PTCDA Research Articles

Perylene-3,4,9,10-tetracarboxylic dianhydride dye intercalated liquid crystal molecules: Synthesis, spectroscopic characterizations and photoluminescence dynamics

The present research explores the interaction between perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA)-dye (PD) and 3b {(E)-1-[3-fluoro-4-(pentyloxy)phenyl]-2-(4-methylphenyl)diazene} liquid crystal (LC) mesophase, 3c{(E)-1-[3-fluoro-4-(hexyloxy)phenyl]-2-(4-methylphenyl)diazene} nematic liquid crystal (NLC) molecule. Spectroscopic characterizations of 3b@PD LC mesophase and 3c@PD NLC molecule were carried out using scanning electron microscopy (SEM), polarizing optical microscope (POM), Raman, Fourier transform infrared spectroscopy (FT-IR), and UV–visible analytical methods. The UV–visible studies revealed a red shift in absorption bands (348.0 nm to 374 nm) with a decrease in optical band gap from 2.43 eV to 2.25 eV. Room temperature photoluminescence (RTPL) spectra of 3b@PD LC mesophase exhibited blue light emission characteristics centred at 453.1 nm and 3c @PD NLC molecule showed broad emission peaks located at 400.7 nm and 324.8 nm. Steady-state photoluminescence (SSPL) spectra showcased indigo-purple emission bands corresponding to the wavelengths 303–353 nm, 420.5 nm, 418 nm, 418.3 nm, and 347.0 nm, however, for the 3c@PD NLC molecule, emission intensity peaks appeared at 429.6 nm, 418.0 nm and 329.0 nm. The stoke’s shift for 3b@PD LC mesophase varied between 0.01 eV to 0.613 eV while for 3c@PD NLC molecule it was found in between 0.317 eV to 0.453 eV. POM analysis unveiled distinct fan-like textures with varied colour interfaces. Time-resolved photoluminescence (TRPL) decay studies unveiled average lifetime of 3b@PD LC mesophase was 1.80 ns, 0.98 ns, 0.308 ns and for 3c@PD NLC molecule, the average lifetime was found to be 0.98 ns, 0.82 ns, and 0.306 ns at various excitation wavelengths. However, phosphorescence decay studies showed faster decay characteristics for 3c@PD NLC molecule (1.40 ns to 4.00 ns) compared with 3b@PD LC mesophase (1.65 to 5.42 ns) when excited at various wavelengths. The interaction between LC molecules and PTCDA demonstrated a significant enhancement in RTPL, TRPL, and SSPL properties, suggesting promising applications in photonics and optoelectronics.

New Mn Electrochemistry for Rechargeable Aqueous Batteries: Promising Directions Based on Preliminary Results

Aqueous batteries with metal anodes exhibit robust anodic capacities, but their energy densities are low because of the limited potential stabilities of aqueous electrolyte solutions. Current metal options, such as Zn and Al, pose a dilemma: Zn lacks a sufficiently low redox potential, whereas Al tends to be strongly oxidized in aqueous environments. Our investigation introduces a novel rechargeable aqueous battery system based on Mn as the anode. We examine the effects of anions, electrolyte concentration, and diverse cathode chemistries. Notably, the ClO4‐based electrolyte solution exhibits improved deposition and dissolution efficiencies. Although stainless steel (SS 316 L) and Ni are stable current collectors for cathodes, they display limitations as anodes. However, using Ti as the anode resulted in increased Mn deposition and dissolution efficiencies. Moreover, we evaluate this system using various cathode materials, including Mn‐intercalation‐based inorganic (Ag0.33V2O5) and organic (perylenetetracarboxylic dianhydride) cathodes and an anion‐intercalation‐chemistry (coronene)‐based cathode. These configurations yield markedly higher output potentials compared to those of Zn metal batteries, highlighting the potential for an augmented energy density when using an Mn anode. This study outlines a systematic approach for use in optimizing metal anodes in Mn metal batteries, unlocking novel prospects for Mn‐based batteries with diverse cathode chemistries.

