Ambient temperature CO oxidation over gold nanoparticles (14 nm) supported on Mg(OH)2 nanosheets

•Au NPs with two sizes (4 &14 nm) were deposited on Mg(OH)2 nanosheets (NSs).•Catalysts with larger Au NPs gave decent activity toward CO oxidation.•Mg(OH)2 NSs were important for the activity of catalysts with larger Au NPs.

Au/Mg(OH)2 catalysts with two different sizes (4 and 14 nm) of Au nanoparticles (NPs) have been prepared by depositing pre-fabricated Au NPs onto Mg(OH)2 nanosheets (NSs). It was found that 14 nm Au NPs supported on Mg(OH)2 exhibited unexpected activity for CO oxidation at ambient temperature that could be comparable with those of Au NPs of 4 nm. The Mg(OH)2 support was suggested to be responsible for the observed catalytic activity of larger gold supported catalysts.