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Ammonia has been responsible for feeding population growth in the 20th century through synthetic fertilizer, and is poised to become the preferred energy storage medium for a society powered by renewable electricity in the 21st century. However, conventional brown ammonia production through the Haber-Bosch process is optimized for utilization of centralized and steady energy supply from fossil-fuels. When shifting to distributed and intermittent energy supply through wind and solar energy, a re-optimization is required for a low-capital and flexible green ammonia production processes. This thesis re-designs and Haber-Bosch process by targeting the integration of reaction and separation in a single process vessel at low pressures, thereby achieving the simplification and down-scaling of the high pressure recycle loop of the Haber-Bosch process. Materials are developed for this purpose, the feasibility of integration is demonstrated, and mathematical modeling is utilized for assessing the application of the single-vessel process to a range of renewable energy sources in comparison to competing ammonia production processes. Herein, a catalyst with low-temperature (< 350°C) and high-conversion (i.e. near equilibrium) activity is developed using ruthenium nanoparticles as the active metal supported on ceria and promoted with cesium to mitigate hydrogen and ammonia inhibition, respectively. This catalyst is compared to commercial iron-based catalyst from the perspective of the final application. Concurrently, a high-temperature (> 300°C) manganese chloride absorbent is developed that resists decomposition and is stable when supported on silica. These catalyst and absorbent are integrated in a layered reactor configuration to demonstrate the feasibility of the integrated process by exceeding single-pass reaction equilibrium. Mathematical modelling of ammonia production processes illustrates that at small-scales (< 1 t day-1) the single-vessel process is optimal compared to the Haber-Bosch process due to its modular design. In addition, it can achieve simpler ramping because the Haber-Bosch process is constrained by heat-integration in the recycle loop and the potential for runaway reaction. For final application, the pairing of ammonia production processes with examples of intermittent solar and wind sources demonstrates that the flexibility of the production process is essential when considering non-ideal sources of energy with a long-term (e.g. seasonal) oscillations. Flexible ammonia production also expands the economic usage of ammonia as an energy storage vector from the seasonal to the weekly time-scale, with advantage compared to batteries or hydrogen. The work of this thesis provides a framework for advancing the electrification of the chemical industry given the novel constrains of intermittent and distributed renewable energy. A systems level approach is applied from the ground up, starting from material design and progressing to optimized process design and application.

The aggravating global problems of energy crisis, rising atmospheric greenhouse gas concentrations and accumulation of persistent waste have attracted the attention of scientists, policy-makers and global organisations to come up with effective and expeditious solutions to address these challenges. In this context, the development of sustainable technologies driven by renewable energy sources for the production of clean fuels and commodity chemicals from diverse waste feedstocks is an appealing approach towards creating a circular economy. Over the years, semiconductor photocatalysts based on TiO₂, CdS, carbon-nitrides (CNx) and carbon dots (CDs) have been widely used for the photocatalytic reforming (PC reforming) of pre-treated waste substrates to organic products, accompanied with clean hydrogen (H₂) generation. However, these conventional solar-driven processes suffer from major drawbacks such as low production rates, poor product selectivity, CO₂ release, challenging process and catalyst optimisation, and harsh waste pre-treatment conditions, which limit their commercial applicability. These challenges are tackled in this thesis with the introduction of new and efficient photoelectrochemical (PEC) and chemoenzymatic processes for reforming a diverse range of waste feedstocks to sustainable fuels. Solar-driven PEC reforming based on halide perovskite light-absorber is first developed as an attractive alternative to PC reforming. The PEC systems consist of a perovskite|Pt photocathode for clean H₂ production and a Cu-Pd alloy anode for reforming diverse