Photocatalytic Oxidative Bromination of Arenes by Al2O3-Supported Perylenetetracarboxylic Dianhydride

Photocatalytic Oxidative Bromination of Arenes by Al2O3-Supported Perylenetetracarboxylic Dianhydride

Engineering an A-D-A structure to enhance internal electric fields in silica-PDI-decorated vertical graphene for efficient photocatalytic oxidation

Efficient charge separation and transfer are crucial for elevating photocatalytic oxidation, and designing a photocatalyst structure with strong internal electric fields (IEF) hold promise for addressing the issue. Herein, we synthesized a silica-PDI (silica-perylene diimides) decorated vertical graphene (s-PDI@VG) architecture with an Acceptor-Donor-Acceptor (A-D-A) structure. The A-D-A configuration facilitated electron transfer from tertiary N-atom to perylene tetracarboxylic dianhydride (PTCDA) and flower-like vertical graphene (VG), resulting in a larger molecular dipole moment of s-PDI@VG compared to PTCDA and s-PDI. Consequently, an IEF with 7.5 times higher than PTCDA and 4.8 times higher than s-PDI was built, which is beneficial for photogenerated charge separation. Additionally, the valence band (VB) of s-PDI@VG deepened from 1.43 eV to 1.62 eV, enabling it to afford a strong oxidation potential. As a proof-of-concept, the 3D s-PDI@VG photocatalyst demonstrated favorable persulfate (PMS) activation and pollutant adsorption, resulting in 1.6 times higher photogenerated holes based on LSCM results. This photocatalyst also achieved 98.2 % mineralization of high-ionization-potential (h-IP) organics within 30 min. This work offers insights into a novel photocatalytic oxidation strategy with high mineralization by engineering A-D-A structure and enhancing the IEF strength of photocatalyst molecules.

Three-dimensional MoS2 nanosheets embeded within NiTe nanorods forming semicoherent heterojunctions achieving high-performance potassium-ion batteries

Three-dimensional MoS2 nanosheets uniformly embedded within NiTe nanorods are synthesized via one-step hydrothermal method and subsequently coated with a carbon layer to form stable NiTe@MoS2@C heterojunctions. The heterojunctions exhibit moderate lattice mismatch (δ =20.0 %), strong electric fields, and uniform carbon shells, resulting in unique electronic configurations and abundant active sites. As an anode for potassium-ion batteries, NiTe@MoS2@C demonstrated an high reversible capacity of 258.4 mAh g−1 after 100 cycles at a rate of 200 mA g−1. Moreover, it showed a stable reversible capacity of 177.5 mAh g−1 at a high rate of 5000 mA g−1, indicating excellent rate performance. Notably, even in the NiTe@MoS2@C//perylene tetracarboxylic dianhydride full battery configuration, a significant reversible capacity of 87.4 mAh g−1 was maintained after 100 cycles at a rate of 200 mA g−1, manifesting its remarkable potential for practical applications in potassium-ion batteries. Theoretical calculations further revealed that the well-designed NiTe@MoS2 heterojunction significantly enhances K+ ion diffusion.

Ultrafast and stable molten salt aluminum organic batteries

Aluminum-organic batteries (AIBs) have gained significant popularity for large-scale energy storage due to their abundance of aluminum reserves, cost-effectiveness, and environmental friendliness. However, the current aluminum-organic batteries primarily relied on ionic liquid electrolytes suffer from slow reaction kinetics and limited cycle life. Herein, we report a novel and efficient aluminum-organic battery that addresses these limitations by utilizing a molten salt electrolyte and designing a strongly interacting organic cathode. By enhancing π-π stacking interactions, we induced a transition in commercial PTCDA (Perylene-3,4,9,10-tetracarboxylic dianhydride) molecules from the β-phase to the highly interactive α-phase, known as PA450. This transformation not only stabilizes the structure of the PA450 electrode, preventing dissolution in the molten salt electrolyte, but also significantly improves electron conductivity. The Al||PA450 molten salt battery demonstrates exceptional electrochemical performance, exhibiting a high reversible capacity of 135 mAh g–1 and outstanding cyclability for up to 2000 cycles at 10 A g−1. Additionally, the structural rearrangement and ion transport properties induced by the co-intercalation of Al3+ and AlCl2+ were studied are investigated. This work provides deep insights into the unique characteristics of organic materials for ultrafast energy storage in molten salt electrolytes.

