Single-source Precursor Research Articles

Supercapacitor with highly efficient rare earth metal conjugated transition metal chalcogenide photoactive electrode In:SnO2/Nd2S3:Ni9S8:Co9S8

The implementation of nanostructure designs that optimize the benefits of all constituent elements and facilitate interfacial interactions between them represents a promising approach for enhancing electrochemical efficiency. This study uses a simple single source precursor technique to produce distinctly shaped Nd2S3:Ni9S8:Co9S8. The material’s crystal, optical, morphological and elemental investigation was performed. The optical band gap of 3.5 eV was identified through UV–visible analysis. Furthermore, X-ray photoelectron spectroscopy and energy dispersive X-ray analysis confirmed the presence of Nd, Ni, Co, as well as S in the composite. Significant functional groups were investigated through FTIR. Electrical investigations involving multiple techniques were performed in a photoelectrochemical cell. Ascribing to the transparent photoactive electrode In:SnO2/Nd2S3:Ni9S8:Co9S8 the results presented an unsurpassed specific capacity of 946 Fg−1 in the presence of light. In each experiment, it was demonstrated that the electrode's photocurrent density was greater when it was exposed to light. This study has successfully introduced a highly valuable photoelectrode that exhibits great potential for practical application in the realm of renewable energy systems.

Synthesis, Assembly, and Applications of Magic-Sized Semiconductor (CdSe)13 Cluster.

ConspectusAtomically precise metal chalcogenide clusters (MCCs) are model molecular compounds of scientifically and technologically important semiconductor nanocrystals, which are known as quantum dots (QDs). The significantly high ambient stability of MCCs of particular sizes, as compared to that of slightly smaller or larger sizes, made them be termed "magic-sized clusters" (MSCs). In other words, MSCs with specific sizes between sizes of precursors (typically, metal-ligand complexes) and nanocrystals (typically, QDs) appear sequentially during the colloidal synthesis of nanocrystals, while the other cluster species decompose to precursor monomers or are consumed during the growth of the nanocrystals. Unlike nanocrystals with an ambiguous atomic-level structure and a substantial size distribution, MSCs possess atomically monodisperse size, composition, and distinct atomic arrangement. Chemical synthesis and exploration of properties of MSCs are of great significance since they help systematically understand the evolution of fundamental properties as well as build structure-activity relationships at distinct molecular levels. Furthermore, MSCs are anticipated to offer atomic-level insights into the growth mechanism of the semiconductor nanocrystals, which is highly desirable in the design of advanced materials with new functions. In this Account, we cover our recent efforts in the advancement of one of the most important stoichiometric CdSe MSCs, (CdSe)13. In particular, we present its molecular structure derived from a single crystal X-ray crystallographic study of the closest MSC, Cd14Se13. The crystal structure of MSC enables not only the understanding of the electronic structure and prediction of the potential sites for heteroatom dopants (e.g., Mn2+ and Co2+) but also the identification of favorable synthetic conditions for the selective synthesis of desired MSCs. Next, we focus on enhancing the photoluminescence quantum yield and stability of Mn2+ doped (CdSe)13 MSCs through their self-assembly, which is facilitated by the rigid diamines. In addition, we show how atomic-level synergistic effects and functional groups of the assemblies of alloy MSCs can be utilized for a highly enhanced catalytic CO2 fixation with epoxides. Benefiting from the intermediate stability, the MSCs are explored as single-source precursors to low-dimensional nanostructures, such as nanoribbons and nanoplatelets, through the controlled transformation. Distinct differences in the outcome of the solid-state and colloidal-state conversion of MSCs suggest the need for careful consideration of the phase and reactivity of MSCs as well as the type of dopant to achieve novel structured multicomponent semiconductors. Finally, we summarize the Account and provide future perspectives on the fundamental and applied scientific research of MSCs.

