Search

Electrocatalytic carbon dioxide reduction reaction (CO2RR) toward value-added chemicals/fuels has offered a sustainable strategy to achieve a carbon-neutral energy cycle. However, it remains a great challenge to controllably and precisely regulate the coordination environment of active sites in catalysts for efficient generation of targeted products, especially the multicarbon (C2+) products. Herein we report the coordination environment engineering of metal centers in coordination polymers for efficient electroreduction of CO2to C2+products under neutral conditions. Significantly, the Cu coordination polymer with Cu–N2S2coordination configuration (Cu–N–S) demonstrates superior Faradaic efficiencies of 61.2% and 82.2% for ethylene and C2+products, respectively, compared to the selective formic acid generation on an analogous polymer with the Cu–I2S2coordination mode (Cu–I–S). In situ studies reveal the balanced formation of atop and bridge *CO intermediates on Cu–N–S, promoting C–C coupling for C2+production. Theoretical calculations suggest that coordination environment engineering can induce electronic modulations in Cu active sites, where the d-band center of Cu is upshifted in Cu–N–S with stronger selectivity to the C2+products. Consequently, Cu–N–S displays a stronger reaction trend toward the generation of C2+products, while Cu–I–S favors the formation of formic acid due to the suppression of C–C couplings for C2+pathways with large energy barriers.

Solar-driven photocatalysis is a promising approach for renewable energy application. H2O2photocatalysis by metal-free graphitic carbon nitride has been gaining attention. Compared with traditional thermal catalysis, metal-free graphitic carbon nitride photocatalysis could lower material cost and achieve greener production of H2O2. Also, to better guide photocatalyst design, a fundamental understanding of the reaction mechanism is needed. Here, we develop a series of model cost-effective metal-free H2O2photocatalysts made from graphitic carbon nitride (melem) and common imide groups. With 4,4′-oxydiphthalic anhydride (ODPA)-modified g-C3N4, a H2O2yield rate of 10781 μmol/h·g·L could be achieved. Transient absorption and ex situFourier transform infrared (FTIR) measurements revealed an ultrafast charge transfer from the melem core to water with ∼3 ps to form unique N–OH intermediates. The electron withdrawing ability of the anhydride group plays a role in governing the rate of electron transfer, ensuring efficient charge separation. Our strategy represents a new way to achieve a low material cost, simple synthesizing strategy, good environment impact, and high H2O2production for renewable energy application.

In this issue of Chem Catalysis, Xu and co-workers used oxidized MXene as support to tune the activities of cobalt phthalocyanine for carbon dioxide reduction reaction (CO2RR). The strong molecule/support interactions enhanced ∗CO hydrogenation, leading to a higher methanol yield. This finding highlights the role of the support effect in molecular electrochemistry.

Organic radicals are unstable and stable radicals usually display non-luminescent properties. Luminescent radicals possess the all-in-one properties of optoelectronics, electronics, and magnetics. To date, the reported structures of luminescent radicals are limited to triphenylmethyl radical derivatives and their analogues, which are stabilized with extended π-conjugation. Here, we demonstrate the first example of a nonconjugated luminescent radical. In spite of the lack of delocalized π-stabilization, the radical polymer readily emits red luminescence in the solid state. A traditional luminescent quencher, 2,2,6,6-tetramethylpiperidin-1-yl turned into a red chromophore when grafted onto a polymer backbone. Experimental data confirm that the emission is associated with the nitroxide radicals and is also affected by the packing of the polymer. This work discloses a novel class of luminescent radicals and a distinctive pathway for luminescence from open-shell materials.

Molecular complexes such as phthalocyanines and porphyrins are attractive due to their outstanding performance towards CO2-to-CO conversion. In this work, immobilized cobalt phthalocyanine (CoPc) is prepared using a CVD-type procedure. Our theoretical calculations suggest that depositing CoPc onto a highly curved substrate leads to structural deformation and electronic tuning that can decrease the activation barrier of CO2. Consistent with theoretical predictions, the intrinsic activity of CoPc supported on SWCNTs is improved by two folds compared to that on less-curved surfaces such as reduced graphene oxide (rGO) or multi-wall carbon nanotubes (MWCNTs). The catalyst exhibits a high Faradaic efficiency for CO of 80% at a low overpotential of 240 mV. At a higher overpotential of 490 mV, a TOF of 26.0 s−1and a TON of ca.90 000 are obtained with a near-unity Faradaic efficiency.

