Interfacial Chemical Bonds Research Articles

2D/2D MgO/g-C3N4 S-scheme heterogeneous tight with Mg–N bonds for efficient photo-Fenton degradation: Enhancing both oxygen vacancy and charge migration

Construction of S-scheme heterojunction is an efficient strategy to enhance photocatalytic efficiency. Besides the retained redox ability, the wide work function gap and intimate interface contact are essential for efficient degradation. Nontoxic magnesium oxide (MgO) with two dimensional (2D) structures and high work function is a potential material for S-scheme photocatalysts. Herein, MgO was used to in-situ grown on graphitic carbon nitride (g-C3N4) for constructing the strongly connected MgO/g-C3N4 S-scheme photocatalyst with tight Mg–N bonds. Meanwhile, the presence of Mg–N bonds induces the formation of oxygen vacancy in MgO, which enhances the Fenton-like degradation. Furthermore, the Mg–N bond promotes the charge migration between MgO and g-C3N4. Consisting of the enhanced Fenton-like process and photocatalysis, the MgO/g-C3N4 shows a higher photo-Fenton degradation activity (80.01%) for degradation of organic pollutants (Rhodamine B, 100 mg L−1) in water, than g-C3N4 (28.46%) and MgO (55.64%). Therefore, the interfacial chemical bonds in heterojunction photocatalysts provide an efficient strategy for further enhancing the photocatalysis of S-scheme photocatalysts.

Interfacial chemical bond and oxygen vacancies modulated Mo2S3/BiOBr high-low junctions for enhanced photocatalysis gatifloxacin degradation

Insufficient light absorption and rapid recombination of photogenerated charges are considered to be the main obstacles limiting the efficiency of photocatalytic degradation of organic pollutants. In this study, a novel Mo2S3/BiOBr high-low junction was constructed by coupling narrow bandgap Mo2S3 to improve the light absorption capacity of BiOBr and enhance the utilization of photogenerated charges. Under simulated visible light irradiation, the optimised Mo2S3/BiOBr-6% high-low junction (90.1%) exhibited higher degradation efficiency of gatifloxacin compared to BiOBr (74.9%) and Mo2S3 (72.4%). The improved photocatalytic activity is mainly attributed to the interfacial chemical bonding and the formation of high-low junctions facilitating the rapid transfer of photogenerated charges between semiconductors, resulting in effective separation of photogenerated charges. In addition, the abundant oxygen vacancies in Mo2S3/BiOBr can act as electron traps to trap electrons and effectively reduce the photogenerated charge complexation. This study provides new perspectives for the construction of high-low junctions with interfacial chemical bonds and abundant oxygen vacancies and their use in the photocatalytic degradation of organic pollutants.

The Effect of Functionalized SEBS on the Properties of PP/SEBS Blends.

Styrene (St) was used as comonomer and glycidyl methacrylate (GMA) as grafting monomer to prepare SEBS-g-(GMA-co-St) graft copolymers via melt grafting. Then, the graft copolymers were employed as a compatibilizer for melt blending polypropylene (PP) and hydrogenated styrene-butadiene-styrene (SEBS) triblock copolymers. The effects of the amount of GMA in the graft copolymers on thermal properties, rheology, crystallization, optical and mechanical properties, and microstructure of the blends were investigated. The results show that GMA and St were successfully grafted onto SEBS. The GMA amount in the graft copolymer significantly influenced the comprehensive properties of PP/SEBS/SEBS-g-(GMA-co-St) blends. The epoxy groups of GMA reacted with PP and SEBS, forming interfacial chemical bonds, thereby enhancing the compatibility between PP and SEBS to varying extents. After introducing SEBS-g-(GMA-co-St) into PP/SEBS blends, crystallinity decreased, crystal size increased while transmittance remained above 91% with rising GMA amount in the graft copolymers, indicating excellent optical properties. Notched impact strength and elongation at break of the blends showed a trend of first increasing and then decreasing with increased amounts of GMA in the graft copolymers. When the amount of GMA in the graft copolymers was 3 wt%, the blends exhibited optimal toughness with notched impact strength and elongation at break of 30,165.82 J/m2 and 1445.40%, respectively. This was attributed to the tightest dispersion interface adhesion and maximum matrix plastic deformation, consistent with the mechanical performance results.

