Doping Elements Research Articles

Interstitial N-Doped TiO2 for Photocatalytic Methylene Blue Degradation under Visible Light Irradiation

Photocatalysis is a promising method for methylene blue (MB) degradation due to its effectiveness and environmental compatibility. Among the photocatalysts, titanium dioxide (TiO2) has been widely used for MB degradation due to its exceptional photocatalytic activity. However, the wide bandgap limits the degradation efficiency of TiO2 under visible light. Here, an interstitial nitrogen-doped TiO2 (5%NT/TiO2) used thiourea as the N source was fabricated for visible light-derived MB degradation. The 5%NT/TiO2 exhibited an extended absorption range of visible light. Moreover, photoelectrochemical measurements showed an improvement in the photocurrent response and charge transfer behavior on N/TiO2. Thus, 5%NT/TiO2 had enhanced photocatalytic activity compared with pristine TiO2 and substitutive N-doped TiO2 (5%NAB/TiO2). The accelerated photocatalytic MB degradation process on N/TiO2 could be mainly attributed to the interstitial N doping, which caused the appearance of new energy states and extended optical properties. Through comparing the impact of interstitial and substitutive in TiO2 activity, our work proposes a suitable form of element doping to enhance the optical properties and photocatalytic activity of TiO2 and even other semiconductors, providing guidance for future work.

Interface and doping engineering of V2C‐MXene‐based electrocatalysts for enhanced electrocatalysis of overall water splitting

AbstractThe restacking and oxidizable nature of vanadium‐based carbon/nitride (V2C‐MXene) poses a significant challenge. Herein, tellurium (Te)‐doped V2C/V2O3 electrocatalyst is constructed via mild H2O2 oxidation and calcination treatments. Especially, this work rationally exploits the inherent easy oxidation characteristic associated with MXene to alter the interfacial information, thereby obtaining stable self‐generated vanadium‐based heterointerfaces. Meanwhile, the microetching effect of H2O2 creates numerous pores to address the restacking issues. Besides, Te element doping settles the issue of awkward levels of absorption/desorption ability of intermediates. The electrocatalyst obtains an unparalleled hydrogen evolution reaction and oxygen evolution reaction with the overpotential of 83.5 and 279.8 mV at −10 and 10 mA cm−2, respectively. In addition, the overall water‐splitting device demonstrates a low cell voltage of 1.41 V to obtain 10 mA cm−2. Overall, the inherent drawbacks of MXene can be turned into benefits based on the planning strategy to create these electrocatalysts with desirable reaction kinetics.

Rare earth element Ce-doped floral In2O3 with high sensing performance for n-butanol

Pure In2O3 and the graded flower-shaped In2O3 structures doped with Ce, a rare earth element, were synthesized by an easy-to-operate template-free hydrothermal method, and the high sensing performance of the sensor for n-butanol was investigated. The micro-morphology and elemental compositions of the samples and their valence states were characterized by XRD, SEM, TEM, XPS and other testing methods. The morphological and compositional characterization showed that Ce doping is able to cause lattice distortion, which affects the sensing performance. The gas-sensitive test results revealed that 3 wt% Ce-doped In2O3 has the best sensing performance. At the optimal operating temperature of 320 °C, the response of 3 wt% Ce-In2O3 to 100 ppm n-butanol was as high as 225.63, which was 3.7 times higher than that of the pure In2O3 sensor (60.36). In addition, the Ce-doped In2O3 sensor also exhibited excellent selectivity, repeatability, long-term stability, and large specific surface area (73.1104 m2g-1). This study enhances the understanding of the mechanism of rare earth element doping to improve gas-sensitive properties and provides a new effective strategy for designing high-performance gas-sensitive materials.It also provides new ideas for the efficient detection of the toxic gas n-butanol.