Investigation of column purified dye derived carbon nanomaterials for security printing and supercapacitor applications

Literature evidence reveals versatile applications of carbon dots (CDs), but generally mixtures of various types of carbon nanomaterials, molecular intermediates as well as side products are obtained upon hydrothermal treatment of the precursor material. This demands isolation of pure components and their complete characterization before these nano carbonaceous materials are chosen for suitable applications. In the present study, perylenetetracarboxylic dianhydride (PTCDA) is subjected to hydrothermal treatment and the mother liquor obtained is separated using column chromatography technique using dichloromethane-methanol solvent system to isolate fractions of various fluorescent carbonaceous nanostructures. The TEM imaging of nano carbonaceous particles of all five fractions indicated that the first and third fractions were composed of nanoribbons, while the latter two fractions largely contained quasi-spherical nanoparticles of both lesser (carbon quantum dots) and greater (carbon nanodots) than 10 nm dimensions. The XPS results of all the fractions suggested separation based on polarity difference. The ID/IG ratios obtained from Raman spectra implied the presence of several defects on the CDs. The time resolved fluorescence spectra of third, fourth and fifth fractions revealed mono-exponential decay of fluorophores with excitation independent average lifetime values. The fifth fraction exhibited good biocompatibility and the highest absolute fluorescence quantum yield of 58.47 % among all the isolated samples. As these CDs displayed a remarkable rise in the quantum yield to 88.60 % when dispersed in water, a water-based flexo-ink was formulated. The photostable pale yellow flexo print proofs obtained on UV dull paper exhibited a green fluorescence under 365 nm illumination, whereas a yellow glow when shined with blue light, which can serve as an authentication feature for security documents and currency notes. Moreover, as the third fraction constitutes mainly of carbon nanoribbons (CNRs), an optimized polymer electrolyte was prepared along with sodium alginate (SA), and MgCl2 to understand their potential use in energy storage application. A supercapacitor was fabricated and tested for its electrochemical performance such as cyclic voltammtery (CV), electrochemical impedance spectroscopy (EIS) and galvanostatic charge/discharge (GCD). An enhanced current window was observed in the CV of SA/CNRs compared to pure SA and SA/CNRs/Mg films, which indicated a structural interaction of CNRs with SA. The conductivity of SA/CNRs/Mg was lesser than SA/CNRs in EIS studies due to the presence of Mg ions, while pure SA showed lesser conductivity. The dual ionic interaction of Na and Mg along with enhanced structural stability due to doped CNRs favors its convenient supercapacitor application. The fabricated eco-friendly supercapacitor showed a specific capacitance of 84 F/g. The GCD of the device displayed pseudocapacitance behaviour and was quite stable for 2000 cycles with coulombic efficiency of 96 %.

CRISPR/Cas12a coupled with In2O3/multiwalled carbon nanotube/PTCDA-EDA-DAP modified electrode self-powered photoelectrochemical assay for EBV-DNA

The design and engineering of photoelectroactive materials is recognized as a crucial step to regulate the performance of photoelectrochemical biosensing. Herein, an organic semiconductor polymer, PTCDA-EDA-DAP, was synthesized from perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA), ethylenediamine (EDA) and 1,3-diamino-2-propanol (DAP). In2O3/multiwalled carbon nanotube/PTCDA-EDA-DAP enable a stable and unchanging photocurrent in the range from 0 V to 0.3 V and an excellent self-powered photocurrent. Based on this superior photoelectrochemical property, we fabricated an ultrasensitive photoelectrochemical assay for EBV-DNA based on CRISPR/Cas12a double cycling signal amplification. The target DNA stimulated Nt.BsmAI nicking, extension growth and a short chain nucleic acid as secondary targets being generated. The secondary target initiated next round of polymerization/cleavage. So that, after the two rounds of slicing and prolongation growth, the exponential growth dsDNA was generated resulting dsDNA bound to the Cas12a-crRNA complex, the trans-cleavage activity of Cas12a was activated, and resulted in amplified photocurrent. This photoelectrochemical assay had a LOD of 45 aM. The successful detection of EBV-DNA in serum samples demonstrated the promising application in real samples.

