Tailoring hypervalent Nickel induced by oxygen vacancy toward enhanced oxygen evolution reaction performance in self-supporting NiFe-(oxy)hydroxides electrodes.

NiFe-(oxy)hydroxides are the most active transition metal oxide electrocatalysts for oxygen evolution reaction (OER) under the alkaline media. Herein, we controllably manipulated oxygen vacancy (VO)-tunable NiFe-(oxy) hydroxides that their OER performances possessed a volcano-type relationship with VO concentration, positively-correlated with Ni3+/Ni2+ ratio. Theoretical simulations further unearthed the enhanced activation and dissociation of H2O by the inserting of VO. As a result, the optimal sample featuring the Ni3+/Ni2+ ratio of 30.3 % and VO of 23.8 % exhibited the overpotential of 243 mV at the current density of 100 mA cm-2, simultaneously lasting 120 h durability without any attenuation, exceding the most reported NiFe-(oxy)hydroxides. This work offers an innovative view to understand the OER performance using hypervalent Ni ratio induced by VO defects.

Deciphering Anion-Modulated Solvation Structure for Calcium Intercalation into Graphite for Ca-Ion Batteries.

Co-intercalation reactions make graphite a feasible anode in Ca ion batteries, yet the correlation between Ca ion intercalation behaviors and electrolyte structure remains unclear. This study, for the first time, elucidates the pivotal role of anions in modulating the Ca ion solvation structures and their subsequent intercalation into graphite. Specifically, the electrostatic interactions between Ca ion and anions govern the configurations of solvated-Ca-ion in dimethylacetamide-based electrolytes and graphite intercalation compounds. Among the anions considered (BH4 -, ClO4 -, TFSI- and [B(hfip)4]-), the coordination of four solvent molecules per Ca ion (CN=4) leads to the highest reversible capacities and the fastest reaction kinetics in graphite. Our study illuminates the origins of the distinct Ca ion intercalation behaviors across various anion-modulated electrolytes, employing a blend of experimental and theoretical approaches. Importantly, the practical viability of graphite anodes in Ca-ion full cells is confirmed, showing significant promise for advanced energy storage systems.

Engineering Atomic Ag1-N6 Sites with Enhanced Performance of Eradication Drug-Resistant Bacteria over Visible-Light-Driven Antibacterial Membrane.

Utilizing visible light for water disinfection is a more convenient, safe, and practical alternative to ultraviolet-light sterilization. Herein, we developed silver (Ag) single-atom anchored g-C3N4 (P-CN) nanosheets (Ag1/CN) and then utilized a spin-coating method to fabricate the Ag1/CN-based-membrane for effective antibacterial performance in natural water and domestic wastewater. The incorporated Ag single atom formed a Ag1-N6 motif, which increased the charge density around the N atoms, resulting in a built-in electric field ∼17.2 times stronger than that of pure P-CN and optimizing the dynamics of reactive oxygen species (ROS) production. Additionally, the Ag1-N6 motif inhibited the release of Ag ions, ensuring good biocompatibility. Based on the first-principles calculation, the adsorption energy of O2 on the Ag1/CN (-0.32 eV) was lower than that of P-CN (-0.07 eV), indicating that loaded Ag single atom can lower the energy barrier for O2 activation, generating extra *OH radicals that cooperated with *O2- to effectively neutralize bacteria. As a result, the Ag1/CN powder-catalyst with the concentration of 30 ppm demonstrated a 99.9% antibacterial efficiency against drug-resistant bacteria (Escherichia coli, Staphylococcus aureus, kanamycin-resistant Escherichia coli, and methicillin-resistant Staphylococcus aureus) under visible-light irradiation for 4 h. This efficacy was 24.8 times higher than that of the P-CN powder catalyst. Moreover, the Ag1/CN-based-membrane can maintain a 99.9% bactericidal efficiency for natural water and domestic wastewater treatment using a homemade flow device, demonstrating its potential for water disinfection. Notably, the visible-light-driven antibacterial efficiency of the Ag1/CN catalyst outperformed the majority of the reported g-C3N4-based catalysts/membranes.

In situ synthesis of graphitic carbon nitride nanosheet/Ti3C2Tx MXene/TiO2 Z-scheme heterojunctions boosting charge transfer for full-spectrum driven photocatalytic sterilization.

