Hollow Carbon Spheres Research Articles

Ultrafast carbothermal shock strategy enabled highly graphitic porous carbon supports for fuel cells

The electronic conductivity and durability of porous carbon supports can be improved by increasing the degree of graphitization in the material; however, the preparation of highly graphitic porous carbon using conventional furnaces remains a significant challenge. Herein, we demonstrate a universal and highly efficient carbothermal shock strategy that significantly improves the degree of graphitization of porous carbon supports, including bowl-like carbon, hollow carbon spheres, ZIF8-derived carbon, BP2000, and Ketjen EC 300J. Taking bowl-like carbon as an example, we illustrate the synthesis of a graphitized bowl-like carbon (G-BC-S) support and evaluate the performance of PtCo/G-BC-S in the oxygen reduction reaction (ORR) in rotating disk electrodes (RDE) and H2/air PEM single cells. PtCo/G-BC-S exhibits faster ORR kinetics than PtCo/BC and Pt/C, with little loss of activity (25%) and only 13 mV of E1/2 decay after 20000 cycles accelerated stress testing under 1.0–1.5 V vs. a reversible hydrogen electrode (RHE).</a> The significantly enhanced performance of the PtCo/G-BC-S catalyst arises from the high activity and chemical/structural stability of the PtCo intermetallic nanoparticles and from the high degree of graphitization and well-defined porous structure of the bowl-like carbon support, which confers excellent electrical conductivity and oxygen transport properties. This study provides a reliable and universal strategy for the development of high-performance porous carbon supports for practical applications in fuel cells.

Preparation of dispersed hollow carbon spheres assisted by silica/carbon shell isolation for supercapacitors

Nitrogen-doped mesoporous hollow carbon spheres are crucial in energy storage and the strategy of converting the inexpensive polymer polyacrylonitrile (PAN) into hollow carbon spheres needs to be improved. In this study, polystyrene/polyacrylonitrile (PSPAN) composite spheres were subjected to silica/carbon shell isolation to prepare nitrogen-doped hollow carbon spheres. In the carbonization process, the pyrolysis of PSPAN lead to the cavity due to the total decomposition behavior of PS. Due to the isolation of silica/carbon shells, the formation of a molten state during the pyrolysis process of PAN can be effectively prevented, thus avoiding the agglomeration of carbon spheres, and obtaining dispersed and regular hollow carbon spheres. The pore structure and specific surface area of the material were adjusted by hydrolyzing tetraethyl orthosilicate on the template surface and introducing dopamine for polymerization after different times. The hollow structure, nitrogen doping characteristics and abundant mesopores endow the NHCS with high performance in supercapacitor.

Electrolyte-Impregnated Mesoporous Hollow Microreactor to Supplement an Inner Reaction Pathway for Boosting the Cyclability of Li-CO2 Batteries.

Li-CO2 batteries that integrate energy storage with greenhouse gas fixation have received a great deal of attention in the pursuit of carbon neutrality. However, cyclic accumulation of the insulative and insoluble Li2CO3 on the cathode surface severely restrains the battery cyclability, especially under a high depth of discharge/charge. Herein, we design and fabricate a microreactor-type catalyst by embedding Ru nanoparticles into the shells of mesoporous hollow carbon spheres. We show that both the hollow cavity and mesoporous shell are indispensable for concertedly furnishing a high activity to catalyze reversible Li2CO3 formation/decomposition. This unique structure ensures that the Ru sites masked by exterior Li2CO3 deposits during charging can resume the redox process of discharge by working with the prestored electrolyte to establish an inner reaction path. The thus fabricated Li-CO2 batteries demonstrate remarkable cyclability of 1085 cycles under 0.5 Ah g-1 and 326 cycles under 2 Ah g-1 at 1 A g-1, outshining most of the literature reports. This study highlights a smart catalyst design to boost the reversibility and cyclability of Li-CO2 batteries through an "in & out" strategy.

