Tailoring Antibonding-Orbital Occupancy State of Selenium in Se-Enriched ReSe2+x Cocatalyst for Exceptional H2 Evolution of TiO2 Photocatalyst

Electron density regulation of active sites can realize an optimal hydrogen-binding strength, whereas the underlying regulation mechanism is still indistinct. Herein, a new concept of antibonding-orbital occupancy state is first proposed to unveil the fundamental influence mechanism of electron density on the Se H_ads bond strength for achieving first-rank adsorption energy toward atomic hydrogen by constructing Se-enriched surrounding to form electron-deficient Se^(2-δ)- active sites in ReSe_2+x nanodots. To this end, the Se-rich ReSe_2+x nanodots (0.3–1 nm) can be dexterously fabricated onto the TiO₂ to prepare Se-rich ReSe_2+x/TiO₂ by an ingenious one-step photosynthesis route. In a surprise, a large number of visual H₂ bubbles are continuously produced on the resultant ReSe_2+x/TiO₂(0.7 wt.%) with an ultrahigh rate of 12 490.4 µmol h⁻¹ g⁻¹ and an apparent quantum efficiency of 60.0%, which is 5.0 times higher than that of traditional ReSe₂/TiO₂, even comparable with benchmark Pt/TiO₂(0.7 wt.%). In situ/ex situ XPS characterizations coupled with density functional theory (DFT) calculations corroborate that a Se-enriched environment can induce the formation of electron-deficient Se^(2-δ)− and then reduce its antibonding-orbital occupancy state, thus increasing the stability of H 1s-p antibonding and accordingly reinforcing the Se H_ads bonds. This holistic study identifies the dominant role of antibonding-orbital occupancy states in the optimization of hydrogen-binding energy.     

Electron Transfer-Induced Metal Spin-Crossover at NiCo2S4/ReS2 2D–2D Interfaces for Promoting pH-universal Hydrogen Evolution Reaction

The development of an efficient pH-universal hydrogen evolution reaction (HER) electrocatalyst is essential for practical hydrogen production. Here, an efficient and stable pH-universal HER electrocatalyst composed of the strongly coupled 2D NiCo₂S₄ and 2D ReS₂ nanosheets (NiCo₂S₄/ReS₂) is demonstrated. The NiCo₂S₄/ReS₂ 2D–2D nanocomposite is directly grown on the surface of the carbon cloth substrate, which exhibits excellent HER performance with overpotentials of 85 and 126 mV at a current density of 10 mA cm⁻² and Tafel slopes of 78.3 and 67.8 mV dec⁻¹ under both alkaline and acidic conditions, respectively. Theoretical and experimental characterizations reveal that the chemical coupling between NiCo₂S₄ and ReS₂ layers induces electron transfer from Ni and Co to interfacial Re-neighbored S atoms, enabling beneficial H atom adsorption and desorption for both acidic and alkaline HER. Simultaneously, an electron transfer-induced spin-crossover generates high-spin interfacial Ni and Co atoms that promote water dissociation kinetics at the NiCo₂S₄/ReS₂ interface, which is the origin of the superior alkaline HER activity. NiCo₂S₄/ReS₂ also shows decent catalytic activity and long-term durability for oxygen evolution reaction, and finally bifunctionality for overall water splitting. This study suggests a rational strategy to enhance water dissociation kinetics by inducing spin-crossover via electron transfer.     

A Cocatalytic Electron‐Transfer Cascade Site‐Selectively Placed on TiO2 Nanotubes Yields Enhanced Photocatalytic H2 Evolution

Separation and transfer of photogenerated charge carriers are key elements in designing photocatalysts. TiO₂ in numerous geometries has been for many years the most studied photocatalyst. To overcome kinetic limitations and achieve swift charge transfer, TiO₂ has been widely investigated with cocatalysts that are commonly randomly placed nanoparticles on a TiO₂ surface. The poor control over cocatalyst placement in powder technology approaches can drastically hamper the photocatalytic efficiencies. Here in contrast it is shown that the site‐selective placement of suitable charge‐separation and charge‐transfer cocatalysts on a defined TiO₂ nanotube morphology can provide an enhancement of the photocatalytic reactivity. A TiO₂–WO₃–Au electron‐transfer cascade photocatalyst is designed with nanoscale precision for H₂ production on TiO₂ nanotube arrays. Key aspects in the construction are the placement of the WO₃/Au element at the nanotube top by site‐selective deposition and self‐ordered thermal dewetting of Au. In the ideal configuration, WO₃ acts as a buffer layer for TiO₂ conduction band electrons, allowing for their efficient transfer to the Au nanoparticles and then to a suitable environment for H₂ generation, while TiO₂ holes due to intrinsic upward band bending in the nanotube walls and short diffusion length undergo a facilitated transfer to the electrolyte where oxidation of hole‐scavenger molecules takes place. These photocatalytic structures can achieve H₂ generation rates significantly higher than any individual cocatalyst–TiO₂ combination, including a classic noble metal–TiO₂ configuration.     

