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A detailed operando DRIFTS study on the CO2 Fischer‐Tropsch reaction with K‐promoted Fe/YZrOx catalysts was performed to investigate the influence of this modification on the catalytic performance in the formation of lower olefins as well as higher hydrocarbons and to gain insights into mechanistic aspects. Catalytic testing revealed an enhanced formation of olefins and hydrocarbons by adding potassium to the catalysts, while spectroscopic studies revealed various stable adsorbates and intermediates such as monodentate carbonates, bicarbonates, formates, formyl, and methoxy on the surface of the K‐promoted Fe/YZrOx catalysts compared to the unpromoted one. Based on gas‐feed switching experiments and statistical analysis of literature IR data regarding Fe‐containing catalysts, it was found that carbonate species interacting with H2 are transformed to higher hydrocarbons and methane via formate and formyl formation, while bicarbonate species are decomposed accompanied by the formation of CO, which then further reacts to form formate or formyl and finally hydrocarbons. [ABSTRACT FROM AUTHOR]

Layered double hydroxide (LDH) nanostructures are commonly used to study the interfacial effects of Pt‐based catalysts in CO oxidation. However, the specific role and detailed intermediates involved in CO oxidation remain unclear. Density functional theory (DFT) predicted that NiFe LDH loaded with single Pt atoms would exhibit satisfactory CO oxidation activity. On this basis, we prepared Pt1NiFe LDH catalysts with various Fe : Ni ratios by using the one‐pot method and achieved favorable dispersion of single Pt atoms. Pt1/FN‐1, which had the optimal Fe : Ni ratio (1 : 1), exhibited satisfactory catalytic performance for CO oxidation and a high turnover frequency, as determined through DFT calculations and experimental characterization. In‐situ diffuse reflectance infrared Fourier transform spectroscopy confirmed that CO directly reacted with Pt1/FN‐1 to produce CO2 and that introduced O2 formed bicarbonate species to produce CO2 together with the adsorbed CO on Pt1 sites. Overall, our work provides new insights into the catalytic mechanism of the well‐known Pt1NiFe LDH catalysts in CO oxidation. [ABSTRACT FROM AUTHOR]

• An integrated in situ DRIFTS-DBD along with online SVUV-PIMS and OES were applied. • Ni/Al 2 O 3 exhibited the highest performance for plasma-catalytic NH 3 decomposition. • The introduction of plasma enhanced the adsorption of NH 3. • Plasma promoted the dissociation of the intermediates and desorption of products. The lack of comprehensive understanding of the reaction mechanism hinders the development of plasma-catalytic ammonia (NH 3) decomposition as a potential route for producing carbon-free hydrogen. Herein, we investigated the reaction process over transition metal-based catalysts in a dielectric barrier discharge (DBD) reactor. For the first time, a combination of an integrated in situ diffuse reflectance infrared Fourier transform spectroscopy-DBD (in situ DRIFTS-DBD) and optical emission spectroscopy (OES) were applied to reveal that as for Ni/Al 2 O 3 , less NH 3 * was observed in the gas phase and more NH 3 adsorbed on the surface. Combined with online synchrotron vacuum ultraviolet-photoionization mass spectrometry (SVUV-PIMS) it was further illustrated that N 2 desorbed more quickly from Ni/Al 2 O 3 than other tested catalysts. Additionally, compared with thermal catalysis, plasma further enhanced the adsorption of NH 3 on Lewis acid sites and facilitated the desorption of N 2. This study provided a better understanding of the plasma-catalytic NH 3 decomposition reaction. [ABSTRACT FROM AUTHOR]

The high efficiency and stability of catalysts are crucial for their practical application in toluene oxidation. Herein, a novel octahedral Pt/Mn 3 O 4 -110 catalyst with excellent structural stability was synthesized and 100 % toluene conversion can be achieved at low-temperature 160 °C. XRD and Raman results indicated that the structure of Pt/Mn 3 O 4 -110 can be well maintained after 120 h on-stream reaction, the resistance to H 2 O (3 or 5 vol%) and high concentration toluene (3000 ppm)/CO 2 (5 vol%) tests. In situ DRIFTS comparative studies between Pt/Mn 3 O 4 -110 and Pt/Mn 3 O 4 -100 (30 % toluene conversion at 160 °C) samples demonstrated that the rate-control steps of toluene oxidation on Pt/Mn 3 O 4 -110 and Pt/Mn 3 O 4 -100 were both the further oxidation of benzoate species in the presence of gas-phase oxygen, while the transformation of benzaldehyde to benzoate species was the rate-control step on Pt/Mn 3 O 4 -100 in the absence of gas-phase oxygen. The weaker Mn-O bonds, richer oxygen vacancies and higher mobility of oxygen species on Pt/Mn 3 O 4 -110 sample than that of Pt/Mn 3 O 4 -100 are beneficial for the easier release of lattice oxygen from the surface of catalyst and then participated in toluene oxidation via Mars-van Krevelen mechanism, contributing to easier oxidation of benzaldehyde to benzoate species and formation of formic acid and bicarbonate species. A novel octahedral Pt/Mn 3 O 4 -110 catalyst with excellent structural stability and water resistance was synthesized and exhibited significantly higher specific reaction rate of toluene oxidation than contrastive Pt/Mn 3 O 4 -100. Comparative investigation of in situ DRIFTS demonstrated the rate-control steps of toluene oxidation on Pt/Mn 3 O 4 -110 and Pt/Mn 3 O 4 -100 were both the further oxidation of benzoate species in the presence of gas-phase oxygen, while the transformation of benzaldehyde to benzoate species was the rate-control step on Pt/Mn 3 O 4 -100 in the absence of gas-phase oxygen. The easier oxidation of toluene on Pt/Mn 3 O 4 -110 sample at low-temperature can be attributed to the weaker Mn-O bonds, richer oxygen vacancies, better mobility of oxygen species and higher ratios of Pt0/(Pt0+Pt2+) than that of Pt/Mn 3 O 4 -110 sample. [Display omitted] • A novel octahedral Pt/Mn 3 O 4 -110 catalyst was applied for toluene oxidation. • Pt/Mn 3 O 4 -110 exhibited remarkable stability and resistance to H 2 O. • Pt/Mn 3 O 4 -110 exhibited higher r norm than that of Pt/Mn 3 O 4 -100 at 150 °C. • The weaker Mn-O bonds contributes to superior activity of Pt/Mn 3 O 4 -110. • Different rate-control steps were found over Pt/Mn 3 O 4 -110 and Pt/Mn 3 O 4 -100. [ABSTRACT FROM AUTHOR]

Ce-based oxides doped with different metal ions can greatly improve CH 4 catalytic activity, but the relationship between the surface microstructure and its activity is not clear. In this article, M(Y, Sm, and Ni)-CeO 2 catalyst prepared by aerosol method is used as the research object. CH 4 is used as a molecular probe for the study. Operando DRIFTS-MS and DFT computation are used to verify the structure-activity relationship between the surface structure and activity of M-CeO 2. Ni-CeO 2 with the smallest atomic radius ratio has the best CH 4 oxidation performance (550 °C) and excellent redox characteristics. Operando DRIFTS-MS results show that the Ni O is more likely to adsorb CH 4 and form the intermediates CH 3 *, gas-phase CO 2 , CO, and H 2 O at low temperatures. At high temperatures, Ni-OH, Ni-O-Ce, and Ce O further react with CH 4. Among them, the formation of M-O v -Ce has a positive role in promoting the decomposition of O₂. Importantly, carbonate is the rate-determining step that affects the activation of M-O v -Ce. Monodentate carbonates decompose more easily at low temperatures. These findings reveal a novel doping effect and provide a new idea for the design and development of Ce based catalysts with high CH 4 removal ability [Display omitted] • Ni-CeO 2 with the smallest atomic radius ratio has the best CH 4 oxidation activity and redox capacity. • Surface M=O of M-CeO 2 has the best reaction characteristics at low temperature. • Ni-O v -Ce promotes the interfacial effect and is beneficial to enhance CH 4 adsorption capacity. • The ratios of different atomic radius are linearly related to each physical quantity. [ABSTRACT FROM AUTHOR]

