Stability and degradation of (oxy)nitride photocatalysts for solar water splitting.

Advancing towards alternative technologies for the sustainable production of hydrogen is a necessity for the successful integration of this potentially green fuel in the future. Photocatalytic and photoelectrochemical water splitting are promising concepts in this context. Over the past decades, researchers have successfully explored several materials classes, such as oxides, nitrides, and oxynitrides, in their quest for suitable photocatalysts with a focus on reaching higher efficiencies.

Conversion of LaTiO to LaTiON ammonolysis: a first-principles investigation.

Perovskite oxynitrides are, due to their reduced band gap compared to oxides, promising materials for photocatalytic applications. They are most commonly synthesized from {110} layered Carpy-Galy (ABO) perovskites thermal ammonolysis, the exposure to a flow of ammonia at elevated temperature. The conversion of the layered oxide to the non-layered oxynitride must involve a complex combination of nitrogen incorporation, oxygen removal and ultimately structural transition by elimination of the interlayer shear plane.

Synthesis and Structure of the Double-Layered Sillén-Aurivillius Perovskite Oxychloride LaBiTiOCl as a Potential Photocatalyst for Stable Visible Light Solar Water Splitting.

Exploring photocatalysts for solar water splitting is a relevant step toward sustainable hydrogen production. Sillén-Aurivillius-type compounds have proven to be a promising material class for photocatalytic and photoelectrochemical water splitting with the advantage of visible light activity coupled to enhanced stability because of their unique electronic structure. Especially, double- and multilayered Sillén-Aurivillius compounds [ABO][BiO]X, with A and B being cations and X a halogen anion, offer a great variety in material composition and properties.

Resolving the structure of VO·HO and Mo-substituted VO·HO.

Vanadate compounds, such as VO·HO, are of high interest due to their versatile applications as electrode material for metal-ion batteries. In particular, VO·HO can insert different ions such as Li, Na, K, Mg and Zn. In that case, well resolved crystal structure data, such as crystal unit-cell parameters and atom positions, are needed in order to determine the structural information of the inserted ions in the VO·HO structure.

Modified H V O to Enhance the Electrochemical Performance for Li-ion Insertion: The Influence of Prelithiation and Mo-Substitution.

Nanostructured H V O is a promising high-capacity cathode material, suitable not only for Li but also for Na+, Mg , and Zn insertion. However, the full theoretical capacity for Li insertion has not been demonstrated experimentally so far. In addition, improvement of cycling stability is desirable.

Scaling Up Electrodes for Photoelectrochemical Water Splitting: Fabrication Process and Performance of 40 cm LaTiO N Photoanodes.

A scalable process for fabrication of particle-based photoanodes is developed. The electrodes are versatilely made of photocatalytically active semiconductor particles, in this case LaTiO N, and optionally coated with cocatalysts and protecting components, all immobilized on a conducting substrate. The involved fabrication steps are restricted to scalable processes such as electrophoretic deposition, annealing in air, and dip coating.

Controlled Design of Functional Nano-Coatings: Reduction of Loss Mechanisms in Photoelectrochemical Water Splitting.

Efficient water splitting with photoelectrodes requires highly performing and stable photoactive materials. Since there is no material known which fulfills all these requirements because of various loss mechanisms, we present a strategy for efficiency enhancement of photoanodes via deposition of functional coatings in the nanometer range. Origins of performance losses in particle-based oxynitride photoanodes were identified and specifically designed coatings were deposited to address each loss mechanism individually.

Design Guidelines for High-Performance Particle-Based Photoanodes for Water Splitting: Lanthanum Titanium Oxynitride as a Model.

Semiconductor powders are perfectly suited for the scalable fabrication of particle-based photoelectrodes, which can be used to split water using the sun as a renewable energy source. This systematic study is focused on variation of the electrode design using LaTiO2 N as a model system. We present the influence of particle morphology on charge separation and transport properties combined with post-treatment procedures, such as necking and size-dependent co-catalyst loading.

Perovskite-related oxynitrides in photocatalysis.

Over the last decades photocatalytic water splitting has become of increasing importance for fundamental and applied research, since the direct conversion of sunlight into chemical energy via the production of H2 has the potential to contribute to the world's energy needs without CO2 generation. One of the unsolved challenges consists of finding a highly efficient photocatalyst that is cheap, environmentally friendly, contains exclusively abundant elements, is (photo)chemically stable and absorbs visible light. Photocatalytic efficiency is closely connected to both structural properties like crystallinity, particle size and surface area and to electronic properties like the band gap and the quantum efficiency.