Structural Design of π-d Conjugated TMx B3 N3 S6 (x=2, 3) Monolayer Toward Electrocatalytic Ammonia Synthesis.

Single-atom catalysts (SACs) have attracted wide attention to be acted as potential electrocatalysts for nitrogen reduction reaction (NRR). However, the coordination environment of the single transition metal (TM) atoms is essential to the catalytic activity for NRR. Herein, we proposed four types of 3-, 4-coordinated and π-d conjugated TMx B3 N3 S6 (x=2, 3, TM=Ti, V, Cr, Mn, Fe, Zr, Nb, Mo, Tc, Ru, Hf, Ta, W, Re and Os) monolayers for SACs. Based on density functional theory (DFT) calculations, I-TM2 B3 N3 S6 and III-TM3 B3 N3 S6 are the reasonable 3-coordinated and 4-coordinated structures screening by structure stable optimizations, respectively. Next, the structural configurations, electronic properties and catalytic performances of 30 kinds of the 3-coordinated I-TM2 B3 N3 S6 and 4-coordinated III-TM3 B3 N3 S6 monolayers with different single transition metal atoms were systematically investigated. The results reveal that B3 N3 S6 ligand is an ideal support for TM atoms due to existence of strong TM-S bonds. The 3-coordinated I-V2 B3 N3 S6 is the best SAC with the low limiting potential (UL ) of -0.01 V, excellent stability (Ef =-0.32 eV, Udiss =0.02 V) and remarkable selectivity characteristics. This work not only provides novel π-d conjugated SACs, but also gives theoretical insights into their catalytic activities and offers reference for experimental synthesis.

Ru nanoclusters anchored on boron- and nitrogen-doped carbon for a highly efficient hydrogen evolution reaction in alkaline seawater.

Electrochemical seawater splitting is an intriguing strategy for green hydrogen production. Constructing advanced electrocatalysts for the hydrogen evolution reaction (HER) in seawater is extremely demanded for accelerating the sluggish kinetic process. Herein, a Ru nanocluster anchored on boron- and nitrogen-doped carbon (Ru/NBC) catalyst was successfully synthesized for the HER in alkaline/seawater electrolytes. Remarkably, Ru/NBC exhibits outstanding activity and durability, delivering low overpotentials@10 mA cm-2 in 1.0 M KOH (30 mV) and 1.0 M KOH + seawater electrolyte (35 mV), outperforming Pt/C, Ru/NC, Ru/BC and Ru/C. Additionally, Ru/NBC also provides a high specific activity of 0.093 mA cm-2ECSA at an overpotential of 150 mV, which is higher than those of Ru/NC, Ru/BC and Ru/C, respectively. Density functional theory calculation results demonstrate that the Ru-B formed interfacial chemical bond can regulate the electronic structure of Ru active sites of Ru/NBC, which can facilitate the adsorption of water and hydrogen in alkaline media. This work provides a feasible strategy to fabricate outstanding electrocatalysts for the HER in alkaline/alkaline seawater electrolytes.

Photosynthesis of Benzonitriles on BiOBr Nanosheets Promoted by Vacancy Associates.

Photocatalytic organic functionalization reactions represent a green, cost-effective, and sustainable synthesis route for value-added chemicals. However, heterogeneous photocatalysis is inefficient in directly activating ammonia molecules for the production of high-value-added nitrogenous organic products when compared with oxygen activation in the formation of related oxygenated compounds. In this study, we report the heterogeneous photosynthesis of benzonitriles by the ammoxidation of benzyl alcohols (99 % conversion, 93 % selectivity) promoted using BiOBr nanosheets with surface vacancy associates. In contrast, the main reaction of catalysts with other types of vacancy sites is the oxidation of benzyl alcohol to benzaldehyde or benzoic acid. Experimental measurements and theoretical calculations have demonstrated a specificity of vacancy type with respect to product selectivity, which arises from the adsorption and activation of NH3 and O2 that is required to promote subsequent C-N coupling and oxidation to nitrile. This study provides a better understanding of the role of vacancies as catalytic sites in heterogeneous photocatalysis.

Engineering Molecular Heterostructured Catalyst for Oxygen Reduction Reaction.

