Porous Hollow Spheres Research Articles

The controllable porous structure and s-doping of hollow carbon sphere synergistically act on the microwave attenuation

Currently, the development of high-efficiency electromagnetic wave (EMW) absorbing materials has received close attention. Due to unique composition and structure, porous hollow carbon spheres (PHCSs) have been extensively studied in the EMW absorption field. In order to obtain the regulated EMW absorber, in the present study, sulfur was successfully doped into the PHCS by hydrogen peroxide etching and high temperature vulcanization. By fixing the amount of sulfur doped and the etching time, the micro-structure of the product could be effectively controlled, and the corresponding electromagnetic parameters would also change accordingly. The optimized sulfur-doped porous hollow carbon sphere (SPCHS) had the minimum reflection loss (RL) value of −27.2 dB, and the effective bandwidth of 4.76 GHz. More importantly, the best effective bandwidth (EAB, RL < −10 dB) could reach 6.72 GHz (11.28–18 GHz) at the thickness of 2.25 mm. It should be pointed out that the sample filling ratio was only 5 wt% in the paraffin matrix. In addition, when the incidence θ reached −60°, the maximum reduction of radar cross section (RCS) was −21.9 dB m2. The convenient and efficient RCS simulation provided reliable support for the practical application of SPHCS materials in the field of EMW absorption.

Mechanism of enhanced H2S sensor ability based on emerging Li0.5La0.5TiO3-SnO2 core-shell structure

The Li0.5La0.5TiO3 (LLTO) is a new sensing material demonstrating ultrafast response to H2S within one second. To further enhance the sensitivity, a LLTO-SnO2 core-shell structure was constructed by the assembly of thin SnO2 nanoflakes on the porous hollow LLTO spheres. The absorption and reaction activity of oxygen on the surface as well as the electron transfer processes were modified and discussed in detail. The formation of oxygen vacancy improves the onset potential of oxygen reduction from 0.61 V to 0.75 V. The effective separation of electrons across the interface helps to take advantage of high response property of SnO2. The response value was improved by 4.5 times than that of pristine LLTO with sub-second response time and excellent stability.

Regulation of Sulfur doping on rational synthesized porous hollow carbon spheres and their superior electromagnetic wave attenuation performance

Recently, developing an ideal electromagnetic wave (EM) absorption material, which can simultaneously possess the good abilities of EM energy dissipation, chemical stability and lightweight, has attracted significant attention. Herein, rational designed porous hollow carbon spheres have been prepared via a controllable chemical etching process and followed by a regulated sulfur doping process in the carbon frameworks. The content of sulfur doping can be exactly tuned by simplify adjusting the amount of thioacetamide during the reaction in which can effectively achieve the good balance between the impedance matching and dielectric loss. Benefiting from the porous hollow structure, good impedance matching condition and high dielectric loss, the as-prepared sulfur-doped porous hollow spheres (HCSs) could obtain an efficiency EM attenuation performance, with a maximum effective absorption bandwidth (ƒE) of 6.7 GHz at an absorbent thickness of 2.0 mm. When the matching thickness was only 1.65 mm, the minimum reflection loss (RL) value reached − 53 dB. Therefore, this work confirms that the sulfur-doped porous hollow carbon spheres are expected to be reliable microwave attenuation materials, which also opens up a potential strategy for design and synthesis of high-performance carbon-based materials with tunable EM properties.

Ultra-High Sulfur-Doped Hierarchical Porous Hollow Carbon Sphere Anodes Enabling Unprecedented Durable Potassium-Ion Hybrid Capacitors.

