Lignite-char-supported highly dispersed ultrasmall Ni-Co alloy for stably dry reforming of methane at low temperature

Abstract

Lignite, abundant in oxygen-containing functional groups, can disperse metal ions through an ion-exchanging method to prepare highly dispersed metal catalysts. Herein, we prepared the Ni-Co bimetallic catalysts using this method and tested their activity and stability in the dry reforming of methane reaction. The Ni0.05-Co0.1 with Ni/Co mass ratio of 1:10 exhibited superior performance due to its higher specific surface area (386 m2/g), smaller metallic particle size (4.85 nm), better dispersion and moderate basicity (0.023 mmol/g), showing the best activity at 650 °C, 2400 mL.h−1.g−1 and atmospheric pressure, with a conversion of 71.5% for CH4, 82.8% for CO2, and a molar ratio of H2/CO of 0.73. Additionally, the catalyst maintained a stable activity throughout a continuous 30 h test at 650 °C, 7200 mL.h−1.g−1 and 0.3 MPa. Overall, this study demonstrates that lignite-char-supported Ni-Co alloy catalysts show great potential for DRM reaction particularly at relatively low temperature and elevated pressure.