Designing of Co3O4/N-doped carbon and Co-Co3O4/N-doped carbon nanomaterials via sol-gel route with unexpected high catalytic performances toward hydrogenation reduction of 4-Nitrophenol

Abstract

Co3O4/N-doped carbon (Co3O4/NC) materials and Co-Co3O4/N-doped carbon materials were prepared by sol-gel method by using ethylene glycol (EG), glycerol or acrylamide as chelating agent and carbon source. The Co3O4/NC materials were obtained by calcination of the precursors at 500 °C, 600 °C or 700 °C in air by employing EG or glycerol as polymerization agent and urea as nitrogen source. The materials prepared at 500 °C by using EG and 600 °C by employing glycerol have excellent catalytic performance toward hydrogenation reduction reaction of 4-nitrophenol (4-NP) where NaHB4 has been used as reduction agent. High activity parameter per mass of oxide (K1 m) of 55.8 and 86.4 s−1·g−1, 108.9 and 157.3 s−1·g−1, 209.9 and 269.5 s−1·g−1, 333.4 and 617.1 s−1·g−1 could be obtained for the two materials prepared at 500 and 600 °C when the molar ratio of NaBH4 to 4-NP was 100:1, 200:1, 500:1 and 1000:1, respectively. Co-Co3O4/NC nanocatalyst was prepared by using acrylamide as sources of C and N without urea when the heating of the precursor was conducted at 600 °C under N2 protecting atmosphere, and high activity parameter (K1) values of 118.1 and 273.3 s−1·g−1 could be achieved when the molar ratio of NaBH4:4-NP was 100:1 and 1000:1. Our results provide new route for designing metal oxide/NC nanocatalysts with high catalytic performances.