Sulfur doping is a promising path to ameliorate the kinetics of carbon-based anodes. However, the similar electronegativity of sulfur and carbon and the poor thermal stability of sulfur severely restrict the development of high-sulfur-content carbon-based anodes. In this work, ultra-high sulfur-doped hierarchical porous hollow carbon spheres (SHCS) with a sulfur content of 6.8 at % are synthesized via a direct high-temperature sulfur-doping strategy. An SHCS has sulfur bonded to the carbon framework including C-S-C and C-SOx-C, which enlarges its interlayer distance (0.411 nm). In the K half-cell, benefiting from the considerable content and the reasonable architecture of sulfur, the SHCS exhibits significantly improved reversible specific capacity, initial Coulombic efficiency, and cyclability than hierarchical porous hollow carbon spheres without sulfur. Remarkably, the potassium ion hybrid capacitor device fabricated with the SHCS anode achieves excellent energy/power density (135.6 W h kg-1/17.7 kW kg-1) and unprecedented durability over 26,000 cycles at 2 A g-1. This research provides a superior strategy to design high-sulfur-content carbon-based anodes with excellent potassium storage performance.

Donor-π-Acceptor Heterosystem-Functionalized Porous Hollow Carbon Microsphere for High-Performance Li-S Cathode Materials with S up to 93 wt.

Lithium-sulfur (Li-S) batteries, as a prospective energy storage system, are still plagued by many problems that prevent them from their application, especially the low content of sulfur in the cathode. Herein, a cathode material with S up to 93 wt % is designed via a hollow donor-π-acceptor heterosystem, which combines catalytic sites, adsorption sites, and good conductivity together. Following this guidance, a hollow porous carbon sphere is prepared with CoO particles and single V atoms decorated on it (Co/V-HPCS), providing ultrahigh volumetric space for sulfur. Even the electrode made of sulfur-loaded Co/V-HPCS (Co/V-HPCS@S) has a high content of 90 wt % (sulfur content in the electrode is ∼83.5 wt %), and the cathode exhibits an excellent discharge capacity of 575.2 mAh g-1 under 0.2C after 100 cycles. With careful analysis by means of a high-resolution transmission electron microscope (HRTEM), the catalytic amounts of CoO particles and single V atoms loaded on the carbon shell are confirmed, which endows the material with outstanding catalytic ability to transfer sulfur and excellent adsorption of polysulfides. This concept of the cathode material increases the possibility of advanced long-life Li-S batteries with high tap density and high energy density.

Porous α-Fe2O3 gas sensor with instantaneous attenuated response toward triethylamine and its reaction kinetics

To achieve highly selective and rapid detection of triethylamine (TEA) at a relatively low temperature remains challenging. In this work, we report an ultrasensitive TEA gas sensor with a specific response based on the porous α-Fe2O3 hollow sphere array, which shell is composed of fusiform particles. At a low operating temperature (160 °C), the sensor shows high response (75.8) toward 10 ppm TEA with a short response time (2 s) and can detect TEA as low as 50 ppb. More importantly, an obvious attenuation characteristic is observed during TEA detection. This distinctive response toward TEA gas is repeatable when the operating temperature is over a threshold (>120 °C). Moreover, the instantaneous attenuated response is found to be independent of the gas concentration and humidity but much related to specific gases, demonstrating its potential to be used as a characteristic signal to achieve highly selective detection of TEA molecules. Furthermore, based on density functional theory (DFT) calculations, the attenuated response can be ascribed to a special surface dynamic reaction process involving the thermal decomposition of TEA molecules and the formation of nitrogen oxides, which is verified by the quasi in-situ X-ray photoelectron spectroscopy analysis. This work will provide a new idea for developing highly selective and sensitive sensors.

Copper atoms inlaid in titanium zirconium oxide spherical shell confine free radicals for the robust Fenton-like treatment of complex biogas slurry

A novel Fenton-like system based on single-atom catalysts was developed for the treatment of biogas slurry under 90 °C conditions. First, a binary composite was synthesized in which porous TiZrO4 hollow spheres provided sites for embedding Cu atoms and confining generated free radicals to promote the efficiency of oxidation reactions. The TiZrO4/Cu catalyst mediated the simultaneous oxidation of approximately 69 % of the chemical oxygen demand and at least 55 % of total nitrogen in biogas slurry within 1 h, and the residual organics, including simple acetic acid and propionic acid, possessed high biodegradability. Correspondingly, all of the fluorescent fulvic acids, proteins, polysaccharides, and humic acids disappeared. DFT calculations further confirmed that the electron-rich single Cu atoms generated hydroxyl radicals by capturing and reducing H2O2, thus improving the treatment efficiency. The special catalyst structure with dispersed Cu atoms maintained excellent catalytic activity and durability with negligible Cu leakage over multiple cycles.

