Sulfur Vacancies Research Articles

Low defect density in MoS2 monolayers grown on Au(111) by metal-organic chemical vapor deposition

Monolayers of transition metal dichalcogenides (TMDs) possess high potential for applications in novel electronic and optoelectronic devices and therefore the development of methods for their scalable growth is of high importance. Among different suggested approaches, metal-organic chemical vapor deposition (MOCVD) is the most promising one for technological applications because of its lower growth temperature compared to the most other methods, e.g., conventional chemical vapor or atomic layer deposition (CVD, ALD). Here we demonstrate for the first time the epitaxial growth of MoS2 monolayers on Au(111) by MOCVD at 450 °C. We confirm the high quality of the grown TMD monolayers down to the atomic scale using several complementary methods. These include Raman spectroscopy, non-contact atomic force microscopy (nc-AFM), X-ray photoelectron spectroscopy and scanning tunneling microscopy (STM). The topographic corrugation of the MoS2 monolayer on Au(111), revealed in a moiré structure, was measured as ≈20 pm by nc-AFM. The estimated defect density calculated from STM images of the as-grown MoS2 monolayers is in the order of 1012 vacancies/cm2. The defects are mainly caused by single sulfur vacancies. Our approach is a step forward towards the technologically relevant growth of high-quality, large-area TMD monolayers.

Co, N co-doping controlled preparation of FeS/FeS2 heterojunction for efficient overall water splitting

The low electrical conductivity and catalytic activity of transition metal sulfides have been identified as the primary factors limiting their application in the field of electrocatalytic water splitting. In this study, FeS2 and Co-FeSx were initially synthesized through a hydrothermal method, followed by further annealing in an NH3 atmosphere to obtain Co,N-FeSx. The introduction of Co led to adjustments in the electronic structure, resulting in the formation of FeS2/FeS (FeSx) heterojunctions that facilitated accelerated charge transfer. Simultaneously, Co element doping increased the electrochemical active surface area, providing more active sites for the reactions. N element doping, on the other hand, introduced sulfur vacancies, thereby enhancing electrical conductivity and improving charge transfer efficiency. As a result, Co,N-FeSx exhibited significantly higher activities for the oxygen evolution reaction (OER) and overall water splitting compared to FeS2, with overpotentials of 290 mV and 330 mV, respectively, at a current density of 10 mA cm−2. Furthermore, the catalyst demonstrated excellent stability. The designed structure of the catalyst provides theoretical support for the study of Fe-based catalysts in OER and overall water splitting.

Activation of peroxymonosulfate by β-FeOOH@Cia-MoS2 for enhancing degradation of tetracycline: Significant roles of surface functional groups and Fe/Mo redox reactions

Vertically oriented interstitial atom carbon-anchored molybdenum disulfide (Cia-MoS2) nanospheres loaded with iron oxyhydroxide (β-FeOOH) were proposed for modulating the surface catalytic activity and stability of the unsaturated catalytic system. The β-FeOOH@Cia-MoS2 efficiently activated peroxymonosulfate (PMS) to degrade 95.4% of tetracycline (TC) within 30 min, owing to the more sulfur vacancies, higher surface hydroxyl density, redox ability and electronic transmission rate of β-FeOOH@Cia-MoS2. According to the characterization and analysis data, the multiple active sites (Fe, Mo and S sites) and oxygen-containing functional groups (CO, –OH) of β-FeOOH@Cia-MoS2 could promote the activation of PMS to form reactive oxygen species (ROS). The oxidation cycle of Fe(II)/Fe(III) and Mo(IV)/Mo(VI), the electron transfer mediator of rich sulfur vacancies, as well as oxygen-containing functional groups on the surface of β-FeOOH@Cia-MoS2 synergistically promoted the formation of ROS (1O2, FeIVO, SO4•- and •OH), among which 1O2 was the main active oxidant. In particular, the β-FeOOH@Cia-MoS2/PMS system could still degrade pollutants efficiently and stably after five recycling cycles. Furthermore, this system had a strong anti-interference ability in the actual water body. This study provided a promising strategy for the removal of difficult-to-degrade organic pollutants.