Interfacial bond characterization of epoxy adhesives to aluminum alloy and carbon fiber-reinforced polyamide by vibrational spectroscopy

Vibrational spectroscopic technique has been utilized to investigate interfacial bonding chemistry of two epoxy adhesive products, XP0012 and XP5005F, on plasma-treated AA6061 and carbon fiber-reinforced polyamide 66 (CFRP-PA66) surfaces. The change in vibrational peak ratios was measured by attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy to deduce bonding mechanisms. Both adhesives showed strong crosslinking polymerization of hydroxyl- and amine-initiated epoxy ring opening on AA6061 surface, but on CFRP surface XP0012 formed a simple amide linkage by the reaction of surface hydroxyl groups and nitrile groups of curing agent, and XP5005F formed a crosslinked network by hydroxyl-initiated epoxy ring opening polymerization. The different interfacial bonding formation of two adhesives on CFRP-PA66 surface is attributed to additive effect. Addition of additives to epoxy adhesives (XP5005F) changed the interfacial bonding mechanism on CFRP-PA66 surface, rather forming hydroxyl-initiated epoxy opening crosslinking polymerization than a simple amide bond formation (XP0012). The interfacial bonding chemistry was also proved by addition of bisphenol A (BA) to a simplified model diglycidyl ether of bisphenol A/dicyandiamide (DGEBA/DICY) epoxy system. When BA was added to the model DGEBA/DICY system, epoxy ring gradually decreased on CFRP-PA66 surface, while without BA, DGEBA/DICY showed only decrease in a nitrile peak intensity in ATR-FTIR. The foregoing different types of interfacial chemical bonds at the adhesive/CFRP-PA66 interfaces can affect the lap shear behavior of the joint.

Chemical bonding and facet modulating of p-n heterojunction enable vectorial charge transfer for enhanced photocatalysis

Heterojunctions have been proved to be the promising photocatalysts for hazardous contaminants removal, but the inferior interfacial contact, low carrier mobility and random carrier diffusion seriously hamper the photoactivity improvement of the conventional heterojunctions. Herein, SO chemically bonded p-n oriented heterostructure is fabricated via selectively anchoring of p-type Ag2S nanoparticles on the lateral facet of n-type Bi4TaO8Cl nanosheet. Such a p-n heterojunction engineering on specific facet of Bi4TaO8Cl semiconductor derives ingenious double internal electric field (IEF), which not only effectively creates the spatially separated oxidation and reduction sites, but also delivers the powerful driving forces for impactful spatial directed photocarrier transfer along the cascade path. Additionally, our experimental and theoretical analyses jointly signify that the interfacial SO bond could serve as an efficient atomic-level interfacial channel, which is conducive to encouraging the vectorial charge separation and migration kinetic. As a result, the Ag2S/Bi4TaO8Cl oriented heterojunction exhibits significantly enhanced visible light driven photocatalytic redox ability for tetracycline oxidation and hexavalent chromium reduction than those of single component and the traditional random/mixed heterojunctions. This study could provide a deeper insight into the synergistic effects of multi-IEF modulation and interfacial chemical bond bridging on optimizing the photogenerated carrier behaviors.

Visible-light induced tetracycline degradation catalyzed by dual Z-scheme InVO4/CuBi2O4/BiVO4 composites: The roles of oxygen vacancies and interfacial chemical bonds

