Mesoporous Carbon Layer Research Articles

Quantum-Sized Co Nanoparticles with Rich Vacancies Enabled the Uniform Deposition of Lithium Metal and Fast Polysulfide Conversion.

The notorious polysulfide shuttling and uncontrollable Li-dendrite growth are the main obstacles to the marketization of Li-S batteries. Herein, a dual-functional material consisting of vacancy-rich quantum-sized Co nanodots anchored on a mesoporous carbon layer (v-Co/meso-C) is proposed. This material exposes more active sites to improve its reaction performance and simultaneously realizes excellent lithiophilicity and sulfiphilicity characteristics in Li-S electrochemistry. As Li metal deposition hosts, v-Co/meso-C shows small nucleation overpotential, low polarization, and ultra-long cycling stability in both half and symmetric cells, as confirmed by experimental studies. On the S cathode side, experimental and theoretical calculations demonstrate that v-Co/meso-C enhances the adsorption of polysulfides and boosts their catalytic conversion rate. This, in turn, suppresses the shuttle effect of polysulfides and improves sulfur utilization efficiency. Finally, a shuttle-free and dendrite-free v-Co/meso-C@Li//v-Co/meso-C@S full cell is fabricated, exhibiting excellent rate performance (739 mAhg-1 at 5.0 C) and good cyclability (capacity decay rate is 0.033% and 0.035% per cycle at 2.0 and 5.0 C, respectively). Even a pouch cell with high sulfur loading (5.5mgcm-2) and lean electrolyte/sulfur (4.8µLmg-1) can still work 50 cycles with 80% capacity retention rate. This study shows far-reaching implications in the design of dendrite-free, shuttle-free Li-S batteries.

Development of Bromine Adsorbing Carbon Felt Electrode by Coating of Nitrogen-Doped Mesoporous Carbon Layer for Highly Stable Flowless Zinc-Bromine Battery

Renewable energy is well known for the extreme volatility of power production, and secondary battery-based energy storage systems (BESS) are the key to the novel and safe energy industry to expand the supply of renewable energy. Currently, lithium-ion battery-based ESS is commonly used, but the frequent ignition accidents from these ESSs rather become an obstacle to the growth of the renewable energy field. Among the redox batteries, the flowless zinc-bromine battery (FLZBB) is studied as the alternative since it uses a non-flammable and cost-effective aqueous Zn- Br2 electrolyte. However, its main challenges are that bromine (Br2) and polybromide anions (), formed at the positive electrode during the charging process, cross over to the negative electrode due to the difference in chemical potential between the electrodes. The diffused Br2 oxidizes the zinc metal, electrodeposited on the negative electrode, and causes a self-discharge reaction that consumes the charging active material and Br2 the battery performance and life. Herein, we present a nitrogen-doped mesoporous carbon coated on the pristine graphite felt fibers (NMC/GF). By uniformly forming a nitrogen-doped porous carbon material on the GF fibers through the evaporation-induced self-assembly (EISA) method, it is a simple and cost-effective method to develop the structural and properties of the GF positive electrode to increase the ability of adsorption and storing the active materials, Br2 and polybromide anions (,, and ) generated during the charging process. In addition, it also improved the bromine redox reaction kinetics by having a strong affinity with the aqueous Zn-Br2 electrolyte. This facilitates long-term charge/discharge cycles, enabling high performance and improved durability for Coulombic efficiency over 95% for 5000 cycles in the FLZBB single-cell platform at a current density of 20 mA cm-2 and a high-rate areal capacity of 2 mAh cm-2.

Ionic Pumping Effect at the Tailored Mesoporous Carbon Interface for an Extra-Stable Lithium Ion Battery at Low Temperatures.

Ion transportation at the interface significantly influences the electrochemical performance of the lithium ion battery, especially at high rates and low temperatures. Here, we develop a controlled self-assembly strategy for constructing a mesoporous carbon nanolayer with a uniform pore size and varied thicknesses on the two-dimensional monolayer MXene substrate. On the basis of the excellent electron conductivity of MXene, the mesoporous carbon layer is found with a voltage-driven ion accumulation effect, acting as an "ionic pump". The thicker mesoporous layer (∼2.28 nm) has the ability to accommodate a substantial quantity of ions, demonstrating enhanced ionic conductivity, remarkable cycling stability (192.8 mAh/g after 9400 cycles at 5.0 A/g), and outstanding rate capability at ambient and sub-zero temperatures (∼601 mAh/g at 0 °C and 0.05 A/g). This work provides valuable insights and guidance for the further development of high-performance electrode materials at high rates or low temperatures.