Introducing a second metal species into atomically dispersed metal-nitrogen-carbon (M-N-C) catalysts to construct diatomic sites (DASs) is an effective strategy to elevate their activities and stabilities. However, the common pyrolysis-based method usually leads to substantial uncertainty for the formation of DASs, and the precise identification of the resulting DASs is also rather difficult. In this regard, we developed a two-step specific-adsorption strategy (pyrolysis-free) and constructed a DAS catalyst featuring FeCo "molecular heterostructures" (FeCo-MHs). In order to rule out the possibility of the two apparently neighboring (in the electron microscopy image) Fe/Co atoms being dispersed respectively on the top/bottom surfaces of the carbon support and thus forming "false" MHs, we conducted in situ rotation (by 8°, far above the critical angle of 5.3°) and directly identified the individual FeCo-MHs. The formation of FeCo-MHs could modulate the magnetic moments of the metal centers and increase the ratio of low-spin Fe(II)-N4 moiety; thus the intrinsic activity could be optimized at the apex of the volcano-plot (a relationship as a function of magnetic moments of metal-phthalocyanine complexes and catalytic activities). The FeCo-MHs catalyst displays an exceptional ORR activity (E1/2 = 0.95 V) and could be used to construct high-performance cathodes for hydroxide exchange membrane fuel cells and zinc-air batteries.

D-Band Center Optimization of Edge-Rich Ultrathin RuZn Nanosheets With Moiré Superlattices for pH-Universal Hydrogen Evolution Reaction.

Electrocatalytic hydrogen evolution reaction (HER) is a promising way to produce pure and clean hydrogen. However, the preparation of efficient and economical catalysts for pH-universal HER remains a challenging but rewarding task. Herein, ultrathin RuZn nanosheets (NSs) with moiré superlattices and abundant edges are synthesized. The RuZn NSs with unique structure exhibit superb HER performance with overpotentials of 11, 13, and 29 mV to achieve 10 mA cm-2 in 1 M KOH, 1 M PBS, and 0.5 M H2 SO4 , respectively, which is substantially lower than those of Ru NSs and RuZn NSs without moiré superlattices. Density functional theory investigations reveal that the charge transfer from Zn to Ru will lead the appropriate downshift of the d-band center of surface Ru atoms, thus accelerating hydrogen desorption from the Ru sites, lowering the dissociation energy barrier of water and greatly improving the HER performance. This work provides an effective design scheme for high-performance HER electrocatalysts over a wide pH range, and propose a general route to prepare Ru-based bimetallic nanosheets with moiré superlattices.

A general strategy to generate oxygen vacancies in bimetallic layered double hydroxides for water oxidation.

A general electrocatalyst design for water splitting through generating oxygen vacancies in bimetallic layered double hydroxides by using carbon nitride is proposed. The excellent OER activity of the achieved bimetallic layered double hydroxides is attributed to oxygen vacancies, which reduce the energy barrier of the rate-determining step.

Significantly Stabilizing Hydrogen Evolution Reaction Induced by Nb-Doping Pt/Co(OH)2 Nanosheets.

High stability and efficiency of electrocatalysts are crucial for hydrogen evolution reaction (HER) toward water splitting in an alkaline media. Herein, a novel nano-Pt/Nb-doped Co(OH)2 (Pt/NbCo(OH)2 ) nanosheet is designed and synthesized using water-bath treatment and solvothermal reduction approaches. With nano-Pt uniformly anchored onto NbCo(OH)2 nanosheet, the synthesized Pt/NbCo(OH)2 shows outstanding electrocatalytic performances for alkaline HER, achieving a high stability for at least 33 h, a high mass activity of 0.65 mA µg-1 Pt, and a good catalytic activity with a low overpotential of 112 mV at 10 mA cm-2 . Both experimental and theoretical results prove that Nb-doping significantly optimizes the hydrogen adsorption free energy to accelerate the Heyrovsky step for HER, and boosts the adsorption of H2 O, which further enhances the water activation. This study provides a new design methodology for the Nb-doped electrocatalysts in an alkaline HER field by facile and green way.

Heterogeneous Iridium Single-Atom Molecular-like Catalysis for Epoxidation of Ethylene.