Dual Z-scheme InVO4/CuBi2O4/BiVO4 (CuInBi) composites with rich oxygen vacancies and chemical bonds at the heterojunction interfaces were fabricated, for the first time, through hydrothermal method with post annealing treatment, in which CuBi2O4 acts as a bridge to connect InVO4 and BiVO4. The as-prepared composites exhibited superior photocatalytic activity compared with the individual semiconductors. Specifically, the degradation rate of tetracycline (20 mg/L) in the presence of CuInBi-1 (1.0 g/L) was up to 5.4, 2.8, and 3.1 times faster than those in the presence of CuBi2O4, InVO4, and BiVO4, respectively. The enhanced photocatalytic performance could be partially attributed to the good light absorption of CuBi2O4, which broadens the visible light response of the InVO4/CuBi2O4/BiVO4 composites. Meanwhile, the interfacial chemical bonds in the dual Z-scheme heterojunction help accelerate charge separation and maintain strong redox activity. In addition, the oxygen vacancies, induced mainly by the low-valent vanadium atoms, facilitate the production of singlet oxygen (1O2) through energy transfer, which easily attacks the electron-rich groups, including phenolic group, dimethylamino group, amine group, and double bonds, in tetracycline. The InVO4/CuBi2O4/BiVO4 composite exhibited excellent reusability and stability, and performed well in photocatalytic degradation of tetracycline in river water and under natural sunlight, demonstrating great potential for practical application. The probable photocatalytic mechanism of InVO4/CuBi2O4/BiVO4 composite was proposed according to the results of density functional theory (DFT) calculations, and the reactive oxygen species (ROSs) and major degradation intermediates detected in the photocatalytic system. This work demonstrates the important roles of oxygen vacancies and interfacial chemical bonds in boosting the photocatalytic activity of Z-scheme heterojunctions and provides a reference for the construction of high-activity photocatalysts for efficient degradation of antibiotics.

Interfacial chemical bond-modulated Z-scheme Cs2AgBiBr6/WO3 enables stable and highly efficient photocatalysis

Lead-free double perovskite Cs2AgBiBr6 has been widely devoted to photocatalysis owing to its outstanding optical properties. However, insufficient redox capacity and high photogenerated carrier recombination efficiency of Cs2AgBiBr6 would limit its effective performance. Herein, we have developed Cs2AgBiBr6/WO3 Z-scheme heterojunction for enabling stable and highly efficient photocatalysis by building interfacial chemical bonds at the interface. The internal electronic structure of Z-scheme heterojuction by regulating close coupling interfacial chemical bonds at the hetero-interface could accelerate the charge transfer, enhance the separation efficiency of photogenerated carriers and maximize the redox ability. The Cs2AgBiBr6/WO3 exhibits superior photocatalytic degradation, which could degrade 93.64% and 100% (complete mineralization) of Methyl Orange and Rhodamine B within 30 min and 25 min, respectively. The effective degradation of pollutants is ascribed to the electron-transfer mechanism of Z-scheme with reducing recombination rate of the photogenerated carriers, which could produce dominant O2– and supporting OH to effectively degrade the pollutants.

Co–N2 Bond Precisely Connects the Conduction Band and Valence Band of g‐C3N4/CoCo‐LDH to Enhance Photocatalytic CO2 Activity by High‐Efficiency S‐Scheme

Precise regulation of photogenic electron transfer path plays an important role in improving photocatalytic carbon dioxide reduction efficiency and product selectivity. Herein, under the guidance of density functional theory calculation, the interface chemical bond (CoN2 bond) at the atomic level is designed, and g‐C3N4/CoCo‐layered double hydroxide (LDH) heterostructure is manufactured. CoCo‐LDH with water oxidation ability and g‐C3N4 were combined to construct S‐scheme heterojunction with redox ability. The valence band and conduction band of g‐C3N4 and CoCo‐LDH are precisely connected by the interfacial CoN2 bond, which realizes the high‐speed transfer of electron transport. Despite the absence of cocatalyst, the heterojunction exhibits high water oxidation and carbon reduction capacity due to the precise regulation of CoN2 bonds. Theoretical calculations and experimental results show that the addition of CoCo‐LDH: reduces the oxidation overpotential of water to provide more H protons; regulates the delocalization charge of g‐C3N4; and reduces the energy barrier of the CO2 intermediate (*COOH) in the reduction half‐reaction. The results show that the selectivity of carbon‐based substances in the products was 100%, and the optimal CO yield was 71.39 μmol g−1 h−1, which is among the highest values of g‐C3N4‐based photocatalysts.

