Selectivity switching resulting in the formation of benzene by surface carbonates on ceria in catalytic gas-phase oxidation of benzyl alcohol

Abstract

The irreversible formation of carbonate deposits on CeO2 leads to complete switching of catalytic selectivity resulting in the formation of benzene in gas-phase oxidation of benzyl alcohol. By integrating experimental spectra and theoretical calculations, we expect that such a shift is derived from further decarbonylation of benzaldehyde via easy trapping of CO fragments by surface carbonate species.

Ceria-Based Materials for Thermocatalytic and Photocatalytic Organic Synthesis

“…For example, XPS is widely used to detect the surface valence states of elements of catalysts; however, the ultrahigh vacuum condition of the traditional XPS may also affect the surface valence states of CeO 2 -based catalysts during the test, which may not reflect the exact surface composition. Low-temperature ESR can be used to identify oxygen vacancies formed in CeO 2 -based catalysts that play an important role in the chemisorption of substrates and formation of specific reaction intermediates, whereas the concentration of oxygen vacancies and the type of reaction intermediates in the actual reaction systems may also be different from the ESR results due to their different temperatures. , To better observe the dynamics during catalytic processes and construct structure-performance correlations, various advanced characterization techniques as well as proper in situ and operando reaction cells and related measurement protocols have been applied to identify reaction intermediates and active sites during the catalytic process with the aim to provide deep mechanistic insights into the fundamentals of heterogeneous catalysis, such as in situ INS spectroscopy, in situ ambient pressure XPS, in situ XAS, in situ nuclear magnetic resonance, synchronous illumination X-ray photoelectron spectroscopy (SIXPS). , Several in situ and operando characterization techniques have also been applied in the mechanistic studies over CeO 2 -based catalysts such as in situ Raman spectroscopy, in situ quadrupole mass spectrometer, in situ TEM, in situ UV–vis spectroscopy, in situ DRIFTS, ,,, or their combinations . For example, in situ DRIFTS is often used to investigate the chemisorption and transformation of reactants with the surface active sites at various temperatures, especially for the gas-phase reactions on CeO 2 -based catalysts. , In the work from Wu et al, in situ INS and in situ DRIFTS were used to discriminate the role of surface cerium hydride (Ce-H) and hydroxyl (OH) groups in the acetylene semihydrogenation over CeO 2 , which explain the reaction mechanism including not only the surface chemistry but also the nature of the active hydrogen species for selective hydrogenation over ceria .…”

“…373,383 To better observe the dynamics during catalytic processes and construct structure-performance correlations, various advanced characterization techniques as well as proper in situ and operando reaction cells and related measurement protocols have been applied to identify reaction intermediates and active sites during the catalytic process with the aim to provide deep mechanistic insights into the fundamentals of heterogeneous catalysis, such as in situ INS spectroscopy, in situ ambient pressure XPS, in situ XAS, in situ nuclear magnetic resonance, synchronous illumination X-ray photoelectron spectroscopy (SIXPS). 406,407 Several in situ and operando characterization techniques have also been applied in the mechanistic studies over CeO 2 -based catalysts such as in situ Raman spectroscopy, 408 in situ quadrupole mass spectrometer, in situ TEM, in situ UV−vis spectroscopy, 281 in situ DRIFTS, 117,199,409,410 or their combinations. 411 For example, in situ DRIFTS is often used to investigate the chemisorption and transformation of reactants with the surface active sites at various temperatures, especially for the gas-phase reactions on CeO 2 -based catalysts.…”

Bimetallic Gold-Silver Nanoparticles Supported on Zeolitic Imidazolate Framework-8 as Highly Active Heterogenous Catalysts for Selective Oxidation of Benzyl Alcohol into Benzaldehyde

“…The selective catalytic oxidation of benzyl alcohols to benzaldehyde is one of the most fundamental transformations both in the laboratory and in the industrial synthetic chemistry [1,2]. Benzaldehyde is an important intermediate and a high-value product in the cosmetic, food, dyestuff, pharmaceutical, and agrochemical industries [2,3,4].…”

“…The selective catalytic oxidation of benzyl alcohols to benzaldehyde is one of the most fundamental transformations both in the laboratory and in the industrial synthetic chemistry [1,2]. Benzaldehyde is an important intermediate and a high-value product in the cosmetic, food, dyestuff, pharmaceutical, and agrochemical industries [2,3,4]. The catalytic performance of supported monometallic and supported bimetallic catalysts such as Au, Pd, Ag, Au–Cu, Au–Pd, and Cu–Ni for the selective oxidation of benzyl alcohol has been extensively studied [4,5,6,7,8].…”

High efficient and stable thiol-modified dendritic mesoporous silica nanospheres supported gold catalysts for gas-phase selective oxidation of benzyl alcohol with ultra-long lifetime

“…Selective oxidation of alcohols to aldehydes, especially benzyl alcohol-to-benzaldehyde, is one of the pivotal reaction in organic synthesis and is of particular importance in both fundamental academic research and practical industrial applications. [1][2][3][4][5] However, most of the classic transformations usually require stoichiometric amounts of high-valent metal salts oxidants or organic compounds as the oxidants, which are expensive and have serious toxicity issues associated with them. 6 Over the past two decades, lots of supported metal (such as Cu, Ag and Au, etc.)…”