CoS2 embedded 3D hollow carbon spheres nanoreactors for high-performance lithium-sulfur batteries

Lithium-sulfur batteries have high theoretical specific capacity benefitting from their own multiple electrons participating in redox reactions, which has attracted wide attention. Whereas, the poor conductivity, shuttle effect and volume expansion hinder the commercial application of lithium-sulfur batteries. Herein, a novel N/S-codoped 3D hollow carbon spheres embedded CoS2 nanoreactors are elaborated, which have competition advantages. Due to the synergistic chemisorption of doped heteroatom sites and polar CoS2 nanoparticles, the nanoreactors have strong adsorption capacity to lithium polysulfides (LiPSs). The 3D hollow graphitized carbon spheres with highly electrical conductivity facilitates fast sulfur electrochemistry redox reaction. The competition advantages effectively improve the performance of the lithium sulfur batteries. Accordingly, the S@CoS2NHGC cathode exhibits excellent specific capacity. It shows excellent electrochemical properties, such as 1570 mAh g−1 at 0.05 C, high cycle stability and Coulombic efficiency at 5 C, and outstanding rate performance at 10 C. We provide a reasonably designed strategy and fully explore the mechanism of improving the performance of Li-sulfur battery.

Constructing Fe‐N4 Sites through Anion Exchange‐mediated Transformation of Fe Coordination Environments in Hierarchical Carbon Support for Efficient Oxygen Reduction

AbstractMetal single atoms (SAs) anchored in carbon support via coordinating with N atoms are efficient active sites to oxygen reduction reaction (ORR). However, rational design of single atom catalysts with highly exposed active sites is challenging and urgently desirable. Herein, an anion exchange strategy is presented to fabricate Fe‐N4 moieties anchored in hierarchical carbon nanoplates composed of hollow carbon spheres (Fe‐SA/N‐HCS). With the coordinating O atoms are substituted by N atoms, Fe SAs with Fe‐O4 configuration are transformed into the ones with Fe‐N4 configuration during the thermal activation process. Insights into the evolution of central atoms demonstrate that the SAs with specific coordination environment can be obtained by modulating in situ anion exchange process. The strategy produces a large quantity of electrochemical accessible site and high utilization rate of Fe‐N4. Fe‐SA/N‐HCS shows excellent ORR electrocatalytic performance with half‐wave potential of 0.91 V (vs. RHE) in 0.1 M KOH, and outstanding performance when used in rechargeable aqueous and flexible Zn‐air batteries. The evolution pathway for SAs demonstrated in this work offers a novel strategy to design SACs with various coordination environment and enhanced electrocatalytic activity.

Constructing Fe-N4 Sites through Anion Exchange-mediated Transformation of Fe Coordination Environments in Hierarchical Carbon Support for Efficient Oxygen Reduction.

Metal single atoms (SAs) anchored in carbon support via coordinating with N atoms are efficient active sites to oxygen reduction reaction (ORR). However, rational design of single atom catalysts with highly exposed active sites is challenging and urgently desirable. Herein, an anion exchange strategy is presented to fabricate Fe-N4 moieties anchored in hierarchical carbon nanoplates composed of hollow carbon spheres (Fe-SA/N-HCS). With the coordinating O atoms are substituted by N atoms, Fe SAs with Fe-O4 configuration are transformed into the ones with Fe-N4 configuration during the thermal activation process. Insights into the evolution of central atoms demonstrate that the SAs with specific coordination environment can be obtained by modulating in situ anion exchange process. The strategy produces a large quantity of electrochemical accessible site and high utilization rate of Fe-N4 . Fe-SA/N-HCS shows excellent ORR electrocatalytic performance with half-wave potential of 0.91 V (vs. RHE) in 0.1 M KOH, and outstanding performance when used in rechargeable aqueous and flexible Zn-air batteries. The evolution pathway for SAs demonstrated in this work offers a novel strategy to design SACs with various coordination environment and enhanced electrocatalytic activity.

