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Cryogenic electron microscopy is one of the fastest and most robust methods for capturing high-resolution images of proteins, but stringent sample preparation, imaging conditions, and in situ radiation damage inflicted during data acquisition directly affect the resolution and ability to capture dynamic details, thereby limiting its broader utilization and adoption for protein studies. We addressed these drawbacks by introducing synthesized giant carbon nano-test tubes (GCNTTs) as radiation-insulating materials that lessen the irradiation impact on the protein during data acquisition, physical molecular concentrators that localize the proteins within a nanoscale field of view, and vessels that create a microenvironment for solution-phase imaging. High-resolution electron microscopy images of single and aggregated hemoglobin molecules within GCNTTs in both solid and solution states were acquired. Subsequent scanning transmission electron microscopy, small-angle neutron scattering, and fluorescence studies demonstrated that the GCNTT vessel protected the hemoglobin molecules from electron irradiation-, light-, or heat-induced denaturation. To demonstrate the robustness of GCNTT as an imaging platform that could potentially augment the study of proteins, we demonstrated the robustness of the GCNTT technique to image an alternative protein, d-fructose dehydrogenase, after cyclic voltammetry experiments to review encapsulation and binding insights. Given the simplicity of the material synthesis, sample preparation, and imaging technique, GCNTT is a promising imaging companion for high-resolution, single, and dynamic protein studies under electron microscopy.

Ordered carbonaceous frameworks (OCFs) are a new class of carbon materials with a three-dimensional ordered structure synthesized by simple carbonization of metalloporphyrin crystals with polymerizable moieties. Carbonization

Oxygen vacancies on the (100) surface of γ-Al2O3 nanoparticles catalyse CH4-CVD for single-layered nanoporous graphenes with no transition metal reaction centre. The rate-limiting step is the proton transfer (PT) in the activation of CH4 on them.

Atomistic calculations reveal the steps controlling the early stages of graphene growth on alumina, including the activation of CH4 and the formation of the reactive CH2* intermediate that couple to form linear CnH2n* (n = 2–6) and cyclic C6 species.

While the functions of carbon materials with precisely controlled nanostructures have been reported in many studies, their chiral discriminating abilities have not been reported yet. Herein, chiral discrimination is achieved using helical carbon materials devoid of chiral attachments. A Fe

Carbon materials with 3D-ordered nanopores doped with metals and nitrogen were synthesized from strategically designed phthalocyanines via the self-assembly of Fe3O4 nanoparticles. Their catalytic activity was determined by the doped metals.

A systematic study considering the microstructural effect of carbon materials on the electrochemical or electrocatalytic performance is essential for developing carbon electrode materials of electric vehicles and smart grids that require durable and robust energy supply. In this study, the edge sites within activated carbons (ACs) were physically modified via thermal treatment to clarify the relationship between the edge density and hydrogen evolution reaction (HER). Moreover, their dominant contribution to the electrochemical performance of lead-carbon batteries was demonstrated. The ACs exhibited decreased defect density and enhanced crystallinity due to the merger of micro-domains during a high-temperature thermal treatment (HTT). In contrast to the specific surface area, the edge area of the ACs, which was quantified via temperature programmed desorption up to 1800 °C, decreased significantly with increasing HTT temperature. We have confirmed a close relationship between the edge densities and HER parameters. The lead-carbon battery unit cell employing HTT1600 with the lowest edge ratio (0.81%) exhibited a higher charging efficiency, higher cycling stability, and lower water loss than the cell employing pristine AC with a high edge ratio (8.42%). The edge ratio of carbon materials can be considered an important parameter in designing electrode materials for electrochemical energy storage.

Durable nanostructured cathode materials for efficient all-solid-state Li-S batteries were prepared using a conductive single-walled 3D graphene with a large pore volume as the cathode support material. At high loadings of the active material (50-60 wt %), microscale phase segregation was observed with a conventional cathode support material during the charging/discharging processes but this was suppressed by the confinement of insulating sulfur into the mesopores of the elastic and flexible nanoporous graphene with a large pore volume of 5.3 mL g-1. As such, durable three-phase contact was achieved among the solid electrolyte, insulating sulfur, and the electrically conductive carbon. Consequently, the electrochemical performances of the assembled all-solid-state batteries were significantly improved and feasible under the harsh conditions of operation at 353 K, and improved cycling stability as well as the highest specific capacity of 716 mA h per gram of cathode (4.6 mA h cm-2, 0.2 C) was achieved with high sulfur loading (50 wt %).

