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While scholars on gender provisions have focused on why and how this type of peace agreement clause gets incorporated, few studies have sought to improve our understanding of the implementation process. Addressing this gap empirically, this study utilizes unique interview material to analyze the initial stages of realizing the 2014 Comprehensive Agreement on the Bangsamoro in the Philippines. The article bridges and expands on key theoretical insights based on three explanations suggested by previous research: 1) state capacity on promoting gender equality; 2) the mobilization of women’s organizations; and 3) gender awareness of international actors. We find that the strategic actions of women’s organizations combined with state capacity accelerated the implementation. However, their influence was dependent on whether or not the government prioritized the gender provisions, and whether international actors provided financial support to the agreement infrastructure.

Hydroconversion of 5-hydroxymethylfurfural (HMF) to 2,5-bis(hydoxymethyl)furan (BHMF) was studied over mono- and bimetallic supported catalysts. It was found that monometallic Ni/SiO2 catalysts exhibited superior performance with a total yield of BHMF of up to 99 wt%. This excellent performance may be attributed to higher Ni dispersion and low acidity of the support. Dimethyl sulfoxide (DMSO) is often present in HMF, due to the route used for its synthesis. DMSO adsorption caused a clear reduction of Ni/SiO2 performance for the HMF hydrodeoxygenation reaction. Characterization of the spent catalysts was performed using HAADF-STEM-EDX, Raman, ICP, and XPS spectroscopies, and showed the presence of sulfur and graphitic carbon, which could explain the deactivation.

The influence of the zeolite framework structure on the formation of N2O during ammonia-SCR of NOx was studied for three different copper-functionalized zeolite samples, namely Cu-SSZ-13 (CHA), Cu-ZSM-5 (MFI), and Cu-BEA (BEA).

The influence of zeolite support materials and their impact on CH4 oxidation activity was studied utilizing Pd supported on H-beta and H-SSZ-13. A correlation between CH4 oxidation activity, Si/Al ratio (SAR), the type of zeolite framework, reduction-oxidation behaviour, and Pd species present was found by combining catalytic activity measurements with a variety of characterization methods (operando XAS, NH3-TPD, SAXS, STEM and NaCl titration). Operando XAS analysis indicated that catalysts with high CH4 oxidation activity experienced rapid transitions between metallic- and oxidized-Pd states when switching between rich and lean conditions. This behaviour was exhibited by catalysts with dispersed Pd particles. By contrast, the formation of ion-exchanged Pd2+ and large Pd particles appeared to have a detrimental effect on the oxidation-reduction behaviour and the conversion of CH4. The formation of ion-exchanged Pd2+ and large Pd particles was limited by using a highly siliceous beta zeolite support with a low capacity for cation exchange. The same effect was also found using a small-pore SSZ-13 zeolite due to the lower mobility of Pd species. It was found that the zeolite support material should be carefully selected so that the well-dispersed Pd particles remain, and the formation of ion-exchanged Pd2+ is minimized.

The formation characteristics of N2O were investigated with respect to copper-functionalized zeolites, i.e., Cu/SSZ-13 (CHA), Cu/ZSM-5 (MFI), and Cu/BEA (BEA) and compared with the corresponding ze...

Passive NOx adsorption (PNA) is a method, in which NOx can be stored at low temperatures and released at higher temperatures where the urea decomposition is functional during selective catalytic reduction (i.e., above 180–200 °C). We have studied the promotion of Pd/BEA with La as a PNA in the presence of high CO concentration. Both the reference and promoted samples exhibited a significant loss of NOx adsorption/desorption capacity after multiple cycles using 4000 ppm CO. However, already after 5 cycles, 99% of the NOx released between 200 and 400 °C was lost for Pd/BEA, compared to only 64% for Pd-La/BEA, which thereafter was stable. XPS and O2-TPD clearly showed that the Pd species were influenced by La. The PNA deactivation in the presence of CO could be related to Pd reduction followed by migration and the formation of more PdOx clusters, as observed by O2-TPD analysis. Interestingly, significantly more PdOx clusters formed on Pd/BEA after 10 cycles compared to Pd-La/BEA.

