Direct conversion of methane to alcohol remains a key challenge. Here, we report a novel aqueous catalyst, cubic platinum (Pt) nanoparticles capped with Cs-2[closo-B12H12], capable of direct oxidation of methane to ethanol and methanol with H2O2 and O-2 under facile conditions. The selective conversion to ethanol exceeded 97% with a yield reaching 148.41 mol.kg(cat)(-1).h(-1) at 50 degrees C. Experiments with 5,5'-dimethyl-1-pyrroline-N-oxide (DMPO) and electron paramagnetic resonance (EPR) tests revealed that methane oxidation occurred via free-radical chain reactions involving CH3 center dot, CH3CH2 center dot, and HO center dot radicals, Theoretical analysis suggested that the {1 0 0} surface of the Pt nanoparticles was capped with Cs-2[closo-B12H12] mediated by Pt-B bonds with a binding energy of -278.6 kcal/mol, This promoted the growth of particles along the direction of the (1 0 0) facets and finally formed a cubic structure. The EPR tests combined with theoretical calculations confirmed the hypothesis that methane-ethane- ethanol conversion was mediated by the catalyst by employing the features of nano-platinum and Cs-2[closo-B12H12], on which only C-1 and C-2 products were generated, while no products with three or more carbon atoms were detected in the reaction systems described above. (C) 2020 Elsevier Inc. All rights reserved.