The creation of efficient artificial systems that mimic natural photosynthesis represents a key current challenge. Here, we describe a high-performance recyclable photocatalytic core–shell nanofibre system that integrates a cobalt catalyst and a photosensitizer in close proximity for hydrogen production from water using visible light. The composition, microstructure and dimensions—and thereby the catalytic activity—of the nanofibres were controlled through living crystallization-driven self-assembly. In this seeded growth strategy, block copolymers with crystallizable core-forming blocks and functional coronal segments were coassembled into low-dispersity, one-dimensional architectures. Under optimized conditions, the nanofibres promote the photocatalytic production of hydrogen from water with an overall quantum yield for solar energy conversion to hydrogen gas of ~4.0% (with a turnover number of >7,000 over 5?h, a frequency of >1,400?h-1and a H2production rate of >0.327?µmol?h-1with 1.34?µg of catalytic polymer (that is, >244,300?µmol?h-1?g-1of catalytic polymer)).

Advances in solar steam generation have made a promise in mitigating the water scarcity problem. However, their practical use could be curtailed by the vaporized pollutants and the longevity limited by biofouling and salt-fouling that are often overlooked. Here, a flake of wood is reported to be engineered into a miniaturized solar water treatment device by a laser engraving process and demonstrates advantages over common solar systems. The device is structured to mimic the centralized water treatment plants, which contains a superhydrophilic graphene bottom layer for lipophilic organic matter rejection and antifouling, an intrinsic wood microchannels layer for water transport and thermal management, and a hydrophobic graphene top layer for solar-driven desalination while inhibiting salt deposition. The pore size of wood differentiates the water flux and hence the evaporation performance, and the balsa wood with a larger pore size possesses a higher evaporation rate of 1.6 ± 0.02 kg m–2h–1compared with pine wood. The hierarchical design achieves a solar energy conversion efficiency of 110% and a lipophilic organic matter removal efficiency of >90% and significantly improves longevity even at high salinity. This work illuminates a sustainable and cost-effective pathway for water treatment and shows potential for wastewater reuse.

Wearing face masks has been widely recommended to contain respiratory virus diseases, yet the improper use of masks poses a threat of jeopardizing the protection effect. We here identified the bacteria viability on common face masks and found that the majority of bacteria (90%) remain alive after 8 h. Using laser-induced graphene (LIG), the inhibition rate improves to ∼81%. Combined with the photothermal effect, 99.998% bacterial killing efficiency could be attained within 10 min. For aerosolized bacteria, LIG also showed superior antibacterial capacity. The LIG can be converted from a diversity of carbon precursors including biomaterials, which eases the supply stress and environmental pressure amid an outbreak. In addition, self-reporting of mask conditions is feasible using the moisture-induced electricity from gradient graphene. Our results improve the safe use of masks and benefit the environment.

Self-assembly processes commonly occur in various biological contexts to form functional biological structures. However, the self-assembly of nanofibers within cells by heterologous molecules showing a biological function is rare. In this work, we reported the intracellular formation of fluorescent nanofibers by a natural small molecule, lycobetaine (LBT), which facilitated the direct physical connection between mitochondria and synchronized their membrane potential oscillations. The luminescent properties of LBT enabled the real-time observation of nanofiber formation, while the semiconductive nature of the LBT nanofiber facilitated electrical signal transduction among the connected mitochondria. This study introduces an approach to modulate mitochondrial connectivity within cells using “nano-cables” which facilitate studies on synchronized mitochondrial operations and the underlying mechanisms of drug action.