Regulating the coordination environment of Co@C catalysts for selective hydrogenation of adiponitrile to hexamethylenediamine

Selective production of hexamethylenediamine (HMDA) by hydrogenation of adiponitrile (ADN) is a precondition to produce high-value added polyamides (e.g., nylon-66) and is still a great challenge by metal catalyst under alkali-free condition. Rational design of metal reactive center via modulated coordination endows a practical cure. We presented the significant role by forming Co-Nx coordinated sties in heterogeneous Co@C catalysts, which induced well crystallization of metallic Co phase with high-yield of HMDA under ultrafast intrinsic reaction rate (TOF of 2746 h−1). Characterizations suggested the simultaneous reduction of Coδ+ accompanied with carbon decomposition during pre-reduction, resulting in the strong Co-C interaction via Co-Nx coordination. Fine and stable Co particles around 5 nm were confined by mesoporous carbon layers with clear lattice distortion/expansion at Co-C interface. DFT calculation confirmed the electron modulation on the d-band center of Co with the strong affinity toward semi-hydrogenated ACN, facilitating the in-depth hydrogenation to HMDA. The Co coordinated states tuned by N was a fine regulator to modulate the spatial and electronic structure of Co active sites, positively correlating with the intrinsic activity. The Co@C-Z400 transformed ADN to HMDA with 90.7 % yield under sharply reduced activation energy of 37.9 kJ/mol.

(Invited) Electrocatalytic Reduction of Carbon Dioxide over Aluminum-Added Coppor Oxide Gas Diffusion Electrode

Electrochemical cells are the key technologies for construction of carbon neutral society to produce hydrogen from water and produce useful chemicals from carbon dioxide utilizing renewable energy. Copper species are the unique catalysts for electrochemical carbon dioxide reduction reaction (CO2RR) with capable of producing C2+ products such as ethanol and ethylene. Selective production of target chemical is one of the most important requirements for the catalysts, and addition of different elements and surface modifications have been reported to be beneficial for the selective production.In the present study, copper oxides-based catalysts prepared with electroless plating techniques were examined for electrochemical CO2RR. To conduct CO2RR at relatively high current densities, the catalysts were examined in the form of gas diffusion electrode (GDE). The Cu2O based GDE was prepared by the combination of physical vapor deposition and electroless plating on hydrophobized carbon paper coated with mesoporous carbon layer. After the electroless plating treatment, the metal precursors were successfully converted to core-shell structured electrocatalyst with Cu2O shell and Cu core. By introducing different elements such as aluminum to the precursor, metallic Cu, the different element added catalysts were successfully prepared in the shape of GDE. Addition of different element significantly improved durability of the core-shell structured catalysts and, as a result, faradaic efficiency of ethylene of 24 hours after starting electrolysis was increase from 32% to 47% under applying cathodic current of 260 mAcm-2. Further surface modifications with Nafion enhanced the durability and the faradaic efficiency of ethylene maintained >50% for over 48 hours and reached about 60% in maximum.In the presentation, we will discuss about the detailed structure of the electrocatalysts, results of full-cell test, and longer durability test over 100 hours.

Boosted Oxygen Kinetics of Hierarchically Mesoporous Mo2C/C for High-current-density Zn-air Battery.

The high-current-density Zn-air battery shows big prospects in next-generation energy technologies, while sluggish O2 reaction and diffusion kinetics barricade the applications. Herein, the sequential assembly is innovatively demonstrated for hierarchically mesoporous molybdenum carbides/carbon microspheres with a tunable thickness of mesoporous carbon layers (Meso-Mo2C/C-x, where x represents the thickness). The optimum Meso-Mo2C/C-14 composites (≈2µm in diameter) are composed of mesoporous nanosheets (≈38nm in thickness), which possess bilateral mesoporous carbon layers (≈14nm in thickness), inner Mo2C/C layers (≈8nm in thickness) with orthorhombic Mo2C nanoparticles (≈2nm in diameter), a high surface area of ≈426m2g-1, and open mesopores (≈6.9nm in size). Experiments and calculations corroborate the hierarchically mesoporous Mo2C/C can enhance hydrophilicity for supplying sufficient O2, accelerate oxygen reduction kinetics by highly-active Mo2C and N-doped carbon sites, and facilitate O2 diffusion kinetics over hierarchically mesopores. Therefore, Meso-Mo2C/C-14 outputs a high half-wave potential (0.88V vs RHE) with a low Tafel slope (51mVdec-1) for oxygen reduction. More significantly, the Zn-air battery delivers an ultrahigh power density (272mWcm-2), and an unprecedented 100h stability at a high-current-density condition (100mAcm-2), which is one of the best performances.

