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Um die Energiewende in der Schweiz zu ermöglichen, hat SCCER BIOSWEET (i) die aktuellen und zukünftigen Potenziale an Primärenergie aus den verschiedenen verholzten Biomassearten in der Schweiz ermittelt; (ii) innovative Technologien für deren Nutzung in den Bereichen Wärme, Strom und Treibstoffe entwickelt und umgesetzt; sowie (iii) die zukünftige Rolle der verholzten Biomasse im Energiesystem untersucht. SCCER BIOSWEET startete mit der Vision von 100 Petajoule (PJ) Primärenergieverbrauch pro Jahr aus Bioenergie bis 2050, was einer Verdoppelung des heutigen Energieverbrauchs aus Biomasse entspricht. Nach den Ergebnissen der im Rahmen von SCCER BIOSWEET durchgeführten Analysen ist dieses Ziel erreichbar und die verholzte Biomasse könnte 50 % dazu beitragen. Im Hinblick auf die Ressourceneffizienz und die Dekarbonisierung von Industrie und Gesellschaft sollte jedoch die stoffliche Nutzung von Holz, zum Beispiel als Dämmstoffe oder als Chemikalien in Bioraffinerien, im Vordergrund stehen und der energetischen vorangehen (Kaskadennutzung). Die energetische Nutzung von Holz umfasst in der Schweiz idealerweise die Produktion von Hochtemperaturwärme für industrielle Prozesse sowie Treibstoffe in gasförmiger und flüssiger Form für den boden- und fluggebundenen Verkehr. Ein weiterer wichtiger Punkt ist der Ausgleich von Schwankungen in der Produktion anderer Energieträger, insbesondere der Solarenergie.

To enable the energy transition in Switzerland, SCCER BIOSWEET (i) assessed the current and future potentials of primary energy from the different woody biomass types in Switzerland; (ii) developed and implemented innovative technologies for biomass utilization in the fields of heat, electricity and fuels; and (iii) investigated the future role of woody biomass in the energy system. SCCER BIOSWEET started with the vision of 100 petajoules (PJ) of primary energy consumption per year from bioenergy by 2050, which means a doubling of the current energy consumption from biomass. According to the results of the analyses completed through SCCER BIOSWEET, this target is achievable and woody biomass could contribute 50 %. Nevertheless, with regard to resource efficiency and the decarbonization of industry and society, priority should be given to the material use of wood (cascading use), for example as chemicals produced in biorefineries. In Switzerland, the use of wood for energy would ideally include the production of high-temperature heat for industrial process heating, as well as fuels in gaseous and liquid form for ground- and air-based transportation. A further key point is the need to compensate for fluctuations in the production of other types of energy, especially solar power.

Pour permettre la transition énergétique en Suisse, SCCER BIOSWEET (i) a évalué les potentiels actuels et futurs de l’énergie primaire provenant des différents types de biomasse ligneuse en Suisse ; (ii) a développé et mis en oeuvre des technologies innovantes pour l’utilisation de la biomasse dans les domaines de la chaleur, de l’électricité et des carburants ; et (iii) a étudié le rôle futur de la biomasse ligneuse dans le système énergétique. SCCER BIOSWEET a commencé avec l’objectif de 100 pétajoules (PJ) de consommation d’énergie primaire par an provenant de la bioénergie d’ici 2050, ce qui signifie un doublement de la consommation d’énergie actuelle provenant de la biomasse. Selon les résultats des analyses réalisées par SCCER BIOSWEET, cet objectif est réalisable et la biomasse ligneuse pourrait y contribuer à hauteur de 50 %. Néanmoins, en ce qui concerne l’efficacité des ressources et la décarbonisation de l’industrie et de la société, la priorité doit être accordée à l’utilisation matérielle du bois (utilisation en cascade), par exemple comme produits chimiques dans les bioraffineries. En Suisse, l’utilisation du bois à des fins énergétiques devrait idéalement inclure la production de chaleur à haute température pour le chauffage des processus industriels, ainsi que de carburants sous forme gazeuse et liquide pour les transports terrestres et aériens. Un autre point essentiel est la nécessité de compenser les fluctuations de la production d’autres sources d’énergie, notamment solaire.