Ni1−xCoxSe2?C/ZnIn2S4 Hybrid Nanocages with Strong 2D/2D Hetero-Interface Interaction Enable Efficient H2-Releasing Photocatalysis

Designing a semiconductor-based heterostructure photocatalyst for achieving the efficient separation of photogenerated electron-hole pairs is highly important for enhancing H₂ releasing photocatalysis. Here, a new class of Ni_1−xCo_xSe₂–C/ZnIn₂S₄ hierarchical nanocages with abundant and compact ZnIn₂S₄ nanosheets/Ni_1−xCo_xSe₂^ C nanosheets 2D/2D hetero–interfaces, is designed and synthesized. The constructed heterostructure photocatalyst exposes rich hetero-junctions, supplying the broad and short transfer paths for charge carriers. The close contacts of these two kinds of nanosheets induce a strong interaction between ZnIn₂S₄ and Ni_1−xCo_xSe₂ C, improving the separation and transfer of photo-generated electron-hole pairs. As a consequence, the distinctive Ni_1−xCo_xSe₂ C/ZnIn₂S₄ hierarchical nanocages without using additional noble-metal cocatalysts, display remarkable H₂-relaesing photocatalytic activity with a rate of 5.10 mmol g⁻¹ h⁻¹ under visible light irradiation, which is 6.2 and 30 times higher than those of fresh ZnIn₂S₄ nanosheets and bare Ni_1−xCo_xSe₂ C nanocages, respectively. Spectroscopic characterizations and theory calculations reveal that the strong interaction between ZnIn₂S₄ and Ni_1−xCo_xSe₂ C 2D/2D hetero-interfaces can powerfully promote the separation of photo-generated charge carriers and the electrons transfer from ZnIn₂S₄ to Ni_1−xCo_xSe₂ C.     

An In Situ Simultaneous Reduction‐Hydrolysis Technique for Fabrication of TiO2‐Graphene 2D Sandwich‐Like Hybrid Nanosheets: Graphene‐Promoted Selectivity of Photocatalytic‐Driven Hydrogenation and Coupling of CO2 into Methane and Ethane

A novel, in situ simultaneous reduction‐hydrolysis technique (SRH) is developed for fabrication of TiO₂‐‐graphene hybrid nanosheets in a binary ethylenediamine (En)/H₂O solvent. The SRH technique is based on the mechanism of the simultaneous reduction of graphene oxide (GO) into graphene by En and the formation of TiO₂ nanoparticles through hydrolysis of titanium (IV) (ammonium lactato) dihydroxybis, subsequently in situ loading onto graphene through chemical bonds (Ti–O–C bond) to form 2D sandwich‐like nanostructure. The dispersion of TiO₂ hinders the collapse and restacking of exfoliated sheets of graphene during reduction process. In contrast with prevenient G‐TiO₂ nanocomposites, abundant Ti³⁺ is detected on the surface of TiO₂ of the present hybrid, caused by reducing agent En. The Ti³⁺ sites on the surface can serve as sites for trapping photogenerated electrons to prevent recombination of electron–hole pairs. The high photocatalytic activity of G‐TiO₂ hybrid is confirmed by photocatalytic conversion of CO₂ to valuable hydrocarbons (CH₄ and C₂H₆) in the presence of water vapor. The synergistic effect of the surface‐Ti³⁺ sites and graphene favors the generation of C₂H₆, and the yield of the C₂H₆ increases with the content of incorporated graphene. The work may open a new doorway for new significant application of graphene for selectively catalytic C–C coupling reaction     