Developing efficient and simple catalysts to reveal the key scientific issues in the epoxidation of ethylene has been a long-standing goal for chemists, whereas a heterogenized molecular-like catalyst is desirable which combines the best aspects of homogeneous and heterogeneous catalysts. Single-atom catalysts can effectively mimic molecular catalysts on account of their well-defined atomic structures and coordination environments. Herein, we report a strategy for selective epoxidation of ethylene, which exploits a heterogeneous catalyst comprising iridium single atoms to interact with the reactant molecules that act analogously to ligands, resulting in molecular-like catalysis. This catalytic protocol features a near-unity selectivity (99%) to produce value-added ethylene oxide. We investigated the origin of the improvement of selectivity for ethylene oxide for this iridium single-atom catalyst and attributed the improvement to the π-coordination between the iridium metal center with a higher oxidation state and ethylene or molecular oxygen. The molecular oxygen adsorbed on the iridium single-atom site not only helps to strengthen the adsorption of ethylene molecule by iridium but also alters its electronic structure, allowing iridium to donate electrons into the double bond π* orbitals of ethylene. This catalytic strategy facilitates the formation of five-membered oxametallacycle intermediates, leading to the exceptionally high selectivity for ethylene oxide. Our model of single-atom catalysts featuring remarkable molecular-like catalysis can be utilized as an effective strategy for inhibiting the overoxidation of the desired product. Implementing the concepts of homogeneous catalysis into heterogeneous catalysis would provide new perspectives for the design of new advanced catalysts.

Interfacial water engineering boosts neutral water reduction.

Hydrogen evolution reaction (HER) in neutral media is of great practical importance for sustainable hydrogen production, but generally suffers from low activities, the cause of which has been a puzzle yet to be solved. Herein, by investigating the synergy between Ru single atoms (RuNC) and RuSex cluster compounds (RuSex) for HER using ab initio molecular dynamics, operando X-ray absorption spectroscopy, and operando surface-enhanced infrared absorption spectroscopy, we establish that the interfacial water governs neutral HER. The rigid interfacial water layer in neutral media would inhibit the transport of H2O*/OH* at the electrode/electrolyte interface of RuNC, but the RuSex can promote H2O*/OH* transport to increase the number of available H2O* on RuNC by disordering the interfacial water network. With the synergy of RuSex and RuNC, the resulting neutral HER performance in terms of mass-specific activity is 6.7 times higher than that of 20 wt.% Pt/C at overpotential of 100 mV.

Engineering Lattice Disorder on a Photocatalyst: Photochromic BiOBr Nanosheets Enhance Activation of Aromatic C-H Bonds via Water Oxidation.

Solar-driven photocatalytic reactions can mildly activate hydrocarbon C-H bonds to produce value-added chemicals. However, the inefficient utilization of photogenerated carriers hinders the application. Here, we report reversible photochromic BiOBr (denoted as p-BiOBr) nanosheets that were colored by trapping photogenerated holes upon visible light irradiation and bleached by water oxidation to generate hydroxyl radicals, demonstrating enhanced carrier separation and water oxidation. The photocatalytic coupling and oxidation reactions of ethylbenzene were efficiently realized by p-BiOBr in a water-based medium under ambient temperature and pressure (apparent quantum yield is 14 times that of pristine BiOBr). The p-BiOBr nanosheets feature lattice disordered defects on the surface, providing rich uncoordinated catalytic sites and inducing structural distortions and lattice strain, which further leads to an altered band structure and significantly enhanced photocatalytic performances. These hole-trapping materials open up the possibility of substantially elevating the utilization efficiency of photogenerated holes for high-efficiency photocatalytic activation of various saturated C-H bonds.

Outstanding Catalytic Effects of 1T'-MoTe2 Quantum Dots@3D Graphene in Shuttle-Free Li-S Batteries.

It is still challenging to develop sulfur electrodes for Li-S batteries with high electrical conductivity and fast kinetics, as well as efficient suppression of the shuttling effect of lithium polysulfides. To address such issues, herein, polar MoTe2 with different phases (2H, 1T, and 1T') were deeply investigated by density functional theory calculations, suggesting that the 1T'-MoTe2 displays concentrated density of states (DOS) near the Fermi level with high conductivity. By optimization of the synthesis, 1T'-MoTe2 quantum dots decorated three-dimensional graphene (MTQ@3DG) was prepared to overcome these issues, and it accomplished exceptional performance in Li-S batteries. Owing to the chemisorption and high catalytic effect of 1T'-MoTe2 quantum dots, MTQ@3DG/S exhibits highly reversible discharge capacity of 1310.1 mAh g-1 at 0.2 C with 0.026% capacity fade rate per cycle over 600 cycles. The adsorption calculation demonstrates that the conversion of Li2S2 to Li2S is the rate-limiting step where the Gibbs free energies are 1.07 eV for graphene and 0.97 eV for 1T'-MoTe2, revealing the importance of 1T'-MoTe2. Furthermore, in situ Raman spectroscopy investigation proved the suppression of the shuttle effect of LiPSs in MTQ@3DG/S cells during the cycle.

