Unravelling structure sensitivity in CO2 hydrogenation over nickel

T he reduction of CO 2 emissions into the Earth's atmosphere is gaining legislative importance in view of its impact on the climate 1–5 . Reduction of the harmful effect of these emissions through reclamation of CO 2 is made attractive because CO 2 can be a zero-or even negative-cost carbon feedstock 6,7 . The conversion of renewably produced hydrogen and CO 2 into methane, or syn-thetic natural gas, over Ni is a solution that combines the potential to reduce CO 2 emissions with a direct answer to the temporal mis-match in renewable electricity production capacity and demand 8–17 . Chemical energy storage in the form of hydrogen production by electrolysis is a relatively mature technology; however, the required costly infrastructure, and inefficiencies in distribution and storage deem it inconvenient for large-scale application in the near future. Point-source CO 2 hydrogenation to methane represents an alterna-tive approach with higher energy density. Furthermore, methane is more easily liquefied and can be stored safely in large quanti-ties through infrastructures that already exist 18,19 . Power-to-gas (in this case methane) is thus actively considered as being capable of balancing electric grid stability, which will allow us to increase the renewable energy supply 20 . The search for fossil fuel alternatives, and application of a process such as that described above can arguably be achieved only with the help of advances in catalysis and the closely related field of nanoma-terials. Continuous efforts in both fields have allowed us to make increasingly smaller and catalytically more active (metal) particles. However, it is already known that making progressively smaller sup-ported catalyst particles does not necessarily linearly correspond to higher catalytic activity 21–23