Layered carbon encapsulated CuOx nanopaticles for selective hydrogenation of furfural to furfuryl alcohol

Abstract

Furfuryl alcohol (FOL) is commercially available by selective hydrogenation of furfural (FAL). A variety of catalysts have been developed for such purpose, among which Cu-based catalysts show superior catalytic performance. However, copper nanoparticles with complex valence states are easy to agglomerate during hydrogenation reaction, which might have a negative influence on the catalytic performance. The carbon coating is an efficient strategy to prevent the sintering of Cu-based catalysts. Herein, a strategy based on the thermal decomposition of Cu-EDTA complex was designed to prepare carbon encapsulated Cu-based catalysts. The prepared catalysts were applied in the selective hydrogenation of FAL to FOL in the batch reactor. The results showed that a nearly quantitative conversion of FAL with a selectivity of 98.7 % towards FOL was achieved using CuOx@NC-150 (molar ratio of Cu: Na4EDTA·4H2O=2:1; obtained by oxidative activation at 150 °C) under 140 °C, 3 MPa in 4 h. The performance was comparable to that of the commercial CuCr2O4 catalyst under the identical conditions. In addition, the developed carbon encapsulated Cu-based catalysts exhibited a slightly better stability than CuCr2O4 catalyst in terms of FOL yield in five consecutive cycles. XPS and XAES characterizations implied that the presence of a suitable surface ratio of Cu+/(Cu++Cu0) of the prepared catalyst may contribute to the selective hydrogenation of FAL to FOL.