Robust nitrogen-doped microporous hollow carbon spheres for energy-efficient CO2 capture from flue gas

Nitrogen (N)-doped microporous hollow carbon spheres were prepared by facilely nanocasting spherical SiO2 with N-containing melamine phenolic resin through a simple in-situ polymerization process. Through regulating the dosage of melamine, N content in microporous hollow carbons could be easily tuned to an unprecedented level of 49.2 wt%. Additionally, in order to address the common problem of relatively poor structural porosity of N-doped carbons, especially after incorporating vast N into carbon frameworks in reported literature, a comprehensive strategy including optimizing carbonization temperature and performing further activation by CO2 and KOH were explored, and their effects on material textural properties and CO2 capacity were systematically studied. Although this strategy did not completely avoid the N loss during activation of carbon materials, it sharply promoted the textural properties of carbon materials at the expenses of partial N and efficiently produced a series of highly microporous carbon materials, still with abundant N species (11.5 ∼ 29.9 wt%) and large structural porosity (330 ∼ 1263 m2/g). More importantly, these N-doped microporous hollow carbons, when used for CO2 capture, showed superior CO2 capacities of 3.00 mmol/g (25 °C and 1 bar) and 1.05 mmol/g (40 °C and 0.1 bar), exceptionally robust cyclic stability, and low regeneration energy of 2.75 GJ/ton CO2, which is much lower than aqueous amine-based absorbents and comparable to amine-supported adsorbents. Thus, these outstanding adsorption performances make the N-doped microporous hollow carbon spheres prepared in this study more promising for energy-effective CO2 capture from dilute gas streams.

One-pot preparation of structurally tunable mesoporous hollow carbon spheres and their application for lithium‑sulfur battery with high sulfur content

Hollow carbon nanomaterials as sulfur hosts have been investigated extensively for lithium‑sulfur (LiS) battery. Herein, we report the preparation of structurally tunable mesoporous hollow carbon spheres (MHCs) by a simple one-pot self-assembly method. The structural parameters (specific surface area, pore capacity, pore size, and cavity) of the MHCs were adjusted by varying the concentration of the reactants. Three representative MHCs were characterized in detail, and the reasons for their formation were explained. Among them, the optimized MHC features a high specific surface area (1547.9 m2 g−1), large pore capacity (2.04 cm3 g−1), moderate pore size (∼ 6 nm), and internal cavity (r2/r1 = 0.62), which can meet the requirements of high sulfur loading, good carbon/sulfur contact, sufficient buffer space, and fast electron/ion transport channels. Consequently, the optimized MHC@S cathode exhibited improved electrochemical properties (maintaining a capacity of 484.7 mAh g−1 after 500 cycles at 0.5C with a decay rate of 0.068 %) under the condition of high sulfur content of 90.02 wt% and the electrolyte/sulfur ratio of 10 μL mg−1. Moreover, the raw materials are cost-effective, and the process is simple to operate without requiring expensive equipment. This study provides a promising candidate for carbon-based materials as sulfur hosts in practical LiS battery.

Adsorption properties of hollow carbon spheres to gaseous cyclohexane using DFT simulation and experiments.

The cyclohexane is the common toxic volatiles emitted from the various industry in worldwide leading to environmental degradation and human illnesses. Hence, there is a requirement for an efficient and stable adsorbent for adsorbing these toxic molecules to safeguard human health and the air atmosphere. Hollow carbon spheres (HCS) are a new type of carbon nanomaterial with large specific surface area, low density, and good chemical and thermal stability. In this study, DFT simulations and static-dynamic adsorption studies of cyclohexane were carried out using HCS as the adsorbent material. Among them, static adsorption focuses on adsorption/desorption isotherm, adsorption isotherm model fitting and isosteric heat of adsorption. Dynamic adsorption was mainly studied the effect of initial concentrations, gas flow rate, and ambient temperature on adsorption performance. The results showed that HCS exhibited very good performance in cyclohexane adsorption.

