Zeolite MCM-22 Modified with Au and Cu for Catalytic Total Oxidation of Methanol and Carbon Monoxide

Abstract

The goal of this work was to use MCM-22 zeolites for preparation of monometallic (Cu or Au) and bimetallic (Cu and Au) catalysts for oxidation reactions. The focus was on precise determination of the nature of gold and copper species and their activity in the oxidation processes. For that purpose several characterization techniques were applied (XRD, N 2 adsorption/desorption, TEM, SEM, UV−vis, H 2 -TPR, 27 Al MAS NMR, FT-IR with the adsorption of pyridine, NO, and CO, ESR spectroscopy). They allowed us to define the following species formed on MCM-22 surface: metallic gold particles (XRD, UV−vis), isolated Cu 2+ with octahedral coordination (UV− vis, ESR), square planar Cu 2+ cations (ESR, IR), Cu + species (ESR+NO, FTIR+CO, and FTIR+NO), and oligonuclear clusters (UV−vis) as well as CuO-like species (H 2 -TPR). The presence of gold on the MCM-22 surface modified further by copper species caused the interaction between two modifiers leading to much easier reduction of CuO-like species and higher mobility of oxygen-promoting oxidative properties. The bimetallic catalyst was highly active in total oxidation of methanol and CO in the temperature range 523−623 K. Cu/Au-MCM-22 zeolite appeared useful for simultaneous removal of CO and methanol (by total oxidation) from gases emitted from automotive devices and during a variety of industrial process operations.

Direct oxidation of methane to methanol on Fe–O modified graphene

“…Single metal atoms have been anchored on supports such as metal oxides [11][12][13][14][15][16][17] and also the inclusion of ion-exchanged metals into porous materials like metal-organic frameworks (MOFs) [18][19][20] and zeolites has been successful. 11,[21][22][23][24] Another class of supports, carbonaceous materials such as nanotubes, fullerene and graphene have become promising support materials for metals as well. [25][26][27][28] Owing to its high surface area and several unique properties, graphene has extensively been used to investigate many reactions via theoretical and experimental approaches.…”

Sinter-Resistant Nanoparticle Catalysts Achieved by 2D Boron Nitride-Based Strong Metal–Support Interactions: A New Twist on an Old Story

“…The zeolite framework MCM-22 with lamellar frameworks has been considered a potential solid acid catalyst, and its surface properties can be modified by doping it with various metal species in the extra positions of the framework. 60 The unique properties of MCM-22 render it a good support to stabilize metal NPs under harsh reaction conditions.…”

Mesoporous cerium–zirconium oxides modified with gold and copper – synthesis, characterization and performance in selective oxidation of glycerol

“…20 Catalysts containing gold that is modied with copper can be useful for the simultaneous total oxidation of carbon monoxide and methanol from gases emitted by automotive devices and during industrial processes. 11,21,22 The bimetallic copper-gold catalysts promoted with ceria and/or zirconia loaded on mesoporous SBA-15 materials exhibited higher activity in methanol oxidation than analogues monometallic gold or copper catalysts. 11 The chemical composition and structure of the support used for gold-copper play an important role in the activation of bimetallic particles.…”