Rapid photocatalytic reduction of hexavalent chromium over Z-scheme MgIn2S4/BiPO4 heterojunction: Performance, DFT calculation and mechanism insight

The accumulation of highly fluid and biotoxic hexavalent chromium (Cr(VI)) impairs water ecosystems. It is urgent to quickly reduce Cr (VI) to trivalent chromium (Cr (III)) in wastewater. Hereby, Z-scheme MgIn2S4/BiPO4 heterojunction was prepared, and MB-30 (mass ratio of BiPO4 to composite) presented a rapid Cr(VI) (10 mg L−1) removal efficiency of 100% within 10 min, its kinetic rate constant was 9.0 and 30.1 folds that of MgIn2S4 and BiPO4, respectively. After four rounds, MB-30 maintained a high removal rate of 93.18% and stabilized crystal texture. First-principles calculations revealed that the formation of Z-scheme heterojunction could ameliorate charge generation, detachment, migration capability, and light utilization. Meanwhile, the coupling of S and O in the two components produced a tight S–O bond, which acted as an atomic-level access to promote carrier migration. The findings were consistent with the structure superiority and optical and electronic properties of MB-30. The Z-scheme pattern was substantiated based on multifarious experiments, which exhibited an elevated reduction potential while emphasizing the significance of interfacial chemical bond and the internal electric field (IEF) on carrier detachment and migration.

Designing Sphere-like FeSe2-Carbon Composites with Rational Construction of Interfacial Traits towards Considerable Sodium-storage Capabilities

Due to their low cost and high stability, sodium-ion batteries have been increasingly studied. However, their further development is limited by the relative energy density, resulting in the search for high-capacity anodes. FeSe2 displays high conductivity and capacity but still suffers from sluggish kinetics and serious volume expansion. Herein, through sacrificial template methods, a series of sphere-like FeSe2-carbon composites are successfully prepared, displaying uniform carbon coatings and interfacial chemical FeOC bonds. Moreover, benefiting from the unique traits of precursor and acid treatment, rich structural voids are prepared, effectively alleviating volume expansion. Utilized as anodes of sodium-ion batteries, the optimized sample displays considerable capacity, achieving 462.9 mAh g−1, with 88.75% coulombic efficiency at 1.0 A g−1. Even at 5.0 A g−1, their capacity can be kept at approximately 318.8 mAh g−1, while the stable cycling can be prolonged to 200 cycles above. Supported by the detailed kinetic analysis, it can be noted that the existing chemical bonds facilitate the fast shuttling of ions at the interface, and the enhanced surface/near-surface properties are further vitrified. Given this, the work is expected to offer valuable insights for the rational design of metal-based samples toward advanced sodium-storage materials.

Microwave-Assisted Rational Designed CNT-Mn3 O4 /CoWO4 Hybrid Nanocomposites for High Performance Battery-Supercapacitor Hybrid Device.

Extensive research interest in hybrid battery-supercapacitor (BSH) devices have led to the development of cathode materials with excellent comprehensive electrochemical properties. In this work, carbon nanotube (CNT)-Mn3 O4 /CoWO4 triple-segment hybrid electrode is synthesized by using a two-step microwave-assisted hydrothermal route. Systematic physical characterization revealed that, with the assistance of microwave, granular Mn3 O4 and spheroid-like CoWO4 with preferred orientation, and oxygen vacancies are stacked or arranged on CNTs skeletons to construct a rational designed hybrid nanocomposite with abundant heterointerfaces and interfacial chemical bonds. Electrochemical evaluations show that the synergistic cooperation in CNT-Mn3 O4 /CoWO4 resulted in an ultra-high specific capacity (1907.5Cg-1 /529.8mAhg-1 at 1Ag-1 ), a wide operating voltage window (1.15V), the satisfactory rate capability (capacity maintained at 1016.5Cg-1 /282.3mAhg-1 at 15Ag-1 ), and excellent cycling stability (117.2% initial capacity retention after 13000 cycles at 15Ag-1 ). In addition, the assembled CNT-Mn3 O4 /CoWO4 //N doped porous carbon (NC) BSH device delivered a stable working voltage of 2.05V and superior energy density of 67.5Whkg-1 at power density of 1025Wkg-1 , as well as excellent stability (92.2% capacity retained at 5Ag-1 for 12600 cycles). This work provides a new and feasible tactic to develop high-performance transition metal oxide-based cathodes for advanced BSH devices.