Bismuth sulfide nanorods by thermal decomposition of a complex: Effect of reaction temperature on microstructural and optical properties

Bismuth sulfide nanorods have been prepared by thermolysis of a bismuth dithiocarbamate complex, as a single-source precursor, in a mixture of solvents (oleylamine, 1-dodecanethiol, and 1-octadecene) at various temperatures. Bismuth sulfide nanorods denoted as BS(120), BS(150), BS(180), BS(200), and BS(220) have been obtained at the specified temperatures (°C). They have been characterized by X-ray diffraction analysis, scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV/Vis spectrophotometry, and photoluminescence (PL) spectroscopy. The effect of temperature on the microstructural and optical properties of the obtained Bi2S3 has been studied. The results show that interactions of the N–H group of oleylamine and the S–H group of dodecanethiol with the nanoparticles are temperature-dependent. The crystallite sizes of the nanoparticles were calculated using the Scherrer equation, Williamson–Hall (W–H) analysis, and Rietveld analysis, which yielded values in the ranges 20.1–45.9, 20.9–26.6, and 23.0–29.6 nm, respectively. Analysis of the microstrain in crystals of the nanoparticles showed that while the strain therein was due to contraction of the nanoparticles obtained at 180 °C, the strains at other temperatures were due to expansion, thereby confirming the effect of temperature on the nature of the defects in Bi2S3 crystals. The lattice strains were estimated by the W–H and Rietveld analyses to be in the ranges 3.19 × 10−5–1.04 × 10−4 and 0.008–0.067, respectively. The crystallite sizes and lattice strains estimated by both W–H and Rietveld analyses were mutually consistent, showing similar trends. SEM and TEM analyses showed that the nanorods were aggregated into longer rods at 120 and 150 °C, whereas shorter rods were obtained at 180 and 220 °C, suggesting a change in preferential growth direction. The widths and lengths of the nanorods were estimated as 20.97–41.25 nm and 79.4–111.0 nm, respectively, giving aspect ratios in the range 1.92–5.52. The band-gap energies of the nanorods varied in the range 1.08–0.78 eV, which can be related to differences in tail state width as observed in the absorption spectra. Calculation of texture coefficients showed preferential growth in the (111), (020), and (321) directions.

Green synthesis of antimony sulphide (Sb2S3) nano-rods in plant oils and study of photocatalytic activity

This study reports the green synthesis of antimony sulphide (Sb2S3) nano-rods synthesized by thermolysis of antimony diethyldithiocarbamate (Sb [S2CNEt2]) complex as a single source precursor in various plants oils acting as capping agents through their carboxylic acid functionality. The reported method reflects a facile and single-step fabrication of antimony sulphide nanorods and reveales their orthorhombic stibinite phase characterized by p-XRD. The quantification of energy dispersive X-ray spectrometric (EDS) analysis depicted an atomic ratio of approximately 2:3 for Sb: S. The morphology of nano-rods was confirmed by scanning electron microscopy (SEM) analysis and crystallize size was observed ranging 8.09–8.27 nm. The band gap calculated from absorption spectra was found to be 1.93 eV to 2.01 eV for all studied samples. The photocatalytic efficiency of synthesized nanorods evaluated by photocatalysis of Janus Green and Rose Bengal showed the dye degradation up to 99.9% in the presence of biosynthesized catalysts at different times.

Thiourea-Derived Single-Source Molecular Precursor For Spin-Coated PbS Thin Films.

In search of a suitable single-source precursor for the deposition of nanostructured PbS thin films at moderate temperatures under ambient conditions, we have synthesized the ligand N-(thiomorpholine-4-carbothioyl)benzamide and its corresponding lead(II) complex. The structures of both compounds were determined by single-crystal X-ray diffraction. In the complex, two ligands coordinate to a lead(II) atom in hemi-directed geometry through S and O atoms. Secondary intermolecular Pb⋅⋅⋅S interactions group the complexes into pairs. As bulk powders, both the ligand and complex show nominal composition and purity as evidenced by elemental analysis, 1 H NMR and IR spectroscopy. Thermal analysis of the lead(II) complex was carried out to understand its thermal decomposition behaviour for establishing a thin film fabrication protocol. Thin films of phase-pure PbS were fabricated using this new molecular precursor at the comparatively low annealing temperature of 250 °C. The film showed nanoparticles with cuboidal morphology and a blue-shifted optical absorption.

