Earth-abundant electrocatalysts for the oxygen evolution reaction (OER) able to work in acidic working conditions are elusive. While many first-row transition metal oxides are competitive in alkaline media, most of them just dissolve or become inactive at high proton concentrations where hydrogen evolution is preferred. Only noble-metal catalysts, such as IrO₂, are fast and stable enough in acidic media. Herein, we report the excellent activity and long-term stability of Co₃O₄-based anodes in 1 M H₂SO₄ (pH 0.1) when processed in a partially hydrophobic carbon-based protecting matrix. These Co₃O₄@C composites reliably drive O₂ evolution a 10 mA cm^–2 current density for >40 h without appearance of performance fatigue, successfully passing benchmarking protocols without incorporating noble metals. Our strategy opens an alternative venue towards fast, energy efficient acid-media water oxidation electrodes.

SnSe has emerged as one of the most promising materials for thermoelectric energy conversion due to its extraordinary performance in its single-crystal form and its low-cost constituent elements. However, to achieve an economic impact, the polycrystalline counterpart needs to replicate the performance of the single crystal. Herein, we optimize the thermoelectric performance of polycrystalline SnSe produced by consolidating solution-processed and surface-engineered SnSe particles. In particular, the SnSe particles are coated with CdSe molecular complexes that crystallize during the sintering process, forming CdSe nanoparticles. The presence of CdSe nanoparticles inhibits SnSe grain growth during the consolidation step due to Zener pinning, yielding a material with a high density of grain boundaries. Moreover, the resulting SnSe–CdSe nanocomposites present a large number of defects at different length scales, which significantly reduce the thermal conductivity. The produced SnSe–CdSe nanocomposites exhibit thermoelectric figures of merit up to 2.2 at 786 K, which is among the highest reported for solution-processed SnSe.

Strong Metal‐Support Interaction (SMSI) is a key concept in heterogeneous catalysis, but it remains underexplored in the context of photon‐to‐hydrogen conversion, as coupling of metallic nanoparticles with photocatalysts is overlooked and only discussed in terms of Schottky barrier formation. In this study, we provide deep insights into the effect of Au encapsulation with TiO ₂ overlayer on enhancing photocatalytic hydrogen generation. Our findings reveal that the construction of a SMSI‐like nanostructure induces the formation of oxygen vacancies at the Au‒TiO ₂ interface which actively facilitate charge carrier separation through interfacial band reconstruction. The presence of defects is evidenced by Electron Paramagnetic Resonance and X‐ray Photoelectron Spectroscopy, unveiling their relationship with photocatalytic activities. Consistent with experimental results, Density Functional Theory (DFT) calculations demonstrate that Au promotes oxygen vacancy formation. These vacancies located at the TiO ₂ surface significantly enhances H ₂ O and MeOH adsorption during H ₂ evolution reactions. The SMSI‐like concept was extended to Pt, Pd, and Ag, in which the oxygen vacancy formation energy at the metal‐semiconductor interface varied depending on the metal, as computed by DFT. The results suggest that photocatalytic activity is related to the ease of oxygen vacancy formation, which is influenced by the nature of the metals.

Catalytic additives able to accelerate the lithium-sulfur redox reaction are a key component of sulfur cathodes in lithium-sulfur batteries (LSBs). Their design focuses on optimizing the charge distribution within the energy spectra, which involves refinement of the distribution and occupancy of the electronic density of states. Herein, beyond charge distribution, we explore the role of the electronic spin configuration on the polysulfide adsorption properties and catalytic activity of the additive. We showcase the importance of this electronic parameter by generating spin polarization through a defect engineering approach based on the introduction of Co vacancies on the surface of CoSe nanosheets. We show vacancies change the electron spin state distribution, increasing the number of unpaired electrons with aligned spins. This local electronic rearrangement enhances the polysulfide adsorption, reducing the activation energy of the Li-S redox reactions. As a result, more uniform nucleation and growth of Li₂S and an accelerated liquid-solid conversion in LSB cathodes are obtained. These translate into LSB cathodes exhibiting capacities up to 1089 mA h g^-1 at 1 C with 0.017% average capacity loss after 1500 cycles, and up to 5.2 mA h cm^-2, with 0.16% decay per cycle after 200 cycles in high sulfur loading cells.