In the present study, a global kinetic model of three-way-catalyst-coated gasoline particulate filters was developed to understand the relevant kinetic mechanisms taking place both in clean and rea...

Two copper-exchanged zeolites, Cu/SSZ-13 and Cu/BEA, were studied as catalysts for the selective reduction of NOx by NH3 (NH3-SCR). Their activities for standard SCR (NOx = NO) and fast SCR (NOx = 50% NO + 50% NO2) were measured before and after sulfur poisoning at 250 °C. The effect of 30 ppm SO2 and a mixture of 24 ppm SO3 + 6 ppm SO2 was evaluated. The repetition of subsequent activity measurements served as regeneration method in SCR conditions. SO2 deactivated Cu/SSZ-13 whereas Cu/BEA was only moderately affected. SO3 led to stronger deactivation of both catalysts than SO2. However, also for this case, the Cu/BEA was significantly less affected than Cu/SSZ-13, even though Cu/BEA contained larger amount of stored sulfur. One possible reason for this could be the large pores of Cu/BEA, where the sulfur species possibly resulted in less sterical hindrance than in the small pore SSZ-13 structure. NH3 temperature-programmed desorption (NH3-TPD) showed no loss of storage sites upon sulfur treatment and subsequent regeneration. Partial activity recovery was observed after a period in SCR conditions at 400 °C and 500 °C. Temperature at 300 °C was insufficient to regenerate the catalysts. Diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) of NO adsorption suggested that SO2 interacts with the ZCuOH sites on Cu/SSZ-13, causing the strong poisoning.

SAPO-34 were synthesized using three structure-directing agents (SDAs), i.e., tetraethylammonium hydroxide (TEAOH), triethylamine (TEA), and morpholine (MO). These SAPO-34 supports were used to prepare Cu/SAPO-34 catalysts via two different Cu-exchange methods: incipient wetness impregnation (IWI) and solid-state ion exchange (SSIE). The catalytic performance of Cu/SAPO-34(TEAOH, TEA, MO) catalysts prepared with IWI and SSIE before and after exposure to water vapor at 70 °C was systemically examined, and their deactivation behavior during low-temperature NH3-SCR reaction was studied. These catalysts were characterized by XRD, BET, ICP-SFMS, SEM/EDX, solid-state NMR, CO-DRIFTS, NO-DRIFTS, and H2-TPR. The various characterization findings for the Cu/SAPO-34 catalysts suggest that the distribution of different Cu2+ species and the mobility of Cu2+ in chabazite (CHA) structure are important for the low-temperature deactivation and regeneration behaviors of the Cu/SAPO-34(TEAOH, TEA, MO)-IWI and -SSIE during the NH3-SCR reaction. Thus, it has been determined that the choice of SDA and Cu-exchange method is vital to design of an efficient Cu/SAPO-34 catalyst that is highly active during a NH3-SCR reaction and has a high tolerance for the low-temperature deactivation caused by exposure to water vapor.

In this study, NH3 adsorption isotherms for a commercial vanadium-based SCR catalyst coated on a monolith substrate were obtained using a gas flow reactor over a wide range of parameters which have not been performed before in a single study. The isotherms were obtained under different conditions, where adsorption temperature, NH3 concentration, water concentration, washcoat loading, and catalyst oxidation state were varied. For this purpose, a systematic data processing method was developed, which characterizes the dispersion and delay effects in the experimental setup using a residence time distribution model, and artifacts such as NH3 adsorbed in the experimental setup and uncertainties in the washcoat loading were removed. As a result, data from different catalyst samples were integrated, and adsorption isotherms with low data spread and well-defined regions were obtained. This allows the identification of the complex nature of the catalyst and dynamics, where multiple types of adsorption sites are present. For instance, the oxidized catalyst has 50% higher NH3 storage capacity compared to the reduced state of the sample. Moreover, water reduces the NH3 storage capacity at high concentrations (5.0%), whereas at low concentration (0.5%), water increases the NH3 adsorption capacity for an oxidized catalyst. The proposed data processing method can be extended for the analysis of further phenomena in catalysts studied using gas flow reactors, complementing current methods and providing information for models with extended validity and lower parameter correlations.