Flexible self‐supporting organic cathode with interface engineering for high‐performance and wide‐temperature sodium‐ion batteries

AbstractFlexible electrode design with robust structure and good performance is one of the priorities for flexible batteries to power emerging wearable electronics, and organic cathode materials have become contenders for flexible self‐supporting electrodes. However, issues such as easy electrolyte solubility and low intrinsic conductivity contribute to high polarization and rapid capacity decay. Herein, we have designed a flexible self‐supporting cathode based on perylene‐3,4,9,10‐tetracarboxylic dianhydride (PTCDA), interfacial engineering enhanced by polypyrrole (PPy), and carbon nanotubes (CNTs), forming the interconnected and flexible PTCDA/PPy/CNTs using polymerization reaction and vacuum filtration methods, effectively curbing those challenges. When used as the cathode of sodium‐ion batteries, PTCDA/PPy/CNTs exhibit excellent rate capability (105.7 mAh g−1 at 20 C), outstanding cycling stability (79.4% capacity retention at 5 C after 500 cycles), and remarkable wide temperature application capability (86.5 mAh g−1 at −30°C and 115.4 mAh g−1 at 60°C). The sodium storage mechanism was verified to be a reversible oxidation reaction between two Na+ ions and carbonyl groups by density functional theory calculations, in situ infrared Fourier transform infrared spectroscopy, and in situ Raman spectroscopy. Surprisingly, the pouch cells based on PTCDA/PPy/CNTs exhibit good mechanical flexibility in various mechanical states. This work inspires more rational designs of flexible and self‐supporting organic cathodes, promoting the development of high‐performance and wide‐temperature adaptable wearable electronic devices.

Graphitic carbon nitride-PTD hybrid catalyst for efficient photocatalytic oxidative coupling of arylamine for the production of azoaromatic under visible light

Oxidative coupling of amine derivatives to selectively synthesize pharmaceutical materials has been realized via photocatalysis. Herein we report on the fabrication and development of a graphitic carbon nitride (G) based visible light active photocatalyst (G-PTD), which is melamine converted graphitic carbon nitride(G) covalently integrated to a light harvesting perylene tetracarboxylic dianhydride (PTD) molecule. The synthesized photocatalyst has various functions in a highly active manner leading to high yield of newly generated azoaromatic compound. The current research endeavour highlights on the fabrication and utilization of a graphitic carbon nitride based photocatalyst for direct oxidative coupling of arylamines.

Rational design of a setaria-like NiTe2/MoS2 semi-coherent heterogeneous interface for enhancing diffusion kinetics in potassium-ion batteries

Constructing unique heterostructures is a highly effective approach for enhancing the K+ storage capability of transition metal selenides. Such structures generate internal electric fields that significantly reduce the charge transfer activation energy. However, achieving a flawless interfacial region that maintains the optimal energy level gradient and degree of lattice matching remains a considerable challenge. In this study, we synthesised Setaria-like NiTe2/MoS2@C heterogeneous interfaces at which three-dimensional MoS2 nanosheets are evenly embedded in NiTe2 nanorods to form stabilised heterojunctions. The NiTe2/MoS2 heterojunctions display distinctive electronic configurations and several active sites owing to their low lattice misfits (δ = 13 %), strong electric fields, and uniform carbon shells. A NiTe2/MoS2@C anode in a potassium-ion battery (KIB) exhibited an impressive reversible capacity of 125.8 mAh/g after 1000 cycles at a rate of 500 mA g−1 and a stable reversible capacity of 111.7 mAh/g even after 3000 cycles at 1000 mA g−1. Even the NiTe2/MoS2@C//perylene tetracarboxylic dianhydride full battery configuration maintained a significant reversible capacity of 92.4 mAh/g after 100 cycles at 200 mA g−1, highlighting its considerable potential for application in KIBs. Calculations further revealed that the well-designed NiTe2/MoS2 heterojunction significantly promotes K+ ion diffusion.