MOF-on-MOF-derived double-shelled iron-doped cobalt sulfide nanosheet arrays modified by CeO2 for asymmetric supercapacitors

Through deliberate design of nanostructures and modifications to the surface, significant advancements in energy storage performance can be achieved. This work focuses on the creation of iron-doped cobalt sulfide hollow nanosheets, featuring a distinctive double-shelled structure. This unique architecture is achieved by replacing the ligand within zeolitic imidazole framework (ZIF)-L with K4Fe (CN)6, followed by a sulfurization process. Subsequently, a layer of CeO2 cladding is integrated using solvothermal synthesis. The resulting hollow double-shelled structure fosters intimate contact between the electrode material and electrolyte, effectively mitigating the challenges associated with substantial volume fluctuations during electrochemical processes. Additionally, the porous characteristics inherited from ZIF, augmented redox reactions resulting from elemental doping, and coordination with the external CeO2 modification further enhance the electrochemical performance of the electrode. Consequently, the Fe-CoS/CeO2 electrode exhibits an impressive specific capacitance of 3727.5 F g−1 at 1 A g−1. When employed in an asymmetric supercapacitor configuration with activated carbon (AC) serving as the negative electrode, the Fe-CoS/CeO2//AC demonstrates exceptional energy storage capabilities, achieving 36.4 W h kg−1 at 800.0 W kg−1 and exhibiting superior long-term stability with 89.8 % retention of initial capacitance after 10,000 cycles at 10 A g−1.

Manufacture and performance assessment of PVDF-La@TiO2 Photocatalyst implanted membrane for efficient produced water treatment via ozonation-adsorption process under visible-light exposure

This research aims to develop a visible light-activated photocatalytic membranes for produced water treatment system by employing the phase inversion technique for implantation of La@TiO2 photocatalytic nanoparticles into PVDF membrane at concentrations varying from 0 % to 2 % wt. The results demonstrated significant amplification of COD and NH3-N removal efficiency. Implantation of the photocatalyst into PVDF membranes via bulk mixing, coupled with elemental doping and combination with La@TiO2 appreciably reduces band gap energy and increases visible light absorption thereby improves membrane's optical properties. SEM-EDX analysis confirms uniform distribution of La@TiO2 nanoparticles on the membrane surface, which leads to amplify membrane's hydrophilicity and water absorption. The modified membrane facilitated concurrent photocatalytic degradation and filtration processes that lead to remarkable reductions in TDS, COD, and NH3-N pollutants, with the highest flux was achieved when 1.5 % wt. La@TiO2 was incorporated into the membrane matrix. Obviously, adsorption and ozonation processes promote synergistic effect and amplify pollutant flux and efficiency to a greater extent. Furthermore, the modified membrane exhibited extraordinary antifouling properties and stability, providing excellent reusability with a 96.22 % fouling reduction rate after five consecutive cycle tests.

Interface engineering of AgI/(P, K)-g-C3N4 novel S-scheme heterostructures as a highly efficient photocatalyst for RhB degradation

In this study, we developed an in-situ deposition method to load small-sized AgI nanoparticles as an oxidative photocatalyst (OP) onto phosphorus (P) and potassium (K) co-doped two-dimensional porous g-C3N4 (PK-CN-N) as a reductive photocatalyst (RP), forming an S-scheme heterojunction photocatalyst AgI/PK-CN-N. PK-CN-N achieved morphology control and element doping, leading to surface functionalization and heterostructure formation for the AgI/PK-CN-N photocatalyst. Notably, the 50AgI/PK-CN-N composite demonstrated an approximately 95 % removal efficiency for RhB within 30 minutes, 17.6 times higher than pure g-C3N4, surpassing most reported g-C3N4-based photocatalysts. The enhanced photocatalytic efficiency is attributed to the surface modification strategy and heterostructure formation of g-C3N4, which broadens the visible light response range, increases the number of active sites, improves the separation of photogenerated electron-hole pairs, and enhances REDOX capabilities. The band structure of the composite was elucidated through Mott-Schottky analysis and UV–vis DRS. The formation of the AgI/PK-CN-N S-scheme heterojunction and its charge transfer mechanism was confirmed through XPS, band structure analysis, KPFM, and EPR spectroscopy. Experimental data confirmed the presence of a strong and effective interface electric field between the two semiconductors, leading to band bending and accelerated charge separation. Additionally, the introduction of small-sized AgI semiconductors enhanced the exposure of the coupling interface, further improving catalytic performance. The reusability and lifespan of the catalyst were also analyzed, showing that after four cycles, the photocatalytic activity remained above 92 %.