Dipole polarization-driven spatial charge separation in defective zinc cadmium sulfoselenide for boosting photocatalytic hydrogen evolution

The industrial interest of ZnCdS as the photocatalytic media for hydrogen evolution reaction (HER) is severely hindered by its sluggish interfacial charge transfer, limited active sites, and serious photocorrosions. Herein, to catalyze more efficient and robust HER, a series of Se-doped ZnCdS with sulfur vacancies (denoted as Se/VS-ZnCdS) are ingeniously designed and facilely synthesized. Experimental and theoretical studies reveal that by inducing dipole polarization through defect engineering synergistic elemental doping, spontaneous polarization field is generated in the bulk phase of ZnCdS, which together with elevated Fermi level renders the Se/VS-ZnCdS with desirable spatial charge separation and transfer. Thus, the optimal 0.6 %Se/VS-ZnCdS exhibits the outstanding performance of 85.3 mmol·gcat−1·h−1 and excellent stability up to 24 h. This work highlights the high efficiency of dipole polarization realized by vacancy synergistic atomic doping in optimizing HER kinetics, and provides a new pathway to develop robust photocatalysts based on metal sulfoselenide for water-splitting reactions.

Spatial confined synthesis of submicron Fe-MoS2 with abundant surface cationic groups and sulfur vacancies for enhanced peroxymonosulfate activation

ABSTRACT The widespread use of emerging refractory organic contaminants poses a significant threat to human health, prompting the need for a cost-effective and efficient removal strategy. While the iron ions/PMS system effectively removes organic pollutants, slow Fe3+ to Fe2+ transformation hampers its efficiency, and the homogeneous distribution of iron ions complicates separation, resulting in secondary sludge pollution. Herein, we developed a novel submicron Fe-MoS2 (S-Fe-MoS2) catalyst with abundant surface cationic groups and sulfur vacancy through a cationic polyacrylamide aerogels (CPAMA) confined hydrothermal synthesis strategy. These features promote active site exposure, enhance reactant adsorption, and accelerate electron transfer between Mo and Fe sites, improving catalytic kinetics and promoting Fe3+/Fe2+ cycle for PMS activation. As a result, the S-Fe-MoS2/PMS system exhibited a high catalytic rate constant (k obs) of 0.32 min−1, in the degradation of 4-chlorophenol (4-CP), 1.5 times higher than that of the conventional Fe-MoS2/PMS system. It also achieved 82.9% total organic carbon (TOC) degradation within 60 min. Additionally, it possessed similar degradation performance for various organic pollutants, along with remarkable reusability (four cycles) and broad pH adaptability (2–8), indicating significant potential for widespread application. This study provided a new way for developing advanced heterogeneous catalysts with high efficiency for water treatment.

Exploring the role of redox-active species on NiS-NiS2 incorporated sulfur-doped graphitic carbon nitride nanohybrid as a bifunctional electrocatalyst for overall water splitting

The advancement of effective and robust catalysts that can replace the precious-metal-based benchmarks for electrocatalytic overall water splitting is a highly fashionable approach to exploring sustainable energy utilization and addressing environmental issues. Herein, we demonstrate a facile single-step fabrication of NiS-NiS2 nanoparticles in situ grown on the layered porous sulfur-doped graphitic carbon nitride nanosheets (NiS-NiS2/SGCN) act as bifunctional electrocatalysts for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in an alkaline medium.Further, an increasing the Ni precursor (fixed sulfur source) increases the formation of NiS-NiS2 on the surface of SGCN (labeled as NS-1.0, NS-2.0, and NS-3.0). Structural and morphological studies such as PXRD, XPS, FTIR, HR-TEM, etc., revealed a uniform distribution of NiS/NiS2 on the surface of S-g-C3N4 nanosheets. The OER and HER activity of NiS-NiS2/SGCN nanohybrid were significantly enhanced by increasing the affinity of accessible surface-active edge sites, interfacial contact allows effective modification of electronic structure, high structural porosity, redox-active centers of Ni2+/Ni3+, and rich in sulfur vacancy. In addition, the enhancement of the exposure of the edge sites is improved by their attachment to a sulfur-doped g-C3N4 framework. As a result, in the half-cell experiments, the NiS-NiS2/SGCN (NS-3.0) catalyst exhibited enhanced performance in both OER and HER, requiring an overpotential of 298 mV to reach 50 mA/cm2 for OER and −144 mV to reach 10 mA/cm2 for HER. Furthermore, the constructed electrolyzer using Ni-S 3.0 as the cathode and anode required a cell voltage of 1.66 V to yield 50 mA/cm2 in overall water splitting. This study may inspire the in-situ synthesis of different metal sulfides on SGCN to provide a unique interfacial approach for improving the performance of bifunctional non-precious electrocatalysts.