CuO nanoparticle loaded ZnO hierarchical heterostructure to boost H2S sensing with fast recovery

• CuO nanoparticle loaded ZnO hierarchical heterostructure were in situ synthesized through a facile method. • The sensor based on the ZnO@CuO-40 exhibited excellent sensing performance with a detection limit of 20 ppb H 2 S at a low temperature (25 °C). • The enhanced sensing mechanism of the ZnO@CuO hierarchical heterostructure toward H 2 S was proposed based on the DFT Calculation and quasi in-situ XPS analysis. To achieve both sensitive and recoverable detection of H 2 S gas at low temperature, ZnO@CuO hierarchical heterostructures composed of porous hollow spheres array are in situ prepared through a template-assisted magnetron sputtering and subsequent annealing treatment. It was found that as the sputtering time of metal copper target is 40 s, the ZnO@CuO hierarchical heterostructure shows remarkably enhanced sensing response (R a /R g = 20.7) with short response/recovery time (33/298 s) toward 10 ppm (ppm) of H 2 S gas at a low operating temperature (25 °C) compared with pristine ZnO and CuO sensing film. Such sensor exhibits a distinct response to an ultralow concentration of 20 parts per billion (ppb) H 2 S gas and possesses easy recovery even when the concentration of H 2 S gas increases to 100 ppm. Density functional theory (DFT) calculations reveal that H 2 S gas molecules tend to be adsorbed on the surface of ZnO@CuO hierarchical heterostructure compared with pristine ZnO. Moreover, the energy barrier for H 2 S decomposition on the heterostructure’s surface is 0.25 eV, indicating that this is a thermodynamically favorable reaction. Calculation and X-ray photoelectron spectroscopy analysis further revealed that the porous hierarchical heterostructure, p-n heterojunction at the interface, and intermediate CuS nanoparticles with small size are the major factors to enhance H 2 S gas sensing properties. Our work affords great potential for the development of high-performance gas sensors for H 2 S detection.

N-doped hierarchical porous hollow carbon spheres with multi-cavities for high performance Na-ion storage

Sodium ion hybrid capacitors (SIHC) have attracted extensive interest owing to their both high energy and power densities as well as long cycle life. Herein, a novel dual-carbon SIHC is assembled with hierarchical porous hollow multicavity carbon spheres (HMCSs) as an intercalated anode and activated HMCSs (AHMCSs) as a capacitive cathode. The HMCSs are prepared from aniline and pyrrole through a one-step carbonization with F-127 as soft template, and show high reversible capacity and good rate performance as anode for sodium ion battery. And AHMCSs delivers high energy densities of 16.6 and 12.2 Wh kg−1 at the power densities of 250.1 and 9996.4 W kg−1 benefiting from their high surface area and hierarchical porous structure after confined KOH activation. The combination of HMCSs anode and AHMCSs cathode endows the SIHC superior energy densities of 140.1 and 87.1 Wh kg−1 under the power densities of 380.0 and 14249.7 W kg−1, and 80.8% capacitance retention after 4400 cycles at 1 A g−1. Our work provides a new approach for developing high performance sodium storage devices.