Monitoring the synergistic effect of Mn/Ni Co-doping and morphological engineering in α-Fe2O3 for energy storage capacity as battery type electrode material

Morphology engineering and elemental doping proved to be an efficient way to enhance the capacitive performance of electroactive materials. To investigate the tuning of morphology via doping here, pure α-Fe2O3 and Ni1-xMnxFeO3+δ (x = 0,0.3,0.5,0.7,1) was synthesized via the hydrothermal method and investigated the impact of Ni and Mn doping on the structural, morphological, and electrochemical properties of α-Fe2O3. The XRD and Raman spectra confirmed the single-phase hematite's rhombohedral crystal structure of pure α-Fe2O3 with no extra peaks confirming the Ni and Mn doping without impurities. SEM analysis demonstrated a shift in the morphology of nanostructures, from spherical to nano-rod structures with increasing the concentration of Mn doping. Cyclic voltammetry results unveiled the battery-type behavior of Ni1-xMnxFeO3+δ nanoparticles while GCD results indicated an escalation in specific capacity from 380 Cg-1 (706 Fg-1) to 751 Cg-1 (1251 Fg-1) with higher Mn content. This increase culminated in the highest specific capacity of 751 Cg-1 (1251 Fg-1) for α-MnFeO3 +δ nanoparticles at the current density of 1 Ag-1 which is higher than α-Fe2O3 (380 Cg-1), NiFeO3+δ (425 Cg-1), Ni0.7Mn0.3FeO3+δ (470 Cg-1), Ni0.5Mn0.5FeO3+δ (530 Cg-1), and Ni0.3Mn0.7FeO3+δ (590 Cg-1). In addition, α-MnFeO3+δ exhibited a remarkable charge capacity retention (96%), and 100% coulomb efficiency after 10,000 consecutive GCD cycles. The noteworthy specific capacity and robust stability of the α-MnFeO3+δ nanorods suggest their suitability as potential candidates for battery type supercapacitors.

Tribological Properties of MoN (Ag‐W)‐MoS2 (W) Multilayer Films in Wide Temperature Range

In nitride films, an enhanced lubrication effect has been achieved through the incorporation of a soft metal element such as Ag. However, at medium and high temperatures, the favorable tribological properties cannot be sustained for an extended period due to the rapid depletion of Ag. To address this issue, a multilayer film design with W element doping is conceived to impede Ag depletion. MoN (Ag‐W)‐MoS2 (W) multilayer films with 4 different layers are prepared, and their tribological properties are systematically characterized across temperatures ranging from 25 to 800 °C. The results indicate that the tribological properties of four different multilayer films vary considerably at different temperatures. The 8‐layer multilayer film exhibits a relatively low friction coefficient that can be maintained at wide‐range temperatures. X‐ray diffractometer patterns are obtained before and after the friction test to elucidate the lubrication phases of different layers within the multilayer films at various temperatures. Additionally, 3D profiles of wear trajectory surfaces are generated, revealing enhanced wear resistance achieved by effectively inhibiting the migration of Ag. The low friction coefficient in multilayer films can be attributed to the oxidation of MoS2 and the generation of new lubrication phases, as confirmed by Raman spectra analysis.

