Acetylene hydrogenation to ethylene by water at low temperature on a Au/α-MoC catalyst

The hydrogenation of coal-based acetylene to ethylene is an important approach to establishing a non-oil route to ethylene production, yet it suffers from high H2 consumption as well as a high energy input. Here we report a H2-free acetylene hydrogenation process achieved by directly using water as the hydrogen source and low-cost CO as the oxygen acceptor over a Au/α-MoC catalyst. The process delivers over 99% acetylene conversion and a high ethylene selectivity of 83% at 80 °C, surpassing the hydrogenation process using H2 as the hydrogen source. Mechanistic studies have revealed that in situ-generated hydroxyl species from water dissociation at the boundary of Au and α-MoC, serving as mild reductants, enable the selective semi-hydrogenation of acetylene with residual O removed by CO. This process circumvents the need for H2 in the classical route and opens avenues for energy-efficient acetylene hydrogenation by water at low temperature. The selective hydrogenation of acetylene to ethylene involves high H2 consumption as well as a high energy input. Now, a thermocatalytic process for acetylene semi-hydrogenation using H2O as H source and CO on a Au/α-MoC catalyst is introduced.