Dual Active Sites Research Articles

Combined Photoredox Catalysis for Value-Added Conversion of Contaminants at Spatially Separated Dual Active Sites.

As 2 indispensable counterparts in one catalysis system, the independent reduction and oxidation reactions require synergetic regulation for cooperatively promoting redox efficiency. Despite the current success in promoting the catalytic efficiency of half reduction or oxidation reactions, the lack of redox integration leads to low energy efficiency and unsatisfied catalytic performance. Here, we exploit an emerging photoredox catalysis system by combining the reactions of nitrate reduction for ammonia synthesis and formaldehyde oxidation for formic acid production, in which superior photoredox efficiency is achieved on the spatially separated dual active sites of Ba single atoms and Ti3+. High catalytic redox rates are accomplished for respective ammonia synthesis (31.99 ± 0.79 mmol gcat -1 h-1) and formic acid production (54.11 ± 1.12 mmol gcat -1 h-1), reaching a photoredox apparent quantum efficiency of 10.3%. Then, the critical roles of the spatially separated dual active sites are revealed, where Ba single atoms as the oxidation site using h+ and Ti3+ as the reduction site using e- are identified, respectively. The efficient photoredox conversion of contaminants is accomplished with environmental importance and competitive economic value. This study also represents a new opportunity to upgrade the conventional half photocatalysis into the complete paradigm for sustainable solar energy utilization.

FePO4 supported Rh subnano clusters with dual active sites for efficient hydrogenation of quinoline under mild conditions.

Chemoselective hydrogenation of quinoline and its derivatives under mild reaction conditions still remains a challenging topic, which requires a suitable interaction between reactants and a catalyst to achieve high performance and stability. Herein, FePO4-supported Rh single atoms, subnano clusters and nanoparticle catalysts were synthesized and evaluated in the chemoselective hydrogenation of quinoline. The results show that the Rh subnano cluster catalyst with a size of ∼1 nm gives a specific reaction rate of 353 molquinoline molRh-1 h-1 and a selectivity of >99% for 1,2,3,4-tetrahydroquinoline under mild conditions of 50 °C and 5 bar H2, presenting better performance compared with the Rh single atoms and nanoparticle counterparts. Moreover, the Rh subnano cluster catalyst exhibits good stability and substrate universality for the hydrogenation of various functionalized quinolines. A series of characterization studies demonstrate that the acidic properties of the FePO4 support favors the adsorption of quinoline while the Rh subnano clusters promote the dissociation of H2 molecules, and then contribute to the enhanced hydrogenation performance. This work provides an important implication to design efficient Rh-based catalysts for chemoselective hydrogenation under mild conditions.

Morphology engineering induces the increase of FeP/CoP heterointerface density for efficient alkaline water splitting driven by interfacial dual active sites

The FeP/CoP electrocatalysts with different hetero-boundary densities were constructed using a morphology control strategy. Stimulated by ample interfacial active sites, FeP/CoP nano-mulberries (FeP/CoP NMs) displayed a promising AWS performance.

Enhancing photocatalytic overall water-splitting performance on dual-active-sites of the Co-P@MoS2 catalysts: a DFT study.

The rational construction of photocatalysts possesses tremendous potential to solve the energy crisis and environmental pollution; however, designing a catalyst for solar-driven overall water-splitting remains a great challenge. Herein, we propose a new MoS2-based photocatalyst (Co-P@MoS2), which skillfully uses the cobalt (Co) atom to stimulate in-plane S atoms and employs the phosphorus (P) atom to stabilize the basal plane by forming the Co-P bands. Using density functional theory (DFT), it was found that oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) can occur at the P site and S2 site of the Co-P@MoS2, respectively, and the dual-active sites successfully makes a delicate balance between the adsorption and dissociation of hydrogen. Furthermore, the improved overall water-splitting performance of Co-P@MoS2 was verified by analyzing the results of the electron structure and the dynamics of photogenerated carries. It was found that the imbalance of electron transfer caused by the introduction of the Co atom was the main contributor to the catalytic activity of Co-P@MoS2. Our study broadens the idea of developing photocatalysts for the overall water-splitting.