Combined Doxorubicin Mesoporous Carbon Nanospheres for Effective Tumor Lymphatic Metastasis by Multi-Modal Chemo-Photothermal Treatment in vivo.

Sentinel lymph node (SLN) is the first regional lymph node where tumor cells metastasize, and its identification and treatment are of great significance for the prevention of tumor metastasis. However, the current clinical modalities for identification and treatment of SLN are still far from satisfactory owing to their high cost, invasiveness and low accuracy. We aim to design a novel nanomedicine system for SLN imaging and treatment with high efficacy. We designed and prepared hollow mesoporous carbon spheres (HMCS) and loaded with the chemotherapeutic drug doxorubicin (DOX), which is then modified with polyvinyl pyrrolidone (PVP) to obtain nanomedicine: HMCS-PVP-DOX. HMCS-PVP with a size of about 150 nm could retain in the lymph nodes for a long time and stain the lymph nodes, which could be easily observed by the naked eye. At the same time, HMCS-PVP exhibited excellent photoacoustic and photothermal imaging capabilities, realizing multimodal imaging to locate lymph nodes precisely. Due to its high specific surface area, HMCS could be largely loaded with the chemotherapeutic drug doxorubicin (DOX). HMCS-PVP-DOX displayed highly efficient synergistic chemotherapy-photothermal therapy for lymphatic metastases in both cellular and animal experiments due to its significant photothermal effect under 1064 nm laser irradiation. HMCS-PVP-DOX also displayed great stability and biosafety. Multifunctional nanomedicine HMCS-PVP-DOX is expected to provide a novel paradigm for designing nanomedicine to the diagnosis and treatment of lymphatic metastases because of its good stability and safety.

Enhanced interfacial evaporation and desalination by solar heat localisation using nitrogenated graphitic carbon and Co3O4 nanorods

The problem of worldwide scarcity of clean water can be resolved efficiently by utilizing the significant heat localizing capability of the solar-driven interfacial evaporator with a nominal impact on the environment. A novel flexible, recyclable, hydrophilic photothermal composite membrane containing a blend of mesoporous Co3O4 nanorod and nanoporous nitrogen-doped graphitic carbon hollow spheres has been proposed. The composite membrane exhibits an enhanced broadband optical absorption which leads to a high interfacial evaporation rate (2.28 kg m−2 h−1) and a notable solar-to-steam generation efficiency (93%) under sunlight (900 W/m2) at 3.5 wt% NaCl salinity. The lower salt accumulation on the evaporation surface and the remarkable recyclability of the photothermal membrane under sunlight prove its practical usability in the desalination of seawater, water purification, salt production, and solar energy harvesting.

Spin state modulation on dual Fe center by adjacent Ni sites enabling the boosted activities and ultra-long stability in Zn-air batteries

Breakthrough in developing cost-effective Fe-based catalysts with superior oxygen reduction reaction (ORR) activities and ultra-long-term stability for application in Zn-air batteries (ZABs) remain a priority but still full of challenges. Herein, the neighboring NiN4 single-metal-atom and Fe2N5 dual-metal-atoms on the N-doped hollow carbon sphere (Fe/Ni-NHCS) were deliberately constructed as the efficient and robust ORR catalyst for ZABs. Both theory calculations and magnetic measurements demonstrate that the introduction of NiN4 provides a significant role on optimizing the electron spin state of Fe2N5 sites and reducing the energy barrier for the adsorption and conversion of the oxygen-containing intermediates, enabling the Fe/Ni-NHCS with excellent ORR performance and ultralow byproduct HO2− yield (0.5%). Impressively, the ZABs driven by Fe/Ni-NHCS exhibit unprecedented long-term rechargeable stability over 1200 h. This work paves a new venue to manipulate the spin state of active sites for simultaneously achieving superior catalytic activities and ultra-long-term stability in energy conversion technologies.

