Pt atomic clusters catalysts with local charge transfer towards selective oxidation of furfural

Abstract

Catalytic oxidation conversion of biomass-derived resource to high value-added products has evoked considerable interest. Herein, we report a Pt atomic clusters catalyst (size: 1.3 nm) supported on rehydrated layered double hydroxides (denoted as Pt/re-Mg4Al-LDHs), which exhibits great catalytic behavior towards selective oxidation reaction of furfural to furoic acid (conversion: 99 %; yield: 97 %; reaction rate: 676.57 mmol gPt−1 h−1). This result stands at the highest standard compared with reported Pt-based catalysts. A combination research confirms the formation of surface Ptδ− species, due to the local electron transfer from support to Pt atomic clusters. LDHs provide a confined effect to achieve tunable size and highly-stabilized metal clusters, which imposes influence on catalytic performance via metal-support interactions. Both experimental methods (In situ DRIFTS, Raman, EPR and Isotope Labelling MS) and theoretical calculations reveal that the negatively-charged Pt active site plays a crucial role in determining catalytic behavior: CO bond undergoes activation adsorption on Ptδ− site, followed by reaction with H2O (Aldehyde-Water Shift); subsequently, oxygen is activated to generate reactive oxide species (O2−) that serves as a hydrogen acceptor (Oxidative Dehydrogenation) to produce furoic acid. This work displays a valuable paradigm for preparation of noble metal atomic clusters catalysts based on memory effect of LDHs support, which would pave a way for the development of heterogeneous catalysts toward selective oxidation reactions.