Synthesis and characterization of Pt nanoparticles with different morphologies in mesoporous silica SBA-15 for methanol oxidation reaction

Abstract

Mesoporous SBA-15 silica materials functionalized with and without carboxylic acid groups were used to effectively control the morphology of Pt crystals, and the materials thus obtained were applied to methanol oxidation reactions. The Pt particles aggregated to form long spheroids inside the channels in pure SBA-15. When carboxylic acid groups were utilized, the SBA-15(-COOH) material facilitated the formation of higher Pt surface area, smaller Pt nanoparticles and nearly spherical shape due to the strong interaction between Pt(4+) ions and carboxylic acid on SBA-15. The Pt(4+) ions on the SBA-15(-COOH) material can be directly transformed to reduced Pt particles during calcination. The methanol oxidation activity on a Pt surface is strongly dependent on the shape of Pt particles. The near-spherical Pt nanoparticles on the SBA-15(-COOH) exhibited higher catalytic activity during methanol oxidation than Pt catalysts on unmodified SBA-15. The near-spherical Pt particles on the SBA-15(-COOH) contained large numbers of terrace sites on their surfaces, which led to high efficiency during methanol oxidation.

Understanding the Promotional Effect of Mn2O3 on Micro-/Mesoporous Hybrid Silica Nanocubic-Supported Pt Catalysts for the Low-Temperature Destruction of Methyl Ethyl Ketone: An Experimental and Theoretical Study

“…43 The bands also observed between 2855 and 3077 cm − 1 may be attributed to the bending and stretching vibrations of C−H 41 and thus must correspond to residual adsorbed hydrocarbon species from the decomposition of MEK. A new bend at 1743 cm − 1 which corresponds to the symmetric C O moiety in acetone can be detected in MEK oxidation over Pt0.3Mn5/SiO2-nc 45 and proves that the Mn2O3 phase has a significant eff ect on the MEK reaction route and oxidation mechanism.…”

Construction of Hierarchically Porous Nanoparticles@Metal–Organic Frameworks Composites by Inherent Defects for the Enhancement of Catalytic Efficiency

“…The presence of metallic Pt in Pt@UiO‐66‐NH 2 before and after heat treatment is testified by high resolution (HR)‐TEM and XAS on Pt L 3 ‐edge shown in Figure I,J and Figure G,H. The d‐spacings of adjacent lattice fringe in Pt@UiO‐66‐NH 2 and Pt@UiO‐66‐NH 2 ‐2h are both 0.23 nm, matching to the (111) facet of Pt . Compared with Pt foil, the increased intensity of Pt white line peak in XANES spectra indicates the slight oxidation of Pt, which is inevitable in the metal nanoparticle.…”

Synthesis of sub-nanosized Pt particles on mesoporous SBA-15 material and its application to the CO oxidation reaction

“…Recently, the shape-and size-controlled syntheses of Pt NPs have become an attractive goal for the development of catalysts with increased fractions of low-coordinated Pt surface atoms. [21][22][23][24][25][26] Alternatively, singleatom catalysts on Pt 1 /FeO x and Pt 1 /Al 2 O 3 supports could be developed and used in the CO oxidation reaction because the Pt loading of these catalysts has been reduced to as low as ∼0.2 wt%. 19,20 In recent years, mesoporous silica materials, e.g., MCM-41, MCM-48 and SBA-15, have been used extensively as catalyst supports because they possess high surface areas.…”