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

Abstract

Rational modulation of metal−support interaction is an effective strategy to enhance the catalytic performance of a supported catalyst. Here, both the activity and selectivity for the direct H 2 O 2 synthesis from H 2 and O 2 are enhanced by the doping of boron atoms at the interface of Pd and TiO 2 . With boron doping, the selectivity and productivity of H 2 O 2 are remarkedly increased from 63.4% and 2.99 mol H 2 O 2 g Pd −1 h −1 to 80.1% and 3.65 mol H 2 O 2 g Pd −1 h −1 in a triphase semicontinuous reaction system at 10 °C and 0.1 MPa, respectively. The modulation effect of boron on the structure of Pd/TiO 2 was thoroughly studied by using multiple techniques such as HRTEM, XRD, XPS, and in situ DRIFTS. The doped boron atom almost has no effect on the particle size of Pd nanoparticle, but enhances the strong metal− support interaction (SMSI) between the Pd particle and TiO 2 , which results in a change of the Pd 2+ /Pd 0 ratio and surface Pd atoms configuration. An appropriate amount of boron atoms doped at the Pd−TiO 2 interface increases the ratio of Pd 2+ species, providing more active sites for the nondissociative activation of O 2 . Furthermore, the electronic effect between boron and Pd species increases the H 2 adsorption and activation, resulting in simultaneous increases in H 2 O 2 selectivity and productivity. This work highlights the significance of the modulation for metal−support interaction on direct H 2 O 2 synthesis, which also provides an effective and economic route by interface doping to improve the performance of supported heterogeneous catalysts.

Fabrication of the PdAu Surface Alloy on an Ordered Intermetallic Au3Cu Core for Direct H2O2 Synthesis at Ambient Pressure

“…This was also confirmed by XRD, where the intensity of the diffraction peak (111) of Au 3 Cu decreased with the increase of reduction time. According to previous studies, it was found that the performance of the catalyst is also affected by the chemical state of Pd. , In bimetallic catalysts, the electronic effect is also not neglected. However, from the results of XPS (Figure a and Table ), the chemical state of Pd in all Au 3 Cu@AuPd catalysts shows no significant difference.…”

Effect of Pd-Sensitization on Poisonous Chlorine Gas Detection Ability of TiO2: Green Synthesis and Low-Temperature Operation

“…The Pd3d spectrum, as shown in Figure 3d, adduces two peaks: one at 341.1 eV corresponding to Pd3d3/2, and the other at 335.8 eV for Pd3d5/2. The appearance of Pd 2+ peak may be due to the partial oxidation of the Pd surface since the Pd particles are very minute in the Pd-TiO2 film sensor [34]. The Ti2p 3/2 peak has a binding energy of 463.9 eV, whereas the low-intensity Ti2p 1/2 peak has a binding energy of 458.1 eV, thus indicating the presence of a Ti 4+ oxidation state [32].…”

“…The Pd3d spectrum, as shown in Figure 3d, adduces two peaks: one at 341.1 eV corresponding to Pd3d 3/2 , and the other at 335.8 eV for Pd3d 5/2 . The appearance of Pd 2+ peak may be due to the partial oxidation of the Pd surface since the Pd particles are very minute in the Pd-TiO 2 film sensor [34].…”

Sustainable and Continuous Flow Preparation of High-Concentration H2O2 by Visible-Light-Activated Molecular Oxygen Oxidation of Lower Alcohols

“…H 2 O 2 is widely recognized as one of the most efficient and environmentally friendly oxidants. It exhibits excellent oxidation properties across all pH ranges, which makes it highly versatile in various applications, such as chemical synthesis, − papermaking, − mining, environmental remediation, and disinfection . With the growing emphasis on green production, the demand for H 2 O 2 is expected to increase significantly .…”