• Redox performance and surface acidity of CoMnCeO x /GR catalyst are better than other ion-doped catalysts. • Ce3+ content and O α ratio of CoMnCeO x /GR catalyst are larger than other ion-doped catalysts. • The low-temperature denitrification activity of MnCeO x /GR catalyst is improved by Co3+ doping. • L-H mechanism and two types of E-R mechanism co-exist on CoMnCeO x /GR catalyst for NH 3 -SCR. The present study demonstrates an innovative approach of doping MnCeO x /GR catalyst with three transition metal ions, namely Fe3+, Co3+, and Ni2+. Subsequently, the catalyst exhibiting superior performance was carefully selected. Meanwhile, the micro-reaction process of MnCeO x /GR and ion-doped MnCeO x /GR catalysts were established by in situ DRIFTS. The phenomena occurred in the experiment process were thoroughly examined through the application of various characteristic analysis, for instance, XRD, Raman, BET, XPS, H 2 -TPR, and NH 3 -TPD to analyze that Co3+ doping had a good improvement of activity and N 2 selectivity on MnCeO x /GR catalyst at low temperature. This was evidenced by the activity test experiments, which revealed that CoMnCeO x /GR catalyst has the highest NO conversion within 150–225 °C temperature range, surpassing 90 %. Our findings showed that Co3+ doping not only enhanced redox capability and surface acidity, but also raised the relative Mn4+, Ce3+, and O α content compared to MnCeO x /GR catalyst, which eventually contributed that the reactant molecules can be more effectively adsorbed onto the catalyst, thereby enhancing activation of NH 3 and O 2 , thus improving efficiency of CoMnCeO x /GR catalyst. Additionally, it was proved that the Eley-Rideal and Langmuir-Hinshelwood mechanisms co-existed on CoMnCeO x /GR catalyst in a competitive way by in situ DRIFTS test. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • Synergistic interaction of copper-manganese oxide (CuMnO δ) enhances the catalytic performance of Cy-H oxidative dehydrogenation. • The participation of lattice oxygen indicates the significance of oxygen availability and mobility in the ODH reaction. • Feed oxygen content critically influences product distribution. • The study unveils Cyclohexanolate, Enolate, Phenolate, Carboxylate, and Bidentate carbonate species formation. • Cyclohexanolate dehydration yields Cy-ene, while Cy-one results from Enolate species rearrangement. Oxidative dehydrogenation (ODH) is a promising technique for converting Cyclohexane (Cy-H) to Cyclohexene (Cy-ene). However, this reaction yields undesired byproducts (Benzene and CO 2) due to deep-dehydrogenation and over-oxidation. Therefore, controlling reaction parameters, comprehending intermediate species, and optimizing catalyst design are crucial for enhancing selective Cy-ene formation. Copper-manganese oxide catalysts were synthesized via the incipient wetness impregnation technique. A solid solution (CuMnO δ) exhibited superior catalytic activity due to synergistic interaction and active site formation. The study elucidated that copper oxide facilitates the deep-dehydrogenation of Cy-H. While manganese oxide incorporation inhibits CO 2 and benzene formation, promoting partial dehydrogenation to Cy-ene. The studies unveiled Cy-H activation via hydrogen abstraction, forming Cyclohexanolate intermediates interacting with surface hydroxyls, yielding Cy-ene via dehydration. Notably, Cy-one formation via Enolate intermediates was also observed. The catalyst 10Cu 0.25 Mn 0.75 O δ /Al 2 O 3 exhibited the highest Cy-ene yield (∼12.1 %), facilitated by the synergistic effect, with a Cy-H conversion (∼15.7 %) at 300 °C. [ABSTRACT FROM AUTHOR]

Catalyst surface active oxygen species have an important influence on plasma catalytic oxidation. However, the reaction process of CO and O 3 migration and transformation on the catalyst surface during discharge at different temperature is still unclear. In this study, β- and γ -MnO 2 are selected to unveil the roles of different oxygen species under in-plasma catalysis configuration at different temperature in CO oxidation. Operando TPR-DRIFTS-MS is used to reveal CO and O 3 oxidation pathways. The results show that O 3 can react with CO at room temperature, and O 3 is also converted to other reactive oxygen species on the catalyst surface. As the temperature increases, the oxygen species of the catalyst itself (Mn O and Mn-O-Mn) can react with CO to form oxygen vacancies (Mn-□-Mn and Mn=□). Mn-□-Mn are beneficial for O 2 decomposition and promotes the regeneration of Mn O and Mn-O-Mn. The carbonate covered on the surface of the catalyst is the rate-determining step of CO oxidation. It is hoped that Mn-based catalysts with more reactive oxygen species and oxygen defects will be prepared to facilitate low-temperature CO oxidation under plasma conditions. [Display omitted] ● Operando TPR-DRIFTS-MS reveals CO and O 3 oxidation pathways. ● O 3 can be converted to other reactive oxygen species on the catalyst surface. ● Carbonate is the rate-determining step in CO oxidation. ● Bridge-type oxygen vacancies (Mn-□-Mn) are beneficial for O 2 decomposition. [ABSTRACT FROM AUTHOR]

In‐situ infrared spectroscopy is one of the most effective methods to study the surface species on solid catalysts. Still, it is sometimes difficult to identify the reactive intermediates because spectator species, the catalyst support, and experimental noise also contribute to the total spectra. In this study, we prepared three archetypical Ni/Al2O3 catalysts that showed significantly different catalytic activity and selectivity for CO2 hydrogenation, depending on the calcination and reduction temperature. After detailed characterization, we used a combination of Modulation Excitation‐Phase Sensitive Detection‐Diffuse Reflectance Infrared Fourier Transform Spectroscopy (ME‐PSD‐DRIFTS) and Steady State Isotopic Kinetic Analysis (SSITKA) to show that bicarbonates and formates are key reactive intermediates. Furthermore, we also observe carbonyls on the catalyst with the most metallic character and highest selectivity towards CH4. These results confirm that the hydrogenation of CO2 occurs in an associative and consecutive reaction pathway that is highly structure‐sensitive. In this way, we also demonstrate how the simultaneous collection of spectroscopic and kinetic data during modulated or transient experiments is a powerful tool for investigating solid catalysts under realistic operation conditions. [ABSTRACT FROM AUTHOR]

[Display omitted] • Use of hydrocarbon as a reductant shows the economical and sustainable path for SCR. • Using C 3 H 6 for NO x reduction over Cu/Mn-BTC prepared via one-step method. • Highest Lewis acid sites in 3.2Cu-Mn-BTC catalyst boost SCR activity. • 3.2Cu/Mn-BTC catalyst showed 80 % NO x reduction with 90 % N 2 selectivity at 300 °C. • Main reaction intermediates were explored by In-situ DRIFT study. The choice of reducing agents and their impact on catalytic performance are important aspects of selective catalytic reduction (SCR) technology. Marking the inaugural use of C 3 H 6 as a reducing agent with the BTC catalyst, a bimetallic organic framework (x Cu-Mn-BTC) was prepared and tested as a catalyst for NO x reduction under oxygen-enriched conditions. The results showed that NO conversion was influenced by the ratio of Cu and Mn metals, among which 3.2Cu-Mn-BTC exhibited the highest denitrification performance (80 % NO x conversion and 94 % N 2 selectivity) at 300 °C. From the characterization results, Cu was successfully incorporated into the BTC framework and 3.2Cu-Mn-BTC became spherical grains with smaller particle sizes. The high catalytic activity of 3.2Cu-Mn-BTC was due to the presence of more adsorbed oxygen O α (89.7 %) and Cu2+ (63 %) species than in the other catalysts. The TPR peak of x Cu-Mn-BTC shifted to a lower temperature and showed better reducibility. The Py-FTIR study shows that x Cu-Mn-BTC contained more Lewis acid but no Brønsted acid, because Cu increased the concentration of Lewis acid on the catalytic surface (42 to 46 mmol/g), and Lewis acid plays an important role in the C 3 H 6 -SCR of NO x. [ABSTRACT FROM AUTHOR]

• N/S co-doping improves the performance of catalysts and broaden their active temperature range. • N/S functional group can generate more acidic sites, active centers, and oxygen vacancies. • N/S functional group reduces the reaction energy barrier, promotes adsorption and activation of reactants. • N-5 and N-6 groups and C-SO 2 -C species combine to affect the catalyst denitrification activity. In this paper a series of N/S co-doped carbon-based low-temperature denitrification catalysts were prepared using thiourea and coal-based activated carbon. Tests such as BET, NH 3 -TPD, XPS and DRIFTS were applied to characterize the performance of the prepared catalysts. It was found that the denitrification activity of NSAC-1.2 catalyst was 2.08 times higher than that of coal-based activated carbon. The denitrification activity of all N/S co-doped carbon-based catalysts was greater than 80 % in the temperature range of 150–260 °C. The presence of N and S functional groups creates more acidic sites and oxygen vacancies on the catalyst surface, which leads to the reduction of the reaction energy barrier, the promotion of the adsorption and activation of reactants and in turn the improvement of the denitrification activity of the catalyst. N/S co-doping for N-5 and N-6 groups as well as C-SO 2 -C species enhancement affect the catalyst denitrification activity improvement comprehensively. The reaction mechanism of NH 3 -SCR process on N/S co-doped carbon-based catalysts was investigated by in-situ DRIFTS. [ABSTRACT FROM AUTHOR]