Analysis of semiconductor properties of fabricated graphene materials

Introducing dopant elements into graphene is a crucial process for creating bandgaps, which will have significant importance in developing nanoelectronic devices in the future. In this study, we provide an analysis of the electrical and carrier mobility properties of graphene doped with BN in ratios of 1 %, 3 %, and 5 %, graphene 95 %, ZnO-3 %, and BN2 %, graphene-95 %, Al2O3-3 % and BN-2 %, graphene-95 %, TiO2-3 % and BN-2 % by using a sintering process. Upon analyzing the band structure, it was determined that the mentioned materials demonstrate a bandgap in graphene. The resistivity values for fabricated graphene materials doped with different nanoparticles are estimated using the Source-meter Unit (SMU) at room temperature (25°C), 100°C and 200°C. The conductivity of graphene is 8.93E+07 Ω−1cm−1 and reduced gradually with the doping percentages. The resistivity of graphene is measured at 1.12 E-08 Ω.cmand increases with the doping percentages, and carrier mobility is measured to be 9239 cm2V−1s−1 and gradually reduced with the doping percentages. The temperature-dependent conductivity is determined using electrical conductivity under the constant relaxation time approximation.

Co/Cu/C multi-doped VOx composite nanobelts for aqueous asymmetric supercapacitors

VOx, possessing multiple stable oxidation states, demonstrates high theoretical capacity, rendering it a promising candidate for supercapacitor electrodes. However, its practical capacity and cyclic performance are hindered by low electrical conductivity and sluggish diffusion kinetics. Incorporating heteroatoms into transition metal oxides has emerged as an effective approach to mitigate these challenges. Nonetheless, the reported capacities and cyclic stabilities of single-element-doped-VOx as supercapacitor electrodes remain unsatisfactory. Herein, we propose a Co/Cu/C multi-doped VOx composite (VCoCuC) nanobelts, which significantly boosts the specific capacity (5.96 C cm−2/398.6 C g−1 @ 10 mA cm−2) and cycling performance (97.1% of the initial capacity after 2,000 cycles @ 60 mA cm−2) compared to samples with only Co/Cu, Co/C, or Cu/C doping. The possible functions of each doping element are discussed. Additionally, an aqueous asymmetric supercapacitor with VCoCuC as the cathode and conductive carbon cloth (CC) as the anode is assembled to demonstrate the potential application of VCoCuC, which delivers high energy density and excellent cyclic performance. These findings highlight the potential for improving the practical capacity and cyclic performance of VOx electrodes via a multi-doping strategy.

Effects of doping of Sm, Y, Ce and La on crystal structure, phase and photocatalytic performance of TiO2 powders prepared by sol-gel method

In the present work, pure and 1 mol% samarium (Sm), yttrium(Y), lanthanum (La), cerium (Ce)-doped titanium dioxide (TiO2) powders were prepared by sol-gel method. Taking Methylene blue (MB) dye as degradation targets the photodegradation performance of the photocatalysts was studied. XRD spectra confirmed that the doping of rare earth elements (RE) could inhibit the transformation of TiO2 from anatase to rutile crystal at high temperature of 800 °C. XPS analyzed the chemical state of the elements in the powder. Characterization such as SEM and TEM found that the doping of the RE elements made the severely agglomerated particles become dispersed and refined, increased the specific surface area, and reduced the optical bandgap. Simulated visible light degradation results of MB showed that the degradation efficiency was significantly improved by doping of the RE elements, and the best efficiency is 88 % for Sm-doped TiO2 powder samples.

Synthesis, Structure, Photoluminescence, and Optical Properties of (Co/B) Co‐Doped ZnO Nanoparticles