Activity-based detection of γ-Glutamyltranspeptidase (GGT) using near-infrared (NIR) fluorescent probes is a promising strategy for early cancer diagnosis. Although NIR pyridinium probes show high performance in biochemical analysis, the aggregation of both the probes and parental fluorochromes in biological environments is prone to result in a low signal-to-noise ratio (SBR), thus affecting their clinical applications. Here, we develop a GGT-activatable aggregate probe called OTBP-G for two-photon fluorescence imaging in various biological environments under 1040 nm excitation. By rationally tunning the hydrophilicity and donor–acceptor strength, we enable a synergistic effect between twisted intramolecular charge transfer and intersystem crossing processes and realize a perfect dark state for OTBP-G before activation. After the enzymatic reaction, the parental fluorochrome exhibits bright aggregation-induced emission peaking at 670 nm. The fluorochrome-to-probe transformation can induce 1000-fold fluorescence ON/OFF ratio, realizing in vitroGGT detection with an SBR > 900. Activation of OTBP-G occurs within 1 min in vivo,showing an SBR > 400 in mouse ear blood vessels. OTBP-G can further enable the early detection of pulmonary metastasis in breast cancer by topically spraying, outperforming the clinical standard hematoxylin and eosin staining. We anticipate that the in-depth study of OTBP-G can prompt the development of early cancer diagnosis and tumor-related physiological research. Moreover, this work highlights the crucial role of hydrophilicity and donor–acceptor strength in maximizing the ON/OFF ratio of the TICT probes and showcases the potential of OTBP as a versatile platform for activity-based sensing.

The electrochemical CO2reduction reaction (CO2RR) has emerged as a promising approach for sustainable carbon cycling and valuable chemical production. Various methods and strategies have been explored to boost CO2RR performance. One of the most promising strategies includes the construction of stable ionic interfaces on metallic or molecular catalysts using organic or inorganic cations, which has demonstrated a significant improvement in catalytic performance. The stable ionic interface is instrumental in adjusting adsorption behavior, influencing reactive intermediates, facilitating mass transportation, and suppressing the hydrogen evolution reaction, particularly under acidic conditions. In this Perspective, we provide an overview of the recent advancements in building ionic interfaces in the electrocatalytic process and discuss the application of this strategy to improve the CO2RR performance of metallic and molecular catalysts. We aim to convey the future trends and opportunities in creating ionic interfaces to further enhance carbon utilization efficiency and the productivity of CO2RR products. The emphasis of this Perspective lies in the pivotal role of ionic interfaces in catalysis, providing a valuable reference for future research in this critical field.

Ultrahigh dose-rate (FLASH) radiotherapy is an emerging technology with excellent therapeutic effects and low biological toxicity. However, tumor recurrence largely impede the effectiveness of FLASH therapy. Overcoming tumor recurrence is crucial for practical FLASH applications. Here, we prepared an agarose-based thermosensitive hydrogel containing a mild photothermal agent (TPE-BBT) and a glutaminase inhibitor (CB-839). Within nanoparticles, TPE-BBT exhibits aggregation-induced emission peaked at 900 nm, while the unrestricted molecular motions endow TPE-BBT with a mild photothermy generation ability. The balanced photothermal effect and photoluminescence are ideal for phototheranostics. Upon 660-nm laser irradiation, the temperature-rising effect softens and hydrolyzes the hydrogel to release TPE-BBT and CB-839 into the tumor site for concurrent mild photothermal therapy and chemotherapy, jointly inhibiting homologous recombination repair of DNA. The enhanced FLASH radiotherapy efficiently kills the tumor tissue without recurrence and obvious systematic toxicity. This work deciphers the unrestricted molecular motions in bright organic fluorophores as a source of photothermy, and provides novel recurrence-resistant radiotherapy without adverse side effects.

Electrocatalytic reduction of CO2and CO to methanol on cobalt phthalocyanine catalysts suffers from low selectivity and an incomplete understanding of the kinetics and underlying mechanism. Reporting in Nature Synthesis, Wang and colleagues systematically investigated the mechanism of electrochemical CO-to-methanol conversion. The mechanistic findings inspired the operation of high-pressure electrolysis, and the catalyst showed remarkable selectivity toward methanol formation.

Graphene is a two-dimensional nanomaterial composed of 1–10 layers of carbon atoms in a honeycomb lattice. It has been 15 years since the first isolation of few-layer graphene from graphite by the Scotch Tape method. Worldwide research efforts on graphene have been rewarded with enormous breakthroughs in fundamental science and innovative applications. To achieve an influential impact on society, graphene must be manufactured at large scales, be superior to existing products, and be safe to use. In this Perspective, we highlight relevant issues in the quest for commercialization of graphene-containing products. We showcase achievements in improving graphene synthesis while also discussing concerns regarding graphene standardization and graphene’s impact on the environment and human health.