Hydrodeoxygenation (HDO) activity of NiMo catalysts have been evaluated in the presence of catalyst poisons in bio-based feedstocks. An in-house synthesized NiMo/Al2O3 catalyst was placed in a refinery unit for biofuel production. Iron (Fe), phosphorus (P) and metals were identified as major contaminants. Calcination treatment was explored to recover the activity of spent catalysts. The effect of Fe, K and phospholipid containing P and Na on catalyst deactivation during hydrodeoxygenation of stearic acid was simulated at lab-scale. Fe caused the most deactivation where the highest feed concentration of the Fe compound resulted in 1480 ppm Fe deposited on the catalyst. Elemental distribution along the radial axis of spent catalysts indicated: Fe deposited only to a depth of 100 μm irrespective of concentration while P and Na from phospholipid and K penetrated deeper in catalyst particles with a distribution profile that was found to be concentration dependent.

Diesel oxidation catalysts (DOC) were investigated for oxidation activity, NO conversion stability, and sulfur poisoning/regeneration on Pd/Al2O3, Pt/Al2O3, and Pd-Pt/Al2O3 catalysts. The Pd/Al2O3 catalyst was more active for CO and hydrocarbon (C3H6 and C3H8) oxidation, while the Pt/Al2O3 catalyst efficiently oxidized NO. The formation of a Pd-Pt alloy in the Pd-Pt/Al2O3 catalyst maintained Pd in a more reduced phase, resulting in the superior activity of this catalyst for the oxidation of CO, C3H6, and NO in comparison with its monometallic counterparts. The Pd-Pt alloy not only provided more low-temperature activity but also retained the stability of NO oxidation. The Pd-Pt alloy also favored the spillover of SO2 to the alumina support, resulting in significantly higher adsorption capacity of the Pd-Pt/Al2O3 catalyst, extensively prolonging its lifetime. However, the stable sulfates on Pd-Pt/Al2O3 made it difficult to completely regenerate the catalyst. The bimetallic sample showed higher activity for CO, C3H8, and C3H6 after sulfur poisoning and regeneration.

BACKGROUND Some 40% of colorectal cancer (CRC) patients present with anemia. Temporal trends of gradually decreasing Hb are suggested as a supplementary diagnostic tool for CRC. We set out to explore this concept in a strictly defined population. METHODS A laboratory database identified patients ≥40 years that had ≥1 Hb test reported from primary care, Orebro county in 2000-17. Linkage to the Swedish Colorectal Cancer Registry identified patients diagnosed with CRC. Other primary care patients served as controls (1:10), matched by age and sex. Prediagnostic Hb in cases and controls were compared and temporal trajectories of Hb modelled using a nonlinear three-parameter logistic function. RESULTS 1,534 CRC patients and 15,333 controls were identified. The average number of reported Hb tests in primary care per year increased successively, and diagnostic delay from detection of anemia to diagnosis of CRC decreased; in 2015-17 it was median 4 (IQR 2-6) months. No association was found between last Hb and stage of right-/left-sided colon, or rectal cancer.A statistically significantly lower Hb in CRC patients was discernable 609 days (20 months) prior to diagnosis for men and 905 days (30 months) for women, both in the range of normal Hb. The frequency of Hb testing in the general population via primary care was surprisingly low, and was ≥50% annually only in octogenarians. CONCLUSION The findings indicate a potential for Hb trends to inform the diagnostic process of CRC but whether it will translate into any clinical advantage is yet uncertain.

