The synergistic effect of the carbon shell pore volume and core Pd size of Pd@hollow@C-X for the synthesis of H₂O₂

Abstract

Yolk–shell Pd@hollow@C-X (X = 1.5, 3.2, 4.5 and 6) catalysts with Pd as the core and porous carbon as the shell were prepared via the inverse microemulsion method.

Pd/CNT with controllable Pd particle size and hydrophilicity for improved direct synthesis efficiency of H2O2

“…Similar results were reported by Wang 17 and Zhang. 18 Burch 19 and Thompson 20 showed that the presence of Pd 0 plays a key role in obtaining higher productivity of H 2 O 2 . In order to regulate and control the Pd nanoparticle size and Pd 0 /Pd 2+ ratio and to improve the selectivity and productivity of H 2 O 2 , halogen ions, metals, metal oxides and acids have been used to modify palladium-based catalysts.…”

“…25,26 (II) The poor solubility of reaction substrates H 2 and O 2 in the reaction medium results in a slow mass transfer rate of them to the active component Pd. 27 Better hydrophilicity is beneficial to enhance the dispersion of catalysts in the hydrophilic reaction medium and increases the contact probability of reaction substrates H 2 and O 2 with the catalyst, thus enlarging the contact area of catalysts and reactant molecules H 2 and O 2 . The higher dispersion of catalysts in the reaction medium can also enlarge its bed height, and in addition, the hydrophilicity of catalysts also influences the desorption ability of H 2 O 2 .…”

Synthesis and performance of PdMulti@HCS catalysts with Pd nanoparticles partially embedded in the inner wall of hollow carbon spheres for the direct synthesis of hydrogen peroxide from hydrogen and oxygen

“…2,6,9,14 The Pd nanoparticle size, support property, and catalyst structure are the key factors for the catalytic activity and stability of Pd catalysts. [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33] At present, the structure of Pd catalysts mainly includes the supported type, tightly coated core-shell type, and hollow core-shell type. [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33] The synthesis methods of traditional supported Pd catalysts are simple, but in the process of high-temperature heat treatment, Pd nanoparticles tend to aggregate into large size Pd particles due to their high surface energy which result in low dispersion and catalytic activity.…”

“…[15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33] At present, the structure of Pd catalysts mainly includes the supported type, tightly coated core-shell type, and hollow core-shell type. [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33] The synthesis methods of traditional supported Pd catalysts are simple, but in the process of high-temperature heat treatment, Pd nanoparticles tend to aggregate into large size Pd particles due to their high surface energy which result in low dispersion and catalytic activity. At the same time, the direct synthesis of H 2 O 2 from H 2 and O 2 is a heterogeneous reaction process with strong mechanical stirring easily making Pd nanoparticles fall off from the support surface, thereby reducing the stability of supported Pd catalysts.…”

“…At the same time, the porous shell of hollow core-shell type Pd catalysts can provide more channels for the transfer and diffusion of reactants and products, and reduce the occurrence of hydrogenation and decomposition side reactions in the transfer channels. [31][32][33] However, the inevitable disadvantage of hollow core-shell type Pd catalysts show that only a single Pd nanoparticle is encapsulated in the hollow structure as an active core, providing limited Pd active sites for H 2 O 2 synthesis and also limited catalyst activity.…”