Direct
conversion of methane to C2 compounds by oxidative
and nonoxidative coupling reactions has been intensively studied in
the past four decades; however, because these reactions have intrinsic
severe thermodynamic constraints, they have not become viable industrially.
Recently, with the increasing availability of inexpensive “green
electrons” coming from renewable sources, electrochemical technologies
are gaining momentum for reactions that have been challenging for
more conventional catalysis. Using solid-state membranes to control
the reacting species and separate products in a single step is a crucial
advantage. Devices using ionic or mixed ionic–electronic conductors
can be explored for methane coupling reactions with great potential
to increase selectivity. Although these technologies are still in
the early scaling stages, they offer a sustainable path for the utilization
of methane and benefit from the advances in both solid oxide fuel
cells and electrolyzers. This review identifies promising developments
for solid-state methane conversion reactors by assessing multifunctional
layers with microstructural control; combining solid electrolytes
(proton and oxygen ion conductors) with active and selective electrodes/catalysts;
applying more efficient reactor designs; understanding the reaction/degradation
mechanisms; defining standards for performance evaluation; and carrying
techno-economic analysis.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.