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Electrochemically reducing CO2 to valuable fuels or feedstocks is recognized as a promising strategy to simultaneously tackle the crises of fossil fuel shortage and carbon emission. Sn‐based catalysts have been widely studied for electrochemical CO2 reduction reaction (CO2RR) to make formic acid/formate, which unfortunately still suffer from low activity, selectivity and stability. In this work, halogen (F, Cl, Br or I) was introduced into the Sn catalyst by a facile hydrolysis method. The presence of halogen was confirmed by a collection of ex situ and in situ characterizations, which rendered a more positive valence state of Sn in halogen‐incorporated Sn catalyst as compared to unmodified Sn under cathodic potentials in CO2RR and therefore tuned the adsorption strength of the key intermediate (*OCHO) toward formate formation. As a result, the halogen‐incorporated Sn catalyst exhibited greatly enhanced catalytic performance in electrochemical CO2RR to produce formate. [ABSTRACT FROM AUTHOR]

Electrochemically reducing CO2 to valuable fuels or feedstocks is recognized as a promising strategy to simultaneously tackle the crises of fossil fuel shortage and carbon emission. Sn‐based catalysts have been widely studied for electrochemical CO2 reduction reaction (CO2RR) to make formic acid/formate, which unfortunately still suffer from low activity, selectivity and stability. In this work, halogen (F, Cl, Br or I) was introduced into the Sn catalyst by a facile hydrolysis method. The presence of halogen was confirmed by a collection of ex situ and in situ characterizations, which rendered a more positive valence state of Sn in halogen‐incorporated Sn catalyst as compared to unmodified Sn under cathodic potentials in CO2RR and therefore tuned the adsorption strength of the key intermediate (*OCHO) toward formate formation. As a result, the halogen‐incorporated Sn catalyst exhibited greatly enhanced catalytic performance in electrochemical CO2RR to produce formate. [ABSTRACT FROM AUTHOR]

Supported Au nanocatalysts have attracted intensive interest because of their unique catalytic properties. Their poor thermal stability, however, presents a major barrier to the practical applications. Here we report an ultrastable Au nanocatalyst by localizing the Au nanoparticles (NPs) in the interfacial regions between the TiO2 and hydroxyapatite. This unique configuration makes the Au NP surface partially encapsulated due to the strong metal-support interaction and partially exposed and accessible by the reaction molecules. The strong interaction helps stabilizing the Au NPs while the partially exposed Au NP surface provides the active sites for reactions. Such a catalyst not only demonstrated excellent sintering resistance with high activity after calcination at 800 °C but also showed excellent durability that outperforms a commercial three-way catalyst in a simulated practical testing, suggesting great potential for practical applications. [ABSTRACT FROM AUTHOR]

In this work, MIL-53(Fe) was synthesized using a solvothermal method under static conditions. However, it was interesting to find that another MIL-53 type material, Fe(BDC)(DMF,F), was obtained when stirring conditions were used while keeping the other conditions fixed. The Fe-containing metal–organic frameworks (MOFs) were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), 57Fe Mössbauer spectrometry and thermogravimetric analysis (TGA). By simply increasing the crystallization time under agitation, the morphology of the Fe(BDC)(DMF,F) crystals went through a striking transition from a bulky irregular shape to a rod-like morphology. The catalytic performance of the Fe-MOFs was evaluated in the degradation of phenol solution at near neutral pH at 35 °C. A significantly better catalytic activity was achieved for Fe(BDC)(DMF,F) than for MIL-53(Fe) and NH2-MIL-53(Fe) due to the existence of Fe(ii) in its framework. Phenol was almost completely decomposed in 3 hours, and the conversions of hydrogen peroxide and chemical oxygen demand (COD) were 74.1% and 78.7%, respectively. [ABSTRACT FROM AUTHOR]

[Display omitted] Cation- and anion-substituted hydroxyapatites (sHAPs) supported gold catalysts showed strong metal-support interaction (SMSI) under oxidative atmosphere. Mg- and Ce-substituted sHAPs stabilized Au clusters and imparted positively charged Au. The Au on these sHAPs became more positively charged upon formation of the oxidative SMSI. The catalytic activities for transvinylation of benzoic acid with vinyl acetate and isomerization of 3,4-diacetoxybut-1-ene (34DABE) correlated well with the cationic properties of Au; Au/Mg0.1SrHAP and Au/Ce0.1SrHAP with SMSI exhibited higher catalytic activity than other Au/sHAPs and the same catalysts without SMSI. The enhanced cationic properties of Au particles induced by oxidative SMSI surpassed the disadvantages of the reduction of the exposed surface Au atoms caused by SMSI. This work reveals that controlling the degree of SMSI is an efficient methodology to tune an optimal electronic state of metal NPs for target reactions and to provide highly active and durable catalysts. [ABSTRACT FROM AUTHOR]