Enhancing welding strength of thermoplastic vulcanizate/aluminum alloy via adding zinc methacrylate

Welding of metals and polymer materials has always been one of the difficult problems. In this work, we incorporated zinc methacrylate (ZDMA) to polypropylene/ethylene propylene diene rubber thermoplastic vulcanizate (PP/EPDM TPV) to improve the welding performance of the TPV and A6061-t6 aluminum alloy (6061). We firstly processed a welding simulation experiment on a flat vulcanizer. In the experiment of simulating heat source, ZDMA effectively improved the strength of TPV/6061 joints, and the strength of the joints with 30 phr (parts per hundreds of rubber) ZDMA increased tenfold compared to that with 5 phr ZDMA. The increase of joint strength was the result of the combined effect of TPV's polarity, dimensional stability, and interfacial chemical bonds. The results of X-ray photoelectron spectroscopy (XPS) and scanning electron microscope (SEM) showed that: during the welding process, the carboxylate ions (-COO-) of ZDMA in TPV migrated to the interface of TPV/6061 joints and constructed chemical bonds (C–O–Al) with 6061. Then, we welded the TPV and 6061 using a Friction Stir Spot Welding (FSSW) machine, the strong interface strength (tension-shear load = 1.2 kN) between TPV and 6061 verified our simulation experiment. Furthermore, the knowledge in this work will benefit the research in welding of TPV and lightweight metals to improve the strength of the interface between plastics and metals.

Boosted Charge Transfer via Coordinate Bond Construction in Porphyrin Metal–Organic Framework/ZnIn2S4 Core–Shell Heterostructures

Intimate interface design at the molecular level in heterojunctions deserves significant attention since the charge transfer efficiency at the interfaces can greatly affect the catalytic performance. Herein, an efficient interface engineering strategy was reported to design a titanium porphyrin metal-organic framework-ZnIn2S4 (TMF-ZIS) core-shell heterojunction which is tightly connected via coordination bonds (-N-Zn-). Such interfacial chemical bonds as the directional carrier transfer channels afforded improved charge separation efficiency compared to the physical composite of TMF and ZIS without chemical bonding. As a result, the optimized TMF-ZIS composite showed a 13.37 mmol·g-1·h-1 H2 production which is 47.7, 3.3, and 2.4 times that of TMF, ZIS, and mechanical mixing samples, respectively. Moreover, the composite also exhibited high photocatalytic tetracycline hydrochloride (TCH) degradation efficiency. Profiting from the core-shell structures, the ZIS shell efficiently prevented the aggregation and photocorrosion of TMF core particles which afforded enhanced chemical stability. Such an interface engineering strategy will be a versatile method to obtain highly effective organic-inorganic heterojunctions and offer new ideas for modulating the interfaces in the heterojunctions at the molecular level.

Quantum Mechanical Study of the Dielectric Response of V2C-ZnO/PPy Ternary Nanocomposite for Energy Storage Application

With the proliferation of electronic gadgets and the internet of things comes a great need for lightweight, affordable, sustainable, and long-lasting power devices to combat the depletion of fossil fuel energy and the pollution produced by chemical energy storage. The use of high-energy-density polymer/ceramic composites is generating more curiosity for future technologies, and they require a high dielectric constant and breakdown strength. Electric percolation and Interface polarization are responsible for the high dielectric constant. To create composite dielectrics, high-conductivity ceramic particles are combined with polymers to improve the dielectric constant. In this work, ternary nanocomposites with better dielectric characteristics are created using a nanohybrid filler of V2C Mxene-ZnO in a polypyrrole (PPy) matrix. Then, the bonding and the uneven charge distribution in the ceramic/ceramic contact area are investigated using quantum mechanical calculations. This non-uniform distribution of charges is intended to improve the ceramic/ceramic interface’s dipole polarization (dielectric response). The interfacial chemical bond formation can also improve the hybrid filler’s stability in terms of structure and, consequently, of the composite films. To comprehend the electron-transfer process, the density of state and electron localization function of the ceramic hybrid fillers are also studied. The polymer nanocomposite is suggested to provide a suitable dielectric response for energy storage applications.