waste streams, including pre-treated cellulosic biomass, polyethylene terephthalate (PET) plastics, and industrial by-product glycerol into industrially-relevant, value-added chemicals (gluconic acid, glycolic acid and glyceric acid) without any externally applied bias or voltage. Additionally, the single light-absorber PEC systems can also convert the airborne waste stream and greenhouse gas CO₂ to diverse products with the simultaneous reforming of PET plastics with no applied voltage. The perovskite-based photocathode enables the integration of different CO₂ reduction catalysts such as a molecular cobalt porphyrin, a Cu-In alloy and formate dehydrogenase enzyme, which produce CO, syngas and formate, respectively. The versatile PEC systems, which can be assembled in either a ‘two-compartment’ or standalone ‘artificial leaf’ configurations achieve 60‒90% oxidation product selectivity (with no over-oxidation) and >100 µmol cm‾² h‾¹ product formation rates, corresponding to 10²‒10⁴ times higher activity than conventional PC reforming systems. In addition to developing PEC platforms, this thesis also explores avenues for circumventing the harsh alkaline pre-treatment strategies (pH >13, 60‒80 ºC) adopted for photoreforming waste substrates. For this purpose, a chemoenzymatic pathway is introduced whereby PET and polycaprolactone plastics were deconstructed using functional enzymes under benign conditions (pH 6‒8, 37‒65 ºC), followed by PC reforming using Pt loaded TiO₂ (TiO₂|Pt) or Ni₂P loaded carbon-nitride (CNx|Ni₂P) photocatalysts. The chemoenzymatic reforming process demonstrates versatility in upcycling polyester films and nanoplastics for H₂ production at high yields reaching ∼10³‒10⁴ µmol gsub‾¹ and activities at >500 µmol gcat‾¹ h‾¹. The utilisation of enzyme pre-treated plastics also allowed the coupling of plastic reforming with photocatalytic CO₂-to-syngas conversion using a phosphonated cobalt bis(terpyridine) co-catalyst immobilised on TiO₂ (TiO₂|CotpyP). Finally, moving beyond solar-driven systems, a bio-electrocatalytic flow process is demonstrated for the conversion of microbe pre-treated food waste to ethylene (an important feedstock in the chemical industry) on graphitic carbon electrodes via succinic acid as the central intermediate. In conclusion, with its focus on improving efficiencies, achieving selective product formation, building versatile platforms, diversifying substrate and product scope, and reducing carbon footprint and economic strain, this thesis aims to bring sustainable waste-to-fuel technologies a step closer to commercial implementation.

Michael Mann has been ‘in the climate wars’ for well over a decade now. As he reminds us frequently in this new book, he has been in the cross-hairs of his enemies, has fought-off the attack-dogs and carries the scars of battle. Even Bill McKibben’s promotional puff for the book valorises Mann in terms of his “scars from the climate wars”. The military framing of climate change long pre-dates Mann’s involvement, but it certainly is a framing he has done much to promote through his blogs, tweets and general persona-at-large in public discourse. Contributing not least to this was his earlier book The Hockey Stick and the Climate Wars: Dispatches from the Front Lines (Columbia, 2012).

The production of charcoal for its many uses requires a careful selection of biomass and pyrolysis conditions, especially temperature, to ensure suitable quality. To do so, physical, chemical, and mechanical energy must be considered. This study aimed to analyze the yields and properties of charcoal produced at different pyrolysis temperatures. Eucalyptus saligna wood was pyrolyzed in a reactor with final temperatures of 450, 550, 650, 750, 850 and 950 °C. The yields of charcoal, pyroligneous liquid and non-condensable gases were determined. Mass loss was determined for each temperature. Charcoal analysis included the determination of the apparent density, proximate analysis, heating value, mechanical strength, X-ray images for the internal visualization of its structure and hygroscopicity test. Relevant charcoal properties for the steel industry and barbecue, such as density, mechanical strength, heating value and hygroscopicity, show variable trends from pyrolysis at 650 °C. The results show that pyrolysis temperature had a great impact on the properties of charcoal. The apparent density of charcoal rose from 500 °C and had no relation to the breaking strength. When the pyrolysis temperature was raised, an increase in both apparent and true densities, internal fissures and cracks and fixed carbon content of charcoal was observed.