The effect of an alumina-based binder on the structure of a commercial Fe-ZSM-5 catalyst has been investigated. Several ex-situ characterization techniques were used to show that the binder in the catalyst formulation allows obtaining a material that possesses improved features in terms of Fe species dispersion, framework Al content and acidity. UV–Vis and X-ray absorption spectroscopy showed that the extent of Fe agglomeration in the extruded catalyst was significantly lower compared to that in the catalyst without binder. 27Al and 29Si-MAS NMR spectroscopy demonstrated a remarkable difference in terms of framework Al migration. NH3-TPD experiments corroborated the NMR results suggesting a retention of Bronsted acidity in the extruded catalyst. We tentatively propose that by providing extra-framework Al species prior to the treatment at elevated temperature, the binder hinders the framework Al dislodgment and Fe agglomeration during calcination.

Catalysts consisting of highly dispersed copper on a mesoporous ZrO2 support were synthesised via a one-pot sol-gel synthesis and were tested for the selective catalytic reduction of NOx by NH3. The copper dispersion was investigated by XRD and TEM, which showed no discernible copper oxide particles up to 6 wt% Cu, while they were detected at 15 wt% Cu., NH3 adsorption and the SCR reaction were followed in situ by diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) on mesoporous ZrO2 and on one-pot synthesized 3 wt% Cu/ZrO2. Cu was found to improve the NH3 adsorption capacity of the catalyst by enhancing the Lewis functionality., The catalysts were efficient for SCR at low temperature, at 150 degrees C 75% of NO was converted over 6 wt% Cu/ ZrO2 at water-free conditions. Increasing the copper loading while maintaining the dispersion improved NOx conversion.

X-ray photoreduction of V5+ in supported vanadia catalysts was detected by XAS during in situ experiments at a synchrotron beamline. Practical strategies helping to recognize and mitigate such problems are suggested.

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 tightening emission regulations have led to the development of commercial DOCs with zoned or layered formulations allowing to cover a wide range of functionalities (i.e. CO, HC and NO oxidation as well as HC or NOx trap). Aging phenomena in such complex formulations are not well understood. To shed light on material deactivation, this study compares phosphorus poisoning and thermal sintering of two DOC monoliths with related formulations: (1) a commercial monolith comprising two catalytic layers where the top layer is rich in Pt, and (2) a model monolith containing only the top layer of the commercial monolith. The activity and characterisation (elemental analysis, microscopy and N2-physisorption) results are used to deconvolute the deactivation process of the two layers and should serve to rationalize the aging in layered catalyst formulations.

Supported vanadia (VOx) is a versatile catalyst for various redox processes, where ceria-supported VOx have shown to be particularly active in oxidative dehydrogenation (ODH) of alcohols. In this work, we clarify the origin of the volcano-shaped ethanol ODH activity trend for VOx/CeOx catalysts using operando quick V K- and Ce L3- edge XAS experiments performed under transient conditions. We quantitatively demonstrate that both vanadium and cerium are synergistically involved in alcohol ODH. The concentration of reversible Ce4+/Ce3+ species was identified as the main descriptor of the alcohol ODH activity. The activity drop in the volcano plot, observed at above ca. 3 V/nm2 surface loading (ca. 30% of VOx monolayer coverage), is related to the formation of spectator V4+ and Ce3+ species, which were identified here for the first time. These results might prove to be helpful for the rational optimization of VOx/CeO2 catalysts and the refinement of the theoretical models.

Natural gas is a suitable alternative to gasoline and diesel fuels to decrease the carbon footprint of the mobility and energy sectors. Unburnt CH4 is typically removed from the exhaust using palla...

Supported ruthenium was used in the liquid phase catalytic transfer hydrogenation of furfural. To improve the stability of Ru against leaching, phosphorous was introduced on a Ru/Al2O3 based catalyst upon impregnation with ammonium hypophosphite followed by either reduction or calcination to study the effect of phosphorous on the physico-chemical properties of the active phase. Characterization using X-ray diffraction, solid state P-31 nuclear magnetic resonance spectroscopy, X-ray absorption spectroscopy, temperature programmed reduction with H-2, infrared spectroscopy of pyridine adsorption from the liquid phase and transmission electron microscopy indicated that phosphorous induces a high dispersion of Ru, promotes Ru reducibility and is responsible for the formation of acid species of Bronsted character. As a result, the phosphorous-based catalyst obtained after reduction was more active for catalytic transfer hydrogenation of furfural and more stable against Ru leaching under these conditions than a benchmark Ru catalyst supported on activated carbon.