Nanoclay-Modulated Interfacial Chemical Bond and Internal Electric Field at the Co3 O4 /TiO2 p-n Junction for Efficient Charge Separation.

To achieve a high separation efficiency of photogenerated carriers in semiconductors, constructing high-quality heterogeneous interfaces as charge flow highways is critical and challenging. This study successfully demonstrates an interfacial chemical bond and internal electric field (IEF) simultaneously modulated 0D/0D/1D-Co3 O4 /TiO2 /sepiolite composite catalyst by exploiting sepiolite surface-interfacial interactions to adjust the Co2+ /Co3+ ratio at the Co3 O4 /TiO2 heterointerface. In situ irradiation X-ray photoelectron spectroscopy and density functional theory (DFT) calculations reveal that the interfacial Co2+ OTi bond (compared to the Co3+ OTi bond) plays a major role as an atomic-level charge transport channel at the p-n junction. Co2+ /Co3+ ratio increase also enhances the IEF intensity. Therefore, the enhanced IEF cooperates with the interfacial Co2+ OTi bond to enhance the photoelectron separation and migration efficiency. A coupled photocatalysis-peroxymonosulfate activation system is used to evaluate the catalytic activity of Co3 O4 /TiO2 /sepiolite. Furthermore, this work demonstrates how efficiently separated photoelectrons facilitate the synergy between photocatalysis and peroxymonosulfate activation to achieve deep pollutant degradation and reduce its ecotoxicity. This study presents a new strategy for constructing high-quality heterogeneous interfaces by consciously modulating interfacial chemical bonds and IEF, and the strategy is expected to extend to this class of spinel-structured semiconductors.

Interfacial chemical bond modulated ultrathin PbBiO2Cl/Bi2O3 Z-scheme heterojunction for promoting charge separation and enhancing photocatalytic activity

Rational design of heterojunction can effectively promote photogenerated charge separation, which is considered to be an effective strategy to enhance the photocatalytic activity. Here, 2D ultrathin PbBiO2Cl/Bi2O3 heterojunction was synthesized in situ by glucose assisted one-step hydrothermal reaction followed by calcination. The theoretical calculations and experimental results indicate that the ultrathin PbBiO2Cl/Bi2O3 heterojunction has a direct Z-scheme band structure modulated by the interfacial chemical bonds of Pb-O and Bi-O, which can significantly improve the charge separation efficiency, thereby enhancing the photocatalytic activity. The full spectrum photocatalytic activity of the ultrathin PbBiO2Cl/Bi2O3 heterojunction is 10 and 30 times higher than that of pristine PbBiO2Cl and Bi2O3, and the visible light photocatalytic activity is 13.5 and 112.3 times higher than that of pristine PbBiO2Cl and Bi2O3, respectively. This work provides a new strategy for in situ construction of ultrathin Z-scheme heterojunction with efficient charge separation modulated by interfacial chemical bonds.

Designed 2D/2D/2D Bi2WO6/Ti3C2/SnNb2O6 Z-scheme heterojunction via interfacial chemical bond with enhanced photocatalytic activity

2D/2D/2D materials are widely used in photocatalysis owing to the advantages of high specific surface area, large contact interface, numerous charge transfer channels and ultrashort charge transfer distance. In this work, 2D/2D/2D Bi2WO6/Ti3C2/SnNb2O6 catalysts were successfully constructed via an anaerobic hydrothermal method. Due to ultrathin 2D Ti3C2 MXene served as an electron mediator and combined with 2D SnNb2O6 and 2D Bi2WO6 by Ti−O−Sn interface bond or Ti–O–Bi interface bond to form Z-scheme heterojunction, which could afford charge transfer channels and increase reactive sites. As a result, the Bi2WO6/Ti3C2/SnNb2O6 composites significantly improved the photodegradation efficiency of tetracycline hydrochloride due to the high redox ability, and its degradation rate in 90 min was 10.22 times that of SnNb2O6. This work provides an effective method to construct 2D/2D/2D Z-scheme heterojunction by tight chemical bond.