Ni-based nanocatalyst protected by ultrathin mesoporous nitrogen-doped carbon layer with hollow structure for the efficient transfer hydrogenation of halogenated nitrobenzenes

It is of great scientific and industrial value to develop cheap and efficient supported non-noble metal-based catalysts for the selective hydrogenation of halogenated nitrobenzenes. In this work, hollow-structured Ni-based nano-catalysts coated with ultrathin nitrogen-doped carbon layers (H-Ni@NC) have been prepared. The etching of SiO2 template before calcination and decomposition of residual Ni3Si2O5(OH)4 shell into SiO2 leads to the resulting catalysts could maintain good mechanical property and stability. The H-Ni@NC catalyst prepared at 600 °C exhibits the optimal catalytic performance for the catalytic selective hydrogenation of halogenated nitrobenzenes under mild conditions (60 °C) when using hydrazine hydrate (N2H4·H2O) as the reducing agent, and could maintain its catalytic properties even after 5 consecutive runs. The contrast experiments confirm that the combination of hollow structure with N-doped carbon protective layer make the catalyst show the best catalytic effect, and the synergistic effects are further discussed in detail combined with characterization analysis. In addition, this work further reveals the mechanism of Ni-based catalysts for the transfer hydrogenation of halogenated nitrobenzenes, which may provide a reference idea for the preparation of other Ni-based catalysts.

Towards high-capacity lithium ion batteries:constructing hollow-structured SiOx-based nanocube anode via a sequential coating strategy

Reserving void space for silicon oxide-based (SiOx-based) anodes has proved highly efficient in tackling their volume expansion and contraction upon lithiation/delithiation. Specially, hollow structure featured with sufficient internal spaces shows great promise in buffering the volumetric effect of SiOx. However, constructing a hollow structure, containing high-capacity SiOx components and high-conductivity carbon components, still remains a great challenge. In this work, we design a sequential coating strategy to initially construct sandwich hollow-structured high-capacity SiOx anode (NC@SiOx@m-C) that consists of an innermost nitrogen-doped porous carbon network (NC), a middle mesoporous SiOx layer, and outermost mesoporous carbon (m-C) layer. The incorporation of high-capacity component SiOx (x < 2) via sequential coating process greatly improves the specific capacity of NC@SiOx@m-C. Both of NC and m-C layers synergistically enhance the overall electronic conductivity of the anode. Moreover, the outermost m-C layer retards the direct contact between SiOx and electrolyte and effectively reduces the side reactions. As a result, the NC@SiOx@m-C nanocubes delivers a capacity as high as 583 mAh g−1 at a high current density of 1 Ag-1 after 500 cycles, giving an excellent electrochemical performance.

Fe–N/C catalysts with tunable mesoporous structures and carbon layer numbers reveal the role of interlayer O2 activation

Fe–N/C catalysts with tunable mesoporous structures and carbon layer numbers were prepared and served as model catalysts for unraveling the important role of interlayer oxygen activation in boosting the oxygen reduction reaction activity.

Formation of one-dimensional hierarchical MoO2@C–Ni/CoNi hybrids as highly efficient catalysts and protein adsorbents

We have developed a facile approach to produce a hierarchical carbon tubular structure with Ni/NiCo NPs intercalated with MoO2 NPs, which manifested excellent performance in protein adsorption and the reduction of 4-nitrophenol.

Tailored MXene Nanoarchitectonics: MXene with Mesoporous Nitrogen-Doped Carbon Confined Ultrafine Molybdenum Carbide Nanodots for Efficient Electrocatalytic Hydrogen Evolution

Two-dimensional (2D) MXene-based mesoporous heterostructures are promising electrode materials for electrochemical charge storage but have rarely been examined as electrocatalysts for hydrogen production reactions. Herein, we describe a 2D MXene-based mesoporous nanoarchitecture consisting of 2D Ti3C2 (MXene) nanosheets sandwiched between ordered mesoporous nitrogen-doped carbon (mNC) layers coupled molybdenum carbide (MoC) nanodots (denoted as mNC-MoC/Ti3C2). The results show that mesopores significantly increase the specific surface area of the material and expose numerous electrocatalytically active sites. Mesopores also shorten the distance of ion transport to the inner surface of the catalyst and accelerate the kinetics of the catalytic reaction. The resulting mNC-MoC/Ti3C2 structure exhibits excellent performance in the hydrogen evolution reaction (HER) in 0.5 M H2SO4, with a small overpotential of 159 mV at 10 mA cm–2, a low Tafel slope of 70.9 mV dec–1, and excellent long-term stability. Theoretical calculations indicate that the mNC-MoC/Ti3C2 surface has a small hydrogen binding energy for the favorable adsorption–desorption of hydrogen and high conductivity for rapid charge transfer during the HER process.