Abstract Biogenic coalbed methane (CBM) is a developing clean energy source. However, it is unclear how the mechanisms of bio-methane production with different sizes of coal. In this work, pulverized coal (PC) and lump coal (LC) were used for methane production by mixed fungi-methanogen microflora. The lower methane production from LC was observed. The aromatic carbon of coal was degraded slightly by 2.17% in LC, while 11.28% in PC. It is attributed to the proportion of lignin-degrading fungi, especially Penicillium, which was reached 67.57% in PC on the 7th day, higher than that of 11.38% in LC. The results suggested that the limited interaction area in LC led to microorganisms hardly utilize aromatics. It also led the accumulation of aromatic organics in the fermentation broth in PC. Increasing the reaction area of coal and facilitating the conversion of aromatic carbon are suggested means to increase methane production in situ.

In many industries, an increasing number of firm owners tie managers’ incentives to sustainability investments. Positive rewards directly increase a manager's total pay when that manager makes sustainability investments, whereas negative rewards directly decrease a manager's pay when those investments are made. Strategic incentive design literature posits that such organizational choices also affect the decisions of a firm's competitors. This paper uses a game-theoretic framework to analyze the effects of sustainability incentives in a setting with two competing firms. In contrast to the existing literature, in the current paper sustainability investments have a demand-enhancing effect and can increase or decrease the unit cost of production, making the current framework more in line with industrial practice. The results show that a firm invests in sustainability only if the demand-enhancing effects outweigh the cost-increasing effects. More importantly, positively rewarding managers for sustainability investments is done in equilibrium only if the innovation capability of the firm is sufficiently high. However, in terms of profits, those positive rewards lead to a prisoner's dilemma. When innovation capability is lower, firm owners use negative rewards and raise their profits. Another finding is that rival firms that cooperate in determining their sustainability incentives increase their profits but do so using negative rewards. These results, which have not been reported in the literature, point to some critical trade-offs in terms of sustainability investments and firm profits when sustainability incentives are considered and are both managerially and academically relevant.

Electrical energy production from renewable energy sources and electrification of consumer energy demand are developments in the ongoing energy transition. These developments urge the demand for flexibility in low voltage distribution networks, on the one hand caused by the intermittency of renewable energy sources, and on the other hand by the high power demand of battery electric vehicles and heat pumps. One of the foremost ways to create flexibility is by using energy storage systems. This paper proposes a method to first optimize the siting, power and capacity rating, technology, and operation of energy storage systems based on the technical and economic value. Secondly the method can be used to make cost- and time-based network planning decisions between network upgrades and network upgrade deferral by energy storage systems. To demonstrate the proposed method, study cases are analyzed of five low voltage distribution networks with different penetrations of photovoltaics, heat pumps and battery electric vehicles. The optimal energy storage systems in the study cases are: flow batteries sited at over 50% of the cable length with a high capacity rating per euro. With the current state of energy storage system development, network upgrade deferral is up to 61% cheaper than network upgrades in the study cases. The energy storage systems can offer additional value by reducing the peak loading of the medium voltage grid which is not taken into account in this research.