In:SnO2/Yb2S3:Cu2S:ZnS: A Rare Earth Metal Sulfide‐Conjugated Transition Metal Sulfide Photoactive Electrode

Spin coating from a single source precursor is used to produce a transparent conductive electrode for a photoelectrochemical cell. Yb2S3:Cu2S:ZnS is discovered in the composite using X‐ray diffraction analysis with a crystallite size of 44 nm. Energy‐dispersive X‐ray analysis and X‐ray photoelectron spectroscopy reveal that the composite comprises Yb, Cu, Zn, and S with an optical bandgap of 2.49 eV. Electrical investigations in a photoelectrochemical cell are measured using cyclic voltammetry, linear sweep voltammetry, transient chronoamperometry (CA), and electrical impedance spectroscopy (EIS). Every experiment shows that the photocurrent density of the electrode is higher than when it is in the light. At all scan rates, light causes the photoelectrode's specific capacitance to increase. Specific capacitance is found to have a maximum value under illumination of 789 Fg−1 as opposed to 745 Fg−1 in the absence of a light source. The highest photocurrent density achieved by the electrode through CA is 23.5 mA. Rs value of 23.4 Ω is subsequently obtained by the EIS investigation. It might be stated that this work introduces a useful photoelectrode that can be used in renewable energy systems such as photovoltaics, supercapacitors, and photoelectrochemical solar cells.

Study of the Mechanism and Increasing Crystallinity in the Self-Templated Growth of Ultrathin PbS Nanosheets.

Colloidal 2D semiconductor nanocrystals, the analogue of solid-state quantum wells, have attracted strong interest in material science and physics. Molar quantities of suspended quantum objects with spectrally pure absorption and emission can be synthesized. For the visible region, CdSe nanoplatelets with atomically precise thickness and tailorable emission have been (almost) perfected. For the near-infrared region, PbS nanosheets (NSs) hold strong promise, but the photoluminescence quantum yield is low and many questions on the crystallinity, atomic structure, intriguing rectangular shape, and formation mechanism remain to be answered. Here, we report on a detailed investigation of the PbS NSs prepared with a lead thiocyanate single source precursor. Atomically resolved HAADF-STEM imaging reveals the presence of defects and small cubic domains in the deformed orthorhombic PbS crystal lattice. Moreover, variations in thickness are observed in the NSs, but only in steps of 2 PbS monolayers. To study the reaction mechanism, a synthesis at a lower temperature allowed for the study of reaction intermediates. Specifically, we studied the evolution of pseudo-crystalline templates toward mature, crystalline PbS NSs. We propose a self-induced templating mechanism based on an oleylamine-lead-thiocyanate (OLAM-Pb-SCN) complex with two Pb-SCN units as a building block; the interactions between the long-chain ligands regulate the crystal structure and possibly the lateral dimensions.

A Low-Temperature Synthetic Route Toward a High-Entropy 2D Hexernary Transition Metal Dichalcogenide for Hydrogen Evolution Electrocatalysis.

High-entropy (HE) metal chalcogenides are a class of materials that have great potential in applications such as thermoelectrics and electrocatalysis. Layered 2D transition-metal dichalcogenides (TMDCs) are a sub-class of high entropy metal chalcogenides that have received little attention to date as their preparation currently involves complicated, energy-intensive, or hazardous synthetic steps. To address this, a low-temperature (500 °C) and rapid (1h) single source precursor approach is successfully adopted to synthesize the hexernary high-entropy metal disulfide (MoWReMnCr)S2 . (MoWReMnCr)S2 powders are characterized by powder X-ray diffraction (pXRD) and Raman spectroscopy, which confirmed that the material is comprised predominantly of a hexagonal phase. The surfaceoxidation states and elemental compositions are studied by X-ray photoelectron spectroscopy (XPS) whilst the bulk morphology and elemental stoichiometry with spatial distribution is determined by scanning electron microscopy (SEM) with elemental mapping information acquired fromenergy-dispersive X-ray (EDX) spectroscopy. The bulk, layered material is subsequently exfoliated to ultra-thin, several-layer 2D nanosheets by liquid-phase exfoliation (LPE). The resultingfew-layer HE (MoWReMnCr)S2 nanosheets are found to contain a homogeneous elemental distribution of metals at the nanoscale by high angle annular dark field-scanning transmission electron microscopy (HAADF-STEM) with EDX mapping. Finally, (MoWReMnCr)S2 is demonstrated as a hydrogen evolution electrocatalyst and compared to 2H-MoS2 synthesized using the molecular precursor approach. (MoWReMnCr)S2 with 20% w/w of high-conductivity carbon black displays a low overpotential of 229mV in 0.5 M H2 SO4 to reach a current density of 10mA cm-2 , which is much lower than the overpotential of 362mV for MoS2 . From density functional theory calculations, it is hypothesised that the enhanced catalytic activity is due to activation of the basal plane upon incorporation of other elements into the 2H-MoS2 structure, in particular, the first row TMs Cr and Mn.

