The localization of hydrogen atoms is an essential part of crystal structure analysis, but it is difficult because of their small scattering power. We report the direct localization of hydrogen atoms in nanocrystalline materials, achieved using the recently developed approach of dynamical refinement of precession electron diffraction tomography data. We used this method to locate hydrogen atoms in both an organic (paracetamol) and an inorganic (framework cobalt aluminophosphate) material. The results demonstrate that the technique can reliably reveal fine structural details, including the positions of hydrogen atoms in single crystals with micro- to nanosized dimensions.

Electron diffraction tomography (EDT) data are in many ways similar to X-ray diffraction data. However, they also present certain specifics. One of the most noteworthy is the specific rocking curve observed for EDT data collected using the precession electron diffraction method. This double-peaked curve (dubbed 'the camel') may be described with an approximation based on a circular integral of a pseudo-Voigt function and used for intensity extraction by profile fitting. Another specific aspect of electron diffraction data is the high likelihood of errors in the estimation of the crystal orientation, which may arise from the inaccuracies of the goniometer reading, crystal deformations or crystal movement during the data collection. A method for the refinement of crystal orientation for each frame individually is proposed based on the least-squares optimization of simulated diffraction patterns. This method provides typical angular accuracy of the frame orientations of less than 0.05 . These features were implemented in the computer program PETS 2.0. The implementation of the complete data processing workflow in the program PETS and the incorporation of the features specific for electron diffraction data is also described. electron crystallography 514 L. Palatinus et al. Structure refinement from PED Acta Cryst. (2019). B75, 512-522 electron crystallography Acta Cryst. (2019). B75, 512-522 L. Palatinus et al. Structure refinement from PED 517 electron crystallography Acta Cryst. (2019). B75, 512-522 L. Palatinus et al. Structure refinement from PED 521

The recently published method for the structure refinement from threedimensional precession electron diffraction data using dynamical diffraction theory [Palatinus et al. (2015). Acta Cryst. A71, 235-244] has been applied to a set of experimental data sets from five different samples -Ni 2 Si, PrVO 3 , kaolinite, orthopyroxene and mayenite. The data were measured on different instruments and with variable precession angles. For each sample a reliable reference structure was available. A large series of tests revealed that the method provides structure models with an average error in atomic positions typically between 0.01 and 0.02 Å . The obtained structure models are significantly more accurate than models obtained by refinement using kinematical approximation for the calculation of model intensities. The method also allows a reliable determination of site occupancies and determination of absolute structure. Based on the extensive tests, an optimal set of the parameters for the method is proposed.

Nanocrystalline electrocatalytically active materials of chemical composition Ru 1-x Zn x O 2 (0< x < 0.3) were synthesized by freeze-drying technique. The diffraction patterns of the prepared samples corresponded to single-phase rutile type oxides. Local structure of the Ru 1-x Zn x O 2 based on refinement of Ru K and Zn K edge EXAFS functions shows clustering of the Zn ions in the blocks with ilmenite structure intergrowing with Ru-rich rutile blocks. Ru 1-x Zn x O 2 oxides are selective catalysts for anodic oxygen evolution. The selectivity toward oxygen evolution in the presence of chlorides is affected by the actual Zn content and can be ascribed to structural hindrance of the formation of the surface peroxo group based active sites for chlorine evolution. The selectivity toward oxygen evolution in presence of chlorides is accompanied by the drop of the total activity, which gets more pronounced with increasing Zn content.

This work is focused on synthesis, characterization, and determination of main parameters of the multilayer P123 templated TiO 2 films. The mesoporous multilayer thin films consist of TiO 2 nanoparticles on the F-doped SnO 2 (FTO) conductive glass substrates. The films were grown by implementing the protocol of supramolecular templating with the amphiphilic triblock copolymer, Pluronic P123. The templated multilayer films were manufactured by repeated dip coating followed by the thermal treatment at 350 °C for 2 h after deposition of each layer. It was found that the multilayer preparation technique at 350 °C has serious limitations. The structure does not further increase its specific surface area (roughness factor) after deposition of more than 3-5 layers. The new surface area added by deposition of the top layer is compensated by the reduction of the surface area lost due to the sintering of the bottom layers. The careful review of the analytical data suggests that the morphology of the P123 templated TiO 2 structure is likely the tightest arrangement of randomly positioned particles of a certain size on a given pore diameter. The bulk material consists of pores evenly formed in all directions while a denser crust is formed on the surface where the fusion was restricted in one direction at the interface with the air. Subsequent thermal treatments of the multilayer films were applied to improve the anatase crystallinity while keeping the open morphology and small particle size. The morphological changes of the mesoporous structure during the subsequent thermal treatment at 425-540 °C were investigated.

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Air-pollution-control (APC) residues are among the most toxic waste materials from secondary Pb metallurgy. Two distinct APC residues collected from bag-type filters of one Czech secondary Pb smelter were subjected to leaching experiments to determine the mineralogical and geochemical controls on leaching of metallic contaminants (Cd, Cu, Pb, Zn). A kinetic 720-h leaching test in deionized water at a liquid-to-solid (L/S) ratio of 10 L kg(-1) and a 48-h leaching test at various L/S ratios (0.5, 1, 5, 10, 50, 100, 500, and 1000 L kg(-1)) were performed and coupled with the mineralogical investigation of solid residues (TEM/EDS, XRD) and PHREEQC-2 speciation-solubility modeling. The rapid release of contaminants into the solution at all the L/S ratios showed the rapid dissolution of primary phases. The leaching at high L/S ratios, representing long-term predictions of leaching behavior, showed that primary alkaline sulfates and chlorides (Na3Pb2(S04)3Cl and KCl.2PbCl2) were dissolved and anglesite (PbSO4) was formed as their final and stable alteration product. Primary amorphous PbSO3 partly crystallized during leaching and oxidized to anglesite. These results are consistent with the mineralogical investigation of soils exposed for decades to Pb smelter emissions, where only anglesite was detected. The leaching experiments showed thatwashing residues at L/S >50 accompanied by spontaneous anglesite precipitation can be an alternative for improved technological treatment of these residues. Although this process would require further treatment of contaminated effluent, the newly precipitated anglesite is more favorable than the primary APC residue phases for an efficient metallurgical recovery of Pb.

TiO2(B) mesoporous thin films were grown in two steps on the F-doped SnO2 conductive glass substrates. In the first step, a small amount of H3PO4, corresponding to 0.15−0.375 wt % P on TiO2 basis, was introduced into concentrated HCl which was subsequently used for hydrolysis of titanium ethoxide. The hydrolyzed colloidal TiO2 suspension was further mixed with a 1-butanol solution of the amphiphilic triblock copolymer Pluronic P123. The obtained precursor mixture was used for dip coating of FTO substrates. To achieve over 1 μm thick films, dip coating (followed by a thermal treatment at 350 °C/2 h) was repeated several times to produce multilayer films. The films consisted of amorphous TiO2 with small amounts of anatase and TiO2(B). The amorphous part was converted into the TiO2(B) in a simple firing step at 500−550 °C. The formation of TiO2(B) phase was accompanied by a significant increase of the film thickness. The films demonstrated unique behavior during the electrochemical lithium insertion that would qualify them for fast battery or electrochromic smart window applications. The efficiency of multiphase TiO2 films in dye sensitized solar cells depends on the composition of individual films: it increases in the series: anatase/amorphous TiO2 < anatase/TiO2(B) < anatase.