To improve the performance of lithium-oxygen (Li-O2) batteries with an extremely high theoretical energy density, redox mediators (RMs) are usually added to liquid electrolytes to assist with the charge process and reduce the overpotential. However, the shuttle effect and the instability of RMs towards a Li metal anode degrade the cycle performance of Li-O2 batteries. Herein, we report a volatilization-dissolution strategy to supply RMs by introducing 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) into the O2 atmosphere (TEMPO-O2) outside an assembled cell. Due to not directly adding RMs to liquid electrolytes, the parasitic reactions between the Li metal anode and TEMPO, including the TEMPO's shuttle effect, are alleviated. TEMPO-O2 mediates the formation-decomposition of lithium peroxide (Li2O2) in Li-O2 batteries and shows a uniform catalytic effect towards commercial Li2O2. Thanks to the continuous redox mediation of volatile TEMPO and the suppression of the RM's shuttle effect, the Li-O2 battery demonstrates an ultra-long cycle life of 400 cycles (1600 h) at 250 mA g−1. Our strategy to supply volatile RMs shows a universal adaptability towards different kinds of cathodes and electrolytes, which may trigger broad applications in various gas-involved Li metal batteries.

Microporous polymers with exposed C

Photoelectrochemical (PEC) water splitting using photocatalysts is a promising technique to convert solar energy into chemical fuels, namely, hydrogen and oxygen. Ta3N5 is a visible-light-responsiv...

Iron-incorporated ordered carbonaceous frameworks (OCFs) have been synthesized by the pyrolysis of iron porphyrin with ethynyl groups as polymerizable/carbonizable moieties at a temperature higher than 600 °C. The pyrolysis behavior is analyzed by thermogravimetry-differential thermal analysis-mass spectrometry, and the obtained carbon materials are characterized by X-ray diffraction, X-ray absorption fine structure, and high-angle annular dark-field scanning transmission electron microscopy. The introduction of ethynyl groups at the meta positions of the peripheral phenyl groups is essential for efficient cross-linking upon thermal polymerization. The thermally stable polymer thus obtained can be transformed into OCFs with high carbonization yield of 93 % at the subsequent carbonization. OCFs possess periodic structural regularity and porphyrin Fe-N4 coordination structure, and exhibit electrocatalysis for the conversion of CO2 into CO.

Graphene mesosponge (GMS) is a new class of mesoporous carbon consisting mainly of single-layer graphene walls. GMS has traditionally been synthesized via chemical vapour deposition (CVD) of methane onto a template of alumina (Al2O3) nanoparticles, which catalyses methane conversion. However, the Al2O3 template needs to be removed using costly and environmentally concerning processes such as hydrofluoric acid or concentrated base. In this work, we examine methane conversion catalysed by magnesium oxide (MgO) and utilized MgO as an alternative catalytic template. In contrast to Al2O3, a solid acid catalyst, MgO is a solid base catalyst that is also active for methane conversion into graphene sheets but dissolves easily in hydrochloric acid. We have investigated the reaction mechanism using in situ weight measurements and gas-emission analysis during CVD complemented by density functional theory calculations. We found that the pure MgO surface is activated via O-elimination with methane above 778 °C. On the activated MgO surface, methane is converted into a graphene sheet with a relatively low activation energy of 134 kJ mol−1. Once the first graphene layer is formed, the methane-to-graphene conversion rate decreases and the activation energy increases to 234 kJ mol−1, which is comparable to that reported in thermal methane-CVD on carbon. As a result of the faster growth rate of the first layer with respect to additional layers, it is easier to obtain single-graphene layers using MgO. The MgO-derived GMS has a unique combination of properties including a high surface area, developed mesopores, high oxidation resistance, significant softness and elasticity, very low bulk modulus (0.05 GPa), and force-driven reversible liquid–gas phase transition. Thus, we expect the MgO-derived GMS can be employed in a variety of applications including high-voltage supercapacitors and as a new type of heat pump based on the force-driven phase transition.

High-density and highly porous graphene-based pellets that exhibit an anomalous gas densification property have been fabricated by using zeolite-templated carbon (ZTC) as the major component and reduced graphene oxide (rGO) as a pure carbon binder. The unique structure of each ZTC particle consists of double-sided graphene fragments connected in a periodic, three-dimensional framework. The graphene-like sheets of rGO strongly connect the ZTC particles upon hot-pressing via the generation of a large amount of unpaired electron spins, yielding monolithic pellets with exceptional mechanical toughness. The uniaxial pressing applied to the isotropic ordered framework of ZTC during pelletization leads to unique anisotropic structures. The so-obtained pellets represent a high density packing of graphene nanofragments with high volumetric surface area that exhibits high volumetric H2 storage at room temperature.

In this study, we present a systematic search for a simple geometrical pore model relating the N2 adsorption data on zeolite templated carbon (ZTC) to its pore size distribution (PSD). Based on the known genesis of the templated carbon and the literature studies suggesting its curved pore structure, we explore possible applicability of simple geometrical pore models for the PSD analysis of the ZTC N2 adsorption isotherm. The isotherm analysis is performed using the models based on the two-dimensional version of the non-local density functional theory (2D-NLDFT). We consider finite and continuous curved cylindrical pores. In agreement with XRD results showing no stacked graphene sheets in the calculations, we assume pore walls to be constructed by single-layer graphenes. In the PSD analysis of the ZTC nitrogen adsorption isotherm using NLDFT models assuming different shapes and length of finite pores as well as continuous curved pores of various curvatures. Based on these analyses, we selected an optimal NLDFT adsorption model that is consistent with the ZTC structure described by the atomistic structural model. The periodicity of this optimal model practically coincides with the periodicity of the ZTC lattice that was uncovered by the TEM image reported in the earlier study.

