II International Symposium on Carbon for Catalysis ABSTRACTS

PP-I-42
PREPARATION OF NEW VANADIUM-PHOSHORUS OXIDE CATALYSTS ON
CARBON SUPPORTS
Sydorchuk V., Zazhigalov V., Diyuk V., Pryhodko G., Tsyba M.
Ukrainian-Polish Laboratory of Catalysis, Institute of Sorption and Problems of
Endoecology, Ukrainian National Academy of Sciences, Kyiv, Ukraine
e-mail: bilychi@online.com.ua
Vanadium-phosphorus oxide (VPO) systems are the most effective catalysts for mild
oxidation of n-butane to maleic anhydride [1]. However this fact was not revealed until
suitable support for these catalysts was found.. Thus oxide carriers interact strongly with
active phase and have negative influence on properties of catalysts. Authors [2] suggested to
use materials without oxygen (SiC, BN) to avoid this influence. We present new approaches
for: /i/ creation of supports for VPO-catalysts and /ii/ modification of the whole process for
preparation of catalysts.
As a supports we used such materials as active carbon (KAU) and carbon nanotubes.
Peculiarity and advantage of this approach consist firstly in the fact that carbon is more inert
with reference to active phase and secondly that surface carbon atoms play a role of reduce
agent in the process of VPO-catalysts synthesis from V 2 O 5 . Consequently preparation of
catalyst can be carried out without adding organic compounds in reaction mixture. All
catalysts were synthesized in autoclave.
Active carbon KAU was subjected to preliminary hydrothermal treatment (HTT) by 30-
50% H 2 O 2 at temperarure 300-360°C for modification of porous structure and oxidation of
surface. HTT of KAU leads to increase of surface area S and pore volume V (table) obviously
at the expense of formation of both micro- and mesopores. Hemyhydrate of
vanadylhydrophosphate VOHPO 4 ⋅0,5H 2 O (HPV) - precursor of catalyst for oxidation n-
butane is formed as result of deposition of VPO on active carbon surface. Degree of HPV
crystallization (and accordingly size of crystallite D) grows after preliminary HTT of KAU.
Non-porous C-nanotubes were obtained by pyrolysis of ethylene under 650°C [3]. These
powders were mixed with water, solutions of H 2 O 2 or reaction medium for synthesis of VPOsystems.
As a result meso-macroporous materials of aerogels type (V=2,5-4,5 ml/g) were
prepared for the first time. Mesoporous supported catalysts with high surface area and pore
202