Ru/CNF catalysts of different Ru nanoparticle (NP) sizes (0.9-2.7 nm) were assessed for their performance in continuous supercritical water gasification (SCWG) of glycerol. A structure sensitivity of Ru was demonstrated, with high initial turnover frequencies (TOF) for Ru NPs smaller than 1.2 nm. Deactivation happens essentially through: 1) coking, which occurs more readily at low Ru surface densities and is limited to nanometric layers, and 2) sintering, which led to final NP sizes ranging from 2 to 3 nm independent of the catalyst loading (1 to 30 wt% Ru). A correlation between TOF and the density of surface Ru atoms was found, with an optimal surface density (0.4-0.7 atomRu,sfc nm−2) resulting in high initial and good steady-state TOFs, allowing longer lifetimes through the delay of coke formation. CNF as a support enables high metal loadings with optimal performance, which could help in decreasing the volume of high-pressure vessels and hence the cost of SCWG plants, making this technology even more attractive.

The role of Lewis and Brønsted acid sites and their potential synergy remains ambiguous for the production of polyoxymethylene dimethyl ethers (OME), which are suitable as a Diesel substitute. Here, this synergistic effect was investigated by using a series of beta polymorph A (BEA) zeolites with various degrees of Brønsted and Lewis acidity. Lewis acidity was introduced in dealuminated zeolites by Sn grafting in dichloromethane. These sites were only active in paraformaldehyde decomposition, OME growth, and acetalization. The Brønsted acid sites arising from bridging hydroxyl groups were active for all reaction steps, and notably for trioxane ring-opening and dissociation to formaldehyde (FA), which did not occur on the Lewis acid sites. Presence of both Lewis and Brønsted acid sites led to a four-fold increase in turnover frequency and a significant decrease of byproduct formation compared with the parent zeolite during OME synthesis from dimethoxymethane and trioxane. The synergistic effect between both types of acid sites is explained by FA insertion on Lewis acid sites leading to OME growth. Interaction between tetrahedral Sn and the carbonyl group of FA resulted in an activated carbonyl bond, which was likely the initial step for insertion of FA into OME.

We report the increased level of mechanistic information that Raman spectroscopy can provide when combined with modulated excitation experimentation. A V2O5/TiO2 catalyst for the selective catalyti...

The reverse water gas shift reaction is considered to be a highly attractive catalytic route for CO2 recycling in a future sustainable economy. Copper-based catalysts are commonly used for this rea...

The use of formate-based ammonia precursors as alternatives to urea in the selective catalytic reduction (SCR) process requires that formic acid released upon their thermolysis in the hot exhaust is rapidly decomposed to carbon dioxide. This work aims at the rational development of a dedicated catalyst that is highly active and selective towards formic acid decomposition to carbon dioxide under SCR-relevant conditions, i.e. under lean conditions and in presence of a large amount of water. The incremental addition of a basic oxide (lanthana) to Au/TiO2 revealed an optimum in the base-induced promotional effect. The base-modification of Au/TiO2 induced a C–H bond weakening of the bidentate formates, which are the dominant surface species and the kinetically relevant intermediates for carbon dioxide formation. At 15 wt% lanthana loading, monodentate formates were substantially suppressed leading to ∼85% reduction in carbon monoxide production. Very high lanthanum surface concentrations lowered the relative coverage of oxygen-derived surface species that are crucial for the decomposition of the abundantly present formates. The linearity of the Constable-Cremer relationship between the apparent activation energy and the natural log of the pre-exponential factor indicates the mechanistic similarity in formic acid decomposition on gold supported on unmodified and lanthanum-modified titania catalysts. Such mechanistic insights helped derive an optimal catalyst. The optimal catalyst exhibited close to three-fold higher activity for ammonium formate decomposition while still maintaining 100% selectivity to ammonia.

