Facet-dependent synthesis of H 2 O 2 from H 2 and O 2 over single Pt atom-modified Pd nanocrystal catalysts.

Hydrogen peroxide (H 2 O 2 ) is one of the most valuable clean energy sources with a rapidly growing requirement in industry and daily life. The direct synthesis of H 2 O 2 from hydrogen and oxygen is considered to be an economical and environmentally friendly manufacturing route to replace the traditional anthraquinone method, although it remains a formidable challenge owing to low H 2 O 2 selectivity and production. Here, we report a catalyst consisting of Pd(111) nanocrystals on TiO 2 modified with single Pt atoms (Pt 1 Pd(111)/TiO 2 ), which displays outstanding reactivity, producing 1921.3 μmol of H 2 O 2 , a H 2 conversion of 62.2% and H 2 O 2 selectivity of 80.3% over 30 min. Kinetic and isotope experiments confirm that the extraordinary catalytic properties are due to stronger H 2 activation (the rate-determining step). DFT calculations confirm that Pt 1 Pd(111) exhibits lower energy barriers for H 2 dissociation and two-step O 2 hydrogenation, but higher energy barriers for side reactions than Pt 1 Pd(100), demonstrating clear facet dependence and resulting in greater selectivity and amount of H 2 O 2 produced.