Highly-configured TiO2 hollow spheres adorned with N-doped carbon dots as a high-performance photocatalyst for solar-induced CO2 reduction to methane

Transforming CO2 into solar fuel using renewable solar energy and a catalyst is an effective approach that simultaneously addresses energy scarcity and climate deterioration. Therefore, it is necessary, albeit challenging, to design a catalyst that works effectively for this purpose. Herein, we have rationally developed a hybrid catalyst composed of highly-configured TiO2 hollow spheres (TOH) and N-doped carbon dots (CD), referred to as CD/TOH, and use this hybrid as a catalyst for photocatalytic CO2 reduction to produce CH4 under simulated sunlight. The electron microscopy results revealed that the CD/TOH hybrid possesses a porous hollow sphere structure uniformly adorned with N-doped carbon dots. Moreover, the CD/TOH hybrid demonstrates many beneficial properties for CO2 photoreduction reactions, including a large surface area, effective light-harvesting capability, high CO2 adsorption, and, most importantly, significantly enhanced separation of photoexcited charges. Consequently, the CD/TOH containing 2 wt% CD achieves an optimum CH4 formation rate of 26.8 μmol h−1 g−1, corresponding to 98% CH4 selectivity against competitive H2 production. Further, the hybrid also demonstrated stable CO2 reduction activity during consecutive test runs. Thus, the insights gained from this study may aid in the development of effective catalysts for CO2 photoreduction.

Sustainable porous hollow carbon spheres with high specific surface area derived from Kraft lignin

Hollow carbon spheres (HCSs) have attracted tremendous interest in recent years due to their intriguing structure-induced physicochemical properties and significant potential for numerous applications. However, the preparation of HCSs with precise structural control using a simple and scalable strategy remains challenging. In this work, hollow carbon particles having a well-defined spherical morphology were successfully produced using a green, economical, and facile spray drying method together with a carbonization process. Kraft lignin was employed as the carbon precursor in place of lignosulfonate with potassium hydroxide (KOH) as an activation agent. The high specific surface area (1536.5–2424.8 m2 g−1) with micro-mesoporous structure of HCSs can be easily tuned by controlling the mass ratio of KOH to carbon precursor. The KOH-to-lignin mass ratios were utilized below 1.5, lower than those in previous studies typically used higher than 3, which was in accordance with green chemistry principles. In addition, these HCSs have applications as electrode materials in supercapacitors for energy storage devices. With the great achievements and continuous efforts in this important field, these results suggest that our approach will open a new path for the development of advanced carbon materials and high value-added utilization of Kraft lignin as a promising material for potential applications.

Preparation and properties of transition metal nitrides caged in N-doped hollow porous carbon sphere for oxygen reduction reaction

A series of transition metal nitrides (MxNy, M=Fe, Co, Ni) nanoparticle (NP) composites caged in N-doped hollow porous carbon sphere (NHPCS) were prepared by impregnation and heat treatment methods. These composites combine the high catalytic activity of nitrides and the high-efficiency mass transfer characteristics of NHPCS. The oxygen reduction reaction results indicate that Fe2N/NHPCS has the synergistic catalytic performance of higher onset potential (0.96 V), higher electron transfer number (~4) and higher limited current density (1.4 times as high as that of commercial Pt/C). In addition, this material is implemented as the air catalyst for zinc-air battery that exhibits considerable specific capacity (795.1 mA·h/g) comparable to that of Pt/C, higher durability and maximum power density (173.1 mW/cm2).

Facilitating redox kinetics of sulfur species by cobalt-nitrogen co-doped porous hollow carbon for high-performance Li-S battery

The shuttle effect of polysulfides is the main obstacle restricting the development of lithium-sulfur batteries. However, most efforts focused on physical adsorption and polar adsorption cannot fundamentally solve the problem of sluggish conversion of polysulfides, especially for high sulfur loading. Herein, a cobalt-nitrogen co-doped porous hollow carbon sphere (Co-CN) is synthesized in one step. The porous conductive carbon spheres can realize a rapid charge transfer, mitigate volume expansion during cycling and enhanced physical adsorption for polysulfides. Nitrogen and cobalt doping provide chemisorption and catalysis for the restriction and conversion of polysulfides. Furthermore, liquid Li2S8 polysulfide was used as sulfur source to guarantee high sulfur loading and fast redox kinetic. Benefiting from the triple effect of physical adsorption, chemical adsorption and catalysis, the Co-CN@Li2S8 cell with sulfur loading of 5.15 mg cm−2 delivers a high reversible initial capacity of 1499 mAhg−1 at 0.1C and 880.9 mAhg−1 after 100 cycles. More excitingly, the capacity decay rate was only 0.012% per cycle at 1C over 1000 cycles, indicating excellent long cycle stability. This work provides a facile and effective route for Co-CN as a sulfur host in lithium-sulfur battery.

