. The surface area is 210 m2/g.
Catalytic experiments were performed in the stainless steel tube reactor in 100–400oC temperature range with 320 mg catalyst load. Acetylene was injected in hydrogen and helium flows with rates of 10 and 40 ml/min, respectively, to form the gas mixture with 0.4% acetylene content. Obtained N-RGO shows close to 100% selectivity by ethylene in acetylene hydrogenation reactions in all the temperature range. Starting from 0.5% at 200oC the acetylene conversion reaches 9.4% at 400oC. The effective activation energy of the process is 33 kJ/mole. The presented material demonstrates high stability.

1.	Daniela C. Marcano et al. Improved Synthesis of Graphene Oxide // 	ACS Nano, 2010, 4 (8), pp 4806–4814