Metallic Bi and oxygen vacancy dual active sites enable efficient oxygen activation: Facet-dependent effect and interfacial synergy

Surface atomic arrangement and coordination of different crystal facets significantly affect the catalytic reactivity of photocatalysts. By modulating the solvent environment, we developed a one-step solvothermal route to synthesize a series of BiOBr nanosheets with different dominating facets ((001) and (010)) and simultaneously decorated metallic Bi and oxygen vacancies (OVs) on the identified preferred facets ((010)). The resulting Bi/OV-BiOBr-(010) outperform BiOBr-(010) with mono OVs, bare BiOBr-(010), and other well-known photocatalysts in both O2 activation and pollutant degradation under both same catalyst loading and optical thickness conditions. The synergistic effects of the Bi-OV dual active sites in O2 adsorption-activation and charge separation-transfer were confirmed by experimental characterization and DFT calculation. This study highlights the facet-dependent synergy of plasmonic metal-defect dual active sites and shed light on the rational design of photocatalysts for more efficient O2 activation and refractory pollutant degradation.

Low-loading Pt nanoparticles combined with the atomically dispersed FeN4 sites supported by FeSA-N-C for improved activity and stability towards oxygen reduction reaction/hydrogen evolution reaction in acid and alkaline media

Reducing the loading of Pt precious metal is the promising pathway to positively promote the large-scale application for fuel cells and water electrolysis. In this work, a composite bifunctional electrocatalyst (named Pt@FeSA-N-C) consisting of the atomically dispersed FeN4 active sites and Pt nanoparticles (NPs) is successfully prepared for oxygen reduction reaction (ORR) and hydrogen evolution reactions (HER). In the process of synthesizing precursor of Pt(OH)4-Fe-Ppy@CNFs, the Fe-Ppy@CNFs was firstly prepared where the highly dispersed Fe3+ ions were pre-anchored into polypyrrole (PPy) matrixes through in-situ polymerization on the surface of cellulose nanofibers (CNFs) and then Pt(OH)4 nano-particles were deposited on Fe-Ppy@CNFs through adjusting the pH of the solution by urea hydrolysis to obtain the Pt(OH)4-Fe-Ppy@CNFs. Compared with the commercial 20 wt.% Pt/C, the obtained Pt@FeSA-N-C possesses 5.5 wt.% low Pt loading. The strong synergistic effect of dual active sites between Pt NPs and FeN4 on one-dimensional (1D) FeSA-N-C support with a large surface area ensures effectively exposure of Fe and especial Pt active sites in the Pt@FeSA-N-C. Both ORR and HER activities of the Pt@FeSA-N-C were greatly improved in acid and alkaline media, even outperforming the commercial 20 wt.% Pt/C. Furthermore, the Pt@FeSA-N-C shows an unordinary stability, with no obvious decrease in the current density after 5000 and 1000 cycles of accelerated durability tests (ADTs) for ORR and HER processes, respectively. This work highlights a preparation strategy for the synergistic effect between low-loading Pt precious metal and non-precious metals in electrocatalytic system.

Incorporating Fe, Co co-doped graphene with PDI supermolecular for promoted photocatalytic activity: A story of electron transfer

Iron-cobalt dual single-atom anchoring on nitrogen-doped graphene (FexCoy-NG) improves the efficiency of migration and separation of photo-generated carriers. In this work, the perylene diimide (PDI) is self-assembled on the FexCoy-NG to form the FexCoy-NG/PDI composites by π-π interaction, which is reported for the first time. The bisphenol A (BPA) degradation of optimized 20% Fe0.2Co0.8-NG/PDI are nearly 100%, and the degradation rate is 1.5 and 12.7 times that of the self-assembled PDI and commercial-grade PDI. The high degradation performance by FexCoy-NG/PDI are mainly due to: (i) regulating the proportion of Fe-Co dual active sites content, so that it can achieve the synergistic interaction to facilitate the transfer of electrons in the catalytic reaction. (ii) PDI is uniformly dispersed by adding the FexCoy-NG, which increases the specific surface area of composites to adsorb more pollutants. Free radical trapping experiments and electron spin-resonance spectroscopy characterization confirmed that the O2–, OH, 1O2 and h+ are the main reactive species (RSs) for BPA degradation. Under the attack of RSs, BPA completes the processes of hydroxylation, demethylation, aromatization, ring-opening, and finally complete mineralization into CO2 and H2O. These results revealed that Fe0.2Co0.8-NG/PDI photocatalysts may be efficiently applied for the remediation of phenol contaminated natural waters.

