An experimental approach for controlling confinement effects at catalyst interfaces

Abstract

Designable materials help pinpoint the role of steric confinement in catalysis.

Controlling Heterogeneous Catalysis with Organic Monolayers on Metal Oxides

“…In some cases this modification can be beneficial, but deposition strategies to avoid metal modification are available . These include deposition of metals onto oxide surfaces with the ligands already present as well as the “protection” of metal sites with removable site blockers. , In general, determination of the organic ligand distribution on supported metal catalysts is most straightforward using STEM-EDS if the metal, oxide, and ligands all contain elements with distinct characteristic X-rays within detection range. Additionally, ligand depositions have been observed on bulk metals (such as platinum or palladium black) and subsequently characterized, for instance with XPS or other elemental analysis techniques, to quantify adsorbate coverages and provide insights into possible metal–ligand interactions. , …”

“…Schematic view of catalysts with control over (top) larger and (bottom) smaller spacing between metal active sites and PA modifiers. From ref . CC BY-NC 3.0.…”

“…In addition, Slot et al demonstrated a methodology for controlling the spacing between supported metal nanoparticles and PA modifiers, creating a tool for investigating interface sites (Figure 7). 37 Here Pt/Al 2 O 3 catalysts were first modified with alkyl thiols, which preferentially bind to the Pt surface, before modification of the oxide with PAs. By increasing the length of the alkyl group on the thiol, one could increase the spacing between the metal nanoparticles and the PA modifiers; the thiols could subsequently be removed by reductive treatment to create "open space" around the catalyst.…”

Ruthenium on Alkali‐Exfoliated Ti3(Al0.8Sn0.2)C2 MAX Phase Catalyses Reduction of 4‐Nitroaniline with Ammonia Borane

“…This species rapidly reduces nitro arenes into the corresponding N‐aryl hydroxylamines, which are reduced further into aryl amines using NH 3 BH 3 [63] . Ammonia borane hydrolysis is believed to proceed through a Langmuir‐Hinshelwood type mechanism with O−H bond cleavage as the rate‐determining step [75,76] . However, the exact reactive species is unknown [77–84] .…”

Ti3C2Tx MXene Polymer Composites for Anticorrosion: An Overview and Perspective

“…For example, Ti 3 C 2 T x consists of three layers of Ti atoms and two layers of C atoms arranged in layers of Ti–C–Ti–C–Ti. The T x component in the formula represents the surface terminations (typically −OH, −F, −O, −Cl) existing on the outer planes of Ti as an outcome of the synthesis method. − Thus, it is easily well-dispersed in water or other solvents, with the highest electrical conductivity (up to 24,000 S cm –1 ) and Young’s modulus (∼334 GPa) among all solution-processed 2D materials. − In addition, the top-down synthesis method via wet chemical selective etching from its precursor, the Ti 3 AlC 2 MAX phase, , makes it quite scalable for industrial synthesis. Owing to these superior properties and its feasibility for solution processability, scalability, and surface functionality, various applications of Ti 3 C 2 T x such as in catalysis, , electromagnetic interference shielding, energy-storage applications, flexible electronics, and biosensors have been reported.…”