Chemical vapor deposition of methane onto a template of alumina (Al2O3) nanoparticles is a prominent synthetic strategy of graphene meso-sponge, a new class of nanoporous carbon materials consisting of single-layer graphene walls. However, the elementary steps controlling the early stages of graphene growth on Al2O3 surfaces are still not well understood. In this study, density functional calculations provide insights into the initial stages of graphene growth. We have modelled the mechanism of CH4 dissociation on (111), (110), (100), and (001) γ-Al2O3 surfaces. Subsequently, we have considered the reaction pathway leading to the formation of a C6 ring. We found the γ-Al2O3(110) and γ-Al2O3(100) are both active for CH4 dissociation, but the (100) surface has a higher catalytic activity towards the carbon growth reaction. The overall mechanism involves the formation of the reactive intermediate CH2* that then can couple to form CnH2n* (n = 2-6) species. The unsaturated CH2 end promotes the sustained carbon growth in a nearly barrierless process. Also, the short length between terminal carbon atoms leads to strong interactions, which might lead to the high activity among unsaturated CH2* of hydrocarbon chain. Analysis of the electron localization and geometries of the carbon chains reveal the formation of C-Al-σ bonds with the chain growing towards the gas rather than C-Al-π bonds covering the γ-Al2O3(100) surface. This growth behaviour prevents catalysis poison during the initial stage of graphene nucleation.

To understand the effect of microstructural characteristics of carbon materials on their electrochemical or electrocatalytic performance, an in-depth study of the edges in carbon materials should be carried out. In this study, catalytically grown platelet-type carbon nanofibers (CNFs) with fully exposed edges were physically and chemically passivated to clarify the relationship between the edge density and the hydrogen evolution reaction (HER) activity. Due to the aligned structure along the fiber axis, the edges on the outer surface of the CNFs were easily modified without using a complex process. The edges on the surface of the CNFs were inactivated by sequentially forming single, double, and multiple loops as the heat treatment temperatures increased. The number of edges within the CNFs was quantitatively measured using temperature-programmed desorption (TPD) up to 1800 °C. The surviving edges on the surface of thermally treated CNFs were identified by chemical functionalization via an amination reaction. We identified a close relationship between the HER activity and the edge density. When evaluating the electrochemical and electrocatalytic activity of carbon materials, it is important to know the portion of the edge surface area with respect to the total surface area and edge ratio.

We demonstrate reversible charge/discharge in ruthenocene, RuCp2 (Cp = η5-C5H5), using activated carbon (AC) as a support. RuCp2 is supported in the micropores of AC as clusters consisting of multi...

One of the challenging targets in materials synthesis is a direct conversion of molecular based crystalline substances into crystalline ordered carbonaceous frameworks (OCFs). Though we have discov...

We discuss the preparation and application of various carbon-rich materials with three-dimensional ordering at the angstrom level., Carbon-rich materials, which contain over 90% carbon, have been mainly synthesized by the carbonization of organic compounds. However, in many cases, their original molecular and ordered structures are decomposed by the carbonization process, which results in a failure to retain their original three-dimensional (3D) ordering at the angstrom level. Recently, we successfully produced carbon-rich materials that are able to retain their 3D ordering at the angstrom level even after the calcination of organic porous pillar[6]arene supramolecular assemblies and cyclic porphyrin dimer assemblies. Other new pathways to prepare carbon-rich materials with 3D ordering at the angstrom level are the controlled polymerization of designed monomers and redox reaction of graph. Electrocatalytic application using these materials is described.

Although nanoporous carbons are ubiquitous materials that are used in many clean energy and environmental applications, most are in powder form, thus requiring binders to hold particles together. This results in uncontrolled and complex pathways between particles, potentially exacerbating mass transport issues. To overcome these problems, we have developed an unprecedented binderless, self-supported, nanoporous carbon scaffold (NCS) with tunable and monodisperse pores (5–100+ nm), high surface area (ca. 200–575 m2 g−1), and 3-dimensional scalability (1–150+ cm2, 1–1000 μm thickness). Here, it is shown that NCS85 membranes (85 nm pores) are particularly promising as a host for the homogeneous and efficient 3-D atomic layer deposition (ALD) of Pt nanoparticles, due to the facile penetration of gas phase Pt precursor throughout the homogeneous, low tortuosity internal structure. Furthermore, the high density of surface defects of the as-synthesized NCS promotes uniform Pt nucleation with minimal agglomeration. These advantageous features are key to the rapid oxygen reduction kinetics observed under polymer electrolyte membrane (PEM) fuel cell MEA testing conditions. Cells constructed with an optimal ALD Pt loading of 30 cycles are shown to exhibit a specific activity of ≥0.4 mA cm−2Pt which is exemplary when compared to two commercial catalyst layers with comparable Pt mass loadings and tested under the same conditions. Furthermore, a maximum power density of 1230 mW cm−2 (IR-corrected) is obtained, with the limiting current densities approaching a very respectable 3 A cm−2.