Fabrication of S,N-Doped Carbon-Coated SnS2/SnS Heterostructures Supported by Hollow Carbon Microspheres for Sodium-Ion Storage

Developing novel anode materials containing electroactive heterostructures which boost ion and charge transfer kinetics in a carbon matrix is still a great challenge. Here we report on a new smartly designed material: SnS2/SnS p-n heterostructures embedded in S,N-doped carbon layer supported by hollow carbon spheres (C@SnSx@C) by a facile method and applied as negative electrode material in sodium ion batteries. The C@SnSx@C2 (at optimized carbon ratio) negative electrode can deliver an initial reversible capacity of 636.5 mAh·g−1 at 0.1 A·g−1, superior rate capability (265.1 mAh·g−1 at rate of 10.0 A·g−1) and long cycle life (capacity retention of 96.3 % at 1.0 A·g−1 after 150 cycles). The SnS2/SnS p-n heterojunctions provide a lower sodium ion diffusion energy barrier (0.38 eV), higher Na+ adsorption energy (−4.66 eV) and higher electronic conductivity due to an internal electric field according to density functional theory calculations compared to plain SnS. Moreover, S,N-doped carbon facilitates electronic conductivity and buffers the volume changes during the conversion reaction-based SnSx upon sodium insertion and extraction process. Porous hollow carbon spheres contribute to prevent the agglomeration of SnS2/SnS nanosheets and keep the structural integrity. Our findings on this unique material might be extended to other ion battery technologies.

Structure engineering in interconnected porous hollow carbon spheres with superior rate capability for supercapacitors and lithium-sulfur batteries

The application of hollow carbon spheres in energy storage devices is still hindered by their relatively low electron transmission and ion diffusion kinetics, as well as their insufficient storage sites. Herein, we prepare interconnected porous honeycomb hollow carbon spheres (IPHHCSs) using hard-templating route by increasing the concentration of template spheres and introducing cationic surfactants simultaneously. The as-obtained IPHHCSs show favorable features for ESD, such as large contacted areas between spheres, high specific surface areas (951 m2 g−1), hierarchical porous frameworks with high volume of mesopores, and rich N-doping (3.36%), achieving a lower interface-resistance between spheres, more ion-storage sites, and developed mesoporous channels for rapid ions diffusion. Thus, such a unique carbon architecture endows IPHHCSs a superior rate capability for supercapacitor and lithium-sulfur battery applications. The IPHHCSs supercapacitor’s electrode delivers a high specific capacitance of 295F g−1 at 1 A g−1, an outstanding rate capability (87% capacitance retention from 1 A g−1 to 20 A g−1), with a high cycling life stability (1.2% loss after 10,000 cycles). As for lithium-sulfur batteries, the IPHHCSs/S cathode with sulfur loading of 70% demonstrated an initial reversible capacity of 1160 mAh g−1 at 0.2C and an excellent rate performance with a capacity retention of 53% at 10C. More notably, IPHHCSs/S electrode could also enable a remarkable cyclic stability that possesses a reversible capacity of 285 mAh g−1 at 10C upon 1000 cycles with a low capacity degradation of 0.042% per cycle. Controllable design of interconnected porous HCSs structures could decrease interface-resistance and promote ion diffusion, which can be an effective way for developing high-rate supercapacitors and Li–S batteries.

