Proton exchange membrane water electrolysers are very promising renewable energy conversion devices to produce hydrogen from sustainable feedstocks. These devices are mainly limited by the sluggish kinetics of the oxygen evolution reaction (OER). Therefore, efficient catalysts in acidic media that allow operating at low overpotential are necessary. Ir‐based nanoparticles are both active and stable for the OER. Surfactants are widely used in the preparation of nanoparticle colloids. A severe drawback for catalysis is the need to remove surfactants by typically costly, hazardous, time and/or energy consuming steps. Herein we present a modified approach of the polyol synthesis that consists of a simple surfactant‐free and NaOH‐free synthesis of Ir nanoparticles in ethylene glycol leading to colloidal nanoparticles of ca. 2.5 nm in diameter. The benefits and drawbacks of the surfactant‐free synthesis are illustrated by comparison with commercial Ir black nanoparticles and Ir nanoparticles obtained using surfactant for the electrocatalytic OER in acidic media.

Results from laboratory tests, conducted to study different aspects regarding the removal of humic substances by the environmentally friendly cationic biopolymer chitosan, are presented. Chitosan was shown to be an efficient remover of the high molecular weight humic substances, significantly reducing the colour and UV absorbance in typical humus-rich Norwegian surface waters with low particle content. By adding small amounts of Fe3+ together with a reduced dose of chitosan, it was possible to significantly improve the removal of the medium molecular weight humic substances. The highest charged (low Fa) chitosans were the most efficient coagulants, indicating that charge neutralisation was the triggering mechanism for the coagulation. Surface charge measurements of coagulated raw water gave strong indications in the same direction. However, net positive surface potentials of flocs after neutralisation indicated that excess chitosan participated in the build-up of flocs, suggesting that bridging or electrostatic patch flocculation could be important mechanisms during flocculation. However, the molecular weight of chitosan had no significant influence on the maximum removal of the humic substances.

Reinforcement of the polymer matrix in injection-molded plastics with fibers of various kinds can improve their mechanical properties. The resulting polymer composite material provides exceptional load-bearing capabilities with flexibility in the molding of complex-shaped components. Mechanical properties of short-fiber-reinforced polymers are highly dependent on the fiber orientation in the matrix. Lack of maturity of injection molding simulation frameworks limits prediction of the complex flow patterns during injection molding, while the requirement for resolving individual fibers in conventional imaging methods significantly restricts the imaged field-of-view. Here we demonstrate 3D characterization of the fiber orientation in a complete FRP component enabled by a novel technique of X-ray tensor tomography. The obtained fiber orientation reconstruction can be efficiently used in reverse engineering applications, serving as a reference for simulations.