To decrease our society’s dependence on polluting fossil resources, alternative sources for chemical and fuel production need to be developed. Organic residual streams are a renewable feedstock that can be used to replace these fossil-based fuels and chemicals. In this thesis bioelectrochemical chain elongation (BCE) has been studied to convert short chain fatty acids (SCFAs, model substrates for acidified organic residual streams) into biobased intermediate chemicals. BCE is subtype of a microbial electrosynthesis (MES) system, in which microorganisms catalyse the elongation of SCFAs and/or CO2 towards medium chain fatty acids in an electrochemical cell.Part 1 of this thesis studied the formation of valuable products from SCFAs using BCE systems. In chapter 2 it started with the proof of concept of using an electrode for the sustained chain elongation of CO2 and acetate in continuous BCE systems. Four BCE reactors were used to study the role of applied current: two were applied with 3.1 A m-2 (projected surface area of electrode) and the other two with 9.4 A m-2. n-Butyrate (nC4) was the main identified product in all reactors. The highest applied current led to the highest nC4 production rate of 0.54 g L-1 d-1 (24.5 mMC d-1). The highest concentration of nC4 reached under high current regime was 0.59 g L-1 (26.8 mMC). Trace amounts of propionate and n-caproate were also produced, but no alcohols were detected over the course of the experiments (163 days).To improve BCE and enhance production, in chapter 2 as well a literature review is provided to give insights into all the reported pathways to produce nC4 in fermentations. In fermentative chain elongation soluble electron donors, like ethanol or lactate, supply reducing equivalents and drive microbial metabolism. Since such compounds were not detected in the BCE reactors, it was hypothesised that nC4 production was limited by intermediate production and subsequent fast consumption of ethanol or lactate.This hypothesis of intermediary production of ethanol or lactate limiting BCE performance was verified in chapter 3. Both ethanol and lactate were separately introduced in triplicate BCE reactors applied with 9.4 A m-2. Both compounds did not significantly affect the rates of nC4 production. Next to these compounds, the effect of formate on nC4 production was tested. Formate injection led to acetate production and decreased nC4 production. The results suggested that formate conversion to acetate competed with acetate elongation to nC4 for electrons. This competition subsequently resulted in decreased production of nC4. To investigate role of the electrode as electron donor, the current was increased to 18.1 A m-2. This increase in applied current doubled the production rates of nC4. Hence, this chapter demonstrates that the nC4 production in our BCE systems was not limited by intermediate production of well-known electron donors, but was driven by electrode-derived electrons.For BCE to become a feasible organic waste valorisation technology, the studied substrate range needs to extend beyond acetate reduction. Therefore, in chapter 4 four different substrate feeding strategies and the subsequent product spectrum were investigated: I) acetate, II) acetate and propionate, III) acetate and n-butyrate, and IV) a mixture of acetate, propionate and n-butyrate. In phase I, nC4 was produced at 0.9 g L-1 d-1 (39.7 mMC d-1). After introduction of propionate in phase II, n-valerate (nC5) production started and sustained until medium was changed at the start of phase III. The maximum concentration of nC5 reached was 1.2 g L-1 (60.6 mMC), and the highest production rate was 1.1 g L-1 d-1 (57.5 mMC d-1) at a high carbon-based selectivity of 73.8 %. This seems contradictory to ethanol chain elongation studies in which acetate is concurrently formed leading to straight fatty acids as by-products. Upon introduction of acetate and n-butyrate, n-caproate (nC6) production started and reached a maximum concentration of 0.3 g L-1 (15.8 mMC). The nC6 formation selectivity was 83.4 % in phase III. When all the three SCFA were supplied as substrate in phase IV, nC5 was the main product (95.4%). The observed preference for propionate elongation over both nC4 formation or nC6 formation is in contrast to fermentative ethanol-based chain elongation studies.Part 2 of this thesis focusses on the extraction