Supercritical millifluidic reactor for the synthesis of efficient GaN nanophotocatalysts

Here, we demonstrate the continuous synthesis of gallium nitride (GaN) nanophotocatalysts exhibiting high quantum confinement using a preheated supercritical millireactor. The GaN quantum dots (QDs) are obtained from the direct thermolysis of a single source amido complex precursor (tris(dimethyl)amido gallium(III) dimer), in anhydrous supercritical cyclohexane. The quality of the synthesized QDs is highly dependent on the chemical pathways for the single source precursor thermolysis. Through the use of numerical modeling, we designed a millifluidic reactor allowing a sufficiently high heating rate for a direct precursor thermolysis towards efficient GaN nanoparticles. The as-designed preheated supercritical flow reactor yields highly reproducible GaN QDs (optical properties, crystallite phase and morphology) at high throughput, enabling gram scale production. Eventually, the photocatalytic properties of the GaN QDs were evaluated in a direct photochemical reaction through the degradation of a dye molecule (Methyl Orange). The obtained results demonstrate the higher photocatalytic activity of such photocatalysts compared to the commercially and reference available Degussa P25.

Deposition of stoichiometry – tailored amorphous Cu-S thin films by MOCVD technique

ABSTRACT Deposition technique and associated deposition parameters play significant roles in determining the stoichiometry of thin films, and consequently, their properties. Herein, Cu-S thin films were deposited on a sodalime glass substrate via metal organic chemical vapour deposition (MOCVD) at temperatures between 350 and 450°C using a single solid source precursor. The deposited Cu-S films were characterized using Rutherford backscattering spectroscopy (RBS), X-ray diffraction (XRD), scanning electron microscopy (SEM), UV–visible spectrophotometry, and four-point probe technique. RBS characterization revealed that the films are non-stoichiometry while thickness increased from 480 to 655 nm as deposition temperature increased. SEM revealed micrographs that are temperature-dependent. A direct band gap value between 2.75 and 3.80 eV was obtained as the deposition temperature increased. Electrical characterization showed ohmic characteristics in which, resistivity decreased from 18.50 × 10−3 Ωcm to 8.20 × 10−3 Ωcm as deposition temperature increased.

Efficacious performance of photoactive electrode In:SnO2/Er2S3:In2S3 in a photoelectrochemical system

A transparent conductive electrode using Erbium sulphide and Indium sulphide composite for a photoelectrochemical cell was created from a single source precursor using spin coating. X-ray diffraction examination presented Er2S3-In2S3 in the composite with 56 nm crystallite size. Hexagonal structures were observed through SEM analysis. Er 4d, In 3d and S 2p core levels were detected by X-ray photoelectron spectroscopy. The composite displayed an optical band gap of 4.12 eV. Using cyclic voltammetry, linear sweep voltammetry, transient chronoamperometry (CA), and electrical impedance spectroscopy, electrical studies in a photoelectrochemical cell were measured. In every experiment, the electrode showed a markedly higher photocurrent density than in dark. A rise in the photoelectrode's specific capacitance in the presence of illumination was also noted across all scan rates. Specific capacitance was determined to have a maximum value under illumination of 421 Fg−1 as contrasted to 381 Fg−1 in the absence of a light source at 5 mVs−1. CA also presented a good photocurrent density of 27.6 mA. Nyquist plot presented the Rs to be 20.8 Ω of the cell and a conductivity of 4.22 × 10−5 Scm−1. An effective photoelectrode that can be employed in renewable energy systems was thus presented by the study.

Double oxalates of Rh(III) with Ni(II) and Co(II) – Effective precursors of nanoalloys for hydrocarbons steam reforming