Real-world vanadium-based catalysts for the selective catalytic reduction (SCR) of NO with NH3 are occasionally exposed to high temperatures, which can induce catalyst aging. In this work, a 2.0 wt% V2O5/WO3-TiO2 catalyst based on commercial WO3-TiO2 was lab aged in dry and wet feed at different time lengths and temperatures. Aging carried out in static atmosphere or in flow only marginally influenced its performance, while e.g. temperature and water in the feed heavily affected the SCR activity. The low temperature NOx conversion (≤300 °C) increased after aging up to 600 °C for 16 h and was more pronounced after hydrothermal aging compared to thermal aging, which was associated with the increased surface coverage of the SCR-active vanadyl groups. Measurements of vanadium volatility in the temperature range selected for the aging temperatures revealed the high mobility of V species induced by the (hydro-)thermal treatments. The onset of catalyst deactivation, observed at lower aging temperature for the hydrothermally aged catalyst compared to the thermally treated one, is possibly due to a larger amount of mobile V and W species and the concurrent loss of specific surface area. The set of catalytic and characterization data showed that water is an essential component in aging protocols because it heavily affects the structure and the resulting catalytic activity of the SCR catalyst. Removal of residual sulfate groups, which are present on the commercial support, also contributed to catalyst activation at 550°C aging temperature as a result of structural changes evidenced by surface area measurements and by IR and Raman spectroscopy, including rearrangement of V species and apparent increase of Lewis acidity.

Catalytic methane oxidation is used in exhaust gas aftertreatment to reduce methane emissions from lean-burn natural gas vehicles as well as in stationary combustion processes. Pd/zeolite catalysts...

The hydrolysis of lignocellulose is the first step in saccharide based bio-refining. The recovery of homogeneous acid catalysts imposes great challenges to the feasibility of conventional hydrolysis processes. Herein, we report a strategy to overcome these limitations by using stable sulfonated carbons as solid acid catalysts in a two-step process, composed of mechanocatalytic pretreatment and secondary hydrolysis in a semi-batch reactor. Without mechanocatalytic pre-treatment the hydrolysis of the insoluble substrate largely occurs through homogeneously catalyzed reactions. Ball-milling induced amorphization promotes a substantially higher substrate reactivity, because homogeneous hydrolysis occurs preferentially from less ordered structural domains in cellulose. In contrast, concerted ball-milling (CBM) of cellulose with the sulfonated carbon promotes a heterogeneously catalyzed hydrolysis to soluble oligosaccharides. By performing an in-depth physicochemical characterization of cellulose subjected to CBM treatment with different carbons, we reveal the crucial role of strong BrOnsted acid sites in facilitating mechanocatalytic depolymerization. Recyclability experiments confirmed that despite being subject to profound structural changes during repeated pre-treatment/semi-batch hydrolysis cycles, the sulfonated carbon retained its catalytic activity. The combination of mechanocatalytic pretreatment with strong solid acids and hydrolysis in the semi-batch reactor was successfully extrapolated for the first time to the hydrolysis of real lignocellulose to achieve quantitative yields in C-5 and high yields in C-6 derived products.

Co-impregnation of vanadia and tungsta on titania produced highly active catalysts for the reduction of nitrogen oxides with ammonia but showed aging tendencies at temperatures around 600 °C. In order to preserve their low temperature activity after hydrothermal aging up to 650 °C, the catalysts were enriched with Si during the co-impregnation process using different SiO2 precursors and amounts. The optimized catalyst composition comprised ca. 4 wt% SiO2, was stable after aging at 650 °C, could preserve the low temperature activity and was more active than the catalysts prepared from commercially available silica-stabilized TiO2 supports. The origin of the effect of SiO2 was investigated by XRD, BET, TEM, STEM and 29Si MAS NMR. SiO2 remained amorphous at all temperatures and 2–4 wt% SiO2 hampered the anatase crystallite growth at 600 °C and 650 °C. In contrast to WO3, SiO2 was unevenly distributed over the TiO2 particles and ca. 60–70% of Si was present as bulky amorphous SiO2 agglomerates after aging at 650 °C. Small and extended SiO2 polymeric entities were identified to be essential for delaying the offset of the catalyst sintering. With the addition of a small amount of SiO2 in the co-impregnation process, the low temperature activity of these catalysts could be preserved up to an aging temperature of 650 °C.