Oxygen Vacancy-Rich RuO2-Co3O4 Nanohybrids as Improved Electrocatalysts for Li-O2 Batteries.

Lithium oxygen (Li-O2) batteries have shown great potential as new energy-storage devices due to the high theoretical energy density. However, there are still substantial problems to be solved before practical application, including large overpotential, low energy efficiency, and poor cycle life. Herein, we have successfully synthesized a RuO2-Co3O4 nanohybrid with a rich oxygen vacancy and large specific surface area. The Li-O2 batteries based on the RuO2-Co3O4 nanohybrid shown obviously reduced overpotential and improved circulatory property, which can cycle stably for more than 100 cycles at a current density of 200 mA g-1. Experimental results and density function theory calculation prove that the introduction of RuO2 can increase oxygen vacancy concentration of Co3O4 and accelerate the charge transfer. Meanwhile, the hollow and porous structure leads to a large specific surface area about 104.5 m2 g-1, exposing more active sites. Due to the synergistic effect, the catalyst of the RuO2-Co3O4 nanohybrid can significantly reduce the adsorption energy of the LiO2 intermediate, thereby reducing the overpotential effectively.

Anion-exchange-mediated internal electric field for boosting photogenerated carrier separation and utilization.

Heterojunctions modulated internal electric field (IEF) usually result in suboptimal efficiencies in carrier separation and utilization because of the narrow IEF distribution and long migration paths of photocarriers. In this work, we report distinctive bismuth oxyhydroxide compound nanorods (denoted as BOH NRs) featuring surface-exposed open channels and a simple chemical composition; by simply modifying the bulk anion layers to overcome the limitations of heterojunctions, the bulk IEF could be readily modulated. Benefiting from the unique crystal structure and the localization of valence electrons, the bulk IEF intensity increases with the atomic number of introduced halide anions. Therefore, A low exchange ratio (~10%) with halide anions (I-, Br-, Cl-) gives rise to a prominent elevation in carrier separation efficiency and better photocatalytic performance for benzylamine coupling oxidation. Here, our work offers new insights into the design and optimization of semiconductor photocatalysts.

In Situ Construction of Mo2 C Quantum Dots-Decorated CNT Networks as a Multifunctional Electrocatalyst for Advanced Lithium-Sulfur Batteries.

The slow redox kinetics during cycling process and the serious shuttle effect caused by the solubility of lithium polysulfides (LiPSs) dramatically hinder the practical application of Li-S batteries. Herein, a facile and scalable spray-drying strategy is presented to construct conductive polar Mo2 C quantum dots-decorated carbon nanotube (CNT) networks (MCN) as an efficient absorbent and electrocatalyst for Li-S batteries. The results reveal that the MCN/S electrode exhibits a high specific capacity of 1303.3 mAh g-1 at 0.2 C, and ultrastable cycling stability with decay of 0.019% per cycle even at 1 C. Theoretical simulation uncovers that Mo2 C exhibits much stronger binding energies for S8 and Li2 Sn . The energy barrier for the conversion between Li2 S4 and Li2 S2 decreases from 1.02 to 0.72 eV when hybriding with Mo2 C. Furthermore, in situ discharge/charge-dependent Raman spectroscopy shows that long-chain Li2 S8 configuration is generated via S8 ring opening near the first plateaus at ≈2.36 V versus Li/Li+ and the S6 2- configuration in CNT/S electrode is maintained below the potential of ≈2.30 V versus Li/Li+ , indicating that the shuttle of soluble LiPSs happens during the whole discharge process. This work provides deep insights into the polar nanoarchitecture design and scalable fabrication for advanced Li-S batteries.

Plasma-Treated Ultrathin Ternary FePSe3 Nanosheets as a Bifunctional Electrocatalyst for Efficient Zinc-Air Batteries.