Bloodstains provide admissible information for crime scene investigators. The ability to resolve latent bloodstains that are commonly found in real scenarios is therefore pivotal to public security. Here, we report a facile approach for invisible bloodstain visualization based on the click reaction between serum albumin and tetraphenylethene maleimide (TPE-MI), an aggregation-induced emission luminogen (AIEgen). Compared to the widely adopted methods based on the harsh catalytic oxidation activity of hemoglobin, this working principle benefits from the specificity of the mild catalyst-free thiol–ene click reaction that improves the reliability and resolution. In addition, the mild conditions preserve DNA information and bloodstain patterns, and the excellent photophysical properties of the AIEgen afford high sensitivity and stability (>1 yr). Such an excellent performance cannot be achieved by conventional AIEgens and aggregation-caused quenching luminogens with similar structures. TPE-MI outperforms the benchmark luminol-based technique in visualizing latent bloodstains as showcased in two mock crime scenes: spattered blood track and transfer blood fingerprint. This disclosed method is an advancement in forensic science that could inspire future development of technology for bloodstain visualization.

Graphene quantum dots (GQDs) have recently been employed in various fields including medicine as antioxidants, primarily because of favorable biocompatibility in comparison to common inorganic quantum dots, although the structural features that lead to the biological activities of GQDs are poorly understood. Here, we report that coal-derived GQDs and their poly(ethylene glycol)-functionalized derivatives serve as efficient antioxidants, and we evaluate their electrochemical, chemical, and in vitro biological activities.

Although photodynamic therapy (PDT) has thrived as a promising treatment, highly active photosensitizers (PSs) and intense light power can cause treatment overdose. However, extra therapeutic response probes make the monitoring process complicated, ex situ and delayed. Now, this challenge is addressed by a self-reporting cationic PS, named TPE-4EP+, with aggregation-induced emission characteristic. The molecule undergoes mitochondria-to-nucleus translocation during apoptosis induced by PDT, thus enabling the in situ real-time monitoring via fluorescence migration. Moreover, by molecular charge engineering, we prove that the in situ translocation of TPE-4EP+ is mainly attributed to the enhanced interaction with DNA imposed by its multivalent positive charge. The ability of PS to provide PDT with real-time diagnosis help control the treatment dose that can avoid excessive phototoxicity and minimize potential side effect. Future development of new generation of PS is envisioned.

Electrochemical carbon dioxide reduction enables conversion of carbon dioxide into fuels and chemicals with renewable energy input. Cobalt-based molecular complexes have exhibited high selectivity, activity, and stability for transforming carbon dioxide into carbon monoxide. Through evaluating immobilized cobalt porphyrins functionalized with various peripheral substituents, we demonstrated that their activity is affected not only by the electronegativity of the substituents, but importantly, also by the charge of the substituents. The performance of immobilized cobalt porphyrins can be improved by introducing electron-donating and positively charged functional groups. Through kinetic studies, we were able to understand the mechanism by which electron-donating groups enhance the observed rates of carbon dioxide reduction and how cationic functionality may contribute towards electrostatic stabilization of the intermediate formed in the rate-determining step. Our methodology provides a robust and experimentally-verified method of computationally predicting the electronic effect of peripheral substitution and hence the catalytic activity of substituted porphyrins.

Laser-assisted materials fabrication is an advanced technique that has propelled recent carbon synthesis approaches. Direct laser writing on polyimide or lignocellulose materials by a CO2laser has successfully transformed the substrates into hierarchical graphene. However, formation of other carbon allotropes such as diamond and fullerene remains challenging. Here, we report the direct synthesis of fluorinated nanodiamonds or fluorinated graphene by treating polytetrafluoroethylene (Teflon, or PTFE) with a 9.3 μm pulsed CO2laser under argon; no exogenous fluorine source is needed. The laser is part of a commercial laser cutting/scribing system that is found in most machine shops. Therefore, it is a readily accessible tool. This discovery could inspire future development for the laser-assisted synthesis of functionalized carbon allotropes.