As well known, the industrial methanation process needs highly active and stable catalysts obtained from cheap and abundant elements. In this work, we propose a high-loaded Ni/Al2O3 catalyst promoted by manganese. Among them, the 20Ni2Mn/Al2O3 catalyst exhibits the best CO2 conversion (90.5%) and excellent methanation stability at 250 °C. In addition, the roles of the Mn promoter on CO2 conversion and selectivity were investigated in detail. The features of natural and promoted catalysts are described through XRD, XRF, BET, TEM, H2-TPR, CO2-TPD, and operando DRIFTS techniques. Based on various characterization results, the addition of Mn will greatly reduce the Ni particle size and improve the Ni dispersion on the alumina support. Furthermore, compared to the unpromoted catalyst, Mn promoted catalysts show better reducibility and have more medium basic sites. And these medium basic sites are favorable to the adsorption and activation of CO2. In-situ DRIFTS experiments for CO2 methanation reveal that manganese could promote the monodentate carbonate hydrogenated to formate rapidly, which could be faster converted towards CH4, contributing to significantly improved activity of the Mn promoted Ni/Al2O3 catalyst. [ABSTRACT FROM AUTHOR]

The effect of H2 activation on the performance of CuFeOx catalyst for low-temperature CO oxidation was investigated. The characterizations of XRD, XPS, H2-TPR, O2-TPD, and in situ DRIFTS were employed to establish the relationship between physicochemical property and catalytic activity. The results showed that the CuFeOx catalyst activated with H2 at 100 °C displayed higher performance, which achieved 99.6% CO conversion at 175 °C. In addition, the H2 activation promoted the generation of Fe2+ species, and more oxygen vacancy could be formation with higher concentration of Oα species, which improved the migration rate of oxygen species in the reaction process. Furthermore, the reducibility of the catalyst was enhanced significantly, which increased the low-temperature activity. Moreover, the in situ DRIFTS experiments revealed that the reaction pathway of CO oxidation followed MvK mechanism at low temperature (<175 °C), and both MvK and L-H mechanism was involved at high temperature. The Cu+-CO and carbonate species were the main reactive intermediates, and the H2 activation increased the concentration of Cu+ species and accelerated the decomposition carbonate species, thus improving the catalytic performance effectively. [ABSTRACT FROM AUTHOR]

In this study, the surface and textural properties as well as the catalytic performance of Ni/CeO2 and NiIn/CeO2 catalysts prepared by wet impregnation (WI) and deposition–precipitation (DP) are investigated. The addition of Ni (3.0 wt.%) resulted in a decrease in the specific surface area and pore volume in the case of the WI method, possibly due to a blockage of mesopores. A minimal addition of In (0.25 wt.%) caused a further decrease in the surface area in both cases. XRD analysis showed that Ni deposited on CeO2 by DP resulted in some lattice incorporation, affecting the crystallinity of the support. The H2-TPR profiles altered depending on the different ways of Ni and In introduction. STEM-EDS-derived elemental maps indicated that the Ni and NiIn particles deposited on CeO2 using the DP method were somewhat smaller than in the WI synthesis. A comprehensive CO-DRIFTS analysis proved a direct Ni-In interaction in bimetallic samples, leading to the formation of a surface NiIn alloy. Ni/CeO2 catalysts showed a higher activity in the process of dry reforming of methane (DRM) than the bimetallic counterparts at 650 °C, with the Ni_DP sample performing slightly better. However, the Ni_DP catalyst showed significant coking, which was drastically reduced by the addition of In. The agglomeration of Ni and/or NiIn particles during the 6 h DRM reaction somewhat impaired the catalyst performance. Overall, this study highlights the intricate relationship between the catalyst preparation, surface properties and catalytic performance in the DRM reaction and emphasizes the beneficial role of In addition in reducing the coking of the monometallic catalyst and the critical location and surface morphology of nickel nanoparticles decorated with indium and in contact with ceria. [ABSTRACT FROM AUTHOR]

• MnCuTi ternary catalyst presented a great simultaneous removal performance due to the synergistic effect between Mn and Cu. • The mechanism of toluene oxidation was proposed by In situ DRIFTS. • NO x inhibits the toluene oxidation because of the nitrate deposition on the catalyst surface. • NH 3 and toluene compete to adsorb on the Lewis acid sites, which inhibits the toluene oxidation. At present, the emission of flue gas from the high-energy-consuming non-electric industries, represented by iron and steel, coking and cement, has become the main source of air pollution in China. Among these, volatile organic compounds (VOCs) and nitrogen oxides (NO x) are the main precursor for PM 2.5 and ozone pollution. Herein, a series of MnCuTi ternary system catalysts with different Mn-Cu molar ratios were synthesized using the sol-gel method for the simultaneous removal of NO x and toluene. Combined with the catalytic performance and physicochemical properties, the results showed that the MnCuTi ternary catalysts possessed a large specific surface area and abundant mesopore structure. The synergistic effect between manganese and copper promoted the cyclic electron migration over the redox reactions, and improved the synergistic reaction performance of NO x reduction and toluene oxidation. Among different catalysts, 1.5MCT catalyst showed the best synergic activity, with 87 % NO conversion and 92 % toluene conversion at 240 °C. The interaction mechanism and the evolution of intermediate species in the collaborative reaction process were thoroughly revealed by in situ DRIFTS, it is discovered that NH 3 and NO x inhibit the toluene oxidation due to the competitive adsorption and the nitrate deposition. However, when NH 3 and NOx were introduced concurrently, they preferentially generated NH 2 NO, thereby diminishing their inhibitory effect. This study provided theoretical basis and technical support for multi-pollutant collaborative control in steel/coking industry. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • Electronegativity of the A species in ACu-CeO 2 affect catalytic activity for CO-SCR reaction. • CuCo-CeO 2 exhibited 100% NO conversion and 100% N 2 selectivity in CO-SCR. • The addition of species A promotes the electron/ion transfer between metals in the catalyst. • The CO-SCR reaction mechanisms was proposed based on in situ DRIFTS. Transition metal-based nanomaterials have gained significant attention as highly active and cost-effective catalysts for the selective catalytic reduction (SCR) of NO with CO. Using a simple wet impregnation method, the catalyst composition and active sites can be modulated. In this paper, we present a novel cerium-based co-solvent catalyst, A-site doped ACu-CeO 2 (A = Co, Fe, Mn), for CO-SCR of NO. The doping of A-site elements induces structural changes and enhances catalytic performance. Among the doped catalysts, CoCu-CeO 2 exhibits a wide temperature window for operation and high selectivity towards nitrogen, achieving 100% NO conversion at 200 °C. Furthermore, A-site modulation not only promotes electron/ion transfer within the catalyst but also enables uniform and dispersed distribution of the active metal species, particularly copper, in the CoCu-CeO 2 catalyst. This provides reaction centers for the selective reduction of NO by CO and enhances the adsorption capacity of the catalyst for NO. The ACu-CeO 2 catalyst demonstrates excellent CO-SCR catalytic performance and resistance to vapor. Characterization techniques such as XPS, Raman spectroscopy, and in situ DRIFTS elucidate the reaction mechanism of the ACu-CeO 2 cerium-based co-solvate in the CO-SCR reaction. This study furthers our understanding and improvement of catalyst design, while also providing an efficient and straightforward denitrification catalyst for controlling air pollutants. [ABSTRACT FROM AUTHOR]

[Display omitted] • Atomically dispersed Ru/Mg-CeO 2 catalyst was prepared and possessed excellent catalytic performance for photo-thermal catalytic CO 2 methanation reaction. • The photo-electron excitation/migration path and the surface structure changes induced by light were systematically characterized by operando experiments. • All potential micro-reaction steps and light intensification steps were determined by in situ DRIFTs experiments. • The reversible dynamic structural evolution between Ru-O-Ce structure and Ru-O v -Ce structure could be induced by light. It is a promising green technology to reduce CO 2 to CH 4 by using renewable solar energy driving photo-thermal catalysis route. However, the efficiency of photo-thermal catalytic CO2 methanation remained to be improved, and the mechanism of this reaction still required further investigation. In this paper, a Ru/Mg-CeO 2 catalyst was designed based on the concepts of single atom catalyst and photo-thermal catalysis concept. The catalyst achieved the CH 4 formation rate of 469 mmol·gcat−1·h−1 at 400 °C under photo-thermal conditions with good catalytic stability. Besides, the superiority of the single-atom of Ru, Ru-O-Ce structure and doping of alkaline metals in catalytic process was proved by a series of physicochemical and optical characterization, and electron migration direction from Ce and Mg elements to Ru sites through Ru-O-Ce and Ru-O-Mg path under photo-thermal catalysis was determined by ISI-XPS experiment. Finally, the comprehensive reaction mechanism and reversible dynamic structural evolution process between Ru-O-Ce and Ru-O v -Ce structures were investigated by in situ DRIFTs experiments, and the source of the excellent performance and structure-function relationship of the catalyst was explored, which provided the theoretical and practical basis for the development of catalyst and industrial application of the reaction. [ABSTRACT FROM AUTHOR]