Heteronuclear coordination compounds of d-metals are suitable single-source precursors for bimetallic nanoalloys, which often show extraordinary catalytic properties due to synergetic effect. In particular, Ni- and Rh-based catalysts are highly effective in low temperature steam reforming processes. Double oxalates of Rh with Ni and Co of the formula {[Rh(H2O)2(C2O4)μ-(C2O4)]2M(H2O)2}·6H2O (M = Ni, Co) were synthesized and structurally characterized. According to thermogravimetric analysis, the complexes decompose completely in He and H2 atmospheres to form corresponding nanoalloys at ∼300 °C. The calcination in O2 atmosphere leads to formation of spinel type mixed oxide. The supported Co–Rh/Al2O3 and Ni–Rh/Al2O3 catalysts were prepared by impregnation of double oxalate complexes in porous support with subsequent calcination and tested in propane low temperature steam reforming in CH4 excess. The Co-containing catalyst showed comparable activity regarding to pure Rh/Al2O3 sample, while bimetallic Ni–Rh/Al2O3 catalyst revealed to be appreciably more active, than monometallic catalysts with higher active component loadings. Rh–Ni catalyst allowed for complete propane conversion at T ≈ 350 °C, whereas for Rh catalyst the temperature was T ≈ 410 °C, and Rh–Co did not reach complete C3H8 conversion at all.

Electrical and Structural Properties of Si1-xGex Nanowires Prepared from a Single-Source Precursor.

Si1-xGex nanowires (NWs) were prepared by gold-supported chemical vapor deposition (CVD) using a single-source precursor with preformed Si-Ge bonds. Besides the tamed reactivity of the precursor, the approach reduces the process parameters associated with the control of decomposition characteristics and the dosing of individual precursors. The group IV alloy NWs are single crystalline with a constant diameter along their axis. During the wire growth by low pressure CVD, an Au-containing surface layer on the NWs forms by surface diffusion from the substrate, which can be removed by a combination of oxidation and etching. The electrical properties of the Si1-xGex/Au core-shell NWs are compared to the Si1-xGex NWs after Au removal. Core-shell NWs show signatures of metal-like behavior, while the purely semiconducting NWs reveal typical signatures of intrinsic Si1-xGex. The synthesized materials should be of high interest for applications in nano- and quantum-electronics.

Laser-enabled localized synthesis of Mo1-xWxS2 alloys with tunable composition

Alloying can tailor the optoelectronic properties of two-dimensional transition metal dichalcogenides (2D-TMDC) by bandgap tuning and shallowing of the deep-level defects, leading to enhancement in their photodetection performance. Hence, seeking for a scalable composition-controlled alloy preparation technology is essential. Here, direct laser-synthesis of micro-patterned Mo1-xWxS2 alloys is demonstrated. By irradiating composite single source precursor films of molybdenum and tungsten sulfides with a laser beam at visible wavelengths, photo-thermal decomposition takes place, thus forming high-quality Mo1-xWxS2 alloys in ambient conditions without any need for high-vacuum based environment. The Mo1-xWxS2 alloys composition is simply regulated by adjusting the volume ratio of the partial single source precursor solutions, in the final mixture solution.The stoichiometry, the structural, morphological and optical characteristics of laser-written alloys with different compositions have been investigated. Analysis of high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) revealed the formation of the long-range (∼30 nm), few-layered crystals with randomly distributed molybdenum and tungsten metal atoms with no evidence of clustering. A photosensing device has been fabricated from laser-written Mo0·5W0·5S2 alloys to demonstrate the functionality of the material.

Evolution of Carbonate-Intercalated γ-NiOOH from a Molecularly Derived Nickel Sulfide (Pre)Catalyst for Efficient Water and Selective Organic Oxidation.

The development of a competent (pre)catalyst for the oxygen evolution reaction (OER) to produce green hydrogen is critical for a carbon-neutral economy. In this aspect, the low-temperature, single-source precursor (SSP) method allows the formation of highly efficient OER electrocatalysts, with better control over their structural and electronic properties. Herein, a transition metal (TM) based chalcogenide material, nickel sulfide (NiS), is prepared from a novel molecular complex [NiII (PyHS)4 ][OTf]2 (1) and utilized as a (pre)catalyst for OER. The NiS (pre)catalyst requires an overpotential of only 255mV to reach the benchmark current density of 10mAcm-2 and shows 63h of chronopotentiometry (CP) stability along with over 95% Faradaic efficiency in 1m KOH. Several ex situ measurements and quasi in situ Raman spectroscopy uncover that NiS irreversibly transformed to a carbonate-intercalated γ-NiOOH phase under the alkaline OER conditions, which serves as the actual active structure for the OER. Additionally, this in situ formed active phase successfully catalyzes the selective oxidation of alcohol, aldehyde, and amine-based organic substrates to value-added chemicals, with high efficiencies.