A core-shell confined Pd@TS-1 @meso-SiO2 catalyst and its synergy effect on styrene oxidation

Dual active sites from acidic zeolite and Pd are not only capable of catalyzing multiple type of reactions, but could also generate unique functions owing to the synergy between metals and acidic sites. However, there are only a few reports on the investigation of the synergy of acid/Pd dual sites in TS-1. Herein, TS-1 confined Pd catalyst with mesoporous silica shell (Pd@TS-1 @meso-SiO2) has been successfully synthesized and its synergy effect contributes to the enhanced conversion rate (19.2%) and selectivity (74.7%) on styrene oxidation. The interaction between Pd and TS-1 has been investigated by EPR and 1H NMR techniques, the experimental measurements show an obvious change in the signal distribution of weakly acidic terminal hydroxyls and hydrogen-bonding silanols. The schematic illustration of selective styrene oxidation in the model of Pd@TS-1 @meso-SiO2 is proposed to clarify the synergistic effect on styrene oxidation between TS-1 and Pd nanoparticles at an atomic-/nanoscale.

Dual Ni active sites mediated by In to separate ethane activation and oxidation for enhanced ethene production via chemical looping scheme

Chemical looping oxidative dehydrogenation (CL-ODH) opens a unique avenue to achieve highly efficient conversion of alkanes to value-added alkenes. The challenge lies in identical metal-oxo active sites responsible for both alkane activation and oxidation causing either insufficient activity or over-oxidation thus inferior ethene yield and productivity at relatively low temperature (< 650 °C). Herein, we designed a novel redox catalyst by the incorporation of main-group In (6NiInx/HY, x indicates the atomic ratio of In/Ni) which achieved more than 92 % ethene selectivity at 40 % ethane conversion and long-term stability at 600 °C with 0.22 mmol g−1 ethene productivity at 650 °C. This was because Ni2+ Lewis acid sites conducted catalytic dehydrogenation of ethane to ethene and hydrogen, and the Ni-O-In moiety outside HY framework enabled selective oxidation of hydrogen rather than ethene due to well-regulated Ni 3d electron densities leading to the reduction of adsorption for ethene thus decreasing over-oxidation.

Fe, Zn Co-Doped Porous Carbon Nanofiber-Based Rechargeable Zinc Air Batteries with Stable Operation over 1600 h

Rational design of effective non-noble metal-based electrocatalysts with high conductivity, abundant active sites, and superior stability for zinc–air batteries (ZABs) with long-term cycling ability is highly demanded. A suitable carrier that can provide a high specific surface and porous structure to facilitate the exposure of active sites and the diffusion of reactants, products, and charges is of great importance. Herein, one-dimensional (1D) Fe–Zn-doped porous carbon fibers (Fe–Zn@NCF) are prepared from a polymer fiber matrix encapsulated with Fe-doped ZIF-8 nanocrystals by pyrolysis. The Fe–Zn@NCF exhibits good performance toward the oxygen reduction reaction or oxygen evolution reaction. Impressively, the assembled ZAB with Fe–Zn@NCF as the catalyst delivers a maximum peak power density of 184.6 mW cm–2, excellent rechargeability with a round-trip efficiency of 66.5%, and stable operation over 1600 h (800 cycles). These excellent electrocatalytic performances can be attributed to the Fe/Zn-based dual catalytic active sites and the 1D carbon fiber support of the catalyst with a hierarchical porous structure, a large surface area, and high conductivity that can facilitate fast mass and electron transportation and maintain the structural stability of the catalyst during cycling.

Hierarchical heterostructure of NiFe2O4 nanoflakes grown on the tip of NiCo2O4 nanoneedles with enhanced interfacial polarization effect to achieve highly efficient electrocatalytic oxygen evolution

In this work, a heterostructure oxygen evolution reaction (OER) electrocatalyst consisting of NiFe2O4 nanoflakes grown on the tip of NiCo2O4 nanoneedles arrays supported on nickel foam (NCO-NNs@NFO-NFs/NF) was obtained via simultaneous cation (Co3+ by Fe3+) and ligand exchange (-OH by 1,4-benzenedicarboxylic acid) and further annealing of the hydroxide/MOF precursor in air. HRTEM and Raman characterizations confirm the formation of NCO/NFO heterostructure. XPS characterization and charge density difference calculations clarify the electron transfer from Fe to Ni and Co at the NCO/NFO heterointerface. Electrochemical tests show that NCO-NNs@NFO-NFs/NF possesses excellent OER electrocatalytic activity (overpotential of 265 mV@50 mA cm−2) and durability (stable for 100 h@1 A cm−2). NCO-NNs@NFO-NFs/NF‖20 % Pt/C two-electrode system can achieve 10 mA cm−2 at 1.398 V for anion exchange membrane (AEM) water splitting in 1.0 M KOH at 85 °C, which exceeds the activity of using commercial RuO2 as an anode at 25 °C, combined with the stability of 100 h at 10 mA cm−2 at 25 °C, demonstrating the practical application in industrial AEM process. XPS and HRTEM characterizations of NCO-NNs@NFO-NFs/NF after the OER V-t test, along with ex-situ Raman characterization, confirm that Co and Fe sites undergo surface reconstruction to form specific CoOOH/FeOOH interfaces, as to exert the synergistic effect of Co and Fe dual active sites during OER process. DOS calculations reveal that the density of state at Fermi energy level increases after the introduction of Fe, thereby improving conductivity and facilitating the activation of adsorbed oxygen species. This study shows a significant methodology for simultaneous improvement of the electrocatalytic stability and activity of spinel oxides-based heterostructures, which is critical for practical application.