Tunable Doping Strategy for Few-Layer MoS2 Field-Effect Transistors via NH3 Plasma Treatment.

Molybdenum disulfide (MoS2) is a promising candidate for next-generation transistor channel materials, boasting outstanding electrical properties and ultrathin structure. Conventional ion implantation processes are unsuitable for atomically thin two-dimensional (2D) materials, necessitating nondestructive doping methods. We proposed a novel approach: tunable n-type doping through sulfur vacancies (VS) and p-type doping by nitrogen substitution in MoS2, controlled by the duration of NH3 plasma treatment. Our results reveal that NH3 plasma exposure of 20 s increases the 2D sheet carrier density (n2D) in MoS2 field-effect transistors (FETs) by +4.92 × 1011 cm-2 at a gate bias of 0 V, attributable to sulfur vacancy generation. Conversely, treatment of 40 s reduces n2D by -3.71 × 1011 cm-2 due to increased nitrogen doping. X-ray photoelectron spectroscopy, Raman spectroscopy, and photoluminescence analyses corroborate these electrical characterization results, indicating successful n- and p-type doping. Temperature-dependent measurements show that the Schottky barrier height at the metal-semiconductor contact decreases by -31 meV under n-type conditions and increases by +37 meV for p-type doping. This study highlights NH3 plasma treatment as a viable doping method for 2D materials in electronic and optoelectronic device engineering.

Solution-Processable Microstructuring of 1T'-Phase Janus MoSSe Monolayers for Boosted Hydrogen Production.

Janus monolayers of transition metal dichalcogenides (TMDs) offer versatile applications due to their tunable polymorphisms. While previous studies focused on conventional 2H-phase Janus monolayers, the scalable synthesis of an unconventional 1T' phase remains challenging. We present a novel solution strategy for fabricating Janus 1T'-MoOSe and MoSSe monolayers by growing sandwiched Se-Mo-O/S shells onto Au nanocores. The Janus Au@1T'-MoSSe catalyst exhibits superior electrocatalytic hydrogen evolution reaction (HER) activity compared to 1T'-MoS2, -MoSe2, and -MoOSe, attributed to its unique electronic structure and intrinsic strain. Remarkably, photoexciting the nanoplasmonic Au cores further enhances the HER via a localized surface plasmon (LSP) effect that drives hot electron injection into surface sulfur vacancies of 1T'-MoSSe monolayer shells, accelerating proton reduction. This synergistic activation of anion vacancies by internal strain and external light-induced Au LSPs, coupled with our scalable synthesis, provides a pathway for developing tailorable polymorphic Janus TMDs for specific applications.

Anion vacancy engineering in carbon coating VS4 microspheres assembled by nanorod arrays for high-performance rechargeable Mg-Li hybrid batteries

Transition metal sulfides (TMSs) stand out as promising cathodes for rechargeable Mg-Li hybrid ion batteries (MLIBs) owing to their high theoretical capacity and rich redox chemistry. Nevertheless, it still faces great challenges involving the sluggish reaction kinetics and insufficient active sites, resulting in unsatisfactory stability and limited rate capability. And the role of anion vacancies on improving electrochemical properties of TMSs is still unclear. Herein, we have successfully designed an anion defect engineering strategy for the construction of carbon coating VS4 microspheres assembled by nanorod arrays (Sv-VS4@C-300) as the high-performance cathode for MLIBs. The systematic electrochemical tests together with theoretical calculations reveal that the sulfur vacancies simultaneously improve ion adsorption ability, facilitate charge transfer rate and boost reaction kinetics. Additionally, the open microsphere structure together with rich sulfur vacancies cooperatively provide more active sites and release the internal stress during cycling, thereby realizing the enhancement of capacity and structural stability. Consequently, these features enable Sv-VS4@C-300 with impressively high reversible capacity (485.1 mAh/g at 50 mA g−1) and exceptional long cycle lifespan (128.3 mAh/g at 2000 mA g−1 after 5000 cycles). This work implements an innovative strategy represented by anion vacancy engineering in the design of high-performance TMSs-based cathodes for rechargeable batteries.