A concept of a layered Pd/SSZ-13 with Cu/SSZ-13 as PNA-SCR dual-layer monolith catalyst for NOx abatement is demonstrated. NO-TPD was employed for determining the NOx storage, and the samples are characterized in detail using SEM-EDX, CO/NO-DRIFTS, XPS and H2-TPR. 750 °C hydrothermal treatment greatly promotes the NOx storage capacity and the addition of CO promotes NOx storage capacity and also shifts the NOx desorption temperature. The dual-layer sample (Pd/SSZ-13+Cu/SSZ-13) maintains most of the NOx storage capacity while the NOx desorption temperature is modified due to Cu/SSZ-13 as the top layer. The layered sample work well for NH3-SCR reaction. Notably, for Pd/SSZ-13+Cu/SSZ-13, more than 80 % of the NOx trapped at low temperature (i.e., 80 °C) can desorb in the suitable SCR temperature region where NOx conversion higher than 80 % is found. However, some loss of NO storage is found after SCR experiments. Overall, the dual-layer concept shows interesting potential for NOx abatement, but requires further developments on the PNA material to ensure stable storage capacity.

Catalytic hydrodeoxygenation (HDO) is an important hydrotreating process that is used to improve the quality of bio-oils to produce biomass-derived fuel components and chemicals. Molybdenum disulfide (MoS2) has been widely used as a catalyst in hydrodesulfurization (HDS) applications for several decades, which can be further improved for effective unsupported catalyst synthesis. Herein, we studied a universally applicable post-annealing treatment to a hydrothermally synthesized MoS2 catalyst towards developing efficient unsupported catalysts for deoxygenation. The effect of the annealing treatment on the catalyst was studied and evaluated for HDO of 4-propylguaiacol (PG) at 300 °C with 50 bar H2 pressure. The annealing of the as-synthesized catalyst under nitrogen flow at 400 °C for 2 h was found to enhance the HDO activity. This enhancement is largely induced by the changes in the microstructure of MoS2 after the annealing in terms of slab length, stacking degree, defect-rich sites and the MoS2 edge-to-corner site ratio. Besides, the effect of hydrothermal synthesis time and acid addition combined with the annealing treatment on the MoS2 catalytic activity was also studied for the same model reaction. The annealed MoS2 with a synthesis time of 12 h under an acidic environment was found to have improved crystallinity and exhibit the highest deoxygenation degree among all the studied catalysts. An acidic environment during the synthesis was found to be crucial in facilitating the growth of MoS2 micelles, resulting in smaller particles that affected the HDO activity. The annealed unsupported MoS2 with the best performance for PG hydrodeoxygenation was further evaluated for the hydrotreatment of kraft lignin and demonstrated a high deoxygenation ability. The results also indicate a catalyst with high activity for deoxygenation and hydrogenation reactions can suppress char formation and favor a high lignin bio-oil yield. This research uncovers the importance of a facile pretreatment on unsupported MoS2 for achieving highly active HDO catalysts.