Wrinkled Hollow Carbon Spheres with Adjustable Diameter for High-Performance Supercapacitors.

Creating more pleated and collapsed structures for carbon-based electrode materials is an important measure to enhance the performance of supercapacitors. Herein, a polymer formed by the aldimine reaction of terephthalaldehyde and aminopropyltriethoxysilane was utilized as the carbon source, and tetraethoxysilane was added as a silica additive to achieve the wrinkled structure on hollow carbon spheres. The silica had a significant modulating effect on the structure of the obtained wrinkled hollow carbon sphere (WHCS), which displayed a visible pleated structure, hollow structure, high specific surface area, and pore volume. As an electrode material for supercapacitors, WHCS exhibits excellent performance with a capacitance of 312 F ⋅ g-1 and remarkable cycle life stability, demonstrating its great potential for use in supercapacitors.

MoS2 nanosheets grown on bowl-shaped hollow carbon spheres as an efficient electrochemical sensor for ultrasensitive determination of nephrotoxic aristolochic acids in Chinese traditional herbs.

Aristolochic acid, a substance in herbs, is highly nephrotoxic, so it is crucial to develop an assay that can rapidly and accurately analyze its content. In this study, bowl-shaped hollow carbon spheres (BHCs) were synthesized using a complex template method, and a MoS2 layer was grown in situ on their surface using a hydrothermal method. The synthesized MoS2-BHCs were used to fabricate an electrochemical sensor for the ultrasensitive and highly selective detection of aristolochic acids (AAs). The optimal conditions for AA detection were determined by tailoring the amount of MoS2 used to modify the BHCs and the pH of the electrolyte. Under optimal conditions, the MoS2-BHC-based sensor presented excellent AA detection performance. The linear concentration ranges of the MoS2-BHC-based sensor for the detection of AA were 0.05-10 μmol L-1 and 10-80 μmol L-1, and the limit of detection of the sensor was 14.3 nmol L-1. Moreover, the MoS2-BHC-based sensor detected AA in Aristolochia and Asarum sieboldii samples. The results were consistent with high-performance liquid chromatography data, demonstrating the satisfactory recovery and accuracy of the sensor. Therefore, we believe that MoS2-BHC-based sensors can be used as effective platforms for detecting AA in traditional Chinese herbs.

Uniform loading of ultrathin MoS2 nanosheets on hollow carbon spheres with mesoporous walls as efficient sulfur hosts for promising lithium-sulfur batteries

The electrochemical performance of lithium-sulfur batteries (LSBs) can be improved by combining rational structural design with the high-efficient catalyst to construct sulfur host materials. The PVP-assisted hydrothermal method was used to synthesize a composite (HCSM@uMoS2) with ultrathin MoS2 nanosheets uniformly loaded on hollow carbon spheres with mesoporous walls (HCSM). The ultrathin MoS2 nanosheets containing 1T metal phase (uMoS2) improved the electrical conductivity of the material while exposing more active sites, enhanced the adsorption to polysulfide and improved the redox reaction kinetics for polysulfide, thus fully suppressing the shuttle effect. Together with the advantages of HCSM, the mesoporous walls and internal cavity can offer enough sulfur storage room and significantly buffer the volume expansion of sulfur species; the high specific surface area and abundant porosity favor electron/ion transfers. As a result, the HCSM@uMoS2-S electrode exhibited outstanding electrochemical performance (675.4 mAh g−1 retention capacity at 0.5 C for 500 cycles) even under the conditions of high areal sulfur loading (5.6 mg cm−2) and less electrolyte (E/S = 10 μL mg−1). This study provides a reference for building sulfur hosts for high-capacity, long-life, and practical LSBs.