Interfacial Chemical Bond Engineering in a Direct Z-Scheme g-C3N4/MoS2 Heterojunction.

The Z-scheme heterojunction shows great potential in photocatalysis due to its superior carrier separation efficiency and strong photoredox properties. However, how to regulate the charge separation at the nanometric interface of heterostructures still remains a challenge. Here, we take g-C3N4 and MoS2 as models and design the Mo-N chemical bond, which connects exactly the CB of MoS2 and VB of g-C3N4. Thus, the Mo-N bond could act as an atomic-level interfacial "bridge" that provides a direct migration path of charge carriers between g-C3N4 and MoS2. Experiments confirmed that the Mo-N bond and the internal electric field promote greatly the photogenerated carrier separation. The optimized photocatalyst exhibits a high hydrogen evolution rate that is about 19.6 times that of the pristine bulk C3N4. This study demonstrates the key role of an atomic-level interfacial chemical bond design in heterojunctions and provides a new idea for the design of efficient catalytic heterojunctions.

Surface Unsaturated Sulfur Modulates Pt Sub‐Nanoparticles on Tandem Homojunction CdS for Efficient Electron Extraction

AbstractThe metal‐semiconductor interfacial photocarrier extraction and utilization are crucial for boosting photocatalytic activity, and the construction of interfacial chemical bonds to anchor the metal active sites is an emerging direction to facilitate interfacial photocarrier extraction. Herein, interfacial PtS bonds are designed via an in situ photoreduction to precisely anchor Pt sub‐nanoclusters (SNCs) on the tandem homojunction CdS (Pt‐CdSx‐T). The optimized Pt0.02‐CdSx‐T photocatalyst exhibits an impressive hydrogen evolution rate of 854.2 µmol h−1 with an apparent quantum yield of 43.55% at 470 nm, which is nearly 13 times that of pristine CdS. Systematic investigations reveal that the abundant coordination‐unsaturated S atoms on CdSx‐T act as sites to anchor Pt SNCs and the thus formed interfacial PtS bonds accelerate the metal‐semiconductor interface directional photocarriers transfer. The homojunction CdSx‐T with its tandem potential barrier promotes the separation of photocarriers via an internal electrostatic field, and the metal‐semiconductor interface electron transfer kinetics and H* adsorption capacity depend on the Pt SNCs size as confirmed by the surface photovoltage spectroscopy and density functional theory calculations. This work affords a new perspective for the exploitation of precisely dispersed cocatalysts on homojunction catalysts to achieve high‐efficiency photocatalytic hydrogen evolution.

Interfacial bond endowing FeS2/Bi2S3 composites superb OER performance

Developing high-efficient main group element Bismuth-based OER electrocatalysts is of great significance to sustainable energy storage and conversion. However, they still suffer from structural deficiencies such as poor electroconductivity, lack of active sites and high absorption energy barriers. Constructing Fe-contained Bismuth-based compounds is regarded as an effective strategy to ameliorate the above deficiencies. In this study, core-shell structured FeS2/Bi2S3 composites are achieved successfully with solvothermal and sulfurization method by constructing interfacial bond Bi–S–Fe. Through in-depth analysis, we confirm that the interfacial chemical bond Bi–S–Fe, act as a bridge to the linkage of FeS2 and Bi2S3, enhance electron transport efficiency and hydrophilicity by regulating charge ordering. Moreover, the proportion of metal active centers (Fe3+, Fe2+, Bi3+, Bi2+) with different absorption/desorption energy could also be modulated by Bi–S–Fe, thus endowing FeS2/Bi2S3 composites a superb OER performance. As expected, FeS2/Bi2S3-0.33 shows ultralow overpotentials of 313 and 419 mV at current densities of 10 and 100 mA cm−2, respectively, and a Tafel slope as low as 25 mV dec−1, which outperforms most of Bismuth-based and even noble/transition metal-based electrocatalysts. This work may shed light on construction of interfacial bond for rational design of high-performance OER catalysts.