Transition metal sulfides (TMSs) are typically used in the traditional petroleum refining industry for hydrodesulfurization (HDS) and hydrodenitrogenation (HDN) applications. Bio-oils require an upgrading process like catalytic hydrodeoxygenation (HDO) to produce advanced biofuels and chemicals. Herein, MoS2/γ-Al2O3 promoted by transition metals like nickel (Ni), copper (Cu), zinc (Zn), and iron (Fe) was evaluated for the HDO of a bio-oil model compound, 4-propylguaiacol (PG) in a batch reactor at 340 °C under 50 bar H2 pressure. The catalyst screening results showed that the sulfided Ni-promoted catalyst gave a high 94% yield of deoxygenated cycloalkanes, however for the sulfided Cu-promoted catalyst, 42% of phenolics remain in the reaction medium after 5 h. The results also revealed that the sulfided Zn and Fe-promoted catalysts gave a final yield of 16% and 19% at full PG conversion, respectively, for deoxygenated aromatics. A kinetic model considering the main side reactions was developed to elucidate the reaction pathway of demethoxylation and dehydroxylation of PG. The developed kinetic model was able to describe the experimental results well with a coefficient of determination of 97% for the Ni-promoted catalyst system. The absence of intermediates like 4-propylcyclohexanone and 4-propylcyclohexanol during the reaction implies that direct deoxygenation (DDO) is the dominant pathway in the deoxygenation of PG employing sulfided catalysts. The current work also demonstrated that the activity of the transition metal promoters sulfides for HDO of PG could be correlated to the yield of deoxygenated products from the hydrotreatment of Kraft lignin.

The efficient conversion of CO2 to hydrocarbons offers a way to replace the dependency on fossil fuels and mitigate the accumulation of surplus CO2 in the atmosphere that causes global warming. Therefore, various efforts have been made in recent years to convert CO2 to fuels and value-added chemicals. In this review, the direct and indirect hydrogenation of CO2 to hydrocarbons via methanol as an intermediate is spotlighted. We discuss the most recent approaches in the direct hydrogenation of CO2 into hydrocarbons via the methanol route wherein catalyst design, catalyst performance, and the reaction mechanism of CO2 hydrogenation are discussed in detail. As a comparison, various studies related to CO2 to methanol on transition metals and metal oxide-based catalysts and methanol to hydrocarbons are also provided, and the performance of various zeolite catalysts in H2, CO2, and H2O rich environments is discussed during the conversion of methanol to hydrocarbons. In addition, a detailed analysis of the performance and mechanisms of the CO2 hydrogenation reactions is summarized based on different kinetic modeling studies. The challenges remaining in this field are analyzed and future directions associated with direct synthesis of hydrocarbons from CO2 are outlined.

Sulfides of NiMo over a series of commercial ultra-stable Y zeolites were studied in an autoclave reactor to elucidate the effect of silica/alumina ratio (SAR = 12, 30, and 80) on the cleavage of etheric C–O (β-O-4) and C–C (both sp3–sp2 and sp2–sp2) linkages present in native/technical lignin and lignin derived bio-oils. 2-Phenethyl phenyl ether (PPE), 4,4-dihydroxydiphenylmethane (DHDPM), and 2-phenylphenol, (2PP) were examined as model dimers at 345 °C and 50 bar of total pressure using dodecane as the solvent. The etheric C–O hydrogenolysis activity was found to be in the order NiMoY30 > NiMoY12 > NiMoY80, despite a high initial rate of C–O cleavage over NiMoY12 owing to its high acid density. A high degree of hydrodeoxygenation (HDO) and hydrocracking reactions were observed with NiMoY30 yielding >80% of deoxygenated products of which ∼58% are benzene, toluene, and ethylbenzenes. A similar experiment with DHDPM showed the rapid cleavage of the methylene-linked C–C dimer (sp3–sp2) to phenols and cresols even with the low acid density (high SAR) catalyst, NiMoY80. Direct hydrocracking of the recalcitrant 5-5′ linkage in 2PP is very slow, however, it cleaved via a cascade of HDO, ring-hydrogenation, and hydrocracking reactions. A high degree of hydrogenolysis and hydrocracking occurs over NiMoY30 due to suitable balance between acidity and pore accessibility, enhanced proximity between acidic and deoxygenation sites leading to a slightly higher dispersion of Ni promoted MoS2 crystallites. Overall, the product spectrum consisted of a high yield of deoxygenated products. The carbon content on the recovered catalyst was in the range of 3–7 wt%. These results pave the way for effective catalysts to break recalcitrant linkages present in lignin to obtain a hydrocarbon-rich liquid transportation fuel. An experiment with Kraft lignin over NiMoY30 shows good selectivity for deoxygenated aromatics and cycloalkanes in the liquid phase.