AbstractCo/B co‐doped ZnO nanoparticles, denoted as Zn0.95‐xBxCo0.05O, are synthesized using the sol–gel method to explore the effects of the defects on optical properties. The stoichiometry is adjusted by varying the doping levels (x = 0.00, 0.01, 0.02, 0.03, 0.04, and 0.05). X‐ray diffraction is employed to analyze the structural characteristics of all Co/B co‐doped ZnO nanoparticles, confirming the presence of a hexagonal Wurtzite structure by assessing the c/a ratios. To investigate structural defects, photoluminescence properties are measured using the Fluorescence Spectrophotometer, revealing violet, blue, green, and red emissions. With the doped of boron (B), a shift from green emission to blue emission occurs, indicating a transformation of singly charged oxygen vacancies (VO+) to VZn vacancies. Fourier Transform Infrared (FTIR) spectra (4000–400 cm−1) are acquired using the Perkin Elmer Spectrum Two FTIR‐ATR spectrophotometer. The surface morphology, crystallite size, and nanoparticle shapes are characterized through Transmission Electron Microscope (TEM) analysis. Elemental compositions are determined using Electron Dispersive Spectroscopy (EDAX). The Shimadzu 2600 UV‐Spectrophotometer is used to examine optical characteristics. The samples' energy band gaps are calculated, and the impact of dopant elements on these optical characteristics is examined. Five different models are used to compute the refractive index.

Cobalt-doped graphitic carbon nitride: A multifunctional material for humidity sensing, electrochemical water splitting and environmental remediation applications

Graphitic carbon nitride (g-C3N4) has emerged as a promising eco-friendly material for catalysis and sensing applications due to their unique properties. However, limitations like low specific surface area, insufficient light absorption, and poor conductivity hinder their broader usability. Elemental doping has been established as an effective approach to modify the electronic structure and bandgap of g-C3N4 thus significantly expanding its light-responsive range for enhanced charge separation. This work reports on the fabrication of cost-effective and stable g-C3N4 and cobalt-doped g-C3N4 (Co@g-C3N4) via a simple one-step calcination process. The humidity sensing performance of both g-C3N4 and Co@g-C3N4 was evaluated across a broad humidity range (7 % - 94 % RH) at various testing frequencies. The results demonstrated good reversibility with Co@g-C3N4 exhibiting superior performance compared to pristine g-C3N4. Furthermore, the synthesized materials were assessed for their suitability as photoelectrochemical water splitting catalysts for hydrogen production, representing a step towards energy-efficient fuel cells. Notably, Co@g-C3N4 displayed enhanced performance with a lower onset potential (420 mV) and a lower Tafel slope (65.4 mV dec-1) for the hydrogen evolution reaction (HER) compared to undoped counterparts. Additionally, Co@g-C3N4 nanorods exhibited remarkable performance for the oxygen evolution reaction (OER), showcasing a lower onset potential (1.505 V) and a considerably low overpotential (270 mV), surpassing numerous reported electrocatalysts and even rivaling precious-metal-based ones. Finally, enhanced photocatalytic activities for organic dyes degradation were recorded for the mentioned materials. Therefore, g-C3N4 and related materials have great potential for their industrial electrochemcial applications.

Effects of electrical and mechanical properties of Ba0.92Ca0.08Zr0.05Ti0.95O3 ceramics with lanthanum dopants

Element doping is one of the important approaches to improve the performance of lead-free piezoelectric ceramics. In this study, Ba0·92Ca0·08Zr0·05Ti0·95O3-xLa (BCZT-xLa) piezoelectric ceramics were prepared by sol–gel method. The effects of La3+ contents on the phase structure, mechanical properties, and electrical properties of BCZT-xLa ceramics were investigated. Results showed that La3+ could affect the properties of ceramics by adjusting the concentration of oxygen vacancies and microstructure. When the La3+ contents were 0.008, the ceramics showed the best performance (the maximum permittivity was 8736.27, the remnant polarisation was 9.69 μC/cm2 and the coercive field was 3.44 kV/cm). The influences of Vickers hardness on ceramics were investigated using various La3+ contents. The lattice energy and oxygen vacancies were the main factors for the change in Vickers hardness. With an increment of x, the Vickers hardness values decreased from 6.271 GPa to 1.438 GPa. This study could provide a reference for BCZT piezoelectric ceramics doped with rare earth elements.