Nitrogen-doped carbon hollow sphere capsules for a novel hybrid inhibitor based on lanthanum cations and 8-hydroxyquinoline: Synthesis, characterization, and self-healing properties in epoxy coating

Fabrication of efficient reservoirs capable of on-demand release during corrosive attacks is of great interest for surface coating applications. Nitrogen-doped carbon hollow spheres (NCHS) are an emerging class of nanocontainers. In this article, La3+ cations and 8-hydroxyquinoline (8HQ) were encapsulated in NCHS to fabricate La.8HQ@NCHS. The structure and morphology of La.8HQ@NCHS nanostructures were assessed by energy-dispersive X-ray spectroscopy and field emission scanning electron microscopy. In addition, Raman spectroscopy, X-ray diffraction spectroscopy, Brunauer-Emmett-Teller, and X-ray photoelectron spectroscopy were employed to further characterize La.8HQ@NCHS nanostructures. Ultraviolet–visible spectroscopy and inductively coupled plasma-optical emission spectroscopy were executed to evaluate the 8HQ and La3+ cations released from the La.8HQ@NCHS capsules at different pHs, respectively. The corrosion inhibition capability of La.8HQ@NCHS nanostructures was analyzed using electrochemical impedance spectroscopy. The characterization results of La.8HQ@NCHS showed that La3+ cations and 8HQ were successfully encapsulated in carbon hollow spheres. The results of impedance and corrosion protection evaluations of coated mild steel samples showed a significant increase in corrosion resistance in the presence of La.8HQ@NCHS.

Sandwich-type electrochemical aptasensor based on HMCS@PDA@AuNPs and PtCu DNs/MUN-CuO-TiO2 for ultrasensitive detection of cardiac troponin I

The key to diagnosing acute myocardial infarction (AMI) lies in the sensitive and accurate analysis of cardiac troponin I (cTnI) content in human blood. Herein, in order to detect the content of cTnI, a novel sandwich-type cTnI electrochemical aptasensor was developed by utilizing dendritic platinum-copper alloy nanoparticles loaded on graphene-like CuO-TiO2 mesoporous ultrathin nanosheet (PtCu DNs/MUN-CuO-TiO2) as label material, and AuNPs loaded on polydopamine modified hollow mesoporous carbon spheres (HMCS@PDA@AuNPs) as electrode-modified material. On the one hand, with its advantages of assistance of Au and PDA coating, abundant pore structure, and large specific surface area, the HMCS@PDA@AuNPs exhibited excellent electronic conductivity but with a low catalytic capacity for the reduction of H2O2, thus enhancing the sensitivity of aptasensor. On the other hand, because of combining the structural and electrochemical performance superiority of MUN-CuO-TiO2 and PtCu DNs, such as short electron transfer distance and abundant reactive sites, the catalytic performance of obtained PtCu DNs/MUN-CuO-TiO2 towards H2O2 reduction was enhanced and realized signal amplification. The constructed electrochemical aptasensor for cTnI detection exhibited a satisfactory dynamic range from 0.01 pg/mL to 500.0 ng/mL and a lower detection limit of 2.3 fg/mL. The recommended sensor has been utilized to detect human serum samples with acceptable results, exhibiting potential for clinical application.

Enhancing the Whole Migration Kinetics of Na+ in the Anode Side for Advanced Ultralow Temperature Sodium‐Ion Hybrid Capacitor

AbstractBoosting the ultralow temperature (below −30 °C) performance of Na‐ion hybrid capacitors (SIHCs), which integrate the high energy density of batteries with the high output power and long life of supercapacitors, is critical for the application of advanced electronics in extreme environments. However, their low‐temperature performance, especially fast charging capability, is hindered by difficult desolvation and slow pass solid electrolyte interphase (SEI) together with sluggish diffusion within the electrode. Herein, a “single‐solute–single‐solvent” electrolyte is developed and a through‐hole hollow carbon sphere (TH‐HCS) is constructed, and it is demonstrated through theoretical calculations and experimental investigations that the weakly solvated structure and high ionic conductivity facilitate the Na+ transportation at low temperatures, the highly fluorinated SEI facilitates the Na+ migration, and the through‐hole hollow structure alleviates the volume expansion during sodiation, thus ensuring fast kinetics and structural stability. As expected, TH‐HCS using this electrolyte exhibits a high specific capacity of 87.5 mAh g−1 after 11 000 cycles at 1.0 A g−1 and −40 °C. Coupled with activated carbon, the assembled SIHC displays an energy density of 106.1 and 52.0 Wh kg−1 at 25 and −40 °C, respectively, far exceeding the performance of commercial energy storage systems at low temperature.