of the bioproducts from dilute aqueous streams using ionic liquids. The conversion of organic waste streams as renewable feedstocks into carboxylic acids (such as SCFAs but as well the medium chain fatty acids (MCFAs)) results in relatively dilute aqueous streams. These relatively low concentrations are a major bottleneck for these bioprocesses to compete with the production of platform chemicals based on fossil resources. A way to overcome this bottleneck is to extract the carboxylates from the fermentation broths using liquid- liquid extraction. Hydrophobic ionic liquids (ILs) are novel extractants which can be used for this purpose. Ionic liquids are salts comprised of ions, with relatively low melting temperatures (often below 100°C). By varying the types of ion and, for example, the branching of the ions, the physical properties of the IL, such as its hydrophobicity, can be tailored. To integrate these ILs as in situ extractants in biotechnologies, the ionic liquid should be compatible with the bioprocess.In chapter 5 the biocompatibility of the two hydrophobic ILs [N8888][oleate] and [P666,14][oleate] were investigated in a two-phase system (IL layer on top of water phase). Commonly, ILs are synthesized in organic solvents, such as toluene and ethanol. After synthesis some trace amounts of these solvents can remain in the IL. When that hydrophobic IL is placed on top of a water phase, the trace amounts of synthesis solvent can leak into the water phase. To circumvent possible toxic effects of the trace amounts of solvent in the IL, water was used as synthesis solvent. After synthesis of the two ILs, their bioprocess compatibility was assessed. Methanogenic granular sludge was placed in medium without carbon source, and on top of that medium the IL phase was placed. After 24 days the sludge was separated from the water phase and placed into fresh medium. Upon transfer of the sludge into fresh medium with acetate as substrate, [P666,14][oleate] exposed granules were completely inhibited. Granules exposed to [N8888][oleate] sustained anaerobic digestion activity, although moderately reduced. Co-ions of the starting materials of the ILs, bromide and oleate, could have remained in the IL after synthesis. Both bromide (5 to 500 ppm) and oleate (10 to 4000 ppm) were demonstrated to not inhibit methanogenic conversion of acetate. Conclusively, [P666,14] was identified as a bioprocess incompatible component and [N8888][oleate] as bioprocess compatible.For an IL to become the envisioned in situ extractants for bioprocesses, the IL needs to be regenerated and reused. In chapter 6 a concept of an IL as transport liquid is presented, in which a product (from a bioprocess) is in situ extracted into a hydrophobic IL. The subsequent extraction of the product from the IL (i.e. regeneration) does not necessarily need to take place in/at the same physical location, time and/or medium as where the extraction of product into the IL occurred. Therefore, the IL can be regarded as transport liquid of the product.To study the feasibility of this concept, the bioprocess compatible hydrophobic IL [N8888][oleate] was used for two successive cycles of i) extraction of SCFAs into the IL [N8888][oleate] and ii) regeneration of the IL. For the regeneration of the IL a novel method was described which employs microorganisms to assist in IL regeneration, naming it ‘microbial assisted regeneration’. Microbial assisted regeneration is beneficial as no additional salt is needed for both pH control of the bioprocess as well as for recovery of the products from the IL. The experiments in this chapter demonstrate the potential of using hydrophobic ILs as transport liquid between two bioprocesses. When the concept of an IL as transport liquid is coupled with the proposed microbial regeneration method, two distinct biological processes can be coupled.For BCE to become an industrial waste valorisation technology, the production needs to be improved. Although the electron transfer pathways are not unravelled yet, chapter 7 gives an overview of all the nowadays described pathways. In this way, the coupling of microbial metabolism with an electrode can be understood more. Based on these insights, several recommendations are provided to improve BCE and to render the technology mature enough to prove its potential using real acidified organic residual streams.

