Atomically dispersed nickel in CeO aerogel catalysts completely suppresses methanation in the water-gas shift reaction.

Nickel-based catalysts are widely studied for water-gas shift (WGS), a key intermediate step in hydrogen production from carbon-based feedstocks. Their viability under practical conditions is limited at high temperatures when Ni aggregates and converts CO to methane, an undesirable side product. Because experimental and computational studies identify undercoordinated Ni step sites as most active toward CH formation, we eliminate Ni step sites by atomically dispersing Ni into networked, nanoparticulate CeO aerogels.