Innovative dual-mode device integrating capacitive desalination and solar vapor generation for high-efficiency seawater desalination

Solar-driven interface evaporation with high solar-to-steam conversion efficiency has shown great potential in seawater desalination. However, due to the influence of latent heat and condensation efficiency, the water yield from solar-driven interface evaporation remains insufficient, posing a significant challenge that requires resolution. In this work, we designed a dual-mode high-flux seawater desalination device that combines solar-driven interface evaporation and capacitive desalination. By utilizing coupled desalination materials exhibiting both photothermal conversion and capacitance activity, the device demonstrated photothermal evaporation rates of 1.41 and 0.97 kg m−2 h−1 for condensate water yield under one-sun irradiation. Additionally, the device exhibited a salt adsorption capacity of up to 48 mg g−1 and a salt adsorption rate of 2.1 mg g−1 min−1. In addition, the salt adsorption capacity increased by approximately 32% under one-sun irradiation. Furthermore, photo-enhanced capacitive desalination performance was explored through numerical simulations and theoretical calculations. Theoretical calculations and characterizations confirmed that the defect energy levels formed by the introduction of sulfur vacancies can effectively widen the light absorption range, improve photothermal conversion performance, and stimulate more photoelectrons to participate in capacitive desalination. Concurrently, the electron distribution state of molybdenum disulfide with sulfur vacancies and surface defect sites contributes to ion/electron transport at the solid-liquid interface. This work provides a novel pathway for integrating solar vapor generation with other low-energy desalination technologies.

Facile synthesis of a novel CeCO3OH@(H/C–CdS) catalyst with synergistic effect of heterophase junction and heterojunction for enhanced visible-light photocatalytic degradation efficiency at room temperature

A new CeCO3OH@(hexagonal/cubic phases–CdS) (CeCO3OH@(H/C–CdS)) composite catalyst was facilely synthesized by a simple microinjection titration–stirring method, in which CdS nanoparticles were dispersed on the surface of CeCO3OH nanolines. The optimal conditions for the preparation of composite catalysts with high photocatalytic performance were determined by single-factor experiments and response surface experiments. Under these conditions, the degradation rate of 30 mL 2.000 g/L rhodamine B (Rh B) by CeCO3OH@(H/C-CdS) in a photocatalytic reaction for 1 h at 25 °C was up to 86.81 % and its degradation rate in a photocatalytic reaction for 150 min was up to 99.62 %. The degradation rate could be maintained above 80 % even after six times recycling. Especially, the photocatalytic degradation efficiency of 2.000 g/L Rh B on the composite catalyst under sunlight and at room temperature for 30 min reached 97.66 %. Meanwhile, the large size of CeCO3OH considerably alleviated the agglomeration of CdS, providing more adsorption and active sites for visible light-mediated degradation of Rh B. Importantly, the Z-scheme charge transfer realized by CdS and CeCO3OH enhanced the efficient separation of photogenerated electrons and holes, and successfully inhibited the recombination of photogenerated electrons with holes. At the same time, owing to the low energy band difference between the two phases of CdS, charge was transferred between the hexagonal and cubic phases, leaving more effective photogenerated charge to participate in the degradation of Rh B. The synergism of the heterophase junction and heterojunction and the presence of oxygen and sulfur vacancies considerably enhanced the degradation performance of the catalyst. Thus, this study provides a new strategy for the modification and enhanced visible-light catalysis performance of CdS-based catalysts.

