Abstract
Stable operations for catalytic dry reforming of methane (DRM) are essential for industrial applications. High stability for syngas production can be achieved via a kinetic balance between formation of carbon species and their removal by oxygen species on the metal surface, which clears the surface for further reaction steps. This study reports highly stable performance by a boron-doped cobalt catalyst as a non-noble-metal coking-free catalyst. Although the precise location of doped boron could not be identified experimentally because of its low concentration, density functional theory calculations suggested that interstitial boron (B) is most likely present in the subsurface region of cobalt (Co) surfaces. B doping was shown both experimentally and computationally to increase the reactivity of Co catalysts toward both methane (CH4) and carbon dioxide (CO2). Moreover, B-doping was found to balance the amounts of surface C and O and maintain the reduced state of Co surfaces while in a steady-state. Nevertheless, a negative kinetic order with respect to CO2 partial pressure indicates that steady-state surface coverage of oxygen species originating from CO2 dissociation was prevalent on B-doped Co, consistent with the coking-free nature of the catalyst. This study introduces a promising Co-B catalyst design for controlling metal surface reactivity toward DRM and relevant catalytic reactions. (C) 2020 The Authors. Published by Elsevier Inc.