Developing novel bifunctional electrocatalysts with advanced oxygen electrocatalytic activity is pivotal for next-generation energy-storage devices. Herein, we present ultrathin oxygen-doped FePSe3 (FePSe3-O) nanosheets by Ar/O2 plasma treatment, with remarkable surface atom reorganization. Such surface atom reorganization generates multiple crystalline-amorphous interfaces that benefit the kinetics of oxygen evolution reaction, achieving a low overpotential of only 261 mV at 10 mA cm-2 with a small Tafel slope of 41.13 mV dec-1. Density functional theory calculation indicates that oxygen doping can also modulate the electrical states at the Fermi level with a decreased band gap responsible for the enhanced electrocatalytic performance. Such unique FePSe3-O nanosheets can be further fabricated as the air cathode in rechargeable liquid zinc-air batteries (ZABs), which deliver a high open circuit potential of 1.47 V, a small charge-discharge voltage gap of 0.80 V, and good cycling stability for more than 800 circles. As a proof of concept, the flexible solid-state ZABs assembled with FePSe3-O nanosheets as cathode also display a favorable charge-discharge performance, durable stability, and good bendability. This work sheds new insights into the rational design of defect-rich ternary thiophosphate nanosheets by plasma treatment toward enhanced oxygen electrocatalysts in metal-air batteries.

Nanostructured Ni2SeS on Porous-Carbon Skeletons as Highly Efficient Electrocatalyst for Hydrogen Evolution in Acidic Medium.

Nickel dichalcogenides have received extensive attention as promising noble-metal-free nanocatalysts for a hydrogen evolution reaction. Nonetheless, their catalytic performance is restricted by the sluggish reaction kinetics, limited exposed active sites, and poor conductivity. In this work, we report on an effective strategy to solve those problems by using an as-designed new porous-C/Ni2SeS nanocatalyst with the Ni2SeS nanostubs anchored on with porous-carbon skeletons process. On the basis of three advantages, as the enhancement of the intrinsic activity using the ternary sulfoselenide, increased number of exposed active sites due to the 3D hollow substrate, and increased conductivity caused by porous-carbon skeletons, the resulting porous-C/Ni2SeS requires an overpotential of only 121 mV at a current density of 10 mA cm-2 with a Tafel slope of 78 mV dec-1 for hydrogen evolution in acidic media and a good long-term stability. Density functional theory calculations also show that the Gibbs free energy of hydrogen adsorption of the Ni2SeS was -0.23 eV, which not only is close to the ideal value (0 eV) and Pt reference (-0.09 eV) but also is lower than those of NiS2 and NiSe2; large electrical states exist in the vicinity of the Fermi level, which further improves its electrocatalytic performance. This work provides new insights into the rational design of ternary dichalcogenides and hollow structure materials for practical applications in HER catalysis and energy fields.

NiAg0.4 3D porous nanoclusters with epitaxial interfaces exhibiting Pt like activity towards hydrogen evolution in alkaline medium.

The necessity of Earth-abundant low-cost catalysts with activity similar to noble metals such as platinum is indispensable in order to realize the production of hydrogen through electrolysis of water. Herein, we report a relatively low-cost NiAg0.4 3D porous nanocluster catalyst whose activity matches with that of the state-of-the-art Pt/C in 1 M KOH solution. The catalyst is designed on the principle of creating an interface between a metal having a positive Gibbs energy of hydrogen adsorption and a metal of negative Gibbs energy based on the volcano plot, to tune the Gibbs energy of hydrogen adsorption near zero for enhanced hydrogen evolution. The synthesized NiAg0.4 3D porous nanoclusters are comprised of nanoparticles of lateral dimension ∼50 nm forming a 3D porous network with pores of 10 nm-80 nm. A high-resolution transmission electron microscopy image reveals the epitaxial growth of Ag (200) on the Ni (111) plane leading to the creation of abundant interfaces between the Ni and Ag lattices. The catalyst needs a low overpotential of 40 mV@10 mA cm-2 with a Tafel slope of 39.1 mV dec-1 in 1 M KOH solution. Furthermore, the catalyst exhibits a high specific activity of 0.1 mA cm-2(ECSA) at an overpotential (η) of 45 mV which matches with the specific activity of Pt/C 20% wt. catalyst (0.1 mA cm-2@η = 26 mV). Density functional theory calculations reveal that the Ni-Ag interface furnishes a pathway with a reduced Gibbs energy of adsorption of -0.04 eV, thus promoting enhanced hydrogen evolution. In summary, this study reveals excellent HER activity at the Ni-Ag interface.