A simple and facile method for obtaining patterned graphene under ambient conditions on the surface of diverse materials ranging from renewable precursors such as food, cloth, paper, and cardboard to high-performance polymers like Kevlar or even on natural coal would be highly desirable. Here, we report a method of using multiple pulsed-laser scribing to convert a wide range of substrates into laser-induced graphene (LIG). With the increased versatility of the multiple lase process, highly conductive patterns can be achieved on the surface of a diverse number of substrates in ambient atmosphere. The use of a defocus method results in multiple lases in a single pass of the laser, further simplifying the procedure. This method can be implemented without increasing processing times when compared with laser induction of graphene on polyimide (Kapton) substrates as previously reported. In fact, any carbon precursor that can be converted into amorphous carbon can be converted into graphene using this multiple lase method. This may be a generally applicable technique for forming graphene on diverse substrates in applications such as flexible or even biodegradable and edible electronics.

The development of catalytic materials for the hydrogen oxidation, hydrogen evolution, oxygen reduction or oxygen evolution reactions with high reaction rates and low overpotentials are key goals for the development of renewable energy. We report here Ru(0) nanoclusters supported on nitrogen-doped graphene as high-performance multifunctional catalysts for the hydrogen evolution reaction (HER) and oxygen reduction reaction (ORR), showing activities similar to that of commercial Pt/C in alkaline solution. For HER performance in alkaline media, sample Ru/NG-750 reaches 10 mA cm–2at an overpotential of 8 mV with a Tafel slope of 30 mV dec–1. The high HER performance in alkaline solution is advantageous because most catalysts for ORR and oxygen evolution reaction (OER) also prefer alkaline solution environment whereas degrade in acidic electrolytes. For ORR performance, Ru/NG effectively catalyzes the conversion of O2into OH–via a 4eprocess at a current density comparable to that of Pt/C. The unusual catalytic activities of Ru(0) nanoclusters reported here are important discoveries for the advancement of renewable energy conversion reactions.

Organic intercalation of layered nanomaterials is an attractive strategy to fabricate organic/inorganic superlattices for a wide range of promising applications. However, the synthesis of 2D organic/inorganic superlattice nanosheets remains a big challenge. Herein, the preparation of 2D polyaniline/MoO3−x(PANI/MoO3−x) superlattice nanosheets via intercalation‐induced morphological transformation from MoO3nanobelts, as efficient Fenton‐like reagents for chemodynamic therapy (CDT), is reported. Micrometer‐long MoO3nanobelts are co‐intercalated with Na+/H2O followed by the guest exchange with aniline monomer for in situ polymerization to obtain PANI/MoO3−xnanosheets. Intriguingly, the PANI intercalation can induce the morphological transformation from long MoO3nanobelts to 2D PANI/MoO3−xnanosheets along with the partial reduction of Mo6+to Mo5+, and generation of rich oxygen vacancies. More importantly, thanks to the PANI intercalation‐induced activation, the PANI/MoO3−xnanosheets exhibit excellent Fenton‐like catalytic activity for generation of hydroxyl radical (·OH) by decomposing H2O2compared with the MoO3nanobelts. It is speculated that the good conductivity of PANI can facilitate electron transport during the Fenton‐like reaction, thereby enhancing the efficiency of CDT. Thus, the polyvinylpyrrolidone‐modified PANI/MoO3−xnanosheets can function as Fenton‐like reagents for highly efficient CDT to kill cancer cells and eradicate tumors. The intercalation‐induced morphological transformation is proposed as a simple but powerful strategy to prepare 2D polyaniline/MoO3−xorganic/inorganic superlattice nanosheets as high‐efficiency Fenton‐like reagents for chemodynamic cancer therapy, thus achieving cell apoptosis and tumor eradication.

