MAXPEEM: a spectromicroscopy beamline at MAX IV laboratory

X-ray analysis of nanowires and nanowire devices: structure, function and synthesis

X-ray methods can offer unique insights into the structural and electronic properties of nanomaterials. Recent years have seen a dramatic improvement in both x-ray sources and x-ray optics, providing unprecedented resolution and sensitivity. These developments are particularly useful for nanowires, which are inherently small and give weak signals. This review gives an overview of how different x-ray methods have been used to analyze nanowires, showing the different types of insight that can be gained. The methods that are discussed include x-ray diffraction, x-ray fluorescence, x-ray photoelectron spectroscopy and x-ray photoelectron emission microscopy, as well as several others. The review is especially focused on high spatial resolution methods used at the single nanowire level, but it also covers ensemble experiments.

Diffusion Bonding 321-Grade Stainless Steel: Failure and Multimodal Characterization

Vacuum diffusion-bonded printed circuit heat exchangers are an attractive choice for the high-temperature, high-pressure demands of next-generation energy applications. However, early reports show that the high-temperature materials desired for these applications suffer from poor bond strengths due to precipitation at the bond line, preventing grain boundary migration. In this study, a diffusion bond of the high-temperature stainless steel grade 321H is investigated, and poor mechanical properties are found to be caused by Ti(C, N) precipitation at the bond line. Through in situ studies, it is found that Ti diffuses from the bulk to the mating surfaces at high temperatures. The Ti subsequently precipitates and, for the first time, an interaction between Ti(C, N) and Al/Mg-oxide precipitates at the bond line is observed, where Ti(C, N) nucleates on the oxides forming a core-shell structure. The results indicate that small amounts of particular alloying elements can greatly impact diffusion bond quality, prompting further research into the microstructural evolution that occurs during bonding conditions.

Activating two-dimensional semiconductors for photocatalysis: a cross-dimensional strategy

The emerging two-dimensional (2D) semiconductors substantially extend materials bases for versatile applications such as semiconductor photocatalysis demanding semiconductive matrices and large surface areas. The dimensionality, while endowing 2D semiconductors the unique properties to host photocatalytic functionality of pollutant removal and hydrogen evolution, hurdles the activation paths to form heterogenous photocatalysts where the photochemical processes are normally superior over these on the mono-compositional counterparts. In this perspective, we present a cross-dimensional strategy to employ thenD (n= 0-2) clusters or nanomaterials as activation partners to boost the photocatalytic activities of the 2D semiconductors. The formation principles of heterogenous photocatalysts are illustrated specifically for the 2D matrices, followed by selection criteria of them among the vast 2D database. The computer investigations are illustrated in the density functional theory route and machine learning benefitted from the vast samples in the 2D library. Synthetic realizations and characterizations of the 2D heterogenous systems are introduced with an emphasis on chemical methods and advanced techniques to understand materials and mechanistic studies. The perspective outlooks cross-dimensional activation strategies of the 2D materials for other applications such as CO2removal, and materials matrices in other dimensions which may inspire incoming research within these fields.

MAX IV Laboratory

MAX IV Laboratory is a Swedish national synchrotron radiation facility that comprises three accelerators with varying characteristics. One of the accelerators, the 3 GeV storage ring, is the world's first fourth-generation ring and pioneered the use of the multibend achromat lattice to provide access to ultrahigh brightness X-rays. MAX IV aims to stay at the forefront of the current and future research needs of its multidisciplinary user community, principally located in the Nordic and Baltic regions. Our 16 beamlines currently offer and continue to develop modern X-ray spectroscopy, scattering, diffraction, and imaging techniques to address scientific problems of importance to society.