The world increasingly depends on batteries to store renewable energy and use that same energy in our vehicles and portable communication devices. This puts exceeding pressure on global resources. We need batteries that charge faster and live longer, such that we can use less resources. Faster charge and longer life are currently limited by the negative electrode, typically graphite, because fast charging would push the potential into the regime of hazardous and cycle-life degrading lithium plating. The ideal potential for fast charge would be low, but just above the around 1 V reduction potential of the electrolyte. Niobium-based metal oxides have the optimal electronegativity to strike this balance, with a nominal potential around 1.6 V, charging rates >5C and a cycle-life projected over 10,000 cycles. Chapter 1 shows that the exact potential can be tuned further by changing the average oxidation state through substitution of Nb5+ with for example W6+ or Ti4+. The range of average oxidation states then directly spans a material phase space classed by anion-to-cation ratios of 2.33 ≤ *y* < 2.82. These "off-stoichiometric" ratios typically force the unit cell to rearrange into an ordered balance of *y*=3 ReO3-type blocks of corner-sharing octahedra that have ample window sites to rapidly intercalate many lithium-ions, interspaced with *y*=2.5 crystallographic shear planes of edge-sharing octahedra that add stability and electronic conductivity to the structure, and anchored at their corner by *y*=2 regions of tetrahedra or edge-sharing octahedra. The influence of this structure on cell performance is relatively unknown. Numerous publications exist on individual members of this Wadsley-Roth (WR) material family, but gaps in theory and varying experimental conditions make it impossible to compare. The aim of this thesis is to provide a fair and fundamental comparison across this material class, relating compositional and structural properties to cell thermodynamics and kinetics that can then be used to optimise the material selection and model any full-scale cell geometry. In total 16 different compounds were synthesised with comparable geometrical parameters. Subsequently, they were fully parameterised with various electrochemical tests. Current theory is still too firmly based on traditional metal plate electrodes. Because the WR materials allow extreme conditions of high currents and could be tuned over an extensive structural and compositional range, their study forms an excellent opportunity to modernise the fundamental understanding of the thermodynamics and kinetics of intercalation lithium-ion batteries, in general, and in relation to structural and compositional parameters. Chapter 2, on thermodynamics and energy density, introduces fundamental principles of configurational entropy to explain the steep bends at the cell potential ends and the detailed peaks in the cyclovoltammogram. Density function theory (DFT) exposed a site filling order and structural straightening. Via molecular orbital theory this was then related to enthalpic effects of relatively steeper potential regions due to progressively poorer charge-compensation and relatively poor shielding, but also relatively flatter potential regions related to metal-to-metal repulsion and pseudo Jahn-Teller effects at the block edge. Owing to their increased edge-sharing, low *y* materials could thus reach lower potentials without reaching the voltage cut-off earlier. Low *y* materials thus exhibit high energy density, particularly considering that they also consist of more lightweight elements. The structural straightening upon reduction was identified as the crucial mechanism that provides a competitive energy density to the WR material. The first cycle data and DFT also revealed the mechanism that tetrahedral linkages are irreversibly trapping lithium and that they can be left out of the structure to achieve nearly 100% first cycle efficiencies. On the other hand, the study in Chapter 3 of their intercalation kinetics through temperature-dependent GITT and PEIS with novel application of the compensation effect shows that lower *y* is at the cost of lower entropy of the diffusion pathways, such that their intercalation diffusion coefficients are lower. In general, the compensation effect and the effect of entropy can not be underestimated, while the effect of activation enthalpy could be misleading. Various PEIS, cyclovoltammetry, PITT and GITT techniques had to be critically reviewed and stripped from metal-plate concepts, to identify the formation of film layers and the trends in diffusion. The charge transfer reaction rate and lithium intercalation diffusion were identified as the main contributors to loss, limiting the charge/discharge rate. However, this study observed that the chemical lithium intercalation diffusion coefficient increases with rate. This surprising effect is no longer adequately described by the conventional mass-transfer theory and suggests effects of non-equilibrium driving forces, excited lithium hopping, lattice vibrations and energy barrier softening. Such a mechanism is essential to explain the high rate performance of WR materials and intercalation materials in general and provides an important direction for future theory and experimental research. All in all, this study showed a tradeoff between energy and rate, with TiNb2O7, Zn2Nb34O87 and PNb9O25 as winners. Independent of the tradeoff, performance could be further improved in the future with the substitution of lightweight cations, and by increasing the crystallographic entropy with multiple cations. In general, this work identified several new applications of theory to the modern battery cell, which will hopefully become more widely applied and further underpinned by in-situ direct observation methods on the particle level. All the theory and full parameterisation methods above were combined into a full cell continuum model in Chapter 4, that not only validates these approaches but also allows the design, verification and prediction of any commercial format multilayer cell geometry. This paves the way for this new class of ultra fast-charge long-life batteries that can power more of the world, with fewer batteries.