[Display omitted] • A preparation method of CoFe alloy carbide catalyst was proposed. • Co-Fe interdiffusion happened in reduction and affect the alloy carbide formation. • ε'-(Co x Fe 1-x) 2.2 C facilitated the synergy between CO insertion and dissociation. • 0.25 wt% Na promoted ε'-(Co x Fe 1-x) 2.2 C formation and enhanced STY of higher alcohols. Higher alcohols synthesis (HAS) from syngas is quite attractive but still challenging due to the unsatisfied product selectivity and stability. Here, we prepared a series of CoFe bimetallic carbide catalysts and investigated the evolution of active species. The catalysts reduced above 300 °C could ensure an adequate interdiffusion between Co and Fe species to form CoFe alloy and then achieved a high fraction of ε'-(Co x Fe 1-x) 2.2 C species during HAS reaction, which exhibited excellent catalytic performance and stability over 200 h. The ε'-(Co x Fe 1-x) 2.2 C, acting as uniformly atomic neighboring Co x C-Fe x C dual sites, facilitated the synergy between CO nondissociative adsorption and CO dissociation, thus boosting the selective production of higher alcohols. It is also demonstrated that adding proper content of Na (0.25 wt%) can enhance the formation of ε'-(Co x Fe 1-x) 2.2 C as well as modulate the surface concentration of intermediates. These results may provide new idea for the design of high-performance catalysts for HAS. [ABSTRACT FROM AUTHOR]

Abstract: This paper describes dehydrogenation reaction of ethylbenzene to styrene with CO2 over iron oxide-based catalysts. Three catalysts of Fe2O3–MgO/γ-Al2O3, Fe2O3/MgAl2O4 and MgFe0.1Al1.9O4 with the same molar ratio of Mg/Fe/Al were prepared by impregnation and sol–gel methods. At 580°C, the ethylbenzene conversion over MgFe0.1Al1.9O4 kept a value of 40% during the time on stream of 20h, whereas that over Fe2O3/MgAl2O4 decreased rapidly from initial 50.0% to 27.4%. The properties of the catalysts were characterized by several techniques such as N2 adsorption/desorption, X-ray diffraction, thermogravimetry, energy dispersive X-ray spectroscopy, Fourier transform-infrared spectroscopy, 57Fe Mössbauer spectroscopy, temperature-programmed reduction, and temperature-programmed desorption of NH3 and CO2. It was found that the iron species of these catalysts are different. In MgFe0.1Al1.9O4, all Fe3+ species are incorporated in the spinel lattice. MgFe0.1Al1.9O4 shows high catalytic activity and stability in ethylbenzene dehydrogenation reaction with CO2. Moreover, the weak surface acidity of MgFe0.1Al1.9O4 prevents from the carbon formation during the reaction. [ABSTRACT FROM AUTHOR]

Two kinds of Fe–Co Prussian blue analogues (Fe–Co PBAs) with different iron valence state, Fe 3 [Co(CN) 6 ] 2 ·12H 2 O and Fe[Co(CN) 6 ]·2H 2 O, were developed as the photo-Fenton catalysts for in-depth investigation of the heterogeneous Fenton reaction mechanism. These two catalysts showed exceptionally high efficiencies for the degradation of Rhodamine B. The efficient redox cycling of iron species in the Fe–Co PBAs photo-Fenton process was deeply explored by Mössbauer spectroscopy. The excellent photo-Fenton activities of these Fe–Co PBAs were ascribed to the existence of highly dispersed water coordinated iron sites and abundant vacancies in the metal-organic-frameworks. Singlet oxygen was identified by radical scavenger experiments and electron paramagnetic resonance spectroscopy, which plays a key role in the photo-Fenton process. Based on these comprehensive experimental results, a novel radical reaction mechanism was proposed. This work not only opens up a new avenue for the application of Fe–Co PBAs, but also gives a deeper insight into the mechanisms of heterogeneous Fenton reactions. [ABSTRACT FROM AUTHOR]

Fe/γ-Al2O3catalysts calcinedat different temperatures were evaluated in the catalytic wet peroxideoxidation (CWPO) of m-cresol. BET, XRD, and 57Fe Mössbauer spectroscopy (MS) were used to characterizethe catalysts and showed that the calcination temperature changedthe crystal particles of α-Fe2O3and theinteractions between α-Fe2O3and the γ-Al2O3support. The reaction-conditionexperiments showed that changing the reaction conditions to higherreaction temperature and acidic pH promoted the degradation of m-cresol. m-Cresol was degraded completely,and TOC removal reached 51.0% after CWPO for 2 h at an initial pHof 4 and a temperature of 60 °C over an Fe/γ-Al2O3catalyst calcined at 350 °C (Fe/γ-Al2O3-350). Both reactions for10 consecutive reaction cycles and for 120 continuous hours in a fixed-bedreactor showed that the Fe/γ-Al2O3-350 catalyst was stable and a promising catalyst for heterogeneousCWPO. The degradation intermediates were identified by GC-MS, andthe possible degradation pathway of m-cresol wasinvestigated. [ABSTRACT FROM AUTHOR]