Ultrastable Organic Anode Enabled by Electrochemically Active MXene Binder toward Advanced Potassium Ion Storage.

Conjugated carbonyl compounds are regarded as promising organic anode materials for potassium ion batteries (PIBs) due to their rich redox sites, excellent reversibility, and structural tunability, but their low electrical conductivity and severe solubility in organic electrolytes have substantially restricted their practical application. Herein, 2D MXene is utilized as an electrochemically active binder to fabricate perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA) electrodes for high-performance PIBs. MXene, coupled with Super-P particles, served as a binder and conductive matrix to facilitate rapid ion and electron transport, restrain the solubility of PTCDA, promote potassium adsorption, and alleviate the volume expansion of PTCDA during potassiation. Consequently, the PTCDA electrode bonded by the MXene/Super-P system delivers excellent potassium storage performance in terms of a high capacity of 462 mAh g-1 at 50 mA g-1, superior rate capability of 116.3 mAh g-1 at 2000 mA g-1, and stable cycle performance over 3000 cycles with a low capacity decay rate of ∼0.0033% per cycle. When configured with the PTCDA@450 cathode, an all-PTCDA potassium ion full cell delivers a maximum energy density of 179.5 Wh kg-1, indicating the superiority of MXene as an electrochemically active binder to promote the practical application of organic anodes for PIBs.

Heterogeneous organophotocatalytic HBr oxidation coupled with oxygen reduction for boosting bromination of arenes

Developing mild photocatalytic bromination strategies using sustainable bromo source has been attracting intense interests, but there is still much room for improvement. Full utilization of redox centers of photocatalysts for efficient generation of Br+ species is the key. Herein we report heterogenous organophotocatalytic HBr oxidation coupled with oxygen reduction to furnish Br2 and H2O2 for effective bromination of arenes over Al2O3 supported perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA). Mechanism studies suggest that O-vacancy in Al2O3 can provide Lewis-acid-type anchoring sites for O2, enabling unexpected dual-electron transfer from anchored photoexcited PTCDA to chemically bound O2 to produce H2O2. The in-situ generated H2O2 and Br2 over redox centers work together to generate HBrO for bromination of arenes. This work provides new insights that heterogenization of organophotocatalysts can not only help to improve their stability and recyclability, but also endow them with the ability to trigger unusual reaction mode via cooperative catalysis with supports.

In Situ Ions Induced Formation of KxF-Rich SEI Layers toward Ultrastable Life of Potassium-Ion Batteries.

Engineering F-rich solid electrolyte interphase (SEI) layers is regarded as an effective strategy to enable the long-term cycling stability of potassium-ion batteries (KIBs). However, in the conventional KPF6 carbonate electrolytes, it is challenging to form F-containing SEI layers due to the inability of KPF6 to decompose into KxF. Herein, AlCl3 is employed as a novel additive to change the chemical environment of the KPF6 carbonate electrolyte. First, due to the large charge-to-radius ratio of Al3+, the Al-containing groups in the electrolyte can easily capture F from PF6 - and accelerate the formation of KxF in SEI layer. In addition, AlCl3 also reacts with trace H2O or solvents in the electrolytes to form Al2O3, which can further act as a HF scavenger. Upon incorporating AlCl3 into conventional KPF6 carbonate electrolyte, the hard carbon (HC) anode exhibits an ultra-long lifespan of 10000 cycles with a high coulombic efficiency of ≈100%. When coupled with perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA), the full cell exhibits a high capacity retention of 81% after 360 cycles-significantly outperforming cells using conventional electrolytes. This research paves new avenues for advancing electrolyte engineering towards developing durable batteries tailored for large-scale energy storage applications.