Louise Olsson and Angela Muvumba Sellstrom Peace Research Institute Oslo (PRIO) and Uppsala University Since the adoption of UNSCR 1820 in 2008, United Nations peacekeeping operations have come und...

Catalyzed gasoline particulate filters (cGPFs) are one of the most promising technologies to meet future stringent gaseous and particulate emission limits for gasoline-powered vehicles. The successful adoption of this technology relies on several important properties including high filtration efficiency, low back-pressure, high conversion efficiency, and great durability compliance. Particularly in this work, the conversion efficiency and durability of model cGPF catalysts were studied under different feed temperatures and multicomponent feed gas mixtures. The samples consisted of soot-free and real soot-loaded GPFs coated with noble metals supported on alumina and Ce-Zr mixed oxides. Prior to testing, the samples were subjected to diverse hydrothermal aging conditions. Some physicochemical characterization techniques, including scanning electron microscopy-energy-dispersive X-ray spectroscopy (SEM-EDS), X-ray diffraction (XRD), transmission electron microscopy (TEM), and nitrogen physisorption, were employed to study the fundamental relations between the state of the samples and their catalytic properties. The results showed that the introduction of soot appeared to have both a positive and negative effect on the catalyst activity. The catalyst surface is masked by the introduction of soot, blocking active sites and inhibiting species conversion. At the same time, the exothermicity of the soot oxidation reaction increases the catalyst temperature, reducing the light-off temperature, for the severely aged samples. Besides the presence of soot, the catalyst aging considerably influences the reactions over cGPFs. In particular, the conversions of ethylene and toluene were more affected by the catalyst aging than CO, which became even worse in the presence of NO in the feed gas. The formation of side products (NH3 and N2O) over the cGPFs was also examined under diverse practical conditions.

Passive NOx adsorption performance was investigated for Pd-based BEA zeolite as a reference sample along with ceria, zirconium, and lanthanum as different promoters. The La-promoted sample showed favorable NOx desorption behavior regarding greater quantities of NOx release at temperatures higher than 200 degrees C. The study was therefore mainly focused on the La-promoted sample and Pd/BEA, since the largest effect was seen using La as a promoter. The effect of water and hydrogen pretreatments for passive NOx adsorption (PNA) processes was therefore studied for La-Pd/BEA and compared with that for pure Pd/BEA. It was shown that the presence of water reduces the NOx desorption at lower temperature. Hydrogen pretreatment decreases the NOx uptake and shifts the adsorption and desorption temperatures to higher values. Interestingly, the La-Pd/BEA sample was less sensitive to H-2 pretreatment. Temperature-programmed oxidation (TPO) and X-ray photoelectron spectroscopy (XPS) results indicated the presence of more stable Pd oxide sites for La-Pd/BEA. Furthermore, Diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) analysis suggested that NO is adsorbed with stronger and more stable bonds in the form of nitrates compared with the Pd/BEA reference sample.

The effect of phosphorus poisoning on the catalytic behavior of diesel oxidation catalysts was investigated over model and supplier monolith catalysts, i.e., Pd–Pt/Al2O3. The results of ICP and XPS from the vapor-phase poisoning over model catalysts suggested that the temperature of phosphorus poisoning affects both the overall content of phosphorus and the dispersion of phosphorus (i.e., inlet/outlet and surface/bulk). Phosphorus oxide (P2O5), metaphosphate (PO3−), and phosphate (PO43−) were identified in the poisoned model and supplier catalysts. The distribution of these species on poisoned model catalysts was highly dependent on the poisoning temperature, i.e., a higher temperature resulted in a higher concentration of PO43−. The outlets of the monoliths contained more PO43− and less P2O5 than the inlets. Both active sites and surface OH groups on model and supplier catalysts were contaminated upon phosphorus poisoning. It is found that PO43− had a stronger influence on the active sites than P2O5. One significant finding in this study is that the vapor-phase phosphorus poisoning could be a practical and cost efficient approach to simulate an accelerated aging/poisoning process.

