Manuel Arturo López Quintela

The increasing occurrence of bisphenol A (BPA) in water sources raises significant environmental and health concerns, demanding efficient and sustainable remediation strategies. In this work, we investigate the photocatalytic degradation of BPA using silver metal clusters (Ag5) supported on anatase TiO2 under simulated solar irradiation. The deposition of Ag5 clusters significantly enhances visible-light absorption, promotes charge separation and improves photocatalytic performance, achieving an apparent rate constant (kobs) of 0.0142 min-1, corresponding to a ~43% improvement compared to bare TiO2. In addition, the Ag5@TiO2 catalyst exhibits higher photocatalytic activity, demonstrating the beneficial effect of Ag5 clusters incorporation. HPLC-MS analysis enabled the identification of intermediate degradation products. Compared to literature reports on modified TiO2-based photocatalysts, the present system demonstrates competitive performance even at significantly lower catalyst loadings. These results highlight the potential of Ag5@TiO2 photocatalysts as highly efficient alternatives for removing endocrine-disrupting compounds from water.

In this study, we report the development of an efficient electrochemical synthesis route for Cu clusters that significantly reduces the formation of deleterious Cu ions during preparation. This breakthrough enabled the controlled production of five‐atom copper clusters (Cu ₅ ), which, when supported on TiO ₂ , exhibit superior catalytic activity compared to previously reported Cu‐based catalysts. Notably, Cu ₅ /TiO ₂ achieves 100% selectivity toward CH ₄ at temperatures as low as 300 °C, with a remarkably low activation energy of 19 kJ·mol ⁻¹ . Operando X‐ray absorption spectroscopy revealed that the reduction in the copper oxidation state during the reaction is due to reversible interactions with hydrogen molecules and CO ₂ in a 4:1 ratio. These results are consistent with DFT calculations of the intrinsic activity of the Cu ₅ cluster, which indicate that CO ₂ methanation may proceed through both methoxide‐ and methylene‐mediated pathways. However, the methoxide route is predicted to be significantly more stable and energetically more favorable than the methylene route, suggesting a mechanistic preference for methoxide‐mediated CH ₄ formation. These insights account for the outstanding catalytic performance of Cu ₅ /TiO ₂ and, combined with the high thermal stability previously reported for Cu ₅ clusters, highlight their great potential as efficient catalysts for industrial CO ₂ ‐to‐CH ₄ conversion.

Looping process to generate with thermal energy & sun light V_O in CeO₂ (or Ce_0.5Zr_0.5O₄), and O₂ in vacuum/inert gas or H₂O from H₂ or CO from CH₄ in the first step, and 100% pure H₂ in the second step from water.

Phonons, the collective excitations responsible for heat transport in crystalline insulating solids, lack electric charge or magnetic moment, which complicates their active control via external fields. This presents a significant challenge in designing thermal equivalents of basic electronic circuit elements, such as transistors or diodes. Achieving these goals requires precise and reversible modification of thermal conductivity in materials. In this work, the continuous tuning of local thermal conductivity in charge‐transfer SrFeO_3‐x and La_0.6Sr_0.4CoO_3‐x oxides using a voltage‐biased Atomic Force Microscopy (AFM) tip at room temperature is demonstrated. This method allows the creation of micron‐sized domains with well‐defined thermal conductivity, achieving reductions of up to 50%, measured by spatially resolved Frequency Domain Thermoreflectance (FDTR). By optimizing the oxide's chemical composition, the thermal states remain stable under normal atmospheric conditions but can be reverted to their original values through thermal annealing in air. A comparison between Mott–Hubbard and charge‐transfer oxides reveals the critical role of redox‐active lattice oxygen in ensuring full reversibility of the process. This approach marks a significant step toward fabricating oxide‐based tunable microthermal resistances and other elements for thermal circuits.

The presence of silicate ions, an inevitable consequence of the current metal cluster purification process, does not hamper the photo absorption ability of the Cu ₅ -modified TiO ₂ support but might even enhance it.

Sub‐nanometer metal clusters have special physical and chemical properties, significantly different from those of nanoparticles. However, there is a major concern about their thermal stability and susceptibility to oxidation. In situ X‐ray Absorption spectroscopy and Near Ambient Pressure X‐ray Photoelectron spectroscopy results reveal that supported Cu₅ clusters are resistant to irreversible oxidation at least up to 773 K, even in the presence of 0.15 mbar of oxygen. These experimental findings can be formally described by a theoretical model which combines dispersion‐corrected DFT and first principles thermochemistry revealing that most of the adsorbed O₂ molecules are transformed into superoxo and peroxo species by an interplay of collective charge transfer within the network of Cu atoms and large amplitude “breathing” motions. A chemical phase diagram for Cu oxidation states of the Cu₅‐oxygen system is presented, clearly different from the already known bulk and nano‐structured chemistry of Cu.

This themed collection includes a collection of articles on stability and properties of new-generation metal and metal-oxide clusters down to subnanometer scale.

We report an easily scalable synthesis method for the preparation of cysteine-capped Cu_≈10 clusters through the reduction of Cu(ii) ions with NaBH₄, using Cu₅ clusters as catalysts.