Composition modulation and edge enrichment are established protocols to steer the electronic structures and catalytic activities of two-dimensional (2D) materials. It is believed that a heteroatom enhances the catalytic performance by activating the chemically inert basal plane of 2D crystals. However, the edge and basal plane have inherently different electronic states, and how the dopants affect the edge activity remains ambiguous. Here we provide mechanistic insights into this issue by monitoring the hydrogen evolution reaction (HER) performance of phosphorus-doped MoS2(P-MoS2) nanosheets via on-chip electrocatalytic microdevices. Upon phosphorus doping, MoS2nanosheet gets catalytically activated and, more importantly, shows higher HER activity in the edge than the basal plane. In situ transport measurement demonstrates that the improved HER performance of P-MoS2is derived from intrinsic catalytic activity rather than charge transfer. Density functional theory calculations manifest that the edge sites of P-MoS2are energetically more favorable for HER. The finding guides the rational design of edge-dominant P-MoS2, reaching a minuscule onset potential of ∼30 mV and Tafel slope of 48 mV/dec that are benchmarked against other activation methods. Our results disclose the hitherto overlooked edge activity of 2D materials induced by heteroatom doping that will provide perspectives for preparing next-generation 2D catalysts.

The development of high-performance miniaturized and flexible airflow sensors is essential to meet the need of emerging applications. Graphene-based airflow sensors are hampered by the sluggish response and recovery speed and low sensitivity. Here we employ laser-induced graphene (LIG) with poststructural biomimicry for fabricating high-performance, flexible airflow sensors, including cotton-like porous LIG, caterpillar fluff-like vertical LIG fiber, and Lepidoptera scale-like suspended LIG fiber (SLIGF) structures. The structural engineering changes the deformation behavior of LIGs under stress, among which the synchronous propagation of the scale-like structure of SLIGF is the most conducive to airflow sensing. The SLIGF achieves the shortest average response time of 0.5 s, the highest sensitivity of 0.11 s/m, and a record-low detection threshold of 0.0023 m/s, benchmarked against the state-of-the-art airflow sensors. Furthermore, we showcase the SLIGF airflow sensors in weather forecasting, health, and communications applications. Our study will help develop next-generation waterflow, sound, and motion sensors.

Breast cancer (BC) remains a significant global health challenge for women despite advancements in early detection and treatment. Isoliquiritigenin (ISL), a compound derived from traditional Chinese medicine, has shown potential as an anti-BC therapy, but its low bioavailability and poor water solubility restrict its effectiveness. In this study, we created theranostic nanoparticles consisting of ISL and a near-infrared (NIR) photosensitizer, TBPI, which displays aggregation-induced emission (AIE), with the goal of providing combined chemo- and photodynamic therapies (PDT) for BC. Initially, we designed an asymmetric organic molecule, TBPI, featuring a rotorlike triphenylamine as the donor and 1-methylpyridinium iodide as the acceptor, which led to the production of reactive oxygen species in mitochondria. We then combined TBPI with ISL and encapsulated them in DSPE-PEG-RGD nanoparticles to produce IT-PEG-RGD nanoparticles, which showed high affinity for BC, better intersystem crossing (ISC) efficiency, and Förster resonance energy transfer (FRET) between TBPI and ISL. In both 4T1 BC cell line and a 4T1 tumor-bearing BC mouse model, the IT-PEG-RGD nanoparticles demonstrated excellent drug delivery, synergistic antitumor effects, enhanced tumor-killing efficacy, and reduced drug dosage and side effects. Furthermore, we exploited the optical properties of TBPI with ISL to reveal the release process and distribution of nanoparticles in cells. This study provides a valuable basis for further exploration of IT-PEG-RGD nanoparticles and their anticancer mechanisms, highlighting the potential of theranostic nanoparticles in BC treatment.

Here, we introduce a systematic strategy to prepare composite materials for wellbore reinforcement using graphene nanoribbons (GNRs) in a thermoset polymer irradiated by microwaves. We show that microwave absorption by GNRs functionalized with poly(propylene oxide) (PPO-GNRs) cured the composite by reaching 200 °C under 30 W of microwave power. Nanoscale PPO-GNRs diffuse deep inside porous sandstone and dramatically enhance the mechanics of the entire structure via effective reinforcement. The bulk and the local mechanical properties measured by compression and nanoindentation mechanical tests, respectively, reveal that microwave heating of PPO-GNRs and direct polymeric curing are major reasons for this significant reinforcement effect.