Interface Co‐Assembly Synthesis of Magnetic Fe3O4@mesoporous Carbon for Efficient Electrochemical Detection of Hg(II) and Pb(II)

AbstractIn recent years, efficient and porous carbon‐layer‐modified magnetic metal oxides demonstrate potentials for the significant improvement of catalytic and adsorption performance. In this study, a novel magnetic coreshell Fe3O4@mesoporous carbon (Fe3O4@MPC) nanochain electrochemical sensor is constructed by using resorcinol‐formaldehyde resin and magnetic Fe3O4 nanospheres as the carbon shell precursor and core, respectively, with a simple emulsion self‐assembly strategy. Microstructural characterizations revealed that the carbon shell exhibited a mesopore distribution of ≈40 nm and the diameter of Fe3O4 nanospheres embedded into carbon is ≈280 nm. The introduction of mesoporous carbon layer increased the electrical conductivity of the active material and maintained the adsorption properties of magnetic Fe3O4. The synergistic effect of the mesoporous carbon layer and Fe3O4 nanochain is beneficial to electrochemically detect heavy metal ions (HMIs). Under optimal conditions, the typical Fe3O4@MPC‐2/GCE exhibited excellent electrochemical sensing for detecting Hg(II) and Pb(II), with limits of detection (LOD) of 7.8 nm and 12.1 nm (S/N = 3), respectively. These good results are attributed to the Fe3O4@MPC nanochain structure and a relatively high specific surface area. This study provides a novel method to prepare magnetic mesoporous carbon nanochain composites for constructing sensitive electrochemical sensors to monitor water quality.

One-pot synthesis of cobalt pyrophosphate nanoparticles combined with mesoporous carbon for asymmetric supercapacitors

One-pot synthesis of the cobalt pyrophosphate (Co2P2O7) nanoparticles combined with mesoporous carbon was fabricated via a simple lyophilization followed by carbonization as an electrode material for asymmetric supercapacitors. Benefiting from nitrogen-rich polyethyleneimine (PEI) polymer as both C and N source and glutaraldehyde as a crosslinking agent, a three-dimensional hierarchical porous structure with dominant mesopores and a few micropores was obtained. It is important to note that glutaraldehyde acts not only to increase porous structure but also to enhance the graphitization of PEI. The electrochemical properties of the Co2P2O7 electrode were investigated in 6 M KOH and displayed excellent electrochemical properties due to the synergistic effect of Co2P2O7 nanoparticles and nitrogen-doped mesoporous carbon layer. The amount of crosslinking agent exhibited a significant influence on the electrochemical properties of the electrode. When the amount of added glutaraldehyde was 200 μl, shown as Co2P2O7@N–C2, the best electrochemical performance was found. The ultrahigh specific capacitance of Co2P2O7@N–C2 was found at 10 mV/s as 384 F/g in a three-electrode configuration. Then, an asymmetric supercapacitor was successfully fabricated, using the Co2P2O7@N–C2 as cathode and the activated carbon (AC) as the anode, and it displayed maximum specific energy of 5.68 Wh/kg at a specific power of 325 W/kg and a maximum specific power of 6500 W/kg at a specific energy of 2.17 Wh/kg. These remarkable electrochemical performances can be ascribed to the nitrogen-doped carbon layer, better graphitization, and enhanced porous structure with abundant mesopores. This facile one-pot method can provide for integrating other transition metal pyrophosphates with nitrogen-doped carbon layer for high-performance supercapacitor electrodes.

