Unveiling a Surface Electronic Descriptor for Fe–Co Mixing Enhanced the Stability and Efficiency of Perovskite Oxygen Evolution Electrocatalysts

The influence of cation mixing on the oxygen evolution reaction (OER) activity of a LaxSr1–xCoyFe1–yO3 (LSCF) double perovskite is investigated using density functional theory (DFT) calculations. The O 2p band center (E2p) has a good linear relation with the binding energy of the OER intermediate species when the chemical composition is varied by only the x or y value, but this relation is insufficient for describing the nonmonotonic behavior over the entire x and y ranges. Based on the projected density of states and wavefunction analysis, the minority spin dxy electrons of surface layer metal atoms are significant due to their stability, where the antibonding states between dxy and the lattice oxygen p become occupied when Co atoms with one d electron more than Fe are present. Thus, by additionally considering the dxy band center, a surface electronic descriptor (E2p – 0.4Edxy) excellently describes the binding energy of the OER intermediates and the stability against oxygen-vacancy formation, which also explains the enhanced OER stability and efficient Fe–Co mixing. Our study unveils the key mechanism of the excellent OER performance and high stability of previously reported LSCF materials as well as provides heterostructure engineering guidance for optimal surface electronic structures

Unveiling the Role of Charge Transfer in Enhanced Electrochemical Nitrogen Fixation at Single-Atom Catalysts on BX Sheets (X = As, P, Sb)

To tune single-atom catalysts (SACs) for effective nitrogen reduction reaction (NRR), we investigate various transition metals implanted on boron-arsenide (BAs), boron-phosphide (BP), and boron-antimony (BSb) using density functional theory (DFT). Interestingly, W-BAs shows high catalytic activity and excellent selectivity with an insignificant barrier of only 0.05 eV along the distal pathway and a surmountable kinetic barrier of 0.34 eV. The W-BSb and Mo-BSb exhibit high performances with limiting potentials of −0.19 and −0.34 V. The Bader-charge descriptor reveals that the charge transfers from substrate to *NNH in the first protonation step and from *NH3 to substrate in the last protonation step, circumventing a big hurdle in NRR by achieving negative free energy change of *NH2 to *NH3. Furthermore, machine learning (ML) descriptors are introduced to reduce computational cost. Our rational design meets the three critical prerequisites of chemisorbing N2 molecules, stabilizing *NNH, and destabilizing *NH2 adsorbates for high-efficiency NRR

Dual Interface Passivation in Mixed-Halide Perovskite Solar Cells by Bilateral Amine

Poor crystallization and nonradiative recombination at charge transfer interfaces are the main challenges in scaling up mixed-halide perovskite solar cells. If the theoretical open-circuit voltage (VOC) limit is to be achieved, surface defects at the perovskite surface and grain boundaries must be suppressed by passivation. However, it is unavoidable that the passivation material will strongly bind to the perovskite without disrupting the three-dimensional (3D) symmetry. When primary amines are introduced into perovskite precursors, they generate a quasi-2D/3D perovskite with poor photocurrent charge transport properties. To address these constraints, we show that secondary amine (N,N′-dimethyl-1,3-propanediammonium dichloride) can stabilize the bulk phase of perovskite materials, passivating both surfaces and improving the charge carrier lifetime. In particular, a record-high VOC of 1.27 V is achieved at an optimal band gap of 1.63 eV. Our findings will help to guide future efforts to improve the performance and stability of perovskite solar cells

Rates of acute kidney injury by baseline (A) serum creatinine value and (B) creatinine clearance.

<p>Note (A). Rates of acute kidney injury were significantly higher for patients with a baseline serum creatinine value ≥1.01 mg/dL compared to ≤0.6 mg/dL at 48 hours (<i>P</i> = 0.01) and 7 days (<i>P</i> = 0.01).</p

Factors associated with colistin-induced Acute Kidney Injury (AKI).

<p>Factors associated with colistin-induced Acute Kidney Injury (AKI).</p