The development of a full-spectrum responsive photocatalytic germicide with excellent charge separation efficiency to harvest high antimicrobial efficacy is a key goal yet a challenging conundrum. Herein, graphitic carbon nitride nanosheet (PCNS)/Ti3C2Tx MXene/TiO2 (PMT) Z-scheme heterojunctions with robust interface contact were crafted by in situ interfacial engineering. The strong internal electrical field (IEF) from PCNS to TiO2, evinced by the Kelvin Probe Force Microscopy (KPFM) characterization, can obtain high charge separation efficiency with 73.99%, compared to Schottky junction PCNS/Ti3C2Tx (PM, 32.88%) and PCNS (17.70%). The Ti3C2Tx component can not only serve as a transfer pathway to accelerate the recombination of photoexcited electrons of TiO2 and holes of PCNS under the Ultraviolet-visible (UV-vis) light irradiation, but also replenish the photogenic electron concentrations to semiconductors in the near-infrared (NIR) light illumination. Meanwhile, the increased temperature due to the localized surface plasmon resonance (LSPR) can further boost the electronic activity to the generation of reactive oxygen species (ROS). Taken together, the PMT performs a high disinfection efficiency up to 99.40% under full solar spectrum illumination, 3.88 and 9.75 times higher than PCNS and TiO2, respectively, surpassing many reported Z-scheme heterojunctions. This work offers guidance for the design of Z-scheme heterojunction with the implanting of plasmons to secure excellent full-spectrum responsive photocatalytic sterilization performance.

Rational Construction of a Triple-Phase Reaction Zone Using CuO-Based Heterostructure Nanoarrays for Enhanced Water Oxidation Reaction.

The development of high-efficiency oxygen evolution reaction (OER) electrocatalysts for the production and conversion of clean energy is paramount yet also full of challenges. Herein, we proposed a simple and universal method to precisely fabricate the hierarchically structured CuO/TMOs loaded on Cu foil (CuO/TMOs/CF) (TMO represents Mn3O4, NiO, CoO, and CuO) nanorod-array electrodes as a highly active and stable OER electrocatalyst, employing Cu(OH)2/CF as a self-sacrificing template by the subsequent H2O2-induced chemical deposition (HiCD) and pyrolysis process. Taking CuO/Mn3O4/CF as an example, we systematically investigated its structure-performance relationship via experimental and theoretical explorations. The enhanced OER activity can be ascribed to the rational design of the nanoarray with multiple synergistic effects of abundant active sites, excellent electronic conductivity of the metallic Cu foil substrate, strong interface charge transfer, and quasi-superhydrophilic/superaerophobic property. Consequently, the optimal CuO/Mn3O4/CF presents an overpotential of 293 mV to achieve a current density of 20 mA cm-2 in 1.0 M KOH media, comparable to that of commercial RuO2 (282 mV), delivering excellent durability by the electrolysis of water at a potential of around 1.60 V [vs reversible hydrogen electrode (RHE)] without evident degeneration. This work might offer a feasible scheme for developing a hybrid nanoarray OER electrocatalyst via regulating electron transportation and mass transfer.

In Situ Fabrication of a 2D/2D MXene/CN Heterojunction for Photothermally Assisted Photocatalytic Sterilization under Visible Light Irradiation.

Constructing an efficient visible light-responsive antibacterial material for water treatment remains a principal goal yet is a huge challenge. Herein, a 2D/2D heterojunction composite with robust interfacial contact, named MXene/CN (MCN), was controllably fabricated by using a urea molecule intercalated into MXene following an in situ calcination method, which can realize the rapid separation and migration of photogenerated carriers under visible light irradiation and significantly improve the carrier concentration of the MXene surface, thus generating more reactive oxygen species. The generation of heat induced by MXene could also increase photogenic electron activity to facilitate the photocatalytic reaction using in situ time-resolved photoluminescence characterization. The visible light-activated germicide exhibits a sterilization efficacy against Escherichia coli of 99.70%, higher than those of pure CN (60.21%) and MXene (31.75%), due to the effect of photothermally assisted photocatalytic treatment. This work is an attempt to construct a visible light-driven antimicrobial material using Schottky junctions achieving photothermally assisted photocatalytic disinfection.

Significantly anisotropic Raman response of the (110) surface in quasi-one-dimensional system (TaSe4)2I by polarized Raman spectroscopy.