Effect of sites of doped Mg on the stability of lattice oxygen in lithium-rich manganese-based cathode materials

Elemental doping is considered as an effective method for altering the localized electronic structure of lattice oxygen in lithium-rich manganese-based oxides (LRMO) and enhancing their structural stability. However, the effect of doping heteroatoms at different sites on the oxygen redox is not clear. In this work, Mg is introduced into transition metals (TM) and lithium (Li) sites of LRMO at co-precipitation stage and lithiation stage to prepare LRMO-TM and LRMO-Li, respectively. The experimental results and density-functional theory calculations demonstrate that the oxygen release is reduced from 4.1653 nmol mg−1 of pristine to 3.3886 nmol mg−1 of LRMO-Li, and 2.7688 nmol mg−1 of LRMO-TM. The reduction of oxygen release of LRMO-Li is related to the formation of strong Mg-O interactions. Different from that, the lower oxygen release of LRMO-TM is mainly due to the reduction of electron holes in the O 2p state caused by the weaker Mn-O covalency, which effectively restricts the over-oxidization of oxygen. The capacity retention of LRMO-TM is 85.18 % at 0.2C after 200 cycles, which is higher than that of LRMO (78.63 %) and LRMO-Li (82.28 %). This work reveals the mechanism of enhancing lattice oxygen stability caused by Mg doping at different sites.

(Y3+/Sm3+)-doped and co-doped CoFe2O4 for heterogeneous advanced oxidation process: structural, magneto-optical, and photocatalytic investigations.

The photocatalytic properties of CoFe2O4 nanoparticles were activated by the doping and co-doping of a low level of Y3+ and Sm3+ cations. After optimizing the annealing temperature, 900°C was found to be the optimal temperature for the successful incorporation of Y3+ and Sm3+ into the spinel structure. The purity of our samples annealed at 900°C was confirmed using several characterization methods, including PXRD, SEM, XPS, VSM, FTIR, and Raman spectroscopy. Thus, we were able to increase the photocatalytic degradation of orange G dye from 9.9 to 64.63% for the Sm3+-doped sample, 76.42% for the Y3+-doped sample, and even 85.81% for the co-doped sample under 60min of UV-visible light irradiation. The beneficial effect of samarium and yttrium doping and co-doping is attributed to several factors: the first factor is doped and co-doped rare earth impurities induce distortion in the lattice, the larger the ionic radii of dopant element, the highest is the photocatalytic activity; second factor, upon doping and co-doping of rare earth impurities in the structure of CoFe2O4 leads to the creation of donor state level within the band gap, causing the Fermi energy to shift near the conduction band. Third factor, co-doping produced strong interactions, which accelerated photocarrier mobility and transport; lastly, longer electron-holes lifetime. We have provided a detailed study of the structural, vibrational, and optical properties to support our conclusions.

Increased interlayer spacing N-doping Ti3C2Tx MXene-based mezzanine heterostructure for enhanced performance lithium/sodium storage

Structure of the electrode materials play a critical role in electrochemical performance for both lithium-ion batteries and sodium ion batteries. Herein, MXene modified by element doping and compositing metal–organic frameworks (MOF)-based Fe2O3@Carbon nanofibers (CNFs) with a mezzanine heterostructure, is constructed to achieve low interfacial impedance, high specific capacity stability in lithium/sodium storage processes. The prepared mezzanine heterostructure Fe2O3@C@N-Ti3C2Tx composite is highly conductive and mesoporous. During the nitrogen-doping thermal treatment process, the interlayer spacing of Ti3C2Tx MXene was increased, providing wider ion transport channels. Additionally, inert carbon atoms were transformed into electrochemically active nitrogen atoms, leading to the construction of more active centers and surface defects. The spatial confinement of N-Ti3C2Tx MXene during the electrochemical process, effectively mitigating volume expansion and maintaining structural stability upon applied as electrode materials. Benefitting from the unique 3D conductive network, the mezzanine heterostructure Fe2O3@C@N-Ti3C2Tx composite nanofibers exhibits excellent Li/Na storage performance. In LIBs, it delivers a capacity of 226 mAh/g at 10 A/g and retains 314 mAh/g after 2800 ultra-long cycles at 5 A/g. For SIBs, it exhibits a capacity of 135 mAh/g at 5 A/g and maintains 209 mAh/g after 3000 cycles at 2 A/g.