Rhodium/graphitic-carbon-nitride composite electrocatalyst facilitates efficient hydrogen evolution in acidic and alkaline electrolytes.

Exploring the highly efficient and durable electrocatalysts for hydrogen evolution reaction (HER) is vitally necessary for sustainable energy conversion and storage system. Herein, we fabricate an interfacial engineered Rh-carbon nitride as advanced electrocatalysts for HER in the acidic and alkaline electrolytes. The interface between Rh nanocrystals and carbon nitride may adjust the electronic structure of Rh, which results in high activity for HER. The optimal Rh-carbon nitride shows low overpotential at current density of -10 mA·cm-2 and small Tafel slope (13 mV and 25.0 mV dec-1 in 0.5 M H2SO4, 46 mV and 42.0 mV dec-1 in 1.0 M KOH, respectively), which is superior to that of commercial Pt/C (21 mV and 28.5 mV dec-1 in 0.5 M H2SO4, 55 mV and 44.0 mV dec-1 in 1.0 M KOH, respectively). Importantly, this composite also exhibits long-term stability in 0.5 M H2SO4 and 1.0 M KOH. The excellent HER performances can be attribute to the interface between Rh and carbon nitride, which downshifts their d-band center positions, tuning the adsorption ability for hydrogen and accelerating the HER kinetics. This work may open up an efficient method to design metal/carbon hybrid for electrocatalysis.

Cu- and Fe-Codoped Ni Porous Networks as an Active Electrocatalyst for Hydrogen Evolution in Alkaline Medium.

Highly active catalysts from the earth-abundant metals are essential to materialize the low-cost production of hydrogen through water splitting. Herein, nickel porous networks codoped with Cu and Fe prepared by thermal reduction of presynthesized Cu, Fe-codoped Ni(OH)2 nanowires are reported. The sample consists of nanoparticles of ∼80 nm, which form highly porous network clusters of ∼1 µm with a pore size of 10-100 nm. Among the various doped compositions, the NiCu0.05Fe0.025 porous network exhibits the best catalytic activity with a low overpotential of 60 mV for a hydrogen evolution reaction (HER) in 1 M KOH solution and a specific activity of 0.1 mA cm-2 at 117 mV overpotential calculated based on the electrochemical active surface area (ECSA). The density functional theory calculations reveal that codoping of Fe and Cu into the Ni lattice results in a shift of d-bands of nickel to lower energy levels and thus in the reduced hydrogen adsorption energy (ΔGH = -0.131 eV), which is close to ΔGH for Pt (-0.09 eV). When NiCu0.05Fe0.025(OH)2 nanowires is used as an oxygen evolution reaction (OER) catalyst and is coupled with NiCu0.05Fe0.025 porous networks for overall water splitting, the NiCu0.05Fe0.025∥NiCu0.05Fe0.025(OH)2 catalyst couple achieves a current density of 10 mA cm-2 at 1.491 V, similar to that of the Pt/C∥RuO2 couple and offers a negligible loss in the performance when operated at 20 mA cm-2 for 30 h.

Phosphorus-Doping-Induced Surface Vacancies of 3D Na2 Ti3 O7 Nanowire Arrays Enabling High-Rate and Long-Life Sodium Storage.

Sodium-ion batteries have attracted interest as an alternative to lithium-ion batteries because of the abundance and cost effectiveness of sodium. However, suitable anode materials with high-rate and stable cycling performance are still needed to promote their practical application. Herein, three-dimensional Na2 Ti3 O7 nanowire arrays with enriched surface vacancies endowed by phosphorus doping are reported. As anodes for sodium-ion batteries, they deliver a high specific capacity of 290 mA h g-1 at 0.2 C, good rate capability (50 mA h g-1 at 20 C), and stable cycling capability (98 % capacity retention over 3100 cycles at 20 C). The superior electrochemical performance is attributed to the synergistic effects of the nanowire arrays and phosphorus doping. The rational structure can provide convenient channels to facilitate ion/electron transport and improve the capacitive contributions. Moreover, the phosphorus-doping-induced surface vacancies not only provide more active sites but also improve the intrinsic electrical conductivity of Na2 Ti3 O7 , which will enable electrode materials with excellent sodium storage performance. This work may provide an effective strategy for the synthesis of other anode materials with fast electrochemical reaction kinetics and good sodium storage performance.