Rational Design of Dynamic Interface Water Evolution on Turing Electrocatalyst toward the Industrial Hydrogen Production.

Manipulating the structural and kinetic dissociation processes of water at the catalyst-electrolyte interface is vital for alkaline hydrogen evolution reactions (HER) at industrial current density. This is seldom actualized due to the intricacies of the electrochemical reaction interface. Herein, this work introduces a rapid, nonequilibrium cooling technique for synthesizing ternary Turing catalysts with short-range ordered structures (denoted as FeNiRu/C). These advanced structures empower the FeNiRu/C to exhibit excellent HER performance in 1 m KOH with an ultralow overpotential of 6.5 and 166.2 mV at 10 and 1000 mA cm-2, respectively, and a specific activity 7.3 times higher than that of Pt/C. Comprehensive mechanistic analyses reveal that abundant atomic species form asymmetric atomic electric fields on the catalyst surface inducing a directed evolution and the dissociation process of interfacial H2O molecules. In addition, the locally topologized structure effectively mitigates the high hydrogen coverage of the active site induced by the high current density. The establishment of the relationship between free water population and HER activity provides a new paradigm for the design of industrially relevant high performance alkaline HER catalysts.

Constructing built-in electric field via ruthenium/cerium dioxide Mott-Schottky heterojunction for highly efficient electrocatalytic hydrogen production.

Ensuring the consumption rate of noble metals while guaranteeing satisfactory hydrogen evolution reaction (HER) performance at different pH values is imperative to the development of Ru-based catalysts. Herein, we design a Mott-Schottky electrocatalyst (Ru/CeO2) with a built-in electric field (BEF) based on density functional theory (DFT). The Ru/CeO2 achieves the criterion current density of 10 mA cm-2 at overpotentials of 55 mV, 80 mV, and 120 mV in alkaline, acidic and neutral media, respectively. Both theoretical calculations and experimental analysis confirm that the improved HER activity in the Ru/CeO2 catalyst could be due to the successful construction of BEF at the interface between the prepared Ru clusters and CeO2. Under the action of BEF, the electron-deficient Ru atoms can optimize the adsorption energy of H* and H2O and thus promote HER kinetics. Furthermore, the Ru/CeO2 catalyst delivers a power density of approximately 94.5 mW cm-2 in alkaline-acidic Zn-H2O cell applications while maintaining good H2 production stability. In this work, we optimize the electrocatalytic performance of the Ru/CeO2 catalyst through examination of the interfacial BEF electrical charge, which combines hydrogen production with power generation and provides a promising method for sustainable energy conversion.

Scanning the latent phases and superconductivity in the Nb-Pb system at high pressure.

So far, few literature studies have been reported on niobium-lead binary intermetallic compounds, which are expected to have very different properties compared to existing niobium-carbon binary compounds, due to the distinct electronic properties of lead when compared to other carbon-group elements. Herein, we carry out a global structure search for the Nb-Pb system based on the evolutionary algorithm and density functional theory. Based on the dynamical and mechanical stability analyses, we unveiled five new phases, P4/m-Nb9Pb, Cmcm-Nb3Pb, I4/mmm-Nb2Pb, Pmm2-Nb5Pb3, and I4/mmm-NbPb2, that are promising candidates for experimental synthesis. Moreover, the superconducting transitions of all Nb-Pb binary intermetallic compounds are performed with electron-phonon calculations. As Nb9Pb exhibited the maximum Tc in the Nb-Pb intermetallics, greater than 3.0 K at 20 GPa, the phonon band structures, partial phonon density of states (PHDOS), the corresponding Eliashberg spectral functions α2F(ω), and integral electron-phonon coupling (EPC) parameters λ as a function of frequency of Nb9Pb were also studied. This work filled the gap in the pressure-tuned Nb-Pb phase transitions from a systematic first principles study for the first time.

Nickel-decorated RuO2 nanocrystals with rich oxygen vacancies for high-efficiency overall water splitting.

Designing transition metal-oxide-based bifunctional electrocatalysts with excellent activity and stability for OER/HER to achieve efficient water splitting is of great importance for renewable energy technologies. Herein, a highly efficient bifunctional catalysts with oxygen-rich vacancies of nickel-decorated RuO2 (NiRuO2-x) prepared by a unique one-pot glucose-blowing approach were investigated. Remarkably, the NiRuO2-x catalysts exhibited excellent HER and OER activity at 10 mA cm-2 in alkaline solution with only a minimum overpotential of 51 mV and 245 mV, respectively. Furthermore, the NiRuO2-x overall water splitting exhibited an ultra-low voltage of 1.6 V to obtain 10 mA cm-2 and stability for more than 10 h. XPS measurement and theoretical calculations demonstrated that the introduction of Ni-dopant and oxygen vacancies make the d-band center to lie close to the Fermi energy level, the chemical bonds between the active site and the adsorbed oxygen intermediate state are enhanced, thereby lowering the reaction activation barriers of HER and OER. The assembly of solar-driven alkaline electrolyzers facilitate the application of the NiRuO2-x bifunctional catalysts.

Superconductivity and topologically nontrivial states in noncentrosymmetric XVSe2 (X = Pb, Sn): a first-principles study.

Noncentrosymmetric superconductors are strong candidates for exploring intrinsic topological superconductivity. Here, we predict two new noncentrosymmetric superconductors SnVSe2 and PbVSe2 by a systematic first-principles study. These two compounds show good thermal and dynamic stabilities. Moreover, the band topology of both compounds is predicted to be nontrivial via Z2 calculation and slab models. We also investigate the electron-phonon interactions in SnVSe2 and PbVSe2, indicating the Tc of SnVSe2 and PbVSe2 without external pressure are predicted to be ∼1.18 K and ∼0.22 K, respectively. Furthermore, the results on pressure engineering in PbVSe2 imply that the Tc of PbVSe2 can be tuned to 2.39 K for enhanced contributions from Pb layers under pressure up to 6.4 GPa. This work may provide new platforms for probing spin-triplet paring and may help with designing and developing new metal-intercalated transition metal dichalcogenides.

First-principles investigations on the anisotropic elasticity and thermodynamic properties of U3Si2-Al.

U3Si2 has been tested as a new type of nuclear fuel, and Al has been proven to improve its oxidation resistance. However, there is no research on its anisotropic mechanical and thermal properties. The mechanical and thermal properties of Al-alloyed U3Si2 nuclear fuel are calculated on the basis of first principles. Through the phonon dispersion curves, two kinetic stable structures sub-U3Si1.5Al0.5 and sub-U2.5Si2Al0.5(I) are screened out. It is found that the toughness of these two compounds after alloying are significantly improved compared to U3Si2. The three-dimensional Young's modulus shows that, the sub-U3Si1.5Al0.5 formed by Al alloying in U3Si2 maintains a higher mechanical isotropy, while sub-U2.5Si2Al0.5(I) shows higher mechanical anisotropy, which is consistent with the value of A u. The calculation result shows that the lattice thermal conductivity of sub-U3Si1.5Al0.5 and sub-U2.5Si2Al0.5(I) after alloying exhibits high isotropy as the temperature increases.