Size-Controlled Palladium Nanoparticles Encapsulated in Silicalite-1 for Methane Catalytic Combustion

Abstract

A series of Pd catalysts with different nanoparticle sizes encapsulated in Silicalite-1 (S-1) zeolite were synthesized using the one-step hydrothermal method to investigate the size dependence on methane catalytic oxidation. The obtained Pd nanoparticle (NP) sizes ranging from 1.8 to 3.2 nm were modulated by changing the addition of the ethylenediamine (EN) ligand during the synthesis process, and Pd/S-1-in-6EN (2.1 nm, the molar composition of 1 Pd:6 EN) displayed the remarkable catalytic performance. Meanwhile, long-term stability tests indicate the outstanding water resistance of Pd/S-1-in-6EN with a smaller particle size. According to the results of in situ CO-DRIFTS, a volcano-shaped curve between the fraction of the step site by size control of Pd nanoparticles and the catalytic performance was presented, and Pd/S-1-in-6EN possessed the optimum one. These allow the further study of the particle size effect on zeolite-confined noble metal catalysts for methane combustion.

Insight into the Catalytic Oxidation Mechanism of Hydrogen Isotopes by Pt Clusters Confined by Silicalite-1

“…This was attributed to the Pt clusters being confined in the zeolitic structure, which was consistent with the HAADF-STEM observations of the material edge being nearly free of Pt clusters and other reported results. 15,16,26 Particle sputtering was employed to obtain information about the active sites confined within the zeolitic structure. 26,27 After ion sputtering treatment, the Pt fine spectra of the catalysts were obtained, as shown in Figure S7b.…”

“…15,16,26 Particle sputtering was employed to obtain information about the active sites confined within the zeolitic structure. 26,27 After ion sputtering treatment, the Pt fine spectra of the catalysts were obtained, as shown in Figure S7b. The fitting process revealed that the main valence states were Pt°and Pt δ+ .…”

Methane Combustion over Zeolite-Supported Palladium-Based Catalysts

“…5 nm. Recently, Liu et al synthesized Pd@S-1 using the different ethylenediamine (EN) ligand contents and investigated the effect of the EN amount on particle size [78]. A volcano-shaped relationship between the step site fraction by size control of Pd NPs and the catalytic activity was observed.…”

Recent advances in nanoscale engineering of Pd-based electrocatalysts for selective CO2 electroreduction to formic acid/formate

“…Even though enormous progress has been made in achieving high Faraday efficiency (FE), it is still challenging to produce formic acid/formate with a high overall energy efficiency because the reactions have sluggish kinetics and high overpotentials on main-group p-block metals. Palladium (Pd), as a member of the platinum group metals, possesses a unique 4d 10 5s 0 electronic structure and demonstrates exceptional performance in a variety of catalytic reactions, including CO 2 electroreduction [33,34] , formic acid oxidation [35] , methane catalytic combustion [36] , and CO oxidation [37] . When acting as an electrocatalyst for ECO 2 RR, Pd is unique because it is the only metal that can electrochemically reduce CO 2 to formic acid/formate at a nearzero overpotential [38][39][40] .…”