NiMoS on alumina, USY and mixed alumina-USY supports was studied in a batch reactor to assess the effect of support acidity in valorizing lignin dimers by hydrodeoxygenation (HDO). The reactivity of α-O-4 (benzyl phenyl ether), β-O-4 (2-phenethyl phenyl ether) and 5-5′ (2,2′-dihydroxybiphenyl) linkages was investigated in dodecane at 593 K and a H2 pressure of 5 MPa. A relatively fast rate of hydrogenolysis of the sp3 hybridized etheric bonds was observed for the catalyst supported on the mixed support. With the α-O-4 linkage, the USY supported catalyst selectively yielded deoxygenated aromatics including BTX products with fewer residual C–C dimers. For the β-O-4 linkage, analogous trends have been observed but with more aromatics. Interestingly, with 5-5′ linkages the catalyst on USY and mixed supports can break the C–C linkages without producing other intermediate C–C dimer byproducts. The results show high hydrocracking and isomerization activities of the catalyst supported on USY and mixed supports. This is consistent with XRD, Raman, XPS and TEM measurements, where enhanced dispersion of the active phase was observed. However, hydrogenation activity on the USY support is reduced to a significant degree which results in a large amount of benzene compared to NiMoS–Al2O3 that produces mostly cyclohexane. In addition, elemental analysis revealed that carbon deposition is higher on the USY-based catalyst compared to the alumina-based catalyst owing to its higher acidity. However, the potential for superior C–C bond cleavage on NiMoS-USY opens the possibility to valorize technical lignin in biorefinery processes.

The Cu/SAPO-34 catalysts, used for NH3 selective catalytic reduction (SCR), are systemically studied with various characterization techniques before and after low temperature water deactivation and regeneration using techniques such as XRD, BET, ICP-SFMS, 27Al MAS NMR, 29Si MAS NMR, and H2-TPR. Analysis of results suggests that, during low-temperature water deactivation, hydrolysis of Si–O–Al occurs resulting in Si condensation and formation of Si clusters. It is proposed that these formed Si clusters are mainly responsible for the deactivation of Cu/SAPO-34 catalysts since they suppress the mobility of [Cu–(NH3)]+ and hinder the formation of the transient [CuI(NH3)2]+–O2–[CuI(NH3)2]+ intermediate, which is considered to be the rate-limiting step for NH3-SCR reaction. The regeneration of the deactivated Cu/SAPO-34 catalysts with acid can be explained by the ability of the acid to convert the Si clusters back to Si–O–H, which is able to revert to the SAPO-34 framework via reverse hydrolysis as the temperature increases.

The performance failure of Cu/SAPO-34 material used as an NH3-SCR catalyst at low temperature in the presence of water has caused a gradual withdrawal of its usage from the market. There is an urgent need to clearly understand its deactivation mechanism and to find a way to regenerate the Cu/SAPO-34 catalyst material. Interestingly and surprisingly, we have discovered that, under certain conditions, 10% H2O can regenerate a previously deactivated Cu/SAPO-34(MO), as long as its zeolite structure is maintained. By using experimental observations of NH3-SCR reaction, solid state NMR, NO-DRIFTS, and in situ H2-TPR, a mechanism is proposed which can explain both the deactivation and regeneration of Cu/SAPO-34(MO). We propose that the transformation of Si(4OAl) and Si(3OAl) to (2Al)Si(2OH) and (3Al)Si(OH) and the Si condensation in the pores of the framework, which result from H2O exposure, are responsible for the deactivation of Cu/SAPO-34(MO). We suggest that the formation of condensed Si which results in Si clusters, hinders the mobility of the linear complex, [Cu–(NH3)2]+, which is the active species during the low temperature NH3-SCR reaction. Moreover, we propose a regeneration mechanism when Cu/SAPO-34(MO) is exposed to 10% H2O, where the Si clusters are transformed back to Si–O–H bonds, and thereafter transferred back to the framework. This can explain the regeneration of deactivated Cu/SAPO-34(MO).