Resonant Tip-Enhanced Raman Spectroscopy of a Single-Molecule Kondo System.

Tip-enhanced Raman spectroscopy (TERS) under ultrahigh vacuum and cryogenic conditions enables exploration of the relations between the adsorption geometry, electronic state, and vibrational fingerprints of individual molecules. TERS capability of reflecting spin states in open-shell molecular configurations is yet unexplored. Here, we use the tip of a scanning probe microscope to lift a perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA) molecule from a metal surface to bring it into an open-shell spin one-half anionic state. We reveal a correlation between the appearance of a Kondo resonance in differential conductance spectroscopy and concurrent characteristic changes captured by the TERS measurements. Through a detailed investigation of various adsorbed and tip-contacted PTCDA scenarios, we infer that the Raman scattering on suspended PTCDA is resonant with a higher excited state. Theoretical simulation of the vibrational spectra enables a precise assignment of the individual TERS peaks to high-symmetry Ag modes, including the fingerprints of the observed spin state. These findings highlight the potential of TERS in capturing complex interactions between charge, spin, and photophysical properties in nanoscale molecular systems and suggest a pathway for designing single-molecule spin-optical devices.

Designing strategically functionalized conjugated microporous polymers with pyrene and perylenetetracarboxylic dianhydride moieties with single-walled carbon nanotubes to enhance supercapacitive energy storage efficiency

We utilize straightforward and traditional Sonogashira coupling reactions to synthesize two conjugated microporous polymers linked with pyrene (referred to as PyT-PTCDA and PyT-PHTD CMPs) by combining the common precursor of 1,3,6,8-tetraethynylpyrene (PyT) with 1,7-dibromo-3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA-Br2) and 3,6-dibromophenanthrene-9,10-dione (PHTD-Br2). Various analytical techniques, including spectroscopy and microscopy, are employed to characterize these two PyT-CMP materials. The PyT-PTCDA CMP exhibits notable thermal stability (with a decomposition temperature of 351 °C and a char yield of 61 wt %). We combine the PyT-PTCDA and PyT-PHTD CMPs with exceptionally conducting single-walled carbon nanotubes (SWCNTs) through π-π stacking interactions between SWCNTs and PyT unit to improve their electrical conductivity and electrochemical performance. Electrochemical evaluations reveal that the PyT-PTCDA CMP/SWCNTs nanocomposite shows an impressive capacitance of 376 F g−1 (at 0.5 A g−1) in a three-electrode system. After undergoing 5000 cycles of charging and discharging, it maintained 98 % of its original capacitance while demonstrating an energy density of 52 Wh/kg. Additionally, in a symmetric coin cell system, the energy density is 17 Wh/kg and the capacitance is 119 F g−1 for PyT-PTCDA CMP/SWCNTs. This approach presents a promising avenue for developing high-performance supercapacitors by strategically blending PyT-CMPs with highly conductive SWCNTs.

Immobilization of Perylenetetracarboxylic Dianhydride on Al2O3 for Efficiently Photocatalytic Sulfide Oxidation.

Perylenetetracarboxylic dianhydride (PTCDA) derivatives have received significant attention as molecule photocatalysts. However, the poor recyclability of molecule-type photocatalysts hinders their widespread applications. Herein, immobilization of PTCDA on Al2O3 was achieved by simply physical mixing, which not only dramatically improved their recyclability, but also surprisingly improved the reactivity. A mechanism study suggested that the photo-exited state (PTCDA*) of PTCDA could promote the oxidation of thioanisole to generate PTCDA•-, which sequentially reduces oxygen to furnish superoxide radicals to achieve the catalytic cycle. Herein, the immobilization support Al2O3 was able to facilitate the strong adsorption of thioanisole, thereby boosting the photocatalytic activity. This work provides a new insight that the immobilization of organic molecular photocatalysts on those supports with proper adsorption sites could furnish highly efficient, stable, and recyclable molecular-based heterogeneous photocatalysts.