Defective S-TiO2−x/CeO2 Heterojunction for Mutual Reinforcing Chemodynamic/Sonocatalytic Antibacterial Therapy and Sonoelectric/Ion-Activated Bone Regeneration

Sonocatalysis and chemodynamics have attracted widespread attention in antibacterial therapy. The transfer efficiency of electrons plays an important role in sonocatalysis and chemodynamics, and how to regulate electron transfer and achieve mutual-reinforcement between sonocatalysis and chemodynamic to achieve efficient antibacterial therapy is a difficult problem. Here, this study develops a defective S-doped TiO₂ and CeO₂ heterojunction(S-TiO_2−x/CeO₂）sonosensitizer that can enhance chemodynamic therapy by regulating valence transitions of Ce^III/Ce^IV by sonoelectrons, and enhancing sonocatalytic therapy by creating heterojunctions to accelerate the transfer of interface electron, thereby achieving mutual reinforcement of sonocatalysis and chemodynamic. It could kill 99.3% of S. aureus under ultrasound (US) irradiation . Due to the presence of mixed valence states Ce^III/Ce^IV in CeO₂, S-TiO_2−x/CeO₂ could be as oxy-substrates. Ce⁴⁺ can deplete glutathione and reacts with H₂O₂ in bacteria to produce reactive oxygen species (ROS). These activities combines with ROS generated from sonocatalysis, resulting in bacterial death. Meanwhile, the electrical signal generated by S-TiO_2−x/CeO₂ under US stimulation and the cerium ions could activate the Wnt/β-catenin signaling pathway to induce hBMSCs to differentiate into osteoblast. S-TiO_2−x/CeO₂ successfully treats osteomyelitis under US irradiation by effectively clearing infection, suppressing inflammatory, and promoting bone regeneration, and it provides effective treatment for patients with deep infection.     

Electrochemically Induced Crystalline-to-Amorphous Transition of Dinuclear Polyoxovanadate for High-Rate Lithium-Ion Batteries

Polyoxometalates are intriguing high-capacity anode materials for alkali-metal-ion storage due to their multi-electron redox capabilities and flexible structure. However, their poor electrical conductivity and high working voltage severely restrict their practical application. Herein, the dinuclear polyoxovanadate Sr₂V₂O₇·H₂O with unusually high electrical conductivity is reported as a promising anode material for lithium-ion batteries. During the initial lithiation process, the Sr₂V₂O₇·H₂O anode experiences an electrochemically induced crystalline-to-amorphous transition. The resulting amorphous structure provides high redox activity and fast reaction kinetics via reversible V^4.9+/V^2.8+ redox couple through the intercalation mechanism. Furthermore, when coupled with the LiFePO₄ cathode, the strong V O bonds of the amorphous anode provide excellent structural stability, with the full-cell capable of performing >12 000 cycles with a capacity retention of 72%. Another advantage of Sr_2xV₂O_7-δ·yH₂O (0.5 ≤ x ≤ 1.0) is its composition adjustability, which enables delicately regulating the Sr vacancy content without destroying the structure. The defect Sr_2xV₂O_7-δ·yH₂O (x = 0.5) electrodes show significantly improved specific capacity and rate capability without sacrificing other key properties, delivering a high specific capacity of 479 mAh g^-1 at 0.1 mA cm^-2 and 41.9% of its capacity in 2 min. Overall, the preliminary study points the way forward for the facile preparation of high-quality polyoxometalates for advanced energy storage applications and beyond.     

Nickel Phosphide Clusters Sensitized TiO2 Nanotube Arrays as Highly Efficient Photoanode for Photoelectrocatalytic Urea Oxidation

The photoelectrocatalytic urea oxidation reaction (PEC-UOR) holds a great promise for the wastewater remediation and energy production. However, the low efficiency of semiconductor/cocatalysts type photoanodes for UOR restricts their applications in photoelectrocatalytic system. Herein, a new semiconductor/cocatalyst, Ni₂P clusters sensitized TiO₂ nanotube arrays photoanode (Ni₂P/TiO₂-NTAs) for PEC-UOR with high efficiency are developed. The 1D TiO₂-NTAs structure accelerates urea molecules diffusion and promotes CO₂ gas release at the electrode interface. Meanwhile, Ni₂P is also beneficial to urea molecule absorption and CO₂ desorption and enable to lower the energy barrier for amine (N H) dehydrogenation. Furthermore, the robust interfacial charge transfer pathway between Ni₂P and TiO₂ interface promotes the separation of photogenerated electrons and holes and the transfer of photogenerated electrons from Ni₂P to TiO₂. Therefore, this photoanode shows excellent PEC-UOR performance with the potential of 1.43 V versus reversible hydrogen electrode (RHE) when the current density reaches 10 mA cm⁻², which is much lower than that of 2.24 V versus RHE and 1.58 V versus RHE for TiO₂-NTAs and Ni(OH)₂/TiO₂-NTAs, respectively.     