Thermochemical processing of lignin ends up with a major problem which is the high yield of char remained from lignin conversion, causing low yields of desired products. The ReS2/Al2O3 catalyst, used in this work, exhibited a high char-suppressing potential and high hydrodeoxygenation efficiency in the reductive liquefaction of kraft lignin. Compared to NiMo/Al2O3, as a conventional sulfide catalyst, ReS2/Al2O3 showed significantly better catalytic performance with 72.4 % lower char yield, due to its high efficiency in stabilizing the lignin-depolymerized fragments. The remarkable catalytic performance of ReS2/Al2O3 is attributed to its high oxophilicity, the metal-like behavior of rhenium sulfide and sufficient acidity. The effects of reaction temperature and different catalyst supports (Al2O3, ZrO2 and desilicated HY zeolite) were also studied. In an alkali (NaOH)-assisted depolymerization of lignin, it was revealed that ReS2/Al2O3-to-NaOH (stabilization-to-depolymerization) ratio plays a crucial role in determining the reaction pathway toward either solid char residues or liquid monomeric products.

The catalytic properties of palladium supported on H-beta and H-SSZ-13 zeolite with different silica to alumina ratio (SAR) have been evaluated for complete CH 4 oxidation in the presence and absence of water vapor and together with SO 2 . Different SAR was successfully obtained by dealumination of the zeolites in an acidic solution at elevated temperature. Flow reactor experiments showed that the SAR of the zeolite support greatly impacts the catalytic activity, especially in the presence of water vapor. Pd supported on a highly siliceous beta zeolite expressed high and stable CH 4 conversion in the presence of water vapor, whereas the activity for Pd supported on zeolites with low SAR or Al 2 O 3 decreased over time due to accumulative water deactivation. Hence, an increased SAR of the zeolite support clearly correlates to a lower degree of water deactivation. We suggest that this is a result of the high hydrophobicity of the siliceous zeolites. The results also imply that the catalytic activity in the presence of water vapor is influenced more by the SAR than the type of the zeolite framework. The CH 4 oxidation activity was also enhanced with increasing SAR under dry conditions. This was addressed to the formation of more Pd particles in relation to ion-exchanged Pd 2+ species and changes of the oxidation-reduction behavior of the Pd. The high number of acidic sites in zeolites with low SAR provided higher dispersion of Pd particles and formation of more monoatomic Pd 2+ species, whereas almost exclusively Pd particles of larger sizes were formed on the highly siliceous zeolites. The monoatomic Pd 2+ species, mostly formed on zeolites with low SAR, were oxidized and reduced at significantly higher temperatures than Pd in the particle form. Hence, complete reduction or oxidation of the Pd supported on highly siliceous zeolites can be achieved at lower temperatures. Moreover, compared to Pd/Al 2 O 3 , the zeolite supported Pd expressed higher sensitivity to SO 2 . However, the major part of the catalytic activity could be regenerated more easily using siliceous zeolites as supports compared to Al 2 O 3 . We suggest that this is an effect of the lower SO 2 adsorption on the zeolite supports than on the Al 2 O 3 support, which results in the formation of more PdSO x species upon SO 2 exposure. On the other hand, the low SO 2 adsorption on the zeolites also results in less spillover of sulfur species from the support to the active PdO, which explains the facilitated regeneration.

Catalysis is essential in the automotive and transportation sectors to target the United Nations sustainable development goals for climate change and the environment. To comply with both the ambitious United Nations goals and step-by-step stringent emission regulations, innovative and economically viable catalytic systems will be a key element in meeting these challenges.