Metal-organic frameworks (MOFs)-based carrier, MIL-100(Fe), was synthesized by hydrothermal method and Ni was supported on the MIL-100(Fe) by wet impregnation method to prepare the catalysts for selective catalytic reduction of NO with C 3 H 6 (C 3 H 6 -SCR). The addition of Ni significantly improved the reactivity of C 3 H 6 -SCR. At 275 °C, the NO conversion of MIL-100(Fe) was 74.5%, whereas the NO conversion of 5.8%Ni/MIL-100(Fe) with 100% N 2 selectivity was 100%. The in-situ DRIFTS prove that the interaction between NO 2 −/NO 3 − and C x H y O z substances generated intermediate isocyanates (R-NCO), and the reaction pathway was proposed based on the DRIFTS results to understand the mechanism. [Display omitted] • Ni-modified MIL-100(Fe) was successfully prepared by the wet impregnation method. • 5.8%Ni/MIL-100(Fe) was used for the C 3 H 6 -SCR reaction. • 5.8% Ni/MIL-100 (Fe) exhibited a 100% NO x conversion and 100% N 2 selectivity at 275 °C. • A possible mechanism was proposed based on the In-situ DRIFTS results. • Ni-NCO and Fe-NCO species facilitate the C 3 H 6 -SCR reaction. [ABSTRACT FROM AUTHOR]

CuO/TiO2 catalysts with varying Sb doping ratios were synthesized and applied in the NH3-SCR process. The results of activity tests revealed that the addition of Sb effectively enhanced the performance of low-temperature SCR. Particularly, the CuSbTiOx-0.2 catalyst exhibited the highest activity, achieving over 91% conversion at 250 °C, along with the highest N2 selectivity and exceptional resistance to SO2. Comprehensive characterization analyses demonstrated that CuSbTiOx-0.2 possessed a significantly large specific surface area, the strongest surface acidity, and superior redox performance among the catalysts studied. In situ DRIFTS experiments provided further insights, indicating that Sb modification generated more active species, thereby enhancing the reactivity of ad-NH3 and ad-NOx species. The SCR reaction mechanism for CuSbTiOx-0.2 predominantly followed the Langmuir–Hinshelwood (L–H) and Eley–Rideal (E–R) mechanisms. These findings have the potential to advance the development of novel and effective non-vanadium SCR catalysts. [ABSTRACT FROM AUTHOR]

Heterogenized molecular catalysts have shown interesting activities in different chemical transformations. In our previous studies, a molecular catalyst, Re(bpy)(CO)3Cl where bpy is 2,2′-bipyridine, was covalently attached to silica surfaces via an amide linkage for use in photocatalytic CO2 reduction. Derivatizing the bpy ligand with electron-withdrawing amide groups led to detrimental effects on the catalytic activity of Re(bpy)(CO)3Cl. In this study, an alkyl amine linkage is utilized to attach Re(bpy)(CO)3Cl onto SiO2 in order to eliminate the detrimental effects of the amide linkage by breaking the conjugation between the bpy ligand and the amide group. However, the heterogenized Re(I) catalyst containing the alkyl amine linkage demonstrates even lower activity than the one containing the amide linkage in photocatalytic CO2 reduction. Infrared studies suggest that the presence of the basic amine group led to the formation of a photocatalytically inactive Re(I)-OH species on SiO2. Furthermore, the amine group likely contributes to the stabilization of a surface Re(I)-carboxylato species formed upon light irradiation, resulting in the low activity of the heterogenized Re(I) catalyst containing the alkyl amine linkage. [ABSTRACT FROM AUTHOR]

Significant interest has emerged for the application of Pd-In2O3 catalysts as high-performance catalysts for CO2 hydrogenation to CH3OH. However, precise active site control in these catalysts and understanding their reaction mechanisms remain major challenges. In this investigation, a series of Pd-InOx catalysts were synthesized, revealing three distinct types of active sites: In-O, Pd-O(H)-In, and Pd2In3. Lower Pd loadings exhibited Pd-O(H)-In sites, while higher loadings resulted in Pd2In3 intermetallic compounds. These variations impacted catalytic performance, with Pd-O(H)-In catalysts showing heightened activity at lower temperatures due to the enhanced CO2 adsorption and H2 activation, and Pd2In3 catalysts performing better at elevated temperatures due to the further enhanced H2 activation. In situ DRIFTS studies revealed an alteration in key intermediates from *HCOO over In-O bonds to *COOH over Pd-O(H)-In and Pd2In3 sites, leading to a shift in the main reaction pathway transition and product distribution. Our findings underscore the importance of active site engineering for optimizing catalytic performance and offer valuable insights for the rational design of efficient CO2 conversion catalysts. [ABSTRACT FROM AUTHOR]

A series of highly dispersed Nia-xMnxAlOy catalysts derived from layered double hydroxides (LDHs) were prepared for selective catalytic reduction of NOx with ammonia (NH3-SCR) at low temperature. The physicochemical and catalytic performance of the prepared catalysts with different M2+/M3+molar ratios were systematically investigated by XRD, BET, XPS, TPX (i.e. TPD and TPR) and in situ DRIFTs. Fortunately, Ni4-xMnxAlOy as the optimal catalyst exhibited prominent NH3-SCR performance with NOx conversion greater than 90% at low temperature range of 120~210 °C. Especially, the influence of H2O and SO2 revealed that the catalyst activity could be miraculously promoted by H2O, while deactivated by SO2. The proper M2+/M3+molar ratios not only provided the surface acidic sites, the high Mn4+ content ratio and the adsorbed oxygen of Nia-xMnxAlOy catalysts, but also promoted the transformation of NOx intermediate species to more stable bidentate nitrates. Results of the in situ DRIFTs illustrated that the SCR reaction path of Nia-xMnxAlOy catalysts followed both E-R and L-H mechanisms, and the former played the dominant role. [ABSTRACT FROM AUTHOR]

Preferential oxidation of carbon monoxide (CO-PROX) in H2-rich mixture is an effective way of hydrogen purification for fuel cells. High-performance PtCo/ZSM-5 catalysts with reduced Pt loading for this process were prepared using polynuclear platinum acetate complex known as platinum acetate blue (PAB) of the empirical formula Pt(CH3COO)2.5 as a novel precursor. The impregnation of HZSM-5 (Si/Al = 15 and 28) with PAB and its decomposition at 200 °C resulted in the stabilization of highly dispersed Pt0 and PtOx species on the zeolite surface. The catalytic properties were improved by the addition of Co(CH3COO)2 followed by calcination at 450 °C. Produced materials were studied by SEM, TEM, EDX, XPS, and DRIFTS methods and tested in a CO-PROX reaction. The relationship between the synthesis conditions, structure, and catalytic behavior of composites is discussed in this paper. The synergistic effect of Pt and Co was observed when they both were located together in zeolite channels. The Pt-Co interaction provides new active catalytic sites and prevents platinum aggregation during the process. Due to this, the 100% CO conversion in the wide temperature range from 50 to 130 °C is achieved for PtCo/ZSM-5 catalysts (Si/Al = 15), which is the best result compared to low-loaded Pt catalysts prepared with traditional precursors. [ABSTRACT FROM AUTHOR]

• The study combines computational and experimental work on the Mo x Ce 1- x PO 4. • The incorporation of Mo improved the NH 3 -SCR activity on the Mo x Ce 1- x PO 4. • The reaction mechanism followed the Eley-Rideal and Langmuir-Hinshelwood mechanism. Developing CePO 4 -based NH 3 -SCR catalysts with high NO x conversion, N 2 selectivity, and SO 2 tolerance at low temperatures is challenging. Analyzing the atomic-level surface structure of these catalysts is particularly important. Hence, we conducted a combined computational and experimental study to design the surface structure of Mo x Ce 1- x PO 4 catalysts, corroborate the reaction performance and structural sensitivity, and investigate the relationship between active sites and structural performance at the atomic level. DFT calculations were used to systematically investigate the NH 3 and NO adsorption capacity of the Mo-doped CePO 4 solid solution structure model. The rationality of using the Mo-doped CePO 4 solid solution structure as a catalyst was further supported by DFT calculation data and experimental results from BET, XRD, Raman, SEM, TEM, HR-TEM, NH 3 -TPD, H 2 -TPR, XPS and in situ DRIFTS. The source of the excellent intrinsic NH 3 -SCR activity of the Mo-doped CePO 4 solid solution structure is disclosed. The role of the Mo dopant in the Mo-doped CePO 4 solid solution as an SO 2 trapping site to protect the catalytic active site from sulfation is discussed from a molecular perspective. [ABSTRACT FROM AUTHOR]