Highly Crystalline Polyimide Covalent Organic Framework as Dual-Active-Center Cathode for High-Performance Lithium-Ion Batteries

Polyimide covalent organic framework (PI-COF) materials that can realize intrinsic redox reactions by changing the charge state of their electroactive sites are considered as emerging electrode materials for rechargeable devices. However, the highly crystalline PI-COFs with hierarchical porosity are less reported due to the rapid reaction between monomers and the poor reversibility of the polyimidization reaction. Here, we developed a water-assistant synthetic strategy to adjust the reaction rate of polyimidization, and PI-COF (COFTPDA-PMDA) with kgm topology consisting of dual active centers of N,N,N',N'-tetrakis(4-aminophenyl)-1,4-benzenediamine (TPDA) and pyromellitic dianhydride (PMDA) ligands was successfully synthesized with high crystallinity and porosity. The COFTPDA-PMDA possesses hierarchical micro-/mesoporous channels with the largest surface area (2669 m2/g) in PI-COFs, which can promote the Li+ ions and bulky bis(trifluoromethanesulfonyl)imide (TFSI-) ions in organic electrolyte to sufficiently interact with the dual active sites on COF skeleton to increase the specific capacity of cathode materials. As a cathode material for lithium-ion batteries, COFTPDA-PMDA@50%CNT which integrated high surface area and dual active center of COFTPDA-PMDA with carbon nanotubes via π-π interactions gave a high initial charge capacity of 233 mAh/g (0.5 A/g) and maintains at 80 mAh/g even at a high current density of 5.0 A/g after 1800 cycles.

Establishing an efficient way via TiO2/MXene catalyst for photoelectro activating PMS degradation of BPA

In this system, a highly-exposed TiO2 photoanode was prepared as an effectively photoelectrocatalyst peroxymonosulfate (PMS) activator. Especially, we realize the highly-exposed TiO2 grown on negatively charged MXene nanosheet which could provide dual active sites for stimulating PMS. The catalysts were characterized by XRD, XPS, SEM, UV–vis, Raman, TEM, and BET. The specific surface area for highly-exposed TiO2 (S-400) is 10 times than Bulk catalyst (B-400), which is displayed in the BET result. The experimental results show that high exposure catalyst has excellent photoelectric activation performance. The degradation efficiency of the PEC + PMS system was 2.94 times higher than the EC + PMS and 2.76 times higher than the PC + PMS process. Compare with free PMS (1.36˚A), PMS adsorbed at the photoanode interface has a high bond angle (2.85˚A) easily to decompose into strong oxidizing SO4−. The electrochemical characterization results demonstrated that the highly-exposed TiO2 had a higher separation rate of photogenerated carriers. From quenching experiments, the holes (h+) contributed 80 % to BPA degradation in PEC + PMS system, the contribution order of other active radicals was O2−>SO4−>OH. It will help improving the control of the optimal free radical ratio. The probable mechanism and pathway of BPA degradation were suggested e− reacts with PMS and other substances to generate radicals. The research offers a new strategy for the effective activation about PMS to oxidation of the refractory organics. Besides, the results provide useful theoretical guidance for the development of new high-activity materials.

