Carbon modified active pairs of Co-Co2C for CO2 hydrogenation to alcohols

Abstract

The transformation process of CO2-to-alcohols can achieve the reduction in emissions of carbon dioxide and hydrogen storage, considered to be the up-and-coming way to realize the utilization of CO2. Co-based catalysts are promising, where Co0/Coδ+ is the critical active pair. The challenge is how to construct and tailor the active pair of Co0/Coδ+, to which a new scheme has been proposed in this work. Dual active sites of Co-Co2C were constructed and tailored by the carbon deposition via catalytic decomposition of methane reaction in this scheme. The formation of Co2C species promoted the non-dissociation of COx intermediates, which greatly contributed to the synthesis of alcohols. Not only the state of the Co active component changed with the addition of carbon species, but its own electron-donating effect increased the activation rate of CO2. The catalyst exhibited a CO2 turnover frequency of 7.4 × 10−3 s−1, 16.9 C-mol% and 29.5 C-mol% for ethanol and methanol selectivity at 270 °C and 3 MPa, respectively. This study provides a reference for catalyst design with the help of carbon species to modulate the state of active components.