Printed-Circuit-Board (PCB) Based Multiplex Sensor for Ion Sensing

Combining electrochemical sensing with microfluidic system presents an attractive approach for in vitro study of physiology and pathophysiology (e.g. organ-on-chip platform) [1] and for inline monitoring of environmental parameters (e.g. water quality) [2]. Ion-selective electrodes (ISE) are potentiometric sensors that measure activities of ions. They offer a simpler analytical method compare to voltammetric sensors or ISFETs. Solid-state ISEs differ from conventional ISEs in that the inner filling solution is replaced by a solid contact material. The removal of liquid compartment can make such sensor more durable and flexible, enabling it to be integrated with microfluidic device. In this work, we fabricated and evaluated a multiplex ion sensing platform by modifying the printed circuit board with solid-state ISEs. The choice of PCB platform allows straightforward multiplexing of electrodes and interfacing with downstream electronics by leveraging standardized PCB technology, which can also be cost effective in terms of fabrication. ISEs for potassium (K+) and nitrate (NO3-) approximately 1.5 mm in diameter were prepared by coating polymeric membrane and mesoporous carbon layers as the solid contact on a pre-patterned transfer tape. The electrode response was significantly stabilized by casting the membrane away from the underlying metal pads. The stabilizing effect was attributed to the increase of effective surface area of mesoporous carbon between membrane and conducting metal. The multiplex sensor was further integrated with a 3D printed microchamber for onchip analysis (Figure 1A). The K+ and NO3- electrodes displayed near-Nernstian slopes of 53 and -50 mV/dec (vs. Ag/AgCl/0.01 M Cl- reference) in KNO3 solutions, respectively. Despite some noise and baseline drift, both electrodes showed reasonable stability and reversibility upon switching solution (Figure 1B). The sensor can be stored dry between measurements. The slope of K+ electrode decayed over time, while NO3- electrode maintained sensitivity for at least one week. The slope decrease was likely due to the diffusion of ion-exchanger (tetraphenylborate) into the surrounding adhesive tape. During integration with the microchamber, the K+ electrode was also found subject to the bonding adhesive between the chamber and transfer tape, where possible reaction and/or degradation of the ion exchanger has caused complete loss of electrode response. Nevertheless, with further improvement, the PCB based multiplex ISEs provides a promising tool for ion sensing in many biomedical and environmental applications.

Rational construction of well-defined hollow double shell SnO2/mesoporous carbon spheres heterostructure for supercapacitors

The selection of proper electrode materials and the design of rational structure are two efficient approaches to improve the electrochemical performance of supercapacitors. Carbonaceous materials have become an important choice of electrode materials due to their good electrical conductivity and accommodation for volume expansion of metal oxides. In this contribution, hollow double-shell structured H-SnO2/MesCHS (mesoporous carbon hollow spheres) heterostructure is successfully achieved by silica template and in-situ polymerization methods. The H-SnO2/MesCHS composites demonstrate a specific surface area of 747.7 m2 g-1 and an average pore size of ca. 4.9 nm in the mesoporous carbon shell, where the outer layer of mesoporous hollow carbon layer act as a buffer to confine the volume expansion of the inner hollow tin oxide sphere. As consequence, hollow double-shell H-SnO2/MesCHS heterostructure demonstrates an excellent electrochemical performance with a high specific capacitance of 470 F g-1, exceptional cycling stability (88.4% retention of capacitance over 4000 cycles) and outstanding coulombic efficiency of 86.5% at high current density of 20 A g−1. The work provides an alternative route for the preparation of spherical hollow heterostructures materials with tunable double shell architectures, which may potentially be used as electrode materials for high-performance of energy storage.

Mesoporous Carbon Fibers with Tunable Mesoporosity for Electrode Materials in Energy Devices.

To improve the properties of mesoporous carbon (MC), used as a catalyst support within electrodes, MC fibers (MCFs) were successfully synthesized by combining organic–organic self-assembly and electrospinning deposition and optimizing heat treatment conditions. The pore structure was controlled by varying the experimental conditions. Among MCFs, MCF-A, which was made in the most acidic condition, resulted in the largest pore diameter (4–5 nm), and the porous structure and carbonization degree were further optimized by adjusting heat treatment conditions. Then, since the fiber structure is expected to have an advantage when MCFs are applied to devices, MCF-A layers were prepared by spray printing. For the resistance to compression, MCF-A layers showed higher resistance (5.5% change in thickness) than the bulk MC layer (12.8% change in thickness). The through-plane resistance was lower when the fiber structure remained more within the thin layer, for example, +8 mΩ for 450 rpm milled MCF-A and +12 mΩ for 800 rpm milled MCF-A against the gas diffusion layer (GDL) 25BC carbon paper without a carbon layer coating. The additional advantages of MCF-A compared with bulk MC demonstrate that MCF-A has the potential to be used as a catalyst support within electrodes in energy devices.