Enhanced photocatalytic H2 production performance of CdS hollow spheres using C and Pt as bi-cocatalysts

Photocatalytic H2 production from water splitting is an effective method to solve energy crisis and environmental pollution simultaneously. Herein, carbon@CdS composite hollow spheres (C@CdS-HS) are fabricated via a facile hydrothermal method using porous carbon hollow spheres (C-HS) as the template. The C@CdS-HS shows an excellent photocatalytic H2-generation rate of 20.9 mmol h−1 g−1 (apparent quantum efficiency of 15.3% at 420 nm), with 1.0 wt% Pt as a cocatalyst under simulated sunlight irradiation; this rate is 69.7, 13.9, and 3.9 times higher than that obtained with pure CdS hollow spheres (CdS-HS), C@CdS-HS, and CdS-HS/Pt, respectively. The enhanced photocatalytic H2-evolution activity of C@CdS-HS/Pt is due to the synergistic effect of C and Pt as the bi-cocatalyst. The C-HS serves not only as an active site provider but also as an electron transporter and reservoir. Moreover, C-HS has a strong photothermal effect that is induced by near infrared light, which kinetically accelerates the H2-production reaction. Additionally, the underlying charge transfer pathway and process from CdS to C−HS is revealed. This work highlights the potential application of C-HS-based nanocomposites in solar-to-chemical energy conversion.

Well-dispersed pyrite-type RuS2 nanocrystals anchored on porous nitrogen and sulfur co-doped hollow carbon spheres for enhanced alkaline hydrogen evolution

The hydrogen evolution reaction (HER) activity in alkaline condition is generally suppressed due to sluggish water dissociation–related Volmer process. Consequently, developing new highly-active and cost-efficient electrocatalysts for the alkaline hydrogen production is greatly desirable for achieving sustainable water splitting in industrial plants. Pyrite-type RuS2 is a potential excellent electrocatalyst for alkaline HER but the related research is still in its infancy. Herein, well-dispersed crystalline RuS2 nanoparticles (c-RuS2 NPs) with ultrasmall particle size anchored on porous nitrogen and sulfur co-doped hollow carbon spheres (NSC) are synthesized for alkaline HER electrocatalysis. The conductive and porous hollow carbon spheres with nitrogen and sulfur doping is used as the effective support to provide abundant anchoring sites and modify the electronic structure of RuS2, beneficial to increasing the active sites and improving the intrinsic activity. Furthermore, the crystallinity modulation of ruthenium sulfide also has a significant impact on HER activity. In 1.0 M KOH solution, the proposed c-RuS2 NPs/NSC catalyst exhibits admirable activity for HER electrocatalysis with a low overpotential of 11 mV at a current density of 10 mA cm−2 and a small Tafel slope of 35.4 mV dec−1. With low Ru loading, superior hydrogen evolution in alkaline media is achieved for c-RuS2 NPs/NSC compared to the commercial Pt/C and the reported ruthenium-sulfide-based electrocatalysts.

In situ grown monolayer N–Doped graphene and ZnO on ZnFe2O4 hollow spheres for efficient photocatalytic tetracycline degradation

Herein, ZnFe2O4/ZnO hollow porous spheres (HPS) of the dual–template and self–dissolution design, on which monolayer nitrogen–doped graphene (NG) is in situ grown by chemical vapor deposition, are applied for realizing effective photocatalytic degradation of antibiotics. The constructed photocatalyst possesses a hollow interior for strengthening visible–light absorption ability and offering large surface area, a porous for facilitating rapidly mass transfer capability, a thin shell for shortening the migration distance of photo–generated electrons (e⎺), tight adhesion for expediting charge separation and mobility, and a monolayer NG cage surface for adsorbing and stimulating activating antibiotics molecules. Benefiting from the novel HPS structure, the prepared ZnFe2O4/NG/ZnO HPS photocatalyst exhibits high activity under visible–light irradiation, currently the largest to the best of our knowledge, which is much enhanced compared with those of the ZnFe2O4/NG/ZnO solid spheres and ZnFe2O4/NG hollow spheres.