Quasi-one-dimensional materials are usually characterized by optical response spectroscopy methods, which show significant polarization dependence. Herein, we report a systematical investigation of polarized Raman scattering on the (110) crystal surface of the layered (TaSe4)2I compound. Taking into account group theory analysis of the crystal structure and the Raman tensor transformation technique, the vibrational mode of the Raman peaks can be differentiated by the angular dependence of the Raman peak intensity in parallel and vertical polarization Raman scattering tests. Moreover, density functional perturbation theory (DFPT) calculation confirmed the form of the Raman tensor of the (110) crystal surface, which was consistent with the result of the Raman tensor transformation technique, and the Raman spectrum and phonon dispersion curve calculations were also performed based on the Vienna ab initio simulation package (VASP). This new method provides useful insight for accurately identifying the lattice vibration behavior in new 2D layered structures.

Facilitating interface charge transfer via constructing NiO/NiCo2O4 heterostructure for oxygen evolution reaction under alkaline conditions.

Designing high-activity electrocatalysts to enhance the slow multielectron-transfer process of the oxygen evolution reaction (OER) is of great importance for hydrogen generation. Here, we employ hydrothermal and subsequent heat-treatment strategies to acquire nanoarrays-structured NiO/NiCo2O4 heterojunction anchored Ni foam (NiO/NiCo2O4/NF) as efficient materials for catalyzing the OER in an alkaline electrolyte. Density functional theory (DFT) results demonstrate that NiO/NiCo2O4/NF exhibits a smaller overpotential than those of single NiO/NF and NiCo2O4/NF owing to interface-triggered numerous interface charge transfer. Moreover, the superior metallic characteristics of NiO/NiCo2O4/NF further enhance its electrochemical activity toward OER. Specifically, NiO/NiCo2O4/NF delivered a current density of 50 mA cm-2 at an overpotential of 336 mV with a Tafel slope of 93.2 mV dec-1 for the OER, which are comparable with those of commercial RuO2 (310 mV and 68.8 mV dec-1). Further, an overall water splitting system is preliminarily constructed via using a Pt net as cathode and NiO/NiCo2O4/NF as anode. The water electrolysis cell performs an operating voltage of 1.670 V at 20 mA cm-2, which outperform the Pt net||IrO2 couple assembled two-electrode electrolyzer (1.725 V at 20 mA cm-2). This study proposes an efficient route to acquire multicomponent catalysts with rich interfaces for water electrolysis.

Enhanced Four-Electron Oxygen Reduction Selectivity of Clamp-Shaped Cobalt(II) Porphyrin(2.1.2.1) Complexes.

The molecular structure, electrochemistry, spectroelectrochemistry and electrocatalytic oxygen reduction reaction (ORR) features of two CoII porphyrin(2.1.2.1) complexes bearing Ph or F5 Ph groups at the two meso-positions of the macrocycle are examined. Single crystal X-ray analysis reveal a highly bent, nonplanar macrocyclic conformation of the complex resulting in clamp-shaped molecular structures. Cyclic voltammetry paired with UV/Vis spectroelectrochemistry in PhCN/0.1 M TBAP suggest that the first electron addition corresponds to a macrocyclic-centered reduction while spectral changes observed during the first oxidation are consistent with a metal-centered CoII /CoIII process. The activity of the clamp-shaped complexes towards heterogeneous ORR in 0.1 M KOH show selectivity towards the 4e- ORR pathway giving H2 O. DFT first-principle calculations on the porphyrin catalyst indicates a lower overpotential for 4e- ORR as compared to the 2e- pathway, consistent with experimental data.

Enhancing the surface polarization effect via Ni/NiMoOx heterojunction architecture for urea-assisted hydrogen generation.

Electrocatalytic urea oxidation (UOR) has attracted significant interest as a promising anodic half-reaction to replace sluggish oxygen evolution reaction (OER) toward water splitting. However, the activation and decomposition of urea molecule maintains a challenge during electrocatalytic process because of its 6e- oxidation procedure. Herein, Ni nanoparticles decorated NiMoOx nanorod (Ni/NiMoOx) electrocatalyst with abundant heterojunction interfaces is fabricated and the density functional theory (DFT) calculation testifies that the interfaces are favorable for enhancing the conductivity and modulating the surface polarization of Ni/NiMoOx, thus improving its UOR's activity. The Ni/NiMoOx performs superb electrocatalytic capacities toward UOR with a potential of 1.355 V (vs RHE) at 20 mA cm-2, and HER with an overpotential of 98 mV at 10 mA cm-2. A hybrid two-electrode water splitting cell is further assembled via applying the Ni/NiMoOx as both anodic and cathodic electrodes with presence of 0.33 M urea, delivering 50 mA cm-2 at voltage of 1.589 V. The findings help to provide a reliable strategy for rational reconstruction of Ni based metal oxide with rich interfaces for diverse electrocatalytic reactions.