Hybrid materials incorporating the advantages of graphene and nanoparticles have been widely studied. Here we develop an improved cost-effective approach for preparation of porous graphene embedded with various types of nanoparticles. Direct laser scribing on metal-complex-containing polyimide film leads to in situformation of nanoparticles embedded in porous graphene. These materials are highly active in electrochemical oxygen reduction reactions, converting O2into OH–, with a low metal loading of less than 1 at. %. In addition, the nanoparticles can vary from metal oxide to metal dichalcogenides through lateral doping, making the composite active in other electrocatalytic reactions such as hydrogen evolution.

Transition metal carbide nanocrystalline M3C (M: Fe, Co, Ni) encapsulated in graphitic shells supported with vertically aligned graphene nanoribbons (VA-GNRs) are synthesized through a hot filament chemical vapor deposition (HF-CVD) method. The process is based on the direct reaction between iron group metals (Fe, Co, Ni) and carbon source, which are facilely get high purity carbide nanocrystals (NCs) and avoid any other impurity at relatively low temperature. The M3C-GNRs exhibit superior enhanced electrocatalystic activity for oxygen reduction reaction (ORR), including low Tafel slope (39, 41, and 45 mV dec–1for Fe3C-GNRs, Co3C-GNRs, and Ni3C-GNRs, respectively), positive onset potential (∼0.8 V), high electron transfer number (∼4), and long-term stability (no obvious drop after 20 000 s test). The M3C-GNRs catalyst also exhibits remarkable hydrogen evolution reaction (HER) activity with a large cathodic current density of 166.6, 79.6, and 116.4 mA cm–2at an overpotential of 200 mV, low onset overpotential of 32, 41, and 35 mV, small Tafel slope of 46, 57, and 54 mV dec–1for Fe3C-GNRs, Co3C-GNRs, and Ni3C-GNRs, respectively, as well as an excellent stability in acidic media.

Heteroatom-doped graphene materials have been intensely studied as active electrodes in energy storage devices. Here, we demonstrate that boron-doped porous graphene can be prepared in ambient air using a facile laser induction process from boric acid containing polyimide sheets. At the same time, active electrodes can be patterned for flexible microsupercapacitors. As a result of boron doping, the highest areal capacitance of as-prepared devices reaches 16.5 mF/cm2, 3 times higher than nondoped devices, with concomitant energy density increases of 5–10 times at various power densities. The superb cyclability and mechanical flexibility of the device are well-maintained, showing great potential for future microelectronics made from this boron-doped laser-induced graphene material.

Bamboo structured nitrogen doped multiwalled carbon nanotubes have been helically unzipped, and nitrogen doped graphene oxide nanoribbons (CNx-GONRs) with a multifaceted microstructure have been obtained. CNx-GONRs have then been codoped with nitrogen and boron by simultaneous thermal annealing in ammonia and boron oxide atmospheres, respectively. The effects of the codoping time and temperature on the concentration of the dopants and their functional groups have been extensively investigated. X-ray photoelectron spectroscopy results indicate that pyridinic and BC3are the main nitrogen and boron functional groups, respectively, in the codoped samples. The oxygen reduction reaction (ORR) properties of the samples have been measured in an alkaline electrolyte and compared with the state-of-the-art Pt/C (20%) electrocatalyst. The results show that the nitrogen/boron codoped graphene nanoribbons with helically unzipped structures (CNx/CBx-GNRs) can compete with the Pt/C (20%) electrocatalyst in all of the key ORR properties: onset potential, exchange current density, four electron pathway selectivity, kinetic current density, and stability. The development of such graphene nanoribbon-based electrocatalyst could be a harbinger of precious metal-free carbon-based nanomaterials for ORR applications.

Bandgaps of photoluminescent graphene quantum dots (GQDs) synthesized from anthracite have been engineered by controlling the size of GQDs in two ways: either chemical oxidative treatment and separation by cross-flow ultrafiltration, or by a facile one-step chemical synthesis using successively higher temperatures to render smaller GQDs. Using these methods, GQDs were synthesized with tailored sizes and bandgaps. The GQDs emit light from blue-green (2.9 eV) to orange-red (2.05 eV), depending on size, functionalities and defects. These findings provide a deeper insight into the nature of coal-derived GQDs and demonstrate a scalable method for production of GQDs with the desired bandgaps.