Exploring effective, facile, and universal tuning strategies to optimize material physicochemical properties and catalysis processes is critical for many sustainable energy systems, but still challenging. Herein, we succeed to introduce tensile strain into various perovskites via a facile thermochemical reduction method, which can greatly improve material performance for the bottleneck oxygen-evolving reaction in water electrolysis. As an ideal proof-of-concept, such a chemical-induced tensile strain turns hydrophobic Ba5Co4.17Fe0.83O14- δ perovskite into the hydrophilic one by modulating its solid–liquid tension, contributing to its beneficial adsorption of important hydroxyl reactants as evidenced by fast operando spectroscopy. Both surface-sensitive and bulk-sensitive absorption spectra show that this strategy introduces oxygen vacancies into the saturated face-sharing Co-O motifs of Ba5Co4.17Fe0.83O14- δ and transforms such local structures into the unsaturated edge-sharing units with positive charges and enlarged electrochemical active areas, creating a molecular-level hydroxyl pool. Theoretical computations reveal that this strategy well reduces the thermodynamic energy barrier for hydroxyl adsorption, lowers the electronic work function, and optimizes the charge/electrostatic potential distribution to facilitate the electron transport between active sites and hydroxyl reactants. Also, this strategy is reliable for other single, double, and Ruddlesden–Popper perovskites. We believe that this finding will enlighten rational material design and in-depth understanding for many potential applications.

Silicon suboxide (SiO x ) has attracted widespread interest as Li-ion battery (LIB) anodes. However, its undesirable electronic conductivity and apparent volume effect during cycling impede its practical applications. Herein, sustainable rice husks (RHs)-derived SiO 2 are chosen as a feedstock to design SiO x /iron-nitrogen co-doped carbon (Fe-N-C) materials. Using a facile electrospray-carbonization strategy, SiO x nanoparticles (NPs) are encapsulated in the nitrogen-doped carbon (N-C) frameworks decorating atomically dispersed iron sites. Systematic characterizations including high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) and X-ray absorption fine structure (XAFS) verify the existence of Fe single atoms and typical coordination environment. Benefiting from its structural and compositional merits, the SiO x /Fe-N-C anode delivers significantly improved discharge capacity of 799.1 mAh g −1 , rate capability, and exceptional durability, compared with pure SiO 2 and SiO x /N-C, which has been revealed by the density functional theory (DFT) calculations. Additionally, the electrochemical tests and in situ X-ray diffraction (XRD) analysis reveal the oxidation of Li x Si phase and the storage mechanism. The synthetic strategy is universal for the design and synthesis of metal single atoms/clusters dispersed N-C frameworks encapsulated SiO x NPs. Meanwhile, this work provides impressive insights into developing various LIB anode materials suffering from inferior conductivity and huge volume fluctuations.

Producing indispensable hydrogen and oxygen for social development via water electrolysis shows more prospects than other technologies. Although electrocatalysts have been explored for centuries, a universal activity descriptor for both hydrogen‐evolving (HER) and oxygen‐evolving reactions (OER) has not been developed. Moreover, a unifying concept has not been established to simultaneously understand HER/OER mechanisms. Here, we rationally bridge the relationships between HER/OER activities in three common electrolytes and over 10 representative material properties on 12 3d‐metal‐based model oxides through statistical methodologies. Orbital charge‐transfer energy (Δ) can serve as an ideal universal descriptor, where a neither too large nor too small Δ (∼1 eV) with optimal electron‐cloud density around Fermi level affords the best activities, fulfilling Sabatier's principle. Systematic experiments and computations unravel that pristine oxide with Δ ≈ 1 eV possesses metal‐like high‐valence configurations and active lattice‐oxygen sites to help adsorb key protons in HER and induce lattice‐oxygen participation in OER, respectively. After reactions, partially generated metals in HER and high‐valence hydroxides in OER dominate proton adsorption and couple with pristine lattice‐oxygen activation, respectively. These can be successfully rationalized by the unifying orbital charge‐transfer theory. This work provides the foundation of rational material design and mechanism understanding for many potential applications.This article is protected by copyright. All rights reserved