Wafer-Scale Production of Two-Dimensional Tin Monoselenide: Expandable Synthetic Platform for van der Waals Semiconductor-Based Broadband Photodetectors.

A synthetic platform for industrially applicable two-dimensional (2D) semiconductors that addresses the paramount issues associated with large-scale production, wide-range photosensitive materials, and oxidative stability has not yet been developed. In this study, we attained the 6 in. scale production of 2D SnSe semiconductors with spatial homogeneity using a rational synthetic platform based on the thermal decomposition of solution-processed single-source precursors. The long-range structural and chemical homogeneities of the 2D SnSe layers are manifested using comprehensive spectroscopic analyses. Furthermore, the capability of the SnSe-based photodetectors for broadband photodetection is distinctly verified. The photoresponsivity and detectivity of the SnSe-based photodetectors are 5.89 A W-1 and 1.8 × 1011 Jones at 532 nm, 1.2 A W-1 and 3.7 × 1010 Jones at 1064 nm, and 0.14 A W-1 and 4.3 × 109 Jones at 1550 nm, respectively. The minimum rise times for the 532 and 1064 nm lasers are 62 and 374 μs, respectively. The photoelectrical analysis of the 5 × 5 SnSe-based photodetector array reveals 100% active devices with 95.06% photocurrent uniformity. We unequivocally validated that the air and thermal stabilities of the photocurrent yielded from the SnSe-based photodetector are determined to be >30 d in air and 160 °C, respectively, which are suitable for optoelectronic applications.

Structural and optical properties of aluminum nitride nano powder prepared from tris (N,N dimethyl-ethylenediamine)AlCl3 precursor

A cost-effective process for preparation of aluminum nitride was developed by using single-source precursor tris (N,N dimethylethylenediamine)AlCl3, which was prepared from anhydrous aluminum chloride and N,N dimethylethylenediamine (DMEDA) in 1:3 molar ratio at room temperature under N2. The pyrolysis of the precursor was carried out at various temperatures, pressures, and flow of gases (N2 and Ar) to optimize parameters. The resultant pyrolyzed residues were investigated using various instrumental techniques. X-ray diffraction (XRD) showed that AlN crystallizes in mixed-phase (hexagonal/cubic) and the grain size was estimated to be in the range of 4–10 nm. The band gap of AlN was investigated by UV-Vis spectroscopy and found to be ∼5.7 eV (6.1 eV bulk); TEM showed agglomerated crystallites of AlN.

Tungsten dichalcogenide WS2xSe2−2x films via single source precursor low-pressure CVD and their (thermo-)electric properties

A series of novel single source precursors, [WECl4(E′nBu2)] (E = S or Se; E′ = S or Se), are developed in this work to deposit stoichiometric WS2xSe2−2x (0 ≤ x ≤ 1) binary and ternary thin films.

Copper diaryl-dithiocarbamate complexes and their application as single source precursors (SSPs) for copper sulfide nanomaterials

Copper diaryl-dithiocarbamate (DTC) complexes have been prepared including [Cu(S2CNAr2)2], [Cu{S2CN(p-tolyl)2}]n and [Cu{S2CN(p-tolyl)2}(PPh3)2] and used as single source precursors to copper sulfide nanomaterials.

Single-source formation and assessment of nitrogen-doped graphitic spheres for lithium- and sodium-ion batteries.

Optimisation of the annealing time for the fabrication of nitrogen-doped graphitic-spheres (NDGSs), formed from a nitrogen-functionalised aromatic precursor at 800 °C, to give high nitrogen doping has been performed. Thorough analysis of the NDGSs, approximately 3 μm in diameter, pinpointed an optimum annealing time of 6 to 12 hours to obtain highest nitrogen content at the surface of the spheres (reaching a stoichiometry of around C3N at the surface and C9N in the bulk), with the quantity of sp2 and sp3 surface nitrogen varying with annealing time. The results suggest that changes in the nitrogen dopant level occur through slow diffusion of the nitrogen throughout the NDGSs, along with reabsorption of nitrogen-based gases produced during annealing. A stable bulk nitrogen dopant level of 9% was revealed in the spheres. The NDGSs performed well as anodes in lithium-ion batteries, providing a capacity of up to 265 mA h g-1 at a charging rate of C/20, but did not perform well in sodium-ion batteries without the use of diglyme, consistent with the presence of graphitic regions, but with low internal porosity.