Catalytic CO Oxidation by Gas-Phase Metal Oxide Clusters

Abstract

Oxidation of CO into CO 2 is a prototypical reaction in heterogeneous catalysis and is one of the extensively studied reactions in the gas phase to explore the underlying mechanisms of related catalysis. In this Feature Article, we present and discuss our recent advances in the fundamental understanding of catalytic CO oxidation by O 2 mediated with heteronuclear metal oxide clusters (HMOCs) using state-of-the-art mass spectrometry and quantum chemistry calculations. The HMOCs can be considered as ideal models for active sites on mixed or oxide supported catalysts at a strictly molecular level. A concept of electronegativity-ladder effect was proposed to account for the enhanced reactivity of noble metal (NM) doped HMOCs, and then this effect was successfully extended in the design of NM-free HMOCs in catalytic CO oxidation by O 2 . The future directions and the challenges were also discussed.

Catalytic conversion of NO and CO into N2 and CO2 by rhodium–aluminum oxides in the gas phase

“…In contrast, the closely related catalytic reactions (2) and (3) involving N 2 O and O 2 as oxidants (bond enthalpies: N 2 –O = 1.73 eV; O–O = 5.16 eV) have been extensively explored. 25–27 CO + N 2 O → CO 2 + N 2 2CO + O 2 → 2CO 2 …”

Exploring Cu/Al cluster growth and reactivity: from embryonic building blocks to intermetalloid, open-shell superatoms

“…12,13 Noteworthy, mass-spectrometry is thereby a key tool for the assessment of cluster identities and of reaction products. [14][15][16] We have been attracted to metal clusters as a research objective from the perspective of challenges in organometallic synthesis across the periodic table, [17][18][19] and we are much inspired by linking solid state chemistry of intermetallics with the molecular chemistry of mixed metal clusters. 20 There are two categories of wet chemical synthetic strategies for obtaining ligand protected intermetalloid clusters [M n ](R) m (n [ m; M ¼ two or more different metal atoms; n ¼ number of metal atoms aggregated in the cluster core; R ¼ hydrocarbon ligand; square brackets denote the cluster core; round brackets denote the core protecting heteroatom-free, all-hydrocarbon ligand shell).…”

Catalytic CO Oxidation by O2 Mediated with Single Gold Atom Doped Titanium Oxide Cluster Anions AuTi2O4–6−

“…In this case, atomic clusters that are considered as the intermediate matter to bridge the isolate atoms and the bulk counterpart are ideal models for the active sites on related condensed-phase catalysts. Cluster reactions can be performed under isolated and well controlled conditions [1][2][3][4][5][6][7][8][9][10][11] to uncover the mechanisms that govern the reactivity of condensed-phase catalysts at a strictly molecular level, and then the mechanisms can be used to guide the design of advanced catalysts. Gold catalysis is a fascinating topic in both of the gas-phase and condensedphase studies since the breakthrough made by Haruta and coworkers that Au/TiO 2 with supported nanosized gold catalysts exhibited extraordinary activity for catalytic CO oxidation at low temperatures.…”

“…Gold catalysis is a fascinating topic in both of the gas-phase and condensedphase studies since the breakthrough made by Haruta and coworkers that Au/TiO 2 with supported nanosized gold catalysts exhibited extraordinary activity for catalytic CO oxidation at low temperatures. [12,13] CO oxidation is also one type of the best studied catalytic reactions in gas phase, [1,14,15] and gold-contain-ing heteronuclear metal oxide clusters (HMOCs) [16][17][18][19][20][21][22][23][24] are promising models for the active sites on oxide supported gold. Catalytic CO oxidation by O 2 mediated with Au-TiÀ O HMOCs is of great importance to uncover the catalytic behaviors of Au/ TiO 2 , one type of the best studied gold catalysts in condensedphase studies until now.…”