Regulating facet exposure and sulfur vacancy in magnetic greigite nanosheet for boosting heterogeneous Fenton-like reaction towards efficient degradation of metronidazole under visible light irradiation: Synergistic enhancement effect, DFT calculations and mechanism insight

Environmentally friendly iron catalysts have attracted widespread attention in the heterogeneous Fenton-like reaction based on peroxymonosulfate (PMS) for the degradation of emerging pollutants in water, while it has always suffered from the disadvantage of low catalytic activity. Herein, we successfully prepared the magnetic greigite (Fe3S4) nanosheet with the exposed {011} facet and rich sulfur vacancies (FS-1) through a simple solvothermal method. The degradation rate of metronidazole by the FS-1 activating PMS under visible light irradiation was 2.93, and 4.48 more than those of the Fe3S4 nanosheet with the exposed {011} facet and poor sulfur vacancies, and Fe3S4 nanobulk with the exposed {112} facet, respectively. The result of electrochemical analysis and theoretical calculation indicated that the exposed {011} facet of prepared FS-1 offered more active sites to adsorb PMS, and the rich sulfur vacancies on the surface accelerated the electron transfer between oxidants and catalyst. This collaborative effect significantly lowered the energy barrier associated with PMS activation, leading to an increased generation of singlet oxygen. Additionally, the degradation mechanism and pathway of metronidazole, including hydroxyethyl cracking, denitrification, and hydroxylation, were explored in detail through theoretical calculations and high-performance liquid chromatography-mass spectrometry, respectively. This work offers insight into boosting the catalytic performance of environmentally friendly iron-based catalysts.

Sulfur vacancies form charge transport channels on the S-type heterojunction engineered interface to enhance photocatalytic performance

This article presents the synthesis of an S-type heterojunction photocatalyst through a straightforward hydrothermal process, which involves the combination of FeWO4 with Zn0.5Cd0.5S containing sulfur vacancies (Zn0.5Cd0.5Ssv). The study delves into the intrinsic role of sulfur vacancies in enhancing the photocatalytic performance of the S-type heterojunction. The creation of sulfur vacancies effectively controls charge separation and triggers a rapid charge transfer pathway at the heterojunction, improving light absorption and permitting the formation of more photoinduced charges. The material demonstrates an impressive degradation efficiency, capable of breaking down 79.38% of IOH within just 40 minutes. It exhibits robust catalytic activity under both mildly acidic and mildly basic conditions, showing notable resistance to various anions and cations present in water, as well as a significant tolerance to high concentrations of humic acid. Further, trapping experiments reveal that hydroxyl radicals (•OH) and superoxide radicals (•O2⁻) are the predominant reactive species driving the photocatalytic process. This research sheds new light on the modulation of photogenerated charge carrier dynamics at the heterointerface, offering valuable guidance for the development of high-performance S-type photocatalysts.

Surface sulphur vacancies of CdS/MIL-68(In)–NH2 for Boosting Visible-Light photocatalytic hydrogen evolution

The incorporation of sulfur vacancies (SVs) during the synthesis of CdS represents an essential approach for enhancing its photocatalytic hydrogen production performance. The CdS/MIL-68(In)–NH2 photocatalytic material with SVs was successfully synthesized via a facile two-step method and employed for visible light photocatalytic hydrogen evolution. Among various loading ratios, the CdS(30)/MIL-68(In)–NH2 composite exhibited remarkable photocatalytic performance, demonstrating hydrogen evolution rates 3.7 times and 7.3 times higher than those of pure CdS and mechanically mixed CdS with MIL-68(In)–NH2, respectively, while maintaining significant photocatalytic stability. The incorporation of MIL-68(In)–NH2 effectively enhanced the dispersion of CdS particles, thereby increasing the availability of active sites for efficient photocatalytic reactions. Moreover, the presence of SVs on the surface of CdS served as electron trapping levels, significantly improving charge separation efficiency. This study not only provides novel insights into fabricating composite photocatalysts but also explores a defect engineering regulation strategy.