[Display omitted] • WO 3 and MoO 3 loadings promoted the reactivity and water resistance of V 2 O 5 /TiO 2. • The activation of NH 3ads-L1 (1284 cm−1, Ti sites) to NH 2 * was revealed by 2D COS. • NH 2 NO* intermediates were produced by the reaction of NH 3ads-L1 with NO. • WO 3 enhanced the activation of NH 3ads-L1 to NH 2 * and the formation of NH 2 NO*. • WO 3 and MoO 3 suppressed the negative effects of H 2 O on active sites of V 2 O 5 /TiO 2. Vanadia-based catalysts have been widely applied in NO x reduction, while the promoting effects of WO 3 and MoO 3 are still under debate. Herein, we prepared V 2 O 5 /TiO 2 , V 2 O 5 -WO 3 /TiO 2 , and V 2 O 5 -MoO 3 /TiO 2 catalysts and revealed that WO 3 and MoO 3 enhanced the activity of V 2 O 5 /TiO 2 , especially under wet conditions. In situ DRIFTS, two-dimensional correlation spectroscopy (2D COS), and DFT calculations demonstrated that NH 3 adsorbed on Lewis acid sites of V 2 O 5 /TiO 2 , resulting in the formation of NH 3ads-L1 (1284 cm−1, Ti sites of O=V–O–Ti) and NH 3ads-L2 (1604 cm−1, V=O sites). By using 2D COS, we found that the NH 3ads-L1 exhibited higher reactivity towards NO to produce NH 2 NO* via NH 2 *, which was promoted by WO 3. Moreover, WO 3 and MoO 3 doping inhibited H 2 O adsorption, and promoted its desorption by increasing temperature, thus protecting the V=O sites on V 2 O 5 /TiO 2. Also, 2D COS provided a new perspective for in-depth understanding of the active sites and intermediates in the NH 3 -SCR reaction. [ABSTRACT FROM AUTHOR]

[Display omitted] • SO 4 2--FeO x -Nb 2 O 5 catalyst exhibits the best activity over the whole temperature range. • Niobium modifies the electronic structure and alleviates the reducibility of catalyst. • Sulfation provides more Brønsted acid sites for surface ammonia adsorption. • Niobium promotes the binding of iron to sulfate to form redox acid sites. A series of iron-based composite oxide catalysts, modified with acid and niobium, were produced for the purpose of selective catalytic reduction of NO x with NH 3 (NH 3 -SCR) via co-precipitation. The obtained SO 4 2--FeO x -Nb 2 O 5 (S-FeNbO x) catalyst exhibited significantly better SCR performance than the unmodified FeO x catalyst, with a NO x conversion above 90% and N 2 selectivity higher than 95% in the temperature range of 275–450 °C. The characterization results suggest that the addition of Nb not only modifies the electronic structure and alleviates the reducibility but also enhances the surface acidity of the catalysts. The sulfuric acid modification of FeO x -Nb 2 O 5 catalyst promotes the formation of redox-acid sites. The in situ Diffuse Reflectance Infrared Fourier Transform spectroscopy (DRIFTs) results revealed that the combining sulfuric acid and niobium modifications resulted in a significant increase in the amount of Brønsted acid sites, and also led to a blue shift of the band related to the Lewis acid sites, implying the existence of a synergistic effect of the two modification methods. The creation of redox-acid sites significantly enhances the adsorption and activation capacity of NH 3 on the catalyst surface. These results suggest that the NH 3 -SCR reaction to primarily follow the Eley-Rideal (E-R) mechanism on the catalyst. [ABSTRACT FROM AUTHOR]

Furfural is a large-volume and widely available biomass-derived platform compound, and its transformation into valuable pentanediols is important for the sustainable production of bio-based polymers. Herein, we report a new catalyst system composed of Pt–Fe bimetallic nanoparticles highly dispersed on a commercial magnesium titanate (MT) support. HAADF-STEM, CO-DRIFTS and XPS characterization studies revealed that Pt was in the metallic state with a particle size of 1–2 nm, while Fe existed as Fe2+ and was decorated on the Pt particles. The electron transfer from Fe to Pt weakened the hydrogenation activity of the furan ring and meanwhile promoted selective ring-opening to 1,2-pentanediol (1,2-PeD). Reaction kinetics studies revealed the reaction rate with respect to hydrogen pressure was close to zero order, which allowed the reaction to proceed at a hydrogen pressure as low as 0.1 MPa. Under mild conditions of 140 °C and 0.1 MPa, the 0.1Pt0.05Fe/MT catalyst offered by far the highest production rate of 178 mol 1,2-PeD per mol Pt per hour, and the Pt–Fe bimetallic catalyst was stable during 200 h of time-on-stream, showing great potential for practical applications. [ABSTRACT FROM AUTHOR]

In this paper, the CoxMn1Cey composite oxide catalyst was synthesized by the co-precipitation method. The structure–activity relationship of the catalyst was analyzed by characterization methods such as XRD, Raman, H2-TPR, NH3/NOx-TPD, XPS, and in situ DRIFTS. The results showed that the Co3Mn1Ce1 catalyst resisted high space velocity, water, and sulfur. In addition, Ce doping could effectively increase the specific surface area of the catalyst. In a sulfur-containing atmosphere, Ce could preferentially react with SO2 and act as a sacrifice site to protect the active components from toxicity. Co-doping greatly enhanced the redox capacity of the catalyst and increased the chemisorbed oxygen (OS) content on the surface of catalysts. Co-presence of Co and Ce increased the content of surface-active Mn species, which further effectively improved the adsorption capacity of the catalyst for NH3 and NO reactants. In situ DRIFTS results showed that the reaction on the Co3Mn1Ce1 catalyst followed both the Langmuir–Hinshelwood and Eley–Rideal mechanisms. [ABSTRACT FROM AUTHOR]

In the propane dehydrogenation process, the structure and catalytic performance stability of the catalyst are determined by its regeneration process, which includes oxidation of coke and oxychlorination to redisperse the supported metal particles. A commercial Pt-Sn catalyst was used in this work to investigate the impact of oxidation temperature on oxychlorination performance. The catalysts after oxidation and oxychlorination were characterized by H2-TPR, CO-DRIFTS, HAADF-STEM, XPS, and CO chemisorption. It was found that mild sintering of Pt occurred during oxidation in the temperature range of 550–650 °C, and the catalyst could be fully restored in the subsequent oxychlorination treatment. Upon oxidation of the catalyst at 700 °C, a severe aggregation of Pt and SnOx could be observed, and the catalyst could not be fully regenerated under the given oxychlorination conditions. However, PDH catalyst deactivation caused by sintering is not irreversible. By tailoring the oxychlorination conditions, the detrimental effect of high oxidation temperature on regeneration could be ruled out. During the oxidation and oxychlorination treatment, the metal tends to migrate to anchor on sites with stronger metal–support interaction, which was helpful for enhancing the catalytic activity. [ABSTRACT FROM AUTHOR]

In this paper, the CoxMn1Cey composite oxide catalyst was synthesized by the co-precipitation method. The structure–activity relationship of the catalyst was analyzed by characterization methods such as XRD, Raman, H2-TPR, NH3/NOx-TPD, XPS, and in situ DRIFTS. The results showed that the Co3Mn1Ce1 catalyst resisted high space velocity, water, and sulfur. In addition, Ce doping could effectively increase the specific surface area of the catalyst. In a sulfur-containing atmosphere, Ce could preferentially react with SO2 and act as a sacrifice site to protect the active components from toxicity. Co-doping greatly enhanced the redox capacity of the catalyst and increased the chemisorbed oxygen (OS) content on the surface of catalysts. Co-presence of Co and Ce increased the content of surface-active Mn species, which further effectively improved the adsorption capacity of the catalyst for NH3 and NO reactants. In situ DRIFTS results showed that the reaction on the Co3Mn1Ce1 catalyst followed both the Langmuir–Hinshelwood and Eley–Rideal mechanisms. [ABSTRACT FROM AUTHOR]

Noble metals have become a research hotspot for the oxidation of light alkanes due to their low ignition temperature and easy activation of C-H; however, sintering and a high price limit their industrial applications. The preparation of effective and low-noble-metal catalysts still presents profound challenges. Herein, we describe how a Ru@CoMn2O4 spinel catalyst was synthesized via Ru in situ doping to promote the activity of propane oxidation. Ru@CoMn2O4 exhibited much higher catalytic activity than CoMn2O4, achieving 90% propane conversion at 217 °C. H2-TPR, O2-TPD, and XPS were used to evaluate the catalyst adsorption/lattice oxygen activity and the adsorption and catalytic oxidation capacity of propane. It could be concluded that Ru promoted synergistic interactions between cobalt and manganese, leading to electron transfer from the highly electronegative Ru to Co2+ and Mn3+. Compared with CoMn2O4, 0.1% Ru@CoMn2O4, with a higher quantity of lattice oxygen and oxygen mobility, possessed a stronger capability of reducibility, which was the main reason for the significant increase in the activity of Ru@CoMn2O4. In addition, intermediates of the reaction between adsorbed propane and lattice oxygen on the catalyst were monitored by in situ DRIFTS. This work highlights a new strategy for the design of a low-noble-metal catalyst for the efficient oxidation of propane. [ABSTRACT FROM AUTHOR]

