Synergistic Hybrid Support Comprising TiO₂–Carbon and Ordered PdNi Alloy for Direct Hydrogen Peroxide Synthesis

Abstract

The development of high-activity catalysts with good selectivity for the direct synthesis of H2O2 from H2 and O2 remains challenging. TiO2–C used as a support material is able to facilitate strong metal–support interactions. We designed catalysts for the direct synthesis of hydrogen peroxide that utilized the synergistic effects of hybrid TiO2–C supports and ordered alloyed PdNi nanoparticles in a neutral reaction solution. Through thermal hydrogen treatment, the ordered structure of the alloyed PdNi nanocatalysts was transformed. 1H NMR was used to measure the amount of water formed as an estimate of selectivity. High-resolution transmission electron microscopy and X-ray photoelectron spectroscopy studies showed an excellent dispersion of the bimetallic PdNi nanocatalyst on the hybrid support. X-ray absorption spectroscopy gave clear evidence of metal–support interactions with electron transfer from the ordered alloyed PdNi nanocatalysts to the defect TiO2–C support, resulting in a noteworthy performance with high H2O2 productivity and selectivity under ambient conditions. This work provides a route to an economically viable alternative to existing Pd-based heterogeneous catalysts for the direct synthesis of hydrogen peroxide.

Understanding the Role of Boron on the Interface Modulation of the Pd/TiO2 Catalyst for Direct Synthesis of H2O2

“…0.9 ± 0.3 and 1.1 ± 0.3 nm, respectively. Through the HR-TEM image (Figure f, h), the interplanar spacing of the nanoparticles is measured to be 0.23 nm, corresponding to the lattice fringes of Pd (111). , It should be noted that the Pd atoms were randomly stacked at the interface between the Pd particles and B-TiO 2 , while the Pd atoms showed regular arrangement of Pd crystals at the interface between the Pd particles and TiO 2 . Moreover, the lattice spacing of B-TiO 2 is 0.18 nm (Figure h), which is slightly smaller than that (0.20 nm) of the (200) plane of anatase TiO 2 .…”

Enhancing the Chemo-Enzymatic One-Pot Oxidation of Cyclohexane via In Situ H2O2 Production over Supported Pd-Based Catalysts

“…The high catalytic performance of PdAu alloys toward H 2 O 2 production has been extensively reported. , However, recent focus has shifted toward the introduction of a range of readily abundant metals into supported Pd nanoparticles, , this includes but is not limited to: Pb, Co, Cu, Sn, Ag, Zn, Ni, , In, Fe and Te . Typically, the improved selectivity of the resulting bimetallic catalysts has been attributed to a combination of Pd oxidation state modification and a reduction of contiguous Pd ensembles, with extended domains of Pd 0 known to promote H 2 O 2 degradation to H 2 O. , In keeping with earlier studies, we also observe the enhanced catalytic efficacy that can be achieved through the alloying of Pd with a range of transition metals (Au, Fe, Co, Ni, Cu, Pt, Zn, In) (Figure ), with a clear reduction in H 2 O 2 degradation rate and a concurrent improvement in H 2 O 2 selectivity also observed (Table S3).…”

Bimetallic Nanocrystals: Structure, Controllable Synthesis and Applications in Catalysis, Energy and Sensing

“…Generally speaking, hydrogen storage materials are mainly small molecules, such as sodium borohydride, hydrazine, lower alcohols and borohydrides, hydrides (LiH, MgH 2 , AlH 3 ) and so on. It has been reported that the common hydrogen production catalysts are Ni-based catalysts (PtNi [181,183], RhNi [182], IrNi [184], PdNi [180,185], FeNi [186] and CoNi [187]), especially Rh-Ni and Pt-Ni alloy catalysts, which have the best activity and selectivity. Moreover, the composition and morphology of the alloy catalyst have a great influence on the performance of the catalyst.…”