Light Enhanced Electron Transduction and Amplified Sensing at a Nanostructure Modified Semiconductor Interface

Visible and UV light are demonstrated to significantly enhance the sensing properties of an n‐type porous silicon (PS) extrinsic semiconductor interface to which TiO₂ and titanium oxynitride (TiO_2‐xN_x) photocatalytic nanostructures are fractionally deposited. The acid/base chemistry of NH₃, a moderately strong base, and NO₂, a moderately strong acid, couples to the majority charge carriers of the doped semiconductor as the strong acid (TiO₂) enhances the extraction of electrons from NH₃, and the more basic TiO_2‐xN_x decreases the efficiency of electron extraction relative to the untreated interface. In contrast, NO₂ and a TiO₂ or TiO_2‐xN_x nanostructure‐decorated PS interface compete for the available electrons leading to a distinct time dependent electron transduction dynamics as a function of TiO₂ and TiO_2‐xN_x concentration. Only small concentrations of TiO₂ and its oxynitride and no self‐assembly are required to enhance the response of the decorated interface. With light intensities of less than a few lumens/cm²‐sterad‐nm, responses are enhanced by up to 150% through interaction with visible (and UV) radiation. These light intensities should be compared to the sun's radiation level, ≈500 lumens/cm²‐sterad‐nm suggesting the possibility of solar pumped sensors. The observed behavior in these systems is largely explained by the recently developed Inverse Hard/Soft Acid/Base (IHSAB) concept.     

Operando Reconstruction of Porous Carbon Supported Copper Selenide Promotes the C2 Production from CO2RR

Precisely regulating surface reconstruction of copper (Cu) chalcogenides-based catalysts to promote the multicarbon (C₂₊)selectivity of the electrochemical CO₂ reduction reaction (CO₂RR) is hampered by the challenging control of the intractable anions and the optimal Cu^δ+ reduction (0 < δ < 1). Herein, a porous carbon-supported copper selenides electrocatalyst that can remarkably improve the C₂-product yield and especially unveil the time-revolved electrochemical CO₂RR reconstruction process to enable the high C₂-selectivity, most notably for ethanol is constructed. The Faradic efficiency (FE) of C₂-products achieved is as high as ≈85.2% with a partial current density of 229.5 mA cm⁻². Operando infrared spectroscopy and density functional theory (DFT) calculations unravel that the surface Se vacancies (V_Se) formation brings closer the neighboring Cu⁺ atoms and activates the Cu sites, thereby rendering efficient generation of the key intermediates (^*CO and ^*CHO) and lowering the C–C coupling barrier for C₂ production. The appearance of metallic Cu can shorten the next-nearest Cu⁰–Cu⁺ distance for O atom to bridge in, leading to the preferential formation of ^*OC₂H₄ towards ethanol instead of C–O bond cleavage to form ethylene. This work opens the avenue of designing suitable local atomic structures catalysts to engage the intermediates for targeted CO₂RR products.     

Modeling and Understanding the Compact Performance of h-BN Dual-Gated ReS2 Transistor

In this study, high-performance few-layered ReS₂ field-effect transistors (FETs), fabricated with hexagonal boron nitride (h-BN) as top/bottom dual gate dielectrics, are presented. The performance of h-BN dual gated ReS₂ FET having a trade-off of performance parameters is optimized using a compact model from analytical choice maps, which consists of three regions with different electrical characteristics. The bottom h-BN dielectric has almost no defects and provides a physical distance between the traps in the SiO₂ and the carriers in the ReS₂ channel. Using a compact analyzing model and structural advantages, an excellent and optimized performance is introduced consisting of h-BN dual-gated ReS₂ with a high mobility of 46.1 cm² V⁻¹ s⁻¹, a high current on/off ratio of ≈10⁶, a subthreshold swing of 2.7 V dec⁻¹, and a low effective interface trap density (N_t,eff) of 7.85 × 10¹⁰ cm⁻² eV⁻¹ at a small operating voltage (<3 V). These phenomena are demonstrated through not only a fundamental current–voltage analysis, but also technology computer aided design simulations, time-dependent current, and low-frequency noise analysis. In addition, a simple method is introduced to extract the interlayer resistance of ReS₂ channel through Y-function method as a function of constant top gate bias.     