Elucidating influence of the existence formation of anchored cobalt phthalocyanine on electrocatalytic CO2-to-CO conversion

Heterogeneous molecular catalysts with inexpensive transition-metal centers have attracted much attention, due to their excellent electrocatalytic performance on electrocatalytic carbon dioxide reduction reaction (CO 2 RR). Among them, metal phthalocyanine (MePc) has aroused great interest. However, the complex existence formation (crystals or evenly dispersion) in the hybrid catalyst, e.g. cobalt (II) phthalocyanine (CoPc), determining the final electrocatalytic CO 2 RR performance still remains debate. To further elucidate the influence of the existence formation of CoPc on electrocatalytic performance of CO 2 -to-CO conversion, we synthesized ultra-thin nitrogen-doped hollow carbon spheres (N-doped HCS) with a high surface area of 653.3 m 2 g −1 as the support to anchor a series of different existence formation of CoPc. The existence formation of CoPc in the hybrid catalyst is closely related with the content of Co atom, the latter of which is the key factor of the CO 2 RR performance. We summarized the nonlinear relationship between the partial CO current density ( j CO ) and the content of Co atom at −0.82 V vs. RHE, and the equation of Faraday efficiency of CO ( FE CO ) vs. the content of Co atom at −0.82 V vs. RHE, which proves the fact that the coexistence of crystals and evenly dispersed CoPc or evenly dispersed and low loading of CoPc both could reach the satisfying results ( j CO > ~14 mA cm −2 , FE CO > ~ 91%, at −0.82 V vs. RHE) under the content of Co atom from 1.26 wt% to 0.14 wt%. The optimal catalyst (Co, 0.49 wt%) achieved a near-unity Faradaic efficiency of 96%, which is close to 4 times that of the unsupported CoPc ( FE CO =24.54%), and an outstanding current density of 20.47 mA cm −2 towards CO, which is c.a. 60 times higher than that of the unsupported CoPc (0.34 mA cm −2 ) at −0.82 V vs. RHE. This work could potentially inspire the rational design of heterogeneous molecular catalysts and promote its application in the energy conversion and storage field. The nitrogen-doped porous hollow carbon spheres anchor a series of cobalt phthalocyanine for electrocatalytic carbon dioxide reduction. • Different amount of Cobalt (II) phthalocyanine (CoPc) is immobilized on N-doped HCS as electrocatalysts. • Their electrochemical CO 2 RR properties were found to be closely related with the existence formation of CoPc. • The nonlinear relationship of existence formation of CoPc and electrocatalytic performance is discussed and elucidated. • Optimized catalyst is enumerated with excellent value of multiparameters. • The mechanism of electroreduction CO 2 -to-CO conversion is deduced for better understanding.

Hierarchical Porous, N-Containing Carbon Supports for High Loading Sulfur Cathodes.

The lithium-polysulfide (LiPS) dissolution from the cathode to the organic electrolyte is the main challenge for high-energy-density lithium-sulfur batteries (LSBs). Herein, we present a multi-functional porous carbon, melamine cyanurate (MCA)-glucose-derived carbon (MGC), with superior porosity, electrical conductivity, and polysulfide affinity as an efficient sulfur support to mitigate the shuttle effect. MGC is prepared via a reactive templating approach, wherein the organic MCA crystals are utilized as the pore-/micro-structure-directing agent and nitrogen source. The homogeneous coating of spherical MCA crystal particles with glucose followed by carbonization at 600 °C leads to the formation of hierarchical porous hollow carbon spheres with abundant pyridinic N-functional groups without losing their microstructural ordering. Moreover, MGC enables facile penetration and intensive anchoring of LiPS, especially under high loading sulfur conditions. Consequently, the MGC cathode exhibited a high areal capacity of 5.79 mAh cm−2 at 1 mA cm−2 and high loading sulfur of 6.0 mg cm−2 with a minor capacity decay rate of 0.18% per cycle for 100 cycles.