Improved ammonia gas adsorption of surface engineered WS2 nanoflakes

Recent investigations into nanostructured WS2 have shown promising results in the detection of reducing gases, such as ammonia. However, this material faces limitations with respect to the vital parameters such as sensitivity, recovery, and repeatability over an extended period in its purest form. To address these challenges, a low-energy (5 keV) argon ion beam was used to irradiate nanostructured WS2 nanoflakes at various fluences, leading to observable morphological and structural changes. The irradiation of WS2 resulted in a significant enhancement in its ability to detect ammonia gas. The sensing response saw a threefold increase, and both the response and recovery times were reduced significantly compared to pristine samples. Ion beam irradiation changes the overall morphology of nanoflakes and induces a certain degree of defects as apparent from electron microscopy, X-ray diffraction, Raman spectroscopy, and X-ray photoelectron spectroscopy studies. The ion-solid interaction simulation predicts a larger amount of sulfur vacancy than tungsten due to irradiation, which is also supported by experimental results. Density functional theory predicts that sulfur vacancy leads a decisive role in better adsorption of ammonia than the pristine surface. The NH3 molecule orients towards the defective surface leading to a higher charge transfer from the NH3 molecule to the surface than the pristine surface along with a smaller adsorption height.

Activation of Bi2MoO6/Zn0.5Cd0.5S charge transfer through interface chemical bonds and surface defects for photothermal catalytic CO2 reduction

The photocatalytic reduction of CO2 to high-value fuels has been proposed as a solution to the energy crisis caused by the depletion of energy resources. Despite significant advancements in photocatalytic CO2 reduction catalyst development, there are still limitations such as poor CO2 adsorption/activation and low charge transfer efficiency. In this study, we employed a defect-induced heterojunction strategy to construct atomic-level interface Cd-O bonds and form Bi2MoO6/Zn0.5Cd0.5S heterojunctions. The sulfur vacancies (VS) formed in Bi2MoO6/Zn0.5Cd0.5S acted as activation sites for CO2 adsorption. While the interfacial stability provided by the Cd-O bonds served as an electron transfer channel that facilitated the movement of electrons from the interface to the catalytic site. The VS and Cd-O bonds simultaneously influence the distribution of charge, inducing the creation of an interface electric field that facilitates the upward displacement of the center of the d-band. This enhances the adsorption of reaction intermediates. The optimized Bi2MoO6/Zn0.5Cd0.5S heterostructure exhibited high selectivity and stability of photoelectrochemical properties for CO, generating 42.97 μmol⋅g−1⋅h−1 of CO, which was 16.65-fold higher than Zn0.5Cd0.5S under visible light drive. This research provides valuable insights for designing photocatalyst interfaces with improved CO2 adsorption conversion efficiency.

Effect of electron redistribution on H adsorption and hydrogen production efficiency

Water electrolysis is a promising, carbonless technology for hydrogen production, however, its widely industrial application is severely limited by the extensive energy consumption caused by sluggish oxygen evolution reaction (OER) kinetics. Herein, the simple Mn doping is employed to finely tune sulfur vacancies (VS). The thoeretic calculations prove that the electron structure has been well controlled. Compared with perfect MoS2 (without VS), the electron re-distribution of Mn-doped MoS2 with VS (Vs-Mn-MoS2) exhibits the both modes: electron depletion near the VS and electron accumulation between two Mo atoms. Furthermore, the well-controlled electron structure obviously promotes H adsorption. The experimental results shows that the 5 wt% Mn–MoS2 exhibits an excellent hydrogen evolution reaction (HER) activity (79 mV/10 mA cm−2, 55.46 mV dec−1), which is better than the other MoS2-based electrolysts in the previous reports. Moreover, an innovative substitution anode reaction is designed, namely, glycerol oxidation reaction (GOR)-based symmetric electrolyser with Mn–MoS2 as the both electrodes. At 60 mA cm−2, the cell voltage of GOR-based electrolyser has decreased by 14.8 %, and its Faradaic efficiency for HER increases by 10.04 % compared to conventional water-based one. This result proves that about 14.8 % of electric energy can be economized. Thus, this innovative electrocatalysis system could be promising for industrial hydrogen production.