Plasmonic Heterostructure TiO2‐MCs/WO3−x‐NWs with Continuous Photoelectron Injection Boosting Hot Electron for Methane Generation

Nonmetallic plasmonic heterostructure TiO₂‐mesocrystals/WO_3?x‐nanowires (TiO₂‐MCs/WO_3?x‐NWs) are constructed by coupling mesoporous crystal TiO₂ and plasmonic WO_3?x through a solvothermal procedure. The continuous photoelectron injection from TiO₂ stabilizes the free carrier density and leads to strong surface plasmon resonance (SPR) of WO_3?x, resulting in strong light absorption in the visible and near‐infrared region. Photocatalytic hydrogen generation of TiO₂‐MCs/WO_3?x‐NWs is attributed to plasmonic hot electrons excited on WO_3?x‐NWs under visible light irradiation. However, utilization of injected photoelectrons on WO_3?x‐NWs has low efficiency for hydrogen generation and a co‐catalyst (Pt) is necessary. TiO₂‐MCs/WO_3?x‐NWs are used as co‐catalyst free plasmonic photocatalysts for CO₂ reduction, which exhibit much higher activity (16.3 µmol g^?1 h^?1) and selectivity (83%) than TiO₂‐MCs (3.5 µmol g^?1 h^?1, 42%) and WO_3?x‐NWs (8.0 µmol g^?1 h^?1, 64%) for methane generation under UV–vis light irradiation. A photoluminescence study demonstrates the photoelectron injection from TiO₂ to WO_3?x, and the nonmetallic SPR of WO_3?x plays a great role in the highly selective methane generation during CO₂ photoreduction.     

Large‐Area Bilayer ReS2 Film/Multilayer ReS2 Flakes Synthesized by Chemical Vapor Deposition for High Performance Photodetectors

Rhenium disulfide (ReS₂) is attracting more and more attention for its thickness‐depended direct band gap. As a new appearing 2D transition metal dichalcogenide, the studies on synthesis method via chemical vapor deposition (CVD) is still rare. Here a systematically study on the CVD growth of continuous bilayer ReS₂ film and single crystalline hexagonal ReS₂ flake, as well as their corresponding optoelectronic properties is reported. Moreover, the growth mechanism has been proposed, accompanied with simulation study. High‐performance photodetector based on ReS₂ flake shows a high responsivity of 604 A·W^?1, high external quantum efficiency of 1.50 × 10⁵ %, and fast response time of 2 ms. ReS₂ film‐based photodetector exhibits weaker performance than the flake one; however, it still demonstrates a much faster response time (≈10³ ms) than other reported CVD‐grown ReS₂‐based photodetector (≈10⁴–10⁵ ms). Such good properties of ReS₂ render it a promising future in 2D optoelectronics.     

H2 In Situ Inducing Strategy on Pt Surface Segregation Over Low Pt Doped PtNi5 Nanoalloy with Superhigh Alkaline HER Activity

Surface segregation constitutes an efficient approach to enhance the alkaline hydrogen evolution reaction (HER) activity of bimetallic Pt_xNi_y nanoalloys. Herein, a new strategy is proposed by utilizing the small gas molecule of H₂ as the structure directing agent (SDA) to in situ induce Pt surface segregations over a series of PtNi₅-n samples with extremely low Pt doping (Pt/Ni = 0.2). Impressively, the sample of PtNi₅-0.3 synthesized under 0.3 MPa H₂ delivers an extremely low overpotential of 26.8 mV (−10 mA cm⁻²) and Tafel slope of 19.2 mV dec⁻¹, which is superior to most of the previously reported Pt_xNi_y electrocatalysts. This is substantially related to the strong H₂ in situ inducing effect to generate Pt-rich@Ni-rich core-shell nanostructure of PtNi₅-0.3 with an ultrahigh Pt surface content of 46%. The specific mechanistic effects of H₂ during the PtNi₅-n synthesis process are well illustrated based on the combined experimental and theoretical studies. The density functional theory mechanism simulations further unravel that the evolved active site of PtNi₅-n can efficiently reduce the reaction Gibbs free energies; especially for the scenario of PtNi₅-0.3, the downward-shifted d band center of the Pt active site significantly reduces the Pt H bond strength, eventually resulting in the lowest absolute value of ΔG_H.     

