The Ti-based metal−organic framework (MOF) MIL-125-NH 2 is one of the promising materials for solar water splitting because it contains a sensitizer and a catalytic center in a single structure. MIL-125-NH 2 as many other MOFs has a microporous structure with pore diameters less than 2 nm. Compared with common MOFs, hierarchical mesoporous materials exhibit very large specific surface areas that facilitate diffusion of active species, accelerate subsequent surface reactions, and increase the bubble release rate by providing larger free spaces. Thus, the development of a facile method to create hierarchical porous MOFs with larger pore sizes remains a chemical challenge. Furthermore, MOF-type semiconducting materials usually have low activities in oxygen evolution reaction, and the presence of a suitable cocatalyst is needed to reduce the large O 2 overpotential. This study attempted to generate a hierarchical MIL-125-NH 2 MOF material with embedded RuO 2 nanoparticles as a highly efficient cocatalyst in a simple one-step process for use in efficient solar water oxidation. Different amounts of RuCl 3 •H 2 O precursor salt were used simultaneously for creating hierarchical porosity in MIL-125-NH 2 and for producing the assumed RuO 2 cocatalyst. For comparison, a hydrochloric acid treatment was applied to generate hierarchical porosity in the MOF in the absence of ruthenium. The samples were characterized using high-resolution transmission electron microscopy (HRTEM), Brunauer−Emmett−Teller adsorption, powder X-ray diffraction, field emission scanning electron microscopy, and X-ray photoelectron spectroscopy. HRTEM gave evidence that in the ruthenium oxidecontaining MIL-125-NH 2 samples, tetragonal RuO 2 nanoparticles are present. The materials were applied as photoelectrodes, and photoelectrochemical (PEC) water oxidation performance under visible light illumination was studied. The PEC water oxidation performance of the MIL-125-NH 2 layer could be strikingly improved with a photocurrent density of about 10 times more than that of the pure MOF at 1.23 V versus reversible hydrogen electrode in artificial seawater, as a result of the hierarchical MOF structure and the presence of RuO 2 as a cocatalyst. Furthermore, density functional theory calculations were performed to shed light on the electronic properties and the role of the RuO 2 in the assumed hole transport.

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The optical properties of pure γ-Al2O3 and in the presence of oxygen point defects are investigated by the density functional theory approach using the PBE-GGA and TB-mBJ-GGA schemes.

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We investigate temperature, pressure, and localization dependence of thermoelectric properties, phonon and de Haas–van Alphen (dHvA) frequencies of the anti-ferromagnetic (AFM) CeIn$$_3$$ 3 using density functional theory (DFT) and local, hybrid, and band correlated functionals. It is found that the maximum values of thermopower, power factor, and electronic figure of merit of this compound occur at low (high) temperatures provided that the 4f-Ce electrons are (not) localized enough. The maximum values of the thermopower, power factor, electronic figure of merit (conductivity parameters), and their related doping levels (do not) considerably depend on the localization degree and pressure. The effects of pressure on these parameters substantially depend on the degree of localization. The phonon frequencies are calculated to be real which shows that the crystal is dynamically stable. From the phonon band structure, the thermal conductivity is predicted to be homogeneous. This prediction is found consistent with the thermal conductivity components calculated along three Cartesian directions. In analogous to the thermoelectric properties, it is found that the dHvA frequencies also depend on both pressure and localization degree. To ensure that the phase transition at Néel temperature cannot remarkably affect the results, we verify the density of states (DOS) of the compound at the paramagnetic phase constructing a non-collinear magnetic structure where the angles of the spins are determined so that the resultant magnetic moment vanishes. The non-collinear results reveal that the DOS and whence the thermoelectric properties of the compound are not changed considerably by the phase transition. To validate the accuracy of the results, the total and partial DOSs are recalculated using DFT plus dynamical mean-field theory (DFT+DMFT). The DFT+DMFT DOSs, in agreement with the hybrid DOSs, predict the Kondo effect in this compound.