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In this manuscript, a comprehensive study is presented on Fe-based electrocatalysts with mono, bi, and tri-metallic compositions, emphasizing the influence of processing-structure correlations on the electrocatalytic activity for the oxygen reduction reaction (ORR) in the alkaline medium. These electrocatalysts were synthesized through the mixing of transition metal phthalocyanines (TM-Pc) with conductive carbon support, followed by controlled thermal treatment at specific temperatures (600 °C and 900 °C). An extensive analysis was conducted, employing various techniques, including X-ray Absorption Spectroscopy (XAS), Transmission Electron Microscopy (TEM), and X-ray Diffraction (XRD), providing valuable insights into the structural characteristics of the synthesized nanoparticles. Importantly, an increase in the Fe-Pc weight percentage from 10% to 30% enhanced the ORR activity, although not proportionally. Furthermore, a comparative analysis between mono, bi, and tri-metallic samples subjected to different functionalization temperatures highlighted the superior electrocatalytic activity of electrocatalysts functionalized at 600 °C, particularly Fe 600 and Fe-Ni-Cu 600. These electrocatalysts featured Eon values of 0.96 V vs. RHE and E1/2 values of 0.9 V vs. RHE, with the added benefit of reduced anionic peroxide production. The potential of these Fe-based electrocatalysts to enhance ORR efficiency is underscored by this research, contributing to the development of more effective and sustainable electrocatalysts for energy conversion technologies.

Ta3N5 shows great potential as a semiconductor photoanode for solar water splitting. However, its performance is hindered by poor charge carrier transport and trapping due to a high density of defects that introduce electronic states deep within its bandgap. Here, we demonstrate that controlled Ti doping of Ta3N5 can dramatically reduce the concentration of deep-level defects and enhance its photoelectrochemical performance, yielding a sevenfold increase in photocurrent density and a 300 mV cathodic shift in photocurrent onset potential compared to undoped material. Comprehensive characterization reveals that Ti+4 ions substitute Ta+5 lattice sites, thereby introducing compensating acceptor states, reducing concentrations of nitrogen vacancies and reduced Ta+3 states, and thereby suppressing trapping and recombination. Importantly, Ti doping offers distinct advantages compared to Zr, an intensively investigated dopant of Ta3N5 in the same group of the periodic table. Specifically, Ti+4 and Ta+5 have more similar atomic radii, allowing for substitution without introducing lattice strain, and Ti exhibits a lower affinity for oxygen than Zr, enabling its incorporation without increasing the oxygen donor content. Consequently, we demonstrate that the electrical conductivity can be tuned by over seven orders of magnitude. Thus, Ti doping in Ta3N5 provides a powerful basis for precisely engineering the optoelectronic characteristics of Ta3N5 and to substantially improve its functional characteristics as an advanced photoelectrode for solar fuels applications.

We present a parton-level study of electro-weak production of vector-boson pairs at the Large Hadron Collider, establishing the sensitivity to a set of dimension-six operators in the Standard Model Effective Field Theory (SMEFT). Different final states are statistically combined, and we discuss how the orthogonality and interdependence of different analyses must be considered to obtain the most stringent constraints. The main novelties of our study are the inclusion of SMEFT effects in non-resonant diagrams and in irreducible QCD backgrounds, and an exhaustive template analysis of optimal observables for each operator and process considered. We also assess for the first time the sensitivity of vector-boson-scattering searches in semileptonic final states.

In this work, platinum group metal-free (PGM-free) electrocatalysts were synthesized, characterized, and tested for hydrogen evolution reaction (HER). These materials were mono-, bi- and trimetallic Ni-based electrocatalysts with the addition of a second or a third transition metal (TM), such as iron and cobalt. TM–phthalocyanine (TMPc) was used as a metal precursor, mixed with a conductive carbon backbone and subjected to pyrolysis under controlled temperature and atmosphere conditions. Two temperatures of pyrolysis (600 °C and 900 °C) were used. The effect of TM loading in the precursors, different pyrolysis temperatures on the surface chemistry and morphology, and electrocatalytic activity towards HER were evaluated. The increase of NiPc in the initial mixture is beneficial to improving the electrocatalytic activity. The addition of a second and a third metal reflects positively on the HER performance. Interestingly, the pyrolysis temperature influences both the formation and growth of the nanoparticles, and this information is supported by high-resolution transmission electron microscopy (HR-TEM) and light synchrotron X-ray absorption spectroscopy (XAS) measurements.

The functional characteristics of double perovskites with a unique ferromagnetic-insulator ground state have been controversial due to the unavoidable presence of antisite disorders (ASDs). Here, we aim to investigate the origin of magnetic ordering on local and global scales in the Sm2NiMnO6 (SNMO) double perovskite system. Different calcination routes are exploited to generate different cation arrangements in SNMO and the corresponding magnetic configurations are examined using the high-energy (E ??? 0.3 eV) ???hot neutrons???, which has helped to overcome Sm absorption as well as to record total (Bragg + diffuse) scattering profiles with high momentum transfer (Qmax ??? 24 ?????1). We have observed that the Ni-Mn sublattice adopts long-range collinear ferromagnetic FxFz structure with a commensurate k = (0, 0, 0) propagation vector, below ordering temperature T < 160 K, irrespective of variable ASD concentrations. In addition, the signatures indicating the antiparallel polarization of Sm paramagnetic moments with respect to the Ni-Mn network are noticed in the vicinity of anomalous magnetic transitions at T < 35 K. The real-space pair distribution function calculations have provided a direct visualization of ASDs by means of broadening in Ni/Mn-Mn/Ni linkage. Employing the reverse Monte Carlo approach on diffuse magnetic scattering profiles, we have observed the negative spin-spin correlation function which suggests the Ni-Ni antiferromagnetic exchange interactions ranging up to first-nearest-neighbor distance. These results confirm that the existence of ASDs in a cation ordered host matrix leads to competing ferromagnetic-antiferromagnetic phases in a broad temperature range, which quantitatively governs the temperature-dependent bulk magnetic observables of the SNMO system.

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