Atomically dispersed Co atoms anchored on sulfur vacancies to accelerate the electron transfer process and efficiently degrade sulfamethoxazole

Molybdenum disulfide serves as an ideal support for single atom catalysts (SACs), offering not only coordination elements but also abundant active sites, such as surface defects and vacancies. Herein, a novel Co-SAC (MoSO-Co-C) containing a four-coordinated configuration (Mo-Co-C3) is designed and synthesized, in which the carbon intercalation is utilized to regulate sulfur vacancies for anchoring the Co atom. The introduction of Co atoms and C intercalation significantly enhances the Eads between catalyst and peroxymonosulfate (PMS), favoring the formation of metastable intermediates. The kobs of sulfamethoxazole (SMX) removal for MoSO-Co-C is 9.2 times and 1.8 times higher than those of catalysts without Co or C intercalation. SMX is removed mainly by electron transfer pathway, wherein SMX and PMS act on the same Co site of MoSO-Co-C, and electrons are transferred from SMX to MoSO-Co-C and eventually to PMS. The MoSO-Co-C demonstrated excellent SMX degradation in the diverse water matrices, and the removal efficiency of SMX maintained above 95 % after 72 h of continuous degradation. This study provides new insights into the design of transition metal-based SAC and in-depth understanding of PMS activation mechanism.

Efficient removal of high concentration organic pollutants by ZnIn2S4 with highly active sulfur vacancy

Metal sulfides have attracted much attention because of their wide light response range and negative conduction band (CB) position, which can generate abundant charges to participate reduction and oxidation reactions. In recent years, efforts are devoted to enhance the charge separation and transfer to improve its overall performance in photocatalytic applications. Herein, we synthesized zinc indium sulfide (ZnIn2S4, named as ZIS) with S vacancy (VS) defects via a hydrothermal method with assist of excess sulfur sources. All the as-prepared samples exhibited significant photocatalytic degradation performance on organic pollutants with high concentration. Among them, the VS-ZIS (TAA) demonstrated exceptionally high photodegradation activity under visible light (λ＞420 nm) irradiation, achieving removal rates up to 96 % and 90 % over TC (80 mg/L) and RhB (40 mg/L), respectively. Moreover, VS-ZIS (TAA) also displayed an excellent cycling stability. Combining experimental and theoretical studies, we unveil that the introduction of VS defects broadens the light absorption range, accelerates carrier separation and transfer, and provides additional surface active sites, thus improving the photocatalytic degradation efficiency. This study suggests that creating VS can induce effective charge separation, thus enhancing the photocatalytic activity and providing a viable pathway for treating high concentration organic pollutants.

(Invited) Activating Nitrogen for Electrochemical Ammonia Synthesis: Modeling the Effects of Electrified Interfaces on π-Backbonding Molecules

Electrocatalysts are expected to play a pivotal role in shaping our future sustainable energy landscape by enabling storage of renewable energy and its conversion into globally important chemicals. Computational simulations yield mechanistic insights that have supported catalyst discovery and optimization. However, the complexity of electrocatalyst interfaces has necessitated the development of quantum chemical methods that can accurately model these effects at reasonable computational cost.In this work, we employ grand canonical density functional theory (GC-DFT) to capture the nuanced effects of applied potential on a solvated catalyst interface, specifically focusing on the nitrogen reduction reaction (NRR) at sulfur vacancies in 1T'-phase MoS2. In the canonical method, the widely used the computational hydrogen electrode (CHE) predicts that adsorbed N2 structure properties are potential independent. In contrast, GC-DFT calculations reveal that reductive potentials activate N2 towards electroreduction by modulating backbonding strength, lengthening the N–N triple bond, and reducing its bond order. Similar trends are identified for CO, a classic backbonding ligand, suggesting broader relevance of this mechanism to diverse electrochemistries involving backbonded adsorbates. Furthermore, reductive potentials are required to make the subsequent N2 hydrogenation steps favorable, but concurrently destabilize both N2 and hydrogen adsorption.Our findings demonstrate that GC-DFT facilitates the comprehensive modeling of these phenomena, underscoring their collective implications in predicting electrocatalyst selectivity for the nitrogen reduction reaction and potentially other reactions. This research contributes valuable insights into the design and optimization of electrocatalysts for sustainable energy conversion. Figure 1