Computational Studies on Holey TMC6 (TM = Mo and W) Membranes for H2 Purification.

The purification of hydrogen (H2) has been a vital step in H2 production processes such as steam−methane reforming. By first-principle calculations, we revealed the potential applications of holey TMC6 (TM = Mo and W) membranes in H2 purification. The adsorption and diffusion behaviors of five gas molecules (including H2, N2, CO, CO2, and CH4) were compared on TMC6 membranes with different phases. Though the studied gas molecules show weak physisorption on the TMC6 membranes, the smaller pore size makes the gas molecules much more difficult to permeate into h-TMC6 rather than into s-TMC6. With suitable pore sizes, the s-TMC6 structures not only show an extremely low diffusion barrier (around 0.1 eV) and acceptable permeance capability for the H2 but also exhibit considerably high selectivity for both H2/CH4 and H2/CO2 (>1015), especially under relatively low temperature (150−250 K). Moreover, classical molecular dynamics simulations on the permeation process of a H2, CO2, and CH4 mixture also validated that s-TMC6 could effectively separate H2 from the gas mixture. Hence, the s-MoC6 and s-WC6 are predicted to be qualified H2 purification membranes, especially below room temperature.

Surface Structure Engineering of PtPd Nanoparticles for Boosting Ammonia Oxidation Electrocatalysis.

Achieving high catalytic ammonia oxidation reaction (AOR) performance of Pt-based catalysts is of paramount significance for the development of direct ammonia fuel cells (DAFCs). However, the high energy barrier of dehydrogenation of *NH2 to *NH and easy deactivation by *N on the Pt surface make the AOR show sluggish kinetics. Here, we have put forward an alloying and surface modulation tactic to optimize Pt catalysts. Several spherical PtM (M = Co, Ni, Cu, and Pd) binary nanoparticles were controllably loaded on reduced graphene oxide (rGO). Among others, spherical PtPd nanoparticles displayed the most efficient catalytic activity. Further surface engineering of PtPd nanoparticles with a cubic-dominant structure has resulted in dramatic AOR activity improvements. The optimized (100)Pt85Pd15/rGO exhibited a low onset potential (0.467 V vs reversible hydrogen electrode (RHE)) and high peak mass activity (164.9 A g-1), much better than commercial Pt/C. Nevertheless, a short-term stability test along with morphology, structure, and composition characterizations indicate that the leaching of Pd atoms from PtPd alloy nanoparticles, their structure transformations, and the possible poisoning effects by the N-containing intermediates could result in the catalyst's activity loss during the AOR electrocatalysis. A temperature-dependent electrochemical test confirmed a reduced activation energy (∼12 kJ mol-1 decrease) of cubic-dominant PtPd compared to Pt/C. Density functional theory calculations further demonstrated that Pd atoms in Pt decrease the reaction energy barrier of electrochemical dehydrogenation of *NH2 to *NH, resulting in an excellent catalytic activity for the AOR.

Enhanced Catalytic Denitrification Performance of Ruthenium-based Catalysts by Hydrogen Spillover from a Palladium Promoter.

Catalytic denitrification, a promising technology for nitrate removal, is increasingly limited by the rising price of Pd. Replacing Pd with less-expensive Ru would significantly reduce the cost; however, Ru-based catalysts have been reported to perform inconsistently in denitrification applications, making their replacement prospects unclear. Herein, the surface oxidation of Ru catalysts was confirmed to be a key factor that inhibits activity. A series of Ru-Pd catalysts containing small amounts of Pd (0.5 wt%) was developed to eliminate the Ru surface-oxide layer through the spillover of hydrogen atoms activated on the Pd promoter. Ru-Pd/Fe3O4 exhibited superior catalytic activity to Ru-Pd/C and Ru-Pd/Al2O3 because the reducible carrier (Fe3O4) has a lower resistance to hydrogen spillover and diffusion, as determined experimentally and supported by density functional theory calculations. This study developed a method that eliminates ruthenium surface oxides in situ and restores its denitrification activity, further reducing the barrier to Ru replacing Pd in catalytic aqueous denitrification.