New Piezoceramic SrBi2Nb2-2xWxSnxO9: Crystal Structure, Microstructure and Dielectric Properties.

By using the method of high-temperature solid-phase reaction, the new piezoceramic SrBi2Nb2-2xWxSnxO9 was obtained, where partial substitution of niobium (Nb) atoms with Sn4+ and W6+ atoms in the compound SrBi2Nb2O9 occurred in the octahedra of the perovskite layer (B-position). X-ray diffraction investigations showed that these compounds are single-phase SrBi2Nb2-2xWxSnxO9 (x = 0.1, 0.2) and two-phase SrBi2Nb2-2xWxSnxO9 (x = 0.3, 0.4), but all of them had the structure of Aurivillius-Smolensky phases (ASPs) with close parameters of orthorhombic unit cells. It corresponded to the space group A21am. The temperature dependences of the relative permittivity ε/ε0 and the tangent of the dielectric loss angle tan d were defined at various frequencies. It was found that doping SrBi2Nb2-2xWxSnxO9 (x = 0.1) improved the electrophysical properties of the compound: losses decreased, and the relative permittivity increased. This result was obtained for the first time. Moreover, a new result was obtained that indicated an improvement in the electrophysical properties of SrBi2Nb2O9 using the chemical element Sn (tin). This refutes the previously existing opinion about the impossibility to use Sn as a doping element.

Manipulating Orbital Hybridization of CoSe2 by S Doping for the Highly Active Catalytic Effect of Lithium-Sulfur Batteries.

In recent years, various transition metal compounds have been extensively studied to deal with the problems of slow reaction kinetics and the shuttle effect of lithium-sulfur (Li-S) batteries. Nevertheless, their catalytic performance still needs to be further improved by enhancing intrinsic catalytic activity and enriching active sites. Doping is an effective means to boost the catalytic performance through adjusting the electron structure of the catalysts. Herein, the electron structure of CoSe2 is adjusted by doping P, S with different p electron numbers and electronegativity. After S doping (S-CoSe2), the content of Co2+ increases, and charge is redistributed. Furthermore, more electrons are transferred between Li2S4/Li2S and S-CoSe2, and optimal Co-S bonds are formed between them with optimized d-p orbital hybridization, making the bonds of Li2S4/Li2S the longest and easy to break and decompose. Consequently, the Li-S batteries with the S-CoSe2-modified separator achieve improved rate performance and cycling performance, benefiting from the better bidirectional catalytic activity. This work will provide reference for the selection of the anion doping element to enhance the catalytic effect of transition metal compounds.

Modulation Strategies for Improving Electrocatalytic Performance of Transition Metal Phosphides

AbstractWith growing concerns regarding global warming and the depletion of fossil fuel resources, there is an increasingly urgent demand for electrochemical energy storage and conversion technologies, including zinc‐air batteries, fuel cells, and integrated water splitting systems. The development of cost‐effective and efficient electrocatalysts is pivotal to the commercial viability of electrocatalytic technologies related to energy. Transition metal phosphides (TMPs) have emerged as promising electrocatalysts in the energy sector owing to their adjustable electronic structure, abundant availability, and distinctive physicochemical properties. Modification of transition metal phosphides can be expected to result in enhanced catalytic performance. In this paper, several commonly employed strategies for improving performance including elemental doping, M/P stoichiometric ratios tuning, vacancy engineering, heterointerface engineering and carbon materials incorporation, which are of reference value for promoting the development of TMPs electrocatalysts and constructing highly active TMPs electrocatalysts to solve a variety of energy and environmental problems.