Theoretical and Experimental Insight into the Mechanism for Spontaneous Vertical Growth of ReS2 Nanosheets

Rhenium disulfide (ReS₂) differs fundamentally from other group‐VI transition metal dichalcogenides (TMDs) due to its low structural symmetry, which results in its optical and electrical anisotropy. Although vertical growth is observed in some TMDs under special growth conditions, vertical growth in ReS₂ is very different in that it is highly spontaneous and substrate‐independent. In this study, the mechanism that underpins the thermodynamically favorable vertical growth mode of ReS₂ is uncovered. It is found that the governing mechanism for ReS₂ growth involves two distinct stages. In the first stage, ReS₂ grows parallel to the growth substrate, consistent with conventional TMD growth. However, subsequent vertical growth is nucleated at points on the lattice where Re atoms are “pinched” together. At such sites, an additional Re atom binds with the cluster of pinched Re atoms, leaving an under‐coordinated S atom protruding out of the ReS₂ plane. This under‐coordinated S is “reactive” and binds to free Re and S atoms, initiating growth in a direction perpendicular to the ReS₂ surface. The utility of such vertical ReS₂ arrays in applications where high surface‐to‐volume ratio and electric‐field enhancement are essential, such as surface enhanced Raman spectroscopy, field emission, and solar‐based disinfection of bacteria, is demonstrated.     

H‐Doped Black Titania with Very High Solar Absorption and Excellent Photocatalysis Enhanced by Localized Surface Plasmon Resonance

Black TiO₂ attracts enormous attention due to its large solar absorption and induced excellent photocatalytic activity. Herein, a new approach assisted by hydrogen plasma to synthesize unique H‐doped black titania with a core/shell structure (TiO₂@TiO_2‐xH_x) is presented, superior to the high H₂‐pressure process (under 20 bar for five days). The black titania possesses the largest solar absorption (≈83%), far more than any other reported black titania (the record (high‐pressure): ≈30%). H doping is favorable to eliminate the recombination centers of light‐induced electrons and holes. High absorption and low recombination ensure the excellent photocatalytic activity for the black titania in the photo‐oxidation of organic molecules in water and the production of hydrogen. The H‐doped amorphous shell is proposed to play the same role as Ag or Pt loading on TiO₂ nanocrystals, which induces the localized surface plasma resonance and black coloration. Photocatalytic water splitting and cleaning using TiO_2‐xH_x is believed to have a bright future for sustainable energy sources and cleaning environment.     

In-Situ Electrochemically Activated Surface Vanadium Valence in V2C MXene to Achieve High Capacity and Superior Rate Performance for Zn-Ion Batteries

Vanadium-based materials are fascinating potential cathodes for high energy density Zn-ion batteries (ZIBs), due to their high capacity arising from multi-electron redox chemistry. Most vanadium-based materials suffer from poor rate capability, however, owing to their low conductivity and large dimension. Here, we propose the application of V₂C MXene (V₂CT_x), a conductive 2D nanomaterial, for achieving high energy density ZIBs with superior rate capability. Through an initial charging activation, the valence of surface vanadium in V₂CT_x cathode is raised significantly from V²⁺/V³⁺ to V⁴⁺/V⁵⁺, forming a nanoscale vanadium oxide (VO_x) coating that effectively undergoes multi-electron reactions, whereas the inner V-C-V 2D multi-layers of V₂CT_x are intentionally preserved, providing abundant nanochannels with intrinsic high conductivity. Owing to the synergistic effects between the outer high-valence VO_x and inner conductive V-C-V, the activated V₂CT_x presents an ultrahigh rate performance, reaching 358 mAh g⁻¹ at 30 A g⁻¹, together with remarkable energy and power density (318 Wh kg⁻¹/22.5 kW kg⁻¹). The structural advantages of activated V₂CT_x are maintained after 2000 cycles, offering excellent stability with nearly 100% Coulombic efficiency. This work provides key insights into the design of high-performance cathode materials for advanced ZIBs.     