Coupling dual metal active sites and low-solvation architecture toward high-performance aqueous ammonium-ion batteries

Aqueous rechargeable ammonium-ion batteries (AIBs) possess the characteristics of safety, low cost, environmental friendliness, and fast diffusion kinetics. However, their energy density is often limited due to the low specific capacity of cathode materials and narrow electrochemical stability windows of electrolytes. Herein, high-performance aqueous AIBs were designed by coupling Fe-substituted manganese-based Prussian blue analog (FeMnHCF) cathodes and highly concentrated NH4CF3SO3 electrolytes. In FeMnHCF, Mn3+/Mn2+-N redox reaction at high potential was introduced, and two metal active redox species of Mn and Fe were achieved. To match such FeMnHCF cathodes, highly concentrated NH4CF3SO3 electrolyte was further developed, where NH4+ ion displays low-solvation structure because of the increased coordination number of CF3SO3- anions. Furthermore, the water molecules are confined by NH4+ and CF3SO3- ions in their solvation sheath, leading to weak interaction between water molecules and thus effectively extending the voltage window of electrolyte. Consequently, the FeMnHCF electrodes present high reversibility during the charge/discharge process. Moreover, owing to a small amount of free water in concentrated electrolyte, the dissolution of FeMnHCF is also inhibited. As a result, the assembled aqueous AIBs exhibit enhanced energy density, excellent rate capability, and stable cycling behavior. This work provides a creative route to construct high-performance aqueous AIBs.

Dual active sites for ammonia synthesis at ambient pressure

Numerous theoretical calculations indicate the synergistic role of bimetals to efficiently activate nitrogen molecules and facilitate ammonia formation through dissociative routes. Here, we experimentally demonstrated the use of dual active sites comprised of Fe with Ru, Co, and Ni. The findings reveal that Ru/Fe and Co/Fe catalysts are stable and effective to form ammonia at ambient pressure and in the temperature range (400–550 °C) with an activation energy of 45.73 kJ∙mol−1 and 46.38 kJ∙mol−1, respectively. In addition to extensive characterizations, an in-depth kinetic study unveils that the inclusion of Ru or Co to the Fe can shift the rate-determining steps to NHx formation. The co-catalysts are negatively charged because of electron-donating Fe sites, which helps to favor N2 dissociation on the bimetallic catalysts.

Boron-Doped and Ketonic Carbonyl Group-Enriched Graphdiyne as a Dual-Site Carbon Nanozyme with Enhanced Peroxidase-Like Activity.

We demonstrate the preparation of a dual-site carbon nanozyme, boron-doped and ketonic carbonyl (-C=O) group-enriched graphdiyne (B-GDY), with an enhanced peroxidase-like activity. Taking advantage of acidic oxidation treatment, GDY oxide (GDYO) with abundant surface oxygen-containing groups is obtained from pristine bulk GDY. Upon further thermal annealing of GDYO with H3BO3 under an inert atmosphere, B is introduced into GDY, while the loading of -C=O groups is increased onto B-GDY. We discover that boron-doped and ketonic carbonyl group-enriched graphdiyne as a dual-site carbon nanozyme endows it with an enhanced peroxidase-like activity, which is nearly 4.2-fold higher than that of GDY without B atoms and 6.6-fold higher than that of GDYO without B atoms and with low loading of -C=O groups. The high peroxidase-like activity of B-GDY is ascribed to the dual active sites (-C=O group and B atom) within it, which facilitates the adsorption and decomposition of H2O2 into hydroxyl radicals revealed by experimental and theoretical studies. Moreover, B-GDY is successfully employed to develop a colorimetric method for the detection of glucose with good sensitivity and selectivity. This work probes into the intrinsic peroxidase activity and structure-reactivity correlation, creating effective strategies for the preparation of GDY-based nanozymes.

A magnetic biochar catalyst with dual active sites of Fe3C and Fe4N derived from floc: The activation mechanism for persulfate on degrading organic pollutant

This study, a magnetic biochar catalyst (Fe-N@MFC) with Fe3C and Fe4N was synthesized via one-step pyrolysis using waste floc as a raw material. Fe-N@MFC shows an efficient catalysis in activating peroxydisulfate (PDS) to degrade tetracycline (TC). 90.5 % of TC (5 mg/L) is removed within 60 min in the Fe-N@MFC/PDS (0.5 g/L and 1.8 mM) system with a degradation rate constant of 0.33043 min−1. Reactive oxygen species (·OH, SO4·−, 1O2, and ·O2−) and electron transfer are generated in the reaction system. ·OH and SO4·− radicals make a major contribution to TC degradation. Variation in material structure and DFT calculations prove that the existence of Fe3C and Fe4N enhances the adsorption energy of PDS and promotes the redox reaction between PDS and Fe species (Fe0 and Fe-N). Based on iron ion leaching, recycling experiment and application in real water, the Fe-N@MFC catalyst is found to exhibit promising potential. This work represents a progress compared to the traditional technology used for preparing FeNC biochar catalysts and provides significant guidance for the further development of biochar in the future.