Reppe carbonylation of acetylene is an atom-economic and non-petroleum approach to synthesize acrylic acid and acrylate esters, which are key intermediates in the textile, leather finishing, and polymer industries. In the present work, a noble metal-free Co@SiO2 catalyst was prepared and evaluated in the methoxycarbonylation reaction of acetylene. It was discovered that pretreatment of the catalyst by different reductants (i.e., C2H2, CO, H2, and syngas) greatly improved the catalytic activity, of which Co/SiO2-H2 demonstrated the best performance under conditions of 160 °C, 0.05 MPa C2H2, 4 MPa CO, and 1 h, affording a production rate of 4.38 gMA+MP gcat−1 h−1 for methyl acrylate (MA) and methyl propionate (MP) and 0.91 gDMS gcat−1 h−1 for dimethyl succinate (DMS), respectively. Transmission electron microscopy (TEM), X-ray diffraction (XRD), and diffuse reflectance infrared Fourier transform spectra of CO adsorption (CO-DRIFTS) measurements revealed that an H2 reduction decreased the size of the Co nanoparticles and promoted the formation of hollow architectures, leading to an increase in the metal surface area and CO adsorption on the catalyst. The hot filtration experiment confirmed that Co2(CO)8 was generated in situ during the reaction or at the pre-activation stage, which served as the genuine active species. Our work provides a facile and convenient approach to the in situ synthetization of Co2(CO)8 for a Reppe carbonylation reaction. [ABSTRACT FROM AUTHOR]

A Fe modified MOF-derived MnOx catalyst has been synthesized and studied for the selective catalytic reduction of NOx with NH3 (NH3-SCR). Compared with pure MnOx, Fe-modified MnOx showed a broader activity temperature window, enhanced N2 selectivity, and improved sulfur tolerance. On one hand, the incorporation of Fe into MnOx increased acidity, thereby facilitating the adsorption of NH3 as well as its activation, which plays a crucial role for the reduction of NOx. On the other hand, the presence of Fe resulted in decreased Mn4+, which contributes to improved N2 selectivity. Over Fe modified MnOx catalyst, the coordinated NH3, NH4+, bridging nitrate and bidentate nitrate are reactive, and participate in the NH3-SCR reaction following both “Eley–Rideal(E-R)” and “Langmuir–Hinshelwood(L–H)” mechanism. The present research provides an idea for broadening the activity temperature window and enhancing the sulfur tolerance of MnOx catalyst for the reduction of NOx, making it more suitable for practical application.Graphical Abstract: A Fe modified MOF-derived MnOx catalyst has been synthesized and studied for the selective catalytic reduction of NOx with NH3 (NH3-SCR). Compared with pure MnOx, Fe-modified MnOx showed a broader activity temperature window, enhanced N2 selectivity, and improved sulfur tolerance. On one hand, the incorporation of Fe into MnOx increased acidity, thereby facilitating the adsorption of NH3 as well as its activation, which plays a crucial role for the reduction of NOx. On the other hand, the presence of Fe resulted in decreased Mn4+, which contributes to improved N2 selectivity. Over Fe modified MnOx catalyst, the coordinated NH3, NH4+, bridging nitrate and bidentate nitrate are reactive, and participate in the NH3-SCR reaction following both “Eley–Rideal(E-R)” and “Langmuir–Hinshelwood(L–H)” mechanism. The present research provides an idea for broadening the activity temperature window and enhancing the sulfur tolerance of MnOx catalyst for the reduction of NOx, making it more suitable for practical application. [ABSTRACT FROM AUTHOR]

Catalytic oxidation is used to control carbon monoxide (CO) emissions from industrial exhaust. In this study, a mesoporous silica material, KCC-1, was synthesized and used as a carrier with a high specific surface area to confine active component FeOx nanoparticles (NPs), and the CO catalytic oxidation performance of x%Fe@KCC-1 catalysts (x represents the mass loading of Fe) was studied. The experimental results showed that due to its large specific surface area and abundant mesopores, the FeOx NPs were highly dispersed on the surface of the KCC-1 carrier. The particle size of FeOx was very small, resulting in strong interactions between FeOx NPs and KCC-1, which enhanced the catalytic oxidation reaction on the catalyst. The FeOx loading improved the CO adsorption capability of the catalyst, which facilitated the catalytic oxidation of CO, with the 7%Fe@KCC-1 catalyst achieving 100% CO conversion at 160 °C. The CO catalytic removal mechanism was investigated by a combination of in-situ DRIFTS and DFT calculations. This study advances scientific understanding of the application potential of nano-catalysts in important oxidation reactions and provides valuable insights into the development of efficient CO oxidation catalysts. [ABSTRACT FROM AUTHOR]

The structure and performance stability of a Pt-based catalyst for propane dehydrogenation during its reaction–regeneration cycles is one of the key factors for its commercial application. A 0.3% Pt/Al2O3 catalyst with a sub-nanometric particle size was prepared and two different types of regeneration processes, long-term dichloroethane oxychlorination and a reaction–oxidation–oxychlorination cycle, were investigated on this catalyst. The fresh, sintered and regenerated catalyst was characterized by HAADF-STEM, CO-DRIFTS, XPS, CO chemisorption and N2 physisorption, and its catalytic performance for propane dehydrogenation was also tested. The results show that the catalysts tend to have a similar particle size, coordination environment and catalytic performance with the extension of the regeneration time or an increase in the number of cycles in the two regeneration processes, and a common steady state could be achieved on the catalysts. This indicates that structure of the catalyst tends to approach its equilibrium state in the regeneration process, during which the utilization efficiency of Pt is maximized by increasing the dispersion of Pt and its intrinsic activity, and the structural robustness is secured. The performance of the catalyst is comparable to that of a single-atom Pt/Al2O3 catalyst. [ABSTRACT FROM AUTHOR]

In this study, The Ag/Co 2 NiO x catalyst showed much better catalytic activity than the Ag/Co 2 CuO x and Ag/Co 3 O 4 samples. The heightened activity observed in Ag/Co 2 NiO x arises from the modulation of the carrier's electronic structure by Ag, leading to a substantial increase in its reducibility and lattice oxygen activity. [Display omitted] • Ag induced the migration of surface electrons from Co ions to Ni ions over Co 2 NiO x and enhanced electronic structure activity. • The Ag/Co 2 NiO x composite exhibited superior levels of surface-adsorbed oxygen and demonstrated weaker metal–oxygen bonds, essential for catalyzing oxidation reactions. • The surface of Co 2 NiO x significantly enhanced the dispersion of Ag, and Ag/Co 2 NiO x nanospheres showed higher specific activity for oxidations of methane. Atom-doped Co 3 O 4 catalysts loaded with Ag were examined as cost-effective catalysts for methane oxidation. The synthesized Ag/Co 2 NiO x catalysts exhibited distinctive surface characteristics in contrast with Ag/Co 3 O 4 and Ag/Co 2 CuO x catalysts prepared using a similar method. Characterization results unveiled that Ag/Co 2 NiO x featured a higher presence of active surface oxygen species, lattice defects, a larger surface area, and enhanced reducibility. A methane oxidation catalytic performance followed the sequence: Ag/Co 2 NiO x > Ag/Co 3 O 4 > Ag/Co 2 CuO x. The investigation delved into methane degradation pathways on the surfaces of three catalysts, examining their behavior under both aerobic and anaerobic atmospheres through in-situ DRIFTS analysis. Furthermore, introducing Ag showed a marked positive effect on Co-Ni mixed oxide, inducing electron transfer and a more active electron system, whereas it exhibited an inverse impact within the surface of Co-Cu mixed oxide. This work provides innovative perspectives on the development of forthcoming environmental catalysts. [ABSTRACT FROM AUTHOR]

The performance of a set of bimetallic Ru-Co catalysts dispersed on the TiO2 anatase phase, synthesized by the co-deposition–precipitation with urea method, was tested in the CO2 production by the entire oxidation of C3H8. The presence of properly dispersed ruthenium nanoparticles on a Co/TiO2-anatase support was notably favorable for enhancing the C3H8 activity/selectivity. Likewise, an increase in the combined acidity (Brönsted and Lewis) was also observed, and the interaction between Ru0-CoOx species stabilized on TiO2 prompted the C3H8 oxidation at low temperature. The performance of bimetallic Ru-Co/TiO2 catalysts was enhanced by increasing Ru0 species and loading, showing more efficient C3H8 oxidation by the combination of Ru0-CoOx, as revealed by DRIFTS, XPS, H2-TPR, and HAADF-STEM characterization outcomes. The higher acidity of the catalysts containing Ru (1.5 wt%) and Co (3 wt%) as well as the reducibility enhancement of the Ru and Co species led to the best capacity of these catalysts for C3H8 oxidation to CO2 under the experimental conditions employed in this study. [ABSTRACT FROM AUTHOR]