Dual plasmonic Au and TiN cocatalysts to boost photocatalytic hydrogen evolution.

Employing a suitable cocatalyst is very important to improve photocatalytic H2 evolution activity. Herein, two plasmonic cocatalysts, Au nanoparticles and TiN nanoparticles were in-situ coupled over the g-C3N4 nanotube to form a ternary 0D/0D/1D Au/TiN/g-C3N4 composite via a successive thermal polycondensation and chemical reduction method. The g-C3N4 nanotube acted as a support for the growth of Au and TiN nanoparticles, leading to intimate contact between g-C3N4 nanotube with Au nanoparticles and TiN nanoparticles. As a result, multiple interfaces and dual-junctions of Au/g-C3N4 Schottky-junction and TiN/g-C3N4 ohmic-junction were constructed, which helped to promote the charged carriers' separation and enhanced the photocatalytic performance. Furthermore, loading plasmonic cocatalysts of Au nanoparticles and TiN nanoparticles can enhance the light absorption capacity. Consequently, the Au/TiN/g-C3N4 composite exhibited significantly enhanced photocatalytic H2 evolution activity (596 µmol g-1 h-1) compared to g-C3N4 or binary composites of Au/g-C3N4 and TiN/g-C3N4. This work highlights the significant role of cocatalysts in photocatalysis.

The synergistic effect of carbon edges and dopants towards efficient oxygen reduction reaction.

Decoration with alien atoms and increasing the edge content are two valid ways to activate the oxygen reduction reaction (ORR) property of nanocarbons. To further enhance their intrinsic activity and explore the underlying ORR mechanism, graphene nanoribbons (GNRs) were selected as an ideal catalyst model. Theoretical simulations have predicted that with the synergistic effect between heteroatom-doping and edge sites, the ORR activity can be significantly improved. Inspired by this, N-GNRs were synthesized via the oxidative unzipping of CNTs followed by nitrogen incorporation with urea. Ample edges and nitrogen doping sites were detected by high-resolution transmission electron microscopy and X-ray photoelectron spectroscopy, respectively. As a result, N-GNRs exhibited remarkably higher ORR properties in terms of onset and half-wave potentials, Tafel slopes, electron transfer number and methanol tolerance than either GNRs, the control sample without doping, or N-CNTs, the control sample without abundant edges, simply clarifying the significance of synergy between dopants and edges. Thus, this work provides a simple but efficient strategy to fabricate high-performance oxygen reduction catalysts.

Construction of UiO-66/Bi4O5Br2 Type-II Heterojunction to Boost Charge Transfer for Promoting Photocatalytic CO2 Reduction Performance.

One of the basic challenges of CO2 photoreduction is to develop efficient photocatalysts, and the construction of heterostructure photocatalysts with intimate interfaces is an effective strategy to enhance interfacial charge transfer for realizing high photocatalytic activity. Herein, a novel UiO-66/Bi4O5Br2 heterostructure photocatalyst was constructed by depositing UiO-66 nanoparticles with octahedral morphology over the Bi4O5Br2 nanoflowers assembled from the Bi4O5Br2 nanosheets via an electrostatic self-assembly method. A tight contact interface and a built-in electric field were formed between the UiO-66 and the Bi4O5Br2, which was conducive to the photo-electrons transfer from the Bi4O5Br2 to the UiO-66 and the formation of a type-II heterojunction with highly efficient charge separation. As a result, the UiO-66/Bi4O5Br2 exhibited improved photocatalytic CO2 reduction performance with a CO generation rate of 8.35 µmol h-1 g-1 without using any sacrificial agents or noble co-catalysts. This work illustrates an applicable tactic to develop potent photocatalysts for clean energy conversion.

Niobium pentoxide based materials for high rate rechargeable electrochemical energy storage.

