Microscopic crystalline structures called metal-organic frameworks (MOFs) may provide 

way  to  solve  one  of  the  biggest  problems in methane functionalization catalysis, an 

economically important chemical process.

The nation's shale gas production boom of recent years has led many researchers to look

 for new ways to functionalize methane—i.e., transform it into something more valuable. O

ne such product could be methanol.

"There are a lot of ways to functionalize methane, but one form that would be cost effective 

and abundant is the transformation of methane to methanol," said Max Delferro, the catalysis 

science program group leader at the U.S. Department of Energy's (DOE) Argonne National 

Laboratory.  "Unfortunately,  methane  is  one  of  the most stable molecules. It's difficult to 

activate methane."

But  now,  a  team  led  by  Delferro  and  Omar Farha, associate professor of chemistry at 

Northwestern University, has demonstrated a new way to activate methane with MOFs, as a 

result  of  their  joint  efforts  in the Inorganometallic Catalyst Design Center, a DOE-funded 

Energy  Frontier  Research  Center.  They  and  seven  co-authors recently published their 

method in Nature Catalysis.

"This example showcases how designing crystalline materials, in particular MOFs, will lead 

to solutions of complex but exciting opportunities," said Farha, who is also president and co-

founder of NuMat Technologies.

A  methane  molecule  consists  of  one  carbon  atom  linked  to  four hydrogen atoms. But 

functionalizing carbon-hydrogen bonds in methane is a particularly challenging process that 

most known catalysts can achieve only under extremely acidic and/or oxidizing conditions.

The  Argonne-Northwestern  team,  however,  has  shown  for the first time that MOFs can 

selectively produce a specific boron-infused methane product by shape-selective catalysis, 

a  widely  used  industrial  technique  for chemicals synthesis and hydrocarbon processing. 

Shape-selective catalysis can distinguish between molecules that are slightly different in size 

and may selectively form only one desired chemical product. But for the technique to work, 

the pore space of the catalyst must be comparable to the size of the molecules involved in

 the reaction.

Since the 1960s, zeolites have been commonly used to perform this type of catalysis. Zeolit

es are microporous crystalline minerals that often include silicon, aluminum and oxygen. They 

are commonly used as commercial adsorbents and catalysts and have a cage-like framework 

in which reactant molecules can become trapped. But if the molecules are too big to fit inside 

the framework, no catalysis can occur.