Lignocellulose-based biofuels are of major importance to mitigate the impact of international traffic and transport on climate change while sustaining agricultural land for food supply. Highly integrated systems like consolidated bioprocessing (CBP), where enzyme production, enzymatic hydrolysis and fermentation of the released sugars are carried out in one reactor, offer the highest potential to save costs and to make lignocellulose-based biofuels economically competitive. The work described here showed that CBP based on a microbial consortium operated at full-scale (2000 t/d) saves up to 27.5 % of the total ethanol production costs compared to conventional ethanol production from lignocellulose in individual process steps. The cost savings are mainly achieved through lower CAPEX due to less apparatus requirements because of the integrated process, as well as through lower OPEX since no glucose is needed for enzyme production. A comparison with literature estimations of cost savings of CBP based on genetically modified microorganisms results in approximately the same range. As a result of a detailed sensitivity analysis, scale and yield were identified as the main cost-pushers from a process point of view, whereas the price level of the plant location has the highest impact on the investment conditions. In the EU, CBP yields enough margin for profitable production and the possibility to decentralize biomass valorization, whereas in the world’s largest ethanol market, the U.S, profitable production of lignocellulosic ethanol can only be achieved by CBP combined with other cost saving techniques, such as utilization of cost-free waste feedstocks, since ethanol has undergone a considerable price slump.

Cu-Al spinel oxide is a highly active catalyst for CO

Methane (CH4) has the prospective of becoming one of the major energy carriers for heavy-duty mobility, but its catalytic abatement remains a challenge. CH4 abatement reaction pathways were analyzed using targeted periodic lean/rich oscillations, which resulted in higher CH4 conversion than under static conditions. At both the lean-to-rich and rich-to-lean transitions of such oscillations, local maxima of CH4 concentration were followed by local minima during each lean and rich phase. The CH4 concentration profile during one oscillation displayed a 'W' shape. Four reaction regimes were identified corresponding to the four sections of the characteristic concentration shape. Entering the rich phase, Steam reforming (SR) started, which was then hampered by the formation of carbonaceous species and CO interaction with the catalytic surface. By entering the lean phase, SR is again enhanced as more active sites became available due to oxygen related reactions. However, increasing chemisorbed oxygen slowed down the oxidation of CH4. The transition between the consecutive regimes was linked to changes of the active Ce3+ coverage ratio, which plays an important role in SR reaction. Similar 'W' shapes were observed under various oscillation conditions and at different measurement points along the catalyst axis. The CH4 concentration profile was found to shift downwards with decreasing oscillation frequencies until a frequency threshold, which is marked by the equivalence of oscillation rich/lean phase length and the time needed to completely deplete/replenish the Oxygen storage capacity (OSC). The conversion characteristics were reproduced by numerical simulations, which revealed the spatial distribution of reactions in the catalyst under these dynamic conditions. Optimal overall CH4 conversion was reached for an even distribution of SR along the catalyst.

The small pore zeolite Cu-SSZ-13 is an efficient material for the standard selective catalytic reduction of nitrogen oxides (NOx) by ammonia (NH3). In this work, Cu-SSZ-13 has been studied at 250 °C under high conversion using a modulation excitation approach and analysed with phase sensitive detection (PSD). While the complementary X-ray absorption near edge structure (XANES) spectroscopy measurements showed that the experiments were performed under cyclic Cu+/Cu2+ redox, Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) experiments provide spectroscopic evidence for previously postulated intermediates Cu–N([double bond, length as m-dash]O)–NH2 and Cu–NO3 in the NH3-SCR deNOx mechanism and for the role of [Cu2+(OH−)]+. These results therefore help in building towards a more comprehensive understanding of the reaction mechanism which to date has only been postulated in silico.

The effect of water on the kinetics of oxymethylene dimethyl ether (OME) synthesis from dimethoxymethane (OME1) and trioxane (TRI) has been investigated in a combined kinetic and in situ infrared s...

Log wood burning is a significant source of volatile organic compounds including aromatic hydrocarbons (ArHC). ArHC are harmful, are reactive in the ambient atmosphere, and are important secondary organic aerosol (SOA) precursors. Consequently, SOA represents a major fraction of the sub-micron organic aerosol pollution from log wood burning. ArHC reduction is thus critical in the mitigation of adverse health and environmental effects of log wood burning. In this study, two Pt-based catalytic converters were prepared and tested for the mitigation of real-world log wood burning emissions, including ArHC and SOA formation, as well as toxic carbon monoxide and methane, a greenhouse gas. Substantial removal of mono- and polycyclic ArHC and phenolic compounds was achieved with both catalysts operated at realistic chimney temperatures (50% conversion was achieved at 200 and 300 °C for non-methane hydrocarbons in our experiments for Pt/Al2O3 and Pt/CeO2-Al2O3, respectively). The catalytically cleaned emissions ex...