Highly efficient oxidation of aqueous contaminants by mesoporous graphitic carbon nitride supported copper phosphide with dual active sites

Rational design of low-cost and high-efficient non-precious-metal based Fenton-like catalysts has drawn tremendous attention. Mesoporous graphitic carbon nitride (m-CN) supported copper phosphide (Cu3P@m-CN) catalysts were synthesized, and applied in organic oxidation using H2O2 as the oxidizing reagent. Cu3P@m-CN exhibited excellent stability and high activities toward various organic pollutants over a wide pH range. Removal efficiency of pollutants depends on catalyst type and loading, main operating parameters (pollutant concentration, H2O2 dosage, reaction temperature and solution pH) and different water matrices. Quenching, electron paramagnetic resonance and fluorescence tests confirm that HO∙ and O2·-/HO2· serve as the main active species for pollutant degradation. The abundant cation (Cuδ+) and anion (Pδ−) as the dual active sites in Cu3P synergistically activate H2O2. Cuδ+ can activate H2O2 and promote the Cu2+/Cu+ cycle by electron transfer. Pδ- has the ability to donate electrons, which can also activate H2O2 and regenerate Cu+ from Cu2+. Porous m-CN materials could not only improve the dispersibility of Cu3P nanoparticles, but also effectively promote electron transfer, thus enhancing the catalytic performance, superior to other traditional supports. Consequently, the work demonstrated that the combination of Cu3P and m-CN was a feasible strategy for preparation of effective catalysts toward mineralization of organic pollutants.

Theoretical insights into the hydrogen oxidation reaction on single metal atoms anchored on the edge of MoS2 nanosheets

The application of alkaline fuel cells (AFCs) is seriously limited by the sluggish kinetics of the anodic hydrogen oxidation reaction (HOR), so it is urgent to develop efficient and stable non-noble metal HOR catalysts. In this work, we explored the HOR performance of single 3d metal atoms anchored at the edge of MoS2 nanosheets (MSA-MoS2, MSA = Fe, Co, and Ni) by the density functional theory calculations. The results suggested that the tetra-coordinated MSA and penta-coordinated meta-Mo atoms at the MoS2 edge could form the dual-active sites for the H* and OH* adsorption. The interaction between MSA and MoS2 supports can efficiently optimize the adsorption free energy of H* (ΔGH*) and OH* (ΔGOH*) by tuning the d band center of the activity sites. The calculated activation energy, rate constant, and exchange current density indicate that among the MSA-MoS2 catalysts, NiSA-MoS2 exhibits the highest activity for HOR, which is attributed to the optimal ΔGH* and ΔGOH*. Moreover, the thermodynamic and electrochemical stability of NiSA-MoS2 is confirmed by the strong formation energy and high oxidation potential. Therefore, NiSA-MoS2 can be considered as a promising candidate for HOR at the anode of AFCs.

Atomically Dispersed Dual-Site Cathode with a Record High Sulfur Mass Loading for High-Performance Room-Temperature Sodium-Sulfur Batteries.

Room-temperature sodium-sulfur (RT-Na/S) batteries possess high potential for grid-scale stationary energy storage due to their low cost and high energy density. However, the issues arising from the low S mass loading and poor cycling stability caused by the shuttle effect of polysulfides seriously limit their operating capacity and cycling capability. Herein, sulfur-doped graphene frameworks supporting atomically dispersed 2H-MoS2 and Mo1 (S@MoS2 -Mo1 /SGF) with a record high sulfur mass loading of 80.9wt.% are synthesized as an integrated dual active sites cathode for RT-Na/S batteries. Impressively, the as-prepared S@MoS2 -Mo1 /SGF display unprecedented cyclic stability with a high initial capacity of 1017mAhg-1 at 0.1Ag-1 and a low-capacity fading rate of 0.05% per cycle over 1000cycles. Experimental and computational results including X-ray absorption spectroscopy, in situ synchrotron X-ray diffraction and density-functional theory calculations reveal that atomic-level Mo in this integrated dual-active-site forms a delocalized electron system, which could improve the reactivity of sulfur and reaction reversibility of S and Na, greatly alleviating the shuttle effect. The findings not only provide an effective strategy to fabricate high-performance dual-site cathodes, but also deepen the understanding of their enhancement mechanisms at an atomic level.