Facet-dependent synthesis of H₂O₂ from H₂ and O₂ over single Pt atom-modified Pd nanocrystal catalysts

Hydrogen peroxide (H2O2) is one of the most valuable clean energy sources with a rapidly growing requirement in industry and daily life. The direct synthesis of H2O2 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 H2O2 selectivity and production. Here, we report a catalyst consisting of Pd(111) nanocrystals on TiO2 modified with single Pt atoms (Pt1Pd(111)/TiO2), which displays outstanding reactivity, producing 1921.3 mu mol of H2O2, a H-2 conversion of 62.2% and H2O2 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 Pt1Pd(111) exhibits lower energy barriers for H-2 dissociation and two-step O-2 hydrogenation, but higher energy barriers for side reactions than Pt1Pd(100), demonstrating clear facet dependence and resulting in greater selectivity and amount of H2O2 produced.