The Comparison between Single Atom Catalysis and Surface Organometallic Catalysis

Abstract

Single atom catalysis (SAC) is a recent discipline of heterogeneous catalysis for which a single atom on a surface is able to carry out various catalytic reactions. A kind of revolution in heterogeneous catalysis by metals for which it was assumed that specific sites or defects of a nanoparticle were necessary to activate substrates in catalytic reactions. In another extreme of the spectrum, surface organometallic chemistry (SOMC), and, by extension, surface organometallic catalysis (SOMCat), have demonstrated that single atoms on a surface, but this time with specific ligands, could lead to a more predictive approach in heterogeneous catalysis. The predictive character of SOMCat was just the result of intuitive mechanisms derived from the elementary steps of molecular chemistry. This review article will compare the aspects of single atom catalysis and surface organometallic catalysis by considering several specific catalytic reactions, some of which exist for both fields, whereas others might see mutual overlap in the future. After a definition of both domains, a detailed approach of the methods, mostly modeling and spectroscopy, will be followed by a detailed analysis of catalytic reactions: hydrogenation, dehydrogenation, hydrogenolysis, oxidative dehydrogenation, alkane and cycloalkane metathesis, methane activation, metathetic oxidation, CO 2 activation to cyclic carbonates, imine metathesis, and selective catalytic reduction (SCR) reactions. A prospective resulting from present knowledge is showing the emergence of a new discipline from the overlap between the two areas.

Facilitating the reduction of V–O bonds on VOx/ZrO2 catalysts for non-oxidative propane dehydrogenation

“…-O-Zr or all of them) is responsible for C-H activation. A potential method to solve this problem is Surface Organometallic Chemistry (SOMC), [41][42][43] which provides access to producing well-dened isolated VO x only possessing V]O and V-O-support. This direction still needs further investigation.…”

Synthesis of High Metal Loading Single Atom Catalysts and Exploration of the Active Center Structure

“…For example, metal hydrides are necessary for C−H bond activation, as well as for chain walking, [209] whereas a metal carbene is essential for olefin metathesis [210] . In some reactions, the real active center comprises single metal atoms with functional ligands, as well as well‐defined surfaces [211–212] . The ligand may control the oxidation state, geometry, and d n electron configuration of the metal center, [212] contributing significantly to the activity, selectivity, and stability of catalysts [213–219] .…”

A New ternary organometallic Pd(ii)/Fe(iii)/Ru(iii) self-assembly monolayer: the essential ensemble synergistic for improving catalytic activity

“…The precise surface modication by introducing proper metals or constructing proper morphology can easily tune the catalytic properties. 36,37 The self-assembly (SA) was an efficient way to get the desired structure with special properties, which can offer the desired controllability of the orientation and stable monolayer. [38][39][40][41][42][43][44][45] Previous studies showed that the activity of the bimetallic catalysts, or their monolayer and their recyclability, could be enhanced by tuning their orientation of the organometallic molecular, component, morphology and distributions of the active species, relating to the electrical characteristics of the supports, ligands, and synergism of the mono-or hetero-bimetallic catalytic lms.…”