Nanomesh NiO-modified carbon cloth for highly efficient self-supporting potassium metal anodes

Potassium metal is one of the most promising anode materials for potassium-ion batteries owing to its low cost and ability to withstand high current density and relatively low operating potential. However, it is restricted from being used in practical implementations because of its high reactivity and disordered dendrite growth. To circumvent these issues, we stabilize potassium metal anodes by growing NiO with high potassium affinity and interconnected network porous structure on carbon cloth fibers (CC-NiO). A symmetric cell assembled from a composite material formed by infiltrating molten K into CC-NiO (K@CC-NiO) can cycle stably for 1840 h at a low overpotential of 33 mV. Furthermore, the first-cycle discharge capacities of the full batteries with carbon nanotubes-interwoven KFeSO4F microspheres (KFSF@CNTs) and perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA) as the cathodes are 101.4 and 105.1 mAh g−1, respectively. The capacity retention of KFSF@CNTs||K@CC-NiO full battery after 1000 cycles is 79.3 %, and the capacity retention of PTCDA||K@CC-NiO full battery after 800 cycles is 70.2 %. The strategy of utilizing NiO as an efficient potassium metal nucleation anchor opens up a new direction for the development of high-energy and long-cycle-life potassium metal batteries.

Cobalt-catalyzed soft-hard carbon composite anodes for enhanced sodium-ion storage

Hard carbon is expected to be a high-capacity anode material for sodium-ion batteries (SIBs). However, its Na+ storage performance, especially the low discharge capacity, remains a great challenge. Herein, the soft-hard carbon composite anodes with high degree of graphitization were synthesized via low-temperature pyrolysis (at only 900 °C) of Cobalt-catalyzed perylene tetracarboxylic dianhydride (PTCDA-Co) and cotton, with subsequent removal of cobalt. The composite resulting from a 2:3 mass ratio of soft to hard carbon exhibits a good discharge capacity of 355.81 mAh g−1 at a current density of 50 mA g−1 and an enhanced initial Coulombic efficiency (ICE) of 81.41%. The enhanced electrochemical storage performance of cotton is attributed to the introduction of PTCDA-Co, which creates low-defect graphitic layer, hierarchical porous channels, and carbon shielding coating on hard carbon.

Efficient separation of photo-generated carriers for in-situ induction of PDI cation radicals to enhance the photocatalytic performance of PDI supramolecules

In order to investigate whether the formation of hydrogen bonds can affect the degradation products of pollutants, a photocatalyst PDI-SE was obtained by end substituting perylene tetracarboxylic dianhydride with serine (SE) in this paper. As a reference, PDI-IS with isopropylamine (IS) terminal alkyl substitution was synthesized simultaneously. Their photocatalytic performance to decompose phenol and tetrabromobisphenol A (TBBPA) were investigated. PDI-SE could degrade 79.3% of phenol or 68.4% of TBBPA within 4 h under visible light. The degradation products of TBBPA were tracked using high-resolution mass spectrometry. The morphology, composition, structure, and optoelectronic properties of two photocatalysts, particularly their transient absorption spectra and fluorescence lifetime were studied. We also conducted theoretical calculations on their binding energy with phenol or TBBPA, distribution and separation of electron and hole of excited state PDI-SE and PDI-IS supramolecules. Due to the formation of hydrogen bonds the binding energy of PDI-SE with phenol or TBBPA is 1.24 eV or 1.99 eV, which is stronger than that of PDI-IS (0.85 eV or 1.66 eV). Although both PDI-SE and PDI-IS can form free radical cations in excited states, the high separation of electrons and holes of PDI-SE leads to a longer lifetime of free radical cations, so caused its excellent photocatalytic activity compared to PDI-IS. This article proposes a new strategy based on molecular design to promote efficient separation of photogenerated electrons and holes, thereby forming stronger oxidizing PDI cationic radicals in situ to enhance the photocatalytic performance of PDI supramolecules.