MnCo spinel oxide catalysts were successfully synthesized by the calcination of bimetallic Mn/Co-MOFs as sacrificial templates. The derived catalysts exhibited optimal catalytic activity, reusability and thermal stability for toluene oxidation, which was ascribed to their large specific surface area, higher number of octahedral metal ions and the weakest metal–oxygen bonds. [ABSTRACT FROM AUTHOR]

The selective catalytic oxidation (SCO) is an effective method for removing slipped high-concentration ammonia from NH3-fueled engine exhaust gas. Herein a novel bifunctional catalyst was synthesized by mechanically mixing sulfated Ce/ZrO2 (Ce/ZrO2-S) with a small fraction of Pt/Al2O3 (Pt 0.1 wt.%) for SCO of NH3. As expected, the introduction of a small amount of Pt/Al2O3 significantly improved NH3 conversion ability of Ce/ZrO2-S catalysts toward low-temperature direction. When the mass ratio of Pt/Al2O3 to Ce/ZrO2-S was 7.5% (the corresponding mixed catalyst was denoted as P@CZS-7.5), T90 temperature was 312 °C. More importantly, P@CZS-7.5 catalyst exhibited a much better N2 selectivity (> 96%) in a wide temperature range (320 ~ 450 °C). H2-TPR results revealed that the addition of a trace amount of Pt/Al2O3 significantly led to a distinct shift of reduction temperature peak toward low-temperature direction, thereby greatly improved the low-temperature redox performance of mixed catalysts. Furthermore, NH3-TPD and BET results showed that P@CZS-7.5 catalyst exhibited a similar NH3 adsorption capacity to Ce/ZrO2-S catalyst, while the former had a relatively higher specific surface area than the latter. It was considered as a crucial factor for P@CZS-7.5 catalyst maintaining superior N2 selectivity in high-concentration NH3 (5000 ppm) removal processes. In situ DRIFTS results indicated that P@CZS-7.5 catalyst followed the internal selective catalytic reduction (i-SCR) mechanism in NH3-SCO reactions. [ABSTRACT FROM AUTHOR]

The dry reforming of methane provides an attractive route to convert greenhouse gases (CH4 and CO2) into valuable syngas, so as to resolve the carbon cycle and environmental issues. However, the development of high-performance catalysts remains a huge challenge. Herein, we report a 0.6% Ir/CeO2−x catalyst with a metal-support interface structure which exhibits high CH4 (~72%) and CO2 (~82%) conversion and a CH4 reaction rate of ~973 μmolCH4 gcat−1 s−1 which is stable over 100 h at 700 °C. The performance of the catalyst is close to the state-of-the-art in this area of research. A combination of in situ spectroscopic characterization and theoretical calculations highlight the importance of the interfacial structure as an intrinsic active center to facilitate the CH4 dissociation (the rate-determining step) and the CH2* oxidation to CH2O* without coke formation, which accounts for the long-term stability. The catalyst in this work has a potential application prospect in the field of high-value utilization of carbon resources. Dry reforming of methane is an attractive route to convert greenhouse gases into valuable syngas. Here, the authors demonstrate design strategy to prepare efficient catalysts towards activation of both C–H and C = O bonds and provide atomic-level insights into interfacial synergistic catalysis. [ABSTRACT FROM AUTHOR]

• The Cu-Mn-Fe/ZSM-5 catalyst showed NO removal rates exceeding 80 % at 150–360 °C, and exhibited excellent stability as well as good tolerance to SO 2 & H 2 O under experimental conditions. • The modification of Cu and Mn promoted more ad-NH 3 and ad-NO x species on the surface of the Fe-based ZSM-5 catalyst, enhancing the redox activity and SCR reaction performance. • The co-doping of Cu and Mn elements increased the proportions of Mn4+, Cu+, Fe3+ and chemisorbed oxygen on the catalyst surface, prompting the catalytic activity. • The NH 3 -SCR reaction followed both E-R and L-H mechanism on the Fe-based ZSM-5 catalyst. In this paper, a series of Fe-based catalysts with Zeolite Socony Mobil-5 (ZSM-5) as supports were synthesized using the sol–gel method to obtain the Fe/ZSM-5, Mn-Fe/ZSM-5, Cu-Fe/ZSM-5 and Cu-Mn-Fe/ZSM-5 catalysts. The synthesized catalysts were examined and characterized via catalytic activity testing, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), N 2 adsorption/desorption, scanning electron microscope (SEM), temperature-programmed desorption of NH 3 (NH 3 -TPD), temperature-programmed reduction with H 2 (H 2 -TPR) and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). The results showed that the Cu-Mn-Fe/ZSM-5 catalyst had the best catalytic performance compared with the other catalysts. In addition, Fe/ZSM-5 and Cu-Mn-Fe/ZSM-5 all exhibited excellent stability as well as good tolerance to SO 2 & H 2 O under the experimental conditions. Further characterization results showed that with co-doping of Cu and Mn, the amount of Mn4+, Cu+, Fe3+ and surface chemisorbed oxygen (O β) on the surface of Fe/ZSM-5 increased, promoting the catalytic performance. The DRIFT studies revealed that the NH 3 -SCR reaction followed both the E-R and L-H mechanism on the surface of the Fe-based ZSM-5 catalyst. The Fe-based ZSM-5 catalyst is a good candidate for NH 3 -SCR both in high reactivity and outstanding stability. [ABSTRACT FROM AUTHOR]

[Display omitted] • Metal particle sizes on ceria-supported catalysts are difficult to measure. • CO 2 can passivate a ceria surface against carbonate formation during exposure to CO. • Pd particle sizes measured were consistent with CO oxidation kinetics. Characterizing ceria-containing catalysts via common characterization techniques can be challenging. CO chemisorption is usually used to measure catalyst dispersion. However, the reaction between CO and ceria lattice oxygen leads to significant carbonate formation, resulting in an overestimation of the CO uptake and metal dispersion. Here, we propose a modified method to characterize ceria-containing catalysts which involves exposing the catalyst to CO 2 prior CO adsorption to prevent further carbonate formation during CO chemisorption. We tested this method on Pd/CeO 2 catalysts characterized by different ceria particle sizes and validated it via DRIFTS and CO oxidation kinetics. Validation conducted using CO oxidation kinetics showed that the TOFs derived by normalizing the reaction rates by the interfacial sites, which are the active sites, are similar for all the catalysts under investigation. Our results show that CO 2 -CO chemisorption can be a reliable technique for estimating metal dispersion of ceria-supported catalysts. [ABSTRACT FROM AUTHOR]

To decode the A‐site substitution effect on the reactivity of Al‐based spinel complex oxides, a series of AAl2O4 (A=Cu, Co, Ni, Zn) compounds were manufactured and tested by toluene combustion. It was confirmed that a pure spinel crystalline phase has been successfully synthesized for all the catalysts. The toluene and CO oxidation activity are sequenced as CuAl2O4>CoAl2O4>NiAl2O4>ZnAl2O4. As discovered, both active surface O2− and acid sites are the two critical factors to determine the reactivity, which can adsorb and activate the reactants effectively to form active intermediates, possibly following a Mars‐van‐Krevelen pathway. The activity improves positively with the amount increasing of these two kinds of active sites, thus showing an evident A‐site replacement effect. CuAl2O4 owns the biggest numbers of these two kinds of active sites, thereby exhibiting the optimal catalytic activity. Moreover, it also shows good stability in a dry feed, and considerable ability to resist water vapor and sulfur poisoning. In‐situ DRIFTS results have indicated that benzyl, benzoate, benzaldehyde and benzoquinone might be the major reaction intermediates. [ABSTRACT FROM AUTHOR]

Hydrogen production by catalytic aqueous phase reforming (APR) of biomass oxygenated derivatives in relatively mild conditions is a promising way to produce hydrogen. In this work, Pt/CeO 2 -HT, Pt/La–CeO 2 -HT and PtLa/CeO 2 catalysts were synthesized by a novel photochemical reduction method and applied to the methanol APR. Extensive characterizations have proved that the mild catalyst preparation method gave it a high dispersion of Pt species and the addition of La modified the metal-support interaction. The results showed that La-modified Pt/La–CeO 2 -HT and PtLa/CeO 2 catalysts exhibited better catalytic performance than the Pt/CeO 2 -HT catalyst, among which the hydrogen yield was the highest for the surface La-modified PtLa/CeO 2 catalyst (177.7 mmol/g cat). This was mainly attributed to the surface modification of La resulted in a significant increase in the number of moderately strong basic sites and surface oxygen vacancies in the PtLa/CeO 2 catalyst. The enhancement of catalyst basicity effectively promoted the dissociation of H 2 O to produce hydroxyl groups, while a large number of surface oxygen vacancies provided more active sites for the adsorption and dissociation of H 2 O. And their synergistic behavior efficiently facilitated the water gas shift (WGS) reaction, resulting in a significant increase in hydrogen yield of methanol APR. Associated with the in situ DRIFTS analyzes and the results indicated by WGS reaction, possible promotion mechanism was proposed. [Display omitted] • Highly-dispersed APR catalysts were prepared by a novel photochemical reduction method. • The PtLa/CeO 2 catalyst exhibited the highest catalytic activity and H 2 yield (177.7 mmol/g cat). • Possible reaction mechanism of the synergistic effect on oxygen vacancies and basic sites is verified. [ABSTRACT FROM AUTHOR]