Electrochemical hydrogen evolution efficiently boosted by interfacial charge redistribution in Ru/MoSe2 embedded mesoporous hollow carbon spheres

The strong metal-support interaction inducing combined effect plays a crucial role in the catalysis reaction. Herein, we revealed that the combined advantages of MoSe2, Ru, and hollow carbon spheres in the form of Ru nanoparticles (NPs) anchored on a two-dimensionally ordered MoSe2 nanosheet-embedded mesoporous hollow carbon spheres surface (Ru/MoSe2@MHCS) for the largely boosted hydrogen evolution reaction (HER) performance. The combined advantages from the conductive support, oxyphilic MoSe2, and Ru active sites imparted a strong synergistic effect and charge redistribution in the Ru periphery which induced high catalytic activity, stability, and kinetics for HER. Specifically, the obtained Ru/MoSe2@MHCS required a small overpotential of 25.5 and 38.4 mV to drive the kinetic current density of 10 mA cm−2 both in acid and alkaline media, respectively, which was comparable to that of the Pt/C catalyst. Experimental and theoretical results demonstrated that the charge transfer from MoSe2 to Ru NPs enriched the electronic density of Ru sites and thus facilitated hydrogen adsorption and water dissociation. The current work showed the significant interfacial engineering in Ru-based catalysts development and catalysis promotion effect understanding via the metal-support interaction.

Construction of high content CoMoS active sites through the combination of Co5Mo10 molecular precursors and inert carbon matrix support for deep hydrodesulfurization

The rational design of high sulfurization and abundant CoMoS active phases catalysts is the key to drive the industrialization of hydrodesulfurization (HDS). Herein, we prepared a nano-catalyst with well-dispersed and numerous CoMoS active sites through confining Co3(II)[Co2(III)Mo10O38H4] (Co5Mo10) polyoxometalates (POMs) molecules with high Co/Mo ratio in hollow mesoporous carbon spheres (HMCS). On the one hand, POMs acted as pre-assembled molecular platform can build and regulate the structure of active phases by precisely adjusting the Co/Mo atomic ratio at molecular level. Meanwhile, the intimate interaction of Co-Mo on the POMs precursor also ensures that the Co species mainly exists as Co-promoted MoS2 active phase after the sulfidation process, thus the highly efficient synergism of the bimetals can be fully utilized in the reaction. On the other hand, the mesoporous carbon sphere with homogeneous pore size and high specific surface area can effectively confine the growth of the catalyst to disperse the active metals. The weakening metal–metal interaction property of such inert support enables the S-Co5Mo10/HMCS-10 catalyst to realize higher sulfurization, shorter slab length and higher stacking number. In addition, the abundant mesopores and high pore capacity of support greatly facilitate the mass transfer process and provide sufficient space for the HDS reaction as the nanoreactor. The unique combination of POMs and HMCS enabled the S-Co5Mo10/H10 catalyst to achieve up to 99.2% conversion of dibenzothiophene (DBT) after 4 h of HDS reaction, while obtaining a TOF value of 1.3 × 10−3 s−1 (calculated when keeping the low conversion at 42% after 0.5 h of reaction). The structural orientation of the POMs precursors to the active phases of HDS catalysts was investigated using various characterization methods, and the structure–activity relationship between the catalytic performance and the sulfide active phases was also revealed in this work.