Refining Energy Levels in ReS2 Nanosheets by Low‐Valent Transition‐Metal Doping for Dual‐Boosted Electrochemical Ammonia/Hydrogen Production

Electrocatalytic nitrogen reduction reaction (NRR) and hydrogen evolution reaction (HER) are intriguing approaches to nitrogen fixation and hydrogen production under ambient conditions, given the need to discover efficient and stable catalysts to light up the “green chemistry” future. However, bottlenecks are often found during N₂/H₂O activation, the very first step of NRR/HER, due to energetic electron injection from the surface of electrocatalysts. It is reported that the bottlenecks for both NRR and HER can be tackled by engineering the energy level via low‐valent transition‐metal doping, simultaneously, where rhenium disulfide (ReS₂) is employed as a model platform to prove the concept. The doped low‐valent transition‐metal domains (e.g., Fe, Co, Ni, Cu, Zn) in ReS₂ provide more active sites for N₂/H₂O chemisorption and electron transfer, not only weakening the N?N/O? H bonds for easier dissociation through proton coupling, but also elevating d‐band center toward the Fermi level with more electron energy for N₂/H₂O reduction. As a result, it is found that iron‐doped ReS₂ nanosheets wrapped nitrogen‐doped carbon nanofiber (Fe‐ReS₂@N‐CNF) catalyst exhibits superior electrochemical activity with eightfold higher ammonia production yield of 80.4 µg h^?1 mg^?1_cat., and lower onset overpotential of 146 mV and Tafel slope of 63 mV dec^?1, when comparing with the pristine ReS₂.     

Strong Band Bowing Effects and Distinctive Optoelectronic Properties of 2H and 1T′ Phase‐Tunable MoxRe1–xS2 Alloys

Structure and energy band engineering of 2D materials via selective doping or phase modulation provide a significant opportunity to design them for optoelectronic devices. Here, the synthesis of high‐quality Mo_xRe_1–xS₂ alloys with tunable composition and phase structure via chemical vapor deposition growth is reported, and their novel energy band structures and optoelectronic properties are explored. The phase separation and structure reconstruction, which are found to be two serious problems in the synthesis of these alloys, are successfully suppressed through tuning their growth thermodynamics. As a result, the obtained Mo_xRe_1–xS₂ alloys have uniform composition, phase structure, and crystal orientation. Together with X‐ray photoelectron spectroscopy analysis and first‐principle calculation, the Re/Mo doping‐induced Fermi level up‐shift/down‐shift, new electronic states, and “sub‐gap” formation in Mo_xRe_1–xS₂ alloys are revealed. Especially, a strong band bowing effect is discovered in the Mo_xRe_1–xS₂ alloys with structure transition between 1T′ and 2H phases. Furthermore, these alloys reveal tunable conduction behavior from n‐type to bipolar and p‐type in 1T′ phase, as well as novel “bipolar‐like” electron conduction behavior in 2H alloys. The results highlight the unique alloying effects, which do not exist in the single‐phase 2D alloys, and provide the feasibility for potential applications in building novel electronic and optoelectronic devices.     

Impurity centers of tin in glassy arsenic chalcogenides

¹¹⁹Sn atoms produced by radioactive decay of ¹¹⁹Sb impurity atoms in the structure of As _x S_{1 − x} and As _x Se_{1 − x} glasses are stabilized in the form of Sn²⁺ and Sn⁴⁺ ions at arsenic sites and correspond to ionized states of the amphoteric two-electron center with negative correlation energy (Sn²⁺ is an ionized acceptor, and Sn⁴⁺ is an ionized donor), whereas the neutral state of the Sn³⁺ center is unstable. The fraction of Sn⁴⁺ states increases with chalcogen content in glass. ¹¹⁹Sn atoms produced by radioactive decay of ^119m Te impurity atoms in the structure of As _x S_{1 − x} and As _x Se_{1 − x} glasses are stabilized at chalcogen sites (they are electrically inactive) and arsenic sites, and the fraction of arsenic atoms decreases with the chalcogen content in glass.