In this work, the phosphomolybdate (HPMo) modification strategy was applied to improve the N 2 selectivity of MnCo-BTC@SiO 2 catalyst for the selective catalytic reduction of NO x , and further, the mechanism of HPMo modification on enhanced catalytic performance was explored. Among MnCo-BTC@SiO 2 -x catalysts with different HPMo concentrations, MnCo-BTC@SiO 2 -0.75 catalyst exhibited not only the highest NH 3 -SCR performance (∼95% at 200-300°C) but also the best N 2 selectivity (exceed 80% at 100-300°C) due to the appropriate redox capacity, greater surface acidity. X-ray photoelectron spectrometer (XPS) and temperature programmed reduction of H 2 (H 2 -TPR) results showed that the modification with HPMo reduced the oxidation-reduction performance of the catalyst due to electron transfer from Mo5+ to Mn4+/Mn3+ and prevent the excessive oxidation of ammonia adsorption species. NH 3 temperature-programmed desorption of (NH 3 -TPD) results showed that the modification with HPMo could significantly improve the surface acidity and NH 3 adsorption, which enhance the catalytic activity and N 2 selectivity. In-situ diffused reflectance infrared Fourier transform spectroscopy (in-situ DRIFTS) revealed that modification with HPMo increased significantly the amount of adsorbed NH 3 species on the Bronsted acid site and C B / C L , it suppressed the production of N 2 O by inhibiting the production of NH species, the deep dehydrogenation of ammonia adsorption species. This study provided a simple design strategy for the catalyst to improve the low-temperature catalytic performance and N 2 selectivity. [Display omitted] [ABSTRACT FROM AUTHOR]

We describe the synthesis of CuIn/ZrO2 catalysts via a facile mechanochemical synthesis method. In doping was demonstrated to promote the formation of strong Cu–In2O3 interactions and increase the number of Cu+ sites. The CuIn0.05/ZrO2 catalyst shows relatively high selectivity and space–time yield of methanol (~50% and ~1.25 gCH3OHgCu−1h−1, respectively) at 300°C and 5 MPa, outperforming those of the Cu/ZrO2 catalyst (~25% and ~1.12 gCH3OHgCu−1h−1, respectively). Time‐resolved in situ DRIFTS results acquired under various reaction conditions (typically H2/D2 isotope exchange) demonstrate that the surface Cu+–bound formate was the most reactive intermediate and the subsequent hydrogenation process should be the rate‐limiting step, which was positively promoted by the inclusion of In. The strong Cu–In2O3 interaction promotes a decrease in Cu0 sites, leading to a weak interaction of the Cu0‐bound CO intermediates, thus facilitating further hydrogenation of these species rather than releasing CO product. [ABSTRACT FROM AUTHOR]

CO2 hydrogenation to chemicals and fuels is a significant approach for achieving carbon neutrality. It is essential to rationally design the chemical structure and catalytic active sites towards the development of efficient catalysts. Here we show a Ce-CuZn catalyst with enriched Cu/Zn-OV-Ce active sites fabricated through the atomic-level substitution of Cu and Zn into Ce-MOF precursor. The Ce-CuZn catalyst exhibits a high methanol selectivity of 71.1% and a space-time yield of methanol up to 400.3 g·kgcat−1·h−1 with excellent stability for 170 h at 260 °C, comparable to that of the state-of-the-art CuZnAl catalysts. Controlled experiments and DFT calculations confirm that the incorporation of Cu and Zn into CeO2 with abundant oxygen vacancies can facilitate H2 dissociation energetically and thus improve CO2 hydrogenation over the Ce-CuZn catalyst via formate intermediates. This work offers an atomic-level design strategy for constructing efficient multi-metal catalysts for methanol synthesis through precise control of active sites. Carbon dioxide hydrogenation is an important industrial reaction. Here, the authors design a CeCuZn catalyst through a metal organic framework template for CO2 hydrogenation to methanol with excellent methanol yield and stability. [ABSTRACT FROM AUTHOR]

The synthesis process of conventional Mn-based denitrification catalysts is relatively complex and expensive. In this paper, a resource application of chlorella was proposed, and a Chlorella@Mn composite denitrification catalyst was innovatively synthesized by electrostatic interaction. The Chlorella@Mn composite denitrification catalyst prepared under the optimal conditions (0.54 g/L Mn2+ concentration, 20 million chlorellas/mL concentration, 450°C calcination temperature) exhibited a well-developed pore structure and large specific surface area (122 m2/g). Compared with MnOx alone, the Chlorella@Mn composite catalyst achieved superior performance, with ∼100% NH 3 selective catalytic reduction (NH 3 -SCR) denitrification activity at 100-225°C. The results of NH 3 temperature-programmed desorption (NH 3 -TPD) and H 2 temperature-programmed reduction (H 2 -TPR) showed that the catalyst had strong acid sites and good redox properties. Zeta potential testing showed that the electronegativity of the chlorella cell surface could be used to enrich with Mn2+. X-ray photoelectron spectroscopy (XPS) confirmed that Chlorella@Mn had a high content of Mn3+ and surface chemisorbed oxygen. In-situ diffuse reflectance infrared Fourier transform spectroscopy (in-situ DRIFTS) experimental results showed that both Langmuir-Hinshelwood (L-H) and Eley-Rideal (E-R) mechanisms play a role in the denitrification process on the surface of the Chlorella@Mn catalyst, where the main intermediate nitrate species is monodentate nitrite. The presence of SO 2 promoted the generation and strengthening of Brønsted acid sites, but also generated more sulfate species on the surface, thereby reducing the denitrification activity of the Chlorella@Mn catalyst. The Chlorella@Mn composite catalyst had the characteristics of short preparation time, simple process and low cost, making it promising for industrial application. [Display omitted] Schematic diagram of NH 3 -SCR performance of Chlorella@Mn composite denitrification catalyst. [ABSTRACT FROM AUTHOR]

Multi-pollutant removal (MPR) of NO and VOCs simultaneously is efficient of flue gas treatment in coal-fired power plants. But reducing the competition for active sites between NH3, NO, C6H6, and C7H8 remains challenging. Herein, Cr, Mn, and Fe were respectively doped to MoWTi catalyst via wet impregnation. The Fe3+ + Mo5+ ↔ Fe2+ + Mo6+ redox cycle led to an increased proportion of low valence ions (Mo5+ and W5+) and facilitated the creation of active oxygen vacancies with several active sites. It also possessed plentiful mild to strong acid sites with ideal ratio. These factors enhanced catalytic activity of Fe-MoWTi. Remarkable MPR efficiencies of NO, C6H6, and C7H8 were achieved under industrial SCR condition, characterized by low oxygen but high SO2 levels at 340 °C, with removal rates reaching 89.85%, 97.57%, and 86.30% respectively. Theory calculations further revealed that Fe-MoWTi favor NH3 and O2 adsorptions. NO elimination was found to follow both Eley–Rideal (E-R) and Langmuir–Hinshelwood (L–H) processes, supported by in situ DRIFTS analysis. The reactions involving NO/NO2/nitrite/nitrate occurred with NH3(ads)/ NH4+(ads)/NH2 (ads). C6H6 and C7H8 underwent gradual oxidation, formatting alcohols, aldehydes, acids, and maleic acids, before eventually being mineralized to gaseous CO2 and H2O. Findings hold significant potential for application, providing guidance for the development of catalysts with improved resistance against SO2 poisoning and enhanced MPR capabilities. [ABSTRACT FROM AUTHOR]

Mn–La0.5/TiO2 denitration catalysts were prepared by impregnation, combustion, coprecipitation, reverse coprecipitation, and in situ deposition method, and their catalytic activities were compared. The catalyst prepared by the in situ deposition method had the highest catalytic activity and N2 selectivity with a T80 of 104.8 °C, a NO conversion of up to 100%, and a temperature window of 104.8–365.6 °C. The water and sulfur resistance of the catalysts prepared by the in situ deposition method and the coprecipitation method were compared. The elemental valence state, composition, redox ability, and surface acidic sites of the catalysts were analyzed by XPS, XRF, H2-TPR and NH3-TPD. The adsorption behavior and NH3-SCR reaction of the catalysts were investigated by in situ diffuse reflectance infrared Fourier transform spectroscopy. Results showed the catalyst prepared by the in situ deposition method had better water and sulfur resistance, higher Mn4+ content, H2 consumption and medium acidic sites, and faster adsorption rate of NH3 and NO when compared with those prepared by other methods. The NH3-SCR reaction on two catalysts followed the Eley–Rideal mechanism, and "fast SCR" played a key role in the reaction. [ABSTRACT FROM AUTHOR]