Fe0.8Zn0.2 Nanoparticles Wrapped in Mesoporous Nitrogen-Doped Carbon Layers as Electrocatalysts for an Efficient Oxygen Reduction Reaction

An efficient oxygen reduction reaction (ORR) can be achieved by accelerating the movement of electrons, ions, reactants, and products. Here, we prepared core–shell nanohybrids with Fe0.8Zn0.2 nanop...

Nanocomposites of reduced graphene oxide modified with mesoporous carbon layers anchored by hollow carbon spheres for energy storage

Reduced graphene oxide (rGO) derived materials are promising materials for energy storage due to good conductivity as well as the ability for effective charge-transfer and mass-transfer. However, the agglomeration properties, poor pores and surface inertness of rGO limit its applications in energy storage. Herein, rGO modified by N-doped mesoporous carbon layers anchored by hollow carbon spheres nanocomposites (rGONC) have been prepared via a strategy of direct multi-constituent co-assembly. The obtained rGONC exerts the synergistic effects of both components with favorable characteristics such as mesoporous hollow structure with separated rGO sheets, high specific surface area and moderate N doping, making it an effective applying in energy storage systems. When rGONC is used for potassium-ion batteries, a high initial reversible capacity, an ultra-long cycling life, as well as a prominent rate capability are received. As an electrode in supercapacitors, rGONC demonstrates outstanding electrochemical performances of a high specific capacitance, a superior cycling stability and an extraordinary rate capability.

1D Co4S3 nanoneedle array with mesoporous carbon derived from double comb copolymer as an efficient solar conversion catalyst

This study investigates the use of a one-dimensional (1D) cobalt sulfide/mesoporous carbon heterogeneous electrocatalyst as counter electrode for high solar energy conversion efficiency in dye-sensitized solar cells (DSSCs). The 1D cobalt oxide (Co3O4) was in situ hydrothermally grown on the fluorine-doped tin oxide glass substrate, followed by sulfurization to form 1D cobalt sulfide (Co4S3) nanoneedle array. The Co4S3 is characterized by a high electrocatalytic activity for reducing/oxidizing the redox couple in the electrolyte. Additionally, the 1D structural feature of the Co4S3 allows fast electron transport through the oriented diffusion pathway. However, the Co4S3 still has relatively low chemical stability and poor electrical conductivity than conventional Pt catalyst. Herein, we incorporated the mesoporous carbon layer derived from the double comb copolymer, i.e., PVDC-g-POEM, which can act as a mesoporous structural template and sufficient carbon source. This strategy increased the electrocatalytic activity and chemical durability of the heterogeneous catalytic materials. The 1D Co4S3/mesoporous carbon heterogeneous catalyst exhibited excellent electrocatalytic activity for the reduction of triiodide, thereby outperforming the conventional Pt counter electrode. The catalytic properties were demonstrated by electrochemical analysis, i.e., cyclic voltammetry and electrochemical impedance spectroscopy. Results suggest that solid-state DSSCs (ssDSSCs) fabricated with the 1D Co4S3/mesoporous carbon counter electrode exhibited a higher solar energy conversion efficiency of 6.2% than the corresponding ssDSSC with conventional Pt (5.7%). The pure 1D Co4S3 or mesoporous carbon showed relatively lower performance than conventional Pt. Accordingly, the 1D Co4S3/mesoporous carbon synergetic approach represents a new strategy for enhancing the catalytic activity and chemical stability for highly efficient ssDSSCs.

N-doped porous carbon-stabilized Pt in hollow nano-TiO2 with enhanced photocatalytic activity

In this study, Pt nanoclusters with small sizes (~1.8 nm) is designed and loaded onto the inner surface of hollow nano-TiO2 through combining polymer anchoring and photochemical solid-phase reduction strategy. The N-doped mesoporous carbon derived from the polymer is beneficial for the exposure of Pt sites and stabilization of Pt nanoclusters (~1.8 nm), and supplying more active N-sites. More importantly, the pore structure of the N-doped mesoporous carbon layer prepared by air-etching method contributes to the diffusion of reactants/products and exposure of more active Pt sites to promote surface reactions. The as-prepared C/Pt@TiO2-3% with 0.54 wt% of Pt shows the largest total pore volume (0.46 cm3 g−1) with an average pore size of ~3 nm, and its catalytic activity is greatly improved with a H2 evolution rate of 9086 μmol h−1 g−1, which is about 48 and 96 times that of bare hollow nano-TiO2 and P25, respectively. In addition, the as-prepared C/Pt@TiO2-3% shows good durability in a 40-h cyclic test.