The demand for high rate energy storage systems is continuously increasing driven by portable electronics, hybrid/electric vehicles and the need for balancing the smart grid. Accordingly, Nb2O5 based materials have gained great attention because of their fast cation intercalation faradaic charge storage that endows them with high rate energy storage performance. In this review, we describe the crystalline features of the five main phases of Nb2O5 and analyze their specific electrochemical characteristics with an emphasis on the intrinsic ion intercalation pseudocapacitive behavior of T-Nb2O5. The charge storage mechanisms, electrochemical performance and state-of-the-art characterization techniques for Nb2O5 anodes are summarized. Next, we review recent progress in developing various types of Nb2O5 based fast charging electrode materials, including Nb2O5 based mixed metal oxides and composites. Finally, we highlight the major challenges for Nb2O5 based materials in the realm of high rate rechargeable energy storage and provide perspectives for future research.

Interfacial Manipulation via In Situ Grown ZnSe Cultivator toward Highly Reversible Zn Metal Anodes.

Zn metal anode has garnered growing scientific and industrial interest owing to its appropriate redox potential, low cost, and high safety. Nevertheless, the instability of Zn anode caused by dendrite formation, hydrogen evolution, and side reactions has greatly hampered its commercialization. Herein, an in situ grown ZnSe overlayer is crafted over one side of commercial Zn foil via chemical vapor deposition in a scalable manner, aiming to achieve optimized electrolyte/Zn interfaces with large-scale viability. Impressively, thus-derived ZnSe coating functions as a cultivator to guide oriented growth of Zn (002) plane at the infancy stage of stripping/plating cycles, thereby inhibiting the formation of Zn dendrites and the occurrence of side reactions. As a result, high cyclic stability (1530 h at 1.0 mA cm-2 /1.0 mAh cm-2 ; 172 h at 30.0 mA cm-2 /10.0 mAh cm-2 ) in symmetric cells is harvested. Meanwhile, when paired with V2 O5 based cathode, assembled full cell achieves an outstanding capacity (194.5 mAh g-1 ) and elongated lifespan (a capacity retention of 84% after 1000 cycles) at 5.0 A g-1 . The reversible Zn anode enabled by the interfacial manipulation strategy via ZnSe cultivator is anticipated to satisfy the demand of commercial use.

Manipulating Electrocatalytic Li2 S Redox via Selective Dual-Defect Engineering for Li-S Batteries.

Lithium-sulfur (Li-S) batteries are promising candidates for next-generation energy storage, yet they are plagued by the notorious polysulfide shuttle effect and sluggish redox kinetics. While rationally designed redox mediators can facilitate polysulfide conversion, favorable bidirectional sulfur electrocatalysis remains a formidable challenge. Herein, selective dual-defect engineering (i.e., introducing both N-doping and Se-vacancies) of a common MoSe2 electrocatalyst is used to manipulate the bidirectional Li2 S redox. Systematic theoretical prediction and detailed electrokinetic analysis reveal the selective electrocatalytic effect of the two types of defects, thereby achieving a deeper mechanistic understanding of the bidirectional sulfur electrochemistry. The Li-S battery using this electrocatalyst exhibits excellent cyclability, with a low capacity decay rate of 0.04% per cycle over 1000 cycles at 2.0 C. More impressively, the potential for practical applications is highlighted by a high areal capacity (7.3 mAh cm-2 ) and the construction of a flexible pouch cell. Such selective electrocatalysis created by dual-defect engineering is an appealing approach toward working Li-S systems.

Identifying the Evolution of Selenium-Vacancy-Modulated MoSe2 Precatalyst in Lithium-Sulfur Chemistry.

Witnessing compositional evolution and identifying the catalytically active moiety of electrocatalysts is of paramount importance in Li-S chemistry. Nevertheless, this field remains elusive. We report the scalable salt-templated synthesis of Se-vacancy-incorporated MoSe2 architecture (SeVs-MoSe2 ) and reveal the phase evolution of the defective precatalyst in working Li-S batteries. The interaction between lithium polysulfides and SeVs-MoSe2 is probed to induce the transformation from SeVs-MoSe2 to MoSeS. Furthermore, operando Raman spectroscopy and ex situ X-ray diffraction measurements in combination with theoretical simulations verify that the effectual MoSeS catalyst could help promote conversion of Li2 S2 to Li2 S, thereby boosting the capacity performance. The Li-S battery accordingly exhibits a satisfactory rate and cycling capability even with and elevated sulfur loading and lean electrolyte conditions (7.67 mg cm-2 ; 4.0 µL mg-1 S ). This work elucidates the design strategies and catalytic mechanisms of efficient electrocatalysts bearing defects.