Addressing CO2 Electrolysis Challenges with Novel Ion-exchange Membranes

As a response to climate change, substantial efforts are being made to achieve global net-zero greenhouse gas emissions by the year of 2050, as established by the Paris agreement. To decrease reliance on fossil fuels, we are transitioning to renewable energies and electrifying various sectors. However, certain segments of the global supply chain...

Spatial Considerations in Membrane Electrode Assembly CO2 Electrolyzers

Carbon dioxide (CO2) electrolysis is an attractive technology for the production of valueadded products and hydrocarbons, establishing a route for leveraging renewable energy sources in the synthesis of fuels and chemicals. Considerable progress has been made in the past decade in advancing CO2 electrolyzers towards commercial scales, however...

Enhancing Piezo- and Electrical Properties of Bismuth Ferrite based Ceramics: Chemical and Physical Approaches

The main objective of the research as described in this thesis was to enhance the piezo- and electrical properties of bismuth ferrite-based (BiFeO3 or BFO) piezoceramics at room and elevated temperatures, using both chemical and physical approaches.

Chasing H- in Rare-earth Metal Oxyhydride Thin Films

Rare-earth metal oxyhydride thin films show a photochromic effect, where their transparency decreases (reversibly) with exposure to light with energy greater than its optical band gap. The precise underlying mechanism behind this effect is unknown, but is investigated in this thesis by using techniques such as muon spin relaxation, or materials...

Catalysts and Operating Conditions for Electrochemical Reduction of Carbon Dioxide

The urgent threat of global warming and the demand for sustainable fuels have made the electroreduction of CO2 a priority, due to its possibility in closed-loop cycle of carbon. The energy conversion and strategy can diminish the content of CO2 in the atmosphere, convert renewable electricity into chemical energy and store it in chemical bonds,...

Photochromism and photoconductivity in rare-earth oxyhydride thin films

The uncommon photochromism, photo-conductivity, and H-mobility of RE oxyhydride materials make them promising candidates for application in optics, opto-electronics and electrochemical devices alike. Additionally, their extreme compositional flexibility and the connected variety of possible (meta)stable phases make them an excellent case study...

Operando spectroscopic methods to study electrochemical processes

Fossil resources are being depleted, while the concentration of CO2 in the atmosphere rises. There clearly is a strong and immediate need for a radical energy transition. Renewable energy is growing strongly as supplier of fossil-free electricity, but it needs large-scale and long-term storage options in order to be able to make a real impact on...

Photochromic Properties of Rare-Earth Oxyhydrides

The experiments presented in this thesis have provided new insights regarding the photochromic properties of rare earth oxyhydrides (REOxHy). We discovered that thin films of rare-earth (Y, Dy, Er, Gd, Nd) oxyhydrides show unique photochromic properties under ambient conditions. We showed that by direct current reactive magnetron sputtering of...

Band-Edge Energetics Control for Solar Hydrogen Production

The global transition from fossil-based resources to renewable energy is critically important to address the sharply increasing threat of global climate change and to ensure long-term energy security. One attractive candidate to substitute for conventional fossil fuels is hydrogen. Hydrogen is an excellent energy carrier that can be directly...

Electrochemical activation of photo- and electrochemical water oxidation catalysts

Our civilization is facing one of the biggest challenges in its entire history: the energy transition. The growing demand for energy, the scarcity of resources and climate change are the three main factors driving the change. Firstly, the world population is expected to keep on growing, and many poor countries are projected to experience rapid...

Selective Electrocatalytic CO2 Conversion on Metal Surfaces

The electrocatalytic conversion of CO2 into fuel and valuable chemicals by coupling with a renewable electricity source is a promising strategy for closing the anthropogenic carbon cycle. The critical step for achieving this practical CO2 utilization is to find a suitable electrocatalyst that is capable of reducing CO2 in a cost-effective...

Tailoring the Hydrogen Detection Properties of Metal Hydrides

Hydrogen plays an essential role in many sectors of the industry. For example, hydrogen is necessary to produce ammonia, it can be used to determine the quality of products (hydrogen is produced during food ageing), or it can result in medical diagnostics (e.g. lactose intolerance). In addition, hydrogen will play an important role as an energy...

Solar energy storage: novel solar-to-fuel and solar-to-electric approaches: Use of sunlight and water to power the world

Towards the production of core-shell nanoparticles with fluidized bed ALD

Reducing particle size or material structure size to nanometer scale can make the material properties, such as light absorption and electronic structure, change compared to the same materials at normal scale. This gives them properties that can make them suitable for the development of highly efficient and improved micro-electronics, sensor...

Destabilization of magnesium hydride through interface engineering

The aim of this thesis is to study the thermodynamics of hydrogenation of nanoconfined magnesium within a thin film multilayer model system. Magnesium hydride is a potential material for hydrogen storage, which is a key component in a renewable energy system based on hydrogen. In bulk form, magnesium hydride is very stable, which means that...

Towards Highly Efficient Bias-Free Solar Water Splitting

Solar water splitting has attracted significant attention due to its potential of converting solar to chemical energy. It uses semiconductor to convert sunlight into electron-hole pairs, which then split water into hydrogen and oxygen. The hydrogen can be used as a renewable fuel, or it can serve as a feedstock material to form hydrocarbons....

Selective Photocatalytic Reduction of NOx with Fe-doped TiO2: A New Approach Towards Photocatalyst Design

Conventional TiO2 based photocatalysts oxidize NOx to nitrates which do not automatically desorb and have to be washed away from the catalyst surface. To avoid this, the research described in this thesis aims to design new photocatalysts that can photo-reduce NO into N2 and O2. Previous efforts in the literature have shown that catalysts...

Validation of Hydrogenography for the search of promising hydrogen storage materials

Hydrogenography is a combinatorial optical thin film technique to study the thermodynamic properties of metal hydride storage materials. It allows to study thousands of compositions simultaneously with exactly the same experimental conditions. Hydrogenography can pin point the most interesting regions/compositions in binary, ternary, quaternary...