obstacles: the slow kinetics, the short operation lifespan of electrodes, and the high price of noble-metal catalysts. [2] Thus, developing low-cost, high-efficiency and robust electrocatalysts for overall water splitting is exceptionally urgent. [3] At present, transition metal compounds (TMCs), with earth-abundant nature, versatile redox valence, and unsaturated transition metal sites, have been widely investigated for overall water splitting. However, the intrinsically poor activity and unsatisfied stability greatly hinder their practical applications. [4] Tuning electronic structure is regarded to be an efficient strategy to enhance the activity of electrocatalysts. Strain engineering is one of the promising routes to manipulate the electronic structure by modifying the distances of atoms and in turn favoring the catalytic activity improvement. [5] Previous studies have suggested that by introducing only 1% strain, the d band center can be shifted by ≈0.1 eV, leading to the enhanced binding strengthen between catalytically active sites and surface adsorbates. [5a,6] At present, lattice mismatch, substrate induced and heteroatom substitution are three common strategies for introducing lattice strain. [7] Lattice Developing highly efficient non-noble-metal electrocatalysts for water splitting is crucial for the development of clean and reversible hydrogen energy. Introducing lattice strain is an effective strategy to develop efficient electrocatalysts. However, lattice strain is typically co-created with heterostructure, vacancy, or substrate effects, which complicate the identification of the strainactivity correlation. Herein, a series of lattice-strained homogeneous NiS x Se 1−x nanosheets@nanorods hybrids are designed and synthesized by a facile strategy. The NiS 0.5 Se 0.5 with ≈2.7% lattice strain exhibits outstanding activity for hydrogen and oxygen evolution reaction (HER/OER), affording low overpotentials of 70 and 257 mV at 10 mA cm −2 , respectively, as well as excellent long-term durability even at a large current density of 100 mA cm −2 (300 h), significantly superior to other benchmarks and precious-metal catalysts. Experimental and theoretical calculation results reveal that the generated lattice strain decreases the metal d-orbital overlap, leading to a narrower bandwidth and a closer d-band center toward the Fermi level. Thus, NiS 0.5 Se 0.5 possesses favorable H* adsorption kinetics for HER and lower energy barriers for OER. This work provides a new insight to regulate the lattice strain of advanced catalyst materials and further improve the performance of energy conversion technologies.

Through systematic molecular dynamics simulations we theoretically investigate the potential applications of hexagonal boron nitride (h-BN) for seawater desalination. Our results indicate that the rationally designed h-BN membranes have great permeability, selectivity, and controllability for water desalination. The size and chemistry of the pores are shown to play an important role in regulating the water flux and salt rejection. Pores with only nitrogen atoms on the edges have higher fluxes than the boron-lined pores. In particular, two-dimensional h-BN with medium-sized N4 pores show 100% salt rejection with outstanding water permeability, which is several orders of magnitude higher than that of conventional reverse osmosis membranes. Furthermore, we study the mechanical strain effect on the desalination performance of monolayer h-BN with relatively small N3 pores, suggesting that water flux and salt rejection can be precisely tuned by tensile strain. The findings in the present work unambiguously propose that porous boron nitride nanosheets are quite promising as new functional membranes for water desalination.

The loss of sulfur in the cathode of a lithium sulfur battery (LSB) severely hinders the practical application of LSBs, and so do the insulativity of S and its lithiation end products. The incorporation of MXene can significantly improve the performance of LSBs; however, the underlying mechanism at the atomic scale has not been deeply explored. In the present work, by using density functional theory calculations, we systemically studied the interactions of lithium (poly)­sulfides (Li2S m ) on Ti-based bare MXenes (Ti n X n–1) and surface functionalized Ti2C with −F, −O, and −OH groups. Through analyzing the geometric and electronic structures, binding energies, and deformation charge densities of Li2S m adsorbed MXenes, we found that the strong Ti–S bonds dominate the interactions between Li2S m and MXenes. The strong Coulombic interactions help cathodes to confine S from dissolution. Besides, the conductivities of MXenes and Li2S m @MXenes are beneficial for the overall performance of the LSB. These will provide in-depth theoretical guidance support for the utilization of MXene in LSBs.

The facile hydrothermal synthesis of Zn10In16S34 atomically thin nanosheet arrays on fluorine‐doped tin oxide glass (FTO) substrates is presented. Through controlling heat treatment in air, O‐doping and Zn, S vacancies were simultaneously introduced in Zn10In16S34 nanosheets with adjusted phase, morphology, chemical compositions, and energy level distribution. The surface defect states are passivated by depositing ultrathin Al2O3 film by atomic layer deposition technology. The performance of Zn10In16S34 photoanodes is largely improved, with 4.7 times higher current density and reduced onset potential. The experimental results and density functional theory calculations indicate that the enhancement is attributed to the fast photoexcited electron–hole pair separation, decreased surface transfer impedance, prolonged carrier lifetime, and reduced overpotential of oxygen evolution reaction.

difficult to obtain the catalysts without defects. [4] Some studies have demonstrated that the catalysts with defects on the surface possess higher activity than the defect-free ones. [4,[14][15][16] For instance, it has been proved that the activity of the edge carbon is higher than basal plane carbon for the ORR. [17] Meanwhile, S-vacancies in the basal plane of MoS 2 provide more exposed Mo atoms to directly bind with hydrogen. [18] The catalysts with controllable defects have great potential for high activity and the commercialization of the noble metal catalysts.Fuel cells are high-efficiency energyconversion devices. [19][20][21][22][23] The best currently known electrocatalysts for ORR and liquid fuels-oxidation reaction are the Ptbased catalysts, which suffers from high cost, undesirable durability, and low CO poisoning tolerance problems. [23] Recently, Pd-based catalysts have been demonstrated to be promising effective catalysts because of their outstanding activities for ORR and electrochemical oxidation of small organic molecules, which show potential alternatives for the Pt-based catalysts. [13,[24][25][26] Previous studies show appreciable enhancement of the activity of the catalysts in water splitting and fuel cells by alloying Pd with the transition metals, exposing the lowcoordinated surface atoms, and altering the distances between surface atoms to control the defect or strain of catalysts. [13,[26][27][28] A range of transition metals, including Fe, Co, and Ni, have been intensively explored into PdCu active bimetallic system by simultaneously decreasing material cost and enhancing Structure-engineered Pd-based catalysts at the atomic level can effectively improve the catalytic performance for oxygen or small organic molecules electrocatalysis, comparable to or even superior to that of commercial Pt/C. Here, PdCuCo anisotropic structure (AS) electrocatalysts are synthesized with abundant vacancy defects on the exterior surface, which is unambiguously verified by aberration-corrected transmission electron microscopy. The PdCuCo-AS with vacancy (v-PdCuCo-AS) shows excellent electrochemical activity toward oxygen reduction (ORR) and oxidation of alcohols. The mass activity of the v-PdCuCo-AS is 0.18 A mg −1 at 0.9 V versus reversible hydrogen electrode (RHE), which is 15.55 times larger than that of the commercial Pd/C catalyst in acidic electrolyte. According to the theoretical calculations, this significant improvement can be understood as a result of the promoted charge transfer by polarized electronic structures of the v-PdCuCo-AS in the processes of ORR. The synergistic effect of the correlated defects and the compressive strain caused by the doping Co and Cu atoms effectively improve the electrocatalysis activity for the ORR in acidic/alkaline electrolyte on the v-PdCuCo-AS stems. This approach provides a strategy to design other AS structures for improving their electrochemical performance. Electrocatalysis