Energy Conversion Devices Research Articles

Acidified Nitrogen Self-Doped Porous Carbon with Superprotonic Conduction for Applications in Solid-State Proton Battery.

Solid proton electrolytes play a crucial role in various electrochemical energy storage and conversion devices. However, the development of fast proton conducting solid proton electrolytes at ambient conditions remains a significant challenge. In this study, a novel acidified nitrogen self-doped porous carbon material is presented that demonstrates exceptional superprotonic conduction for applications in solid-state proton battery. The material, designated as MSA@ZIF-8-C, is synthesized through the acidification of nitrogen-doped porous carbon, specifically by integrating methanesulfonic acid (MSA) into zeolitic imidazolate framework-derived nitrogen self-doped porous carbons (ZIF-8-C). This study reveals that MSA@ZIF-8-C achieves a record-high proton conductivity beyond 10-2 Scm-1 at ambient condition, along with good long-term stability, positioning it as a cutting-edge alternative solid proton electrolyte to the default aqueous H2 SO4 electrolyte in proton batteries.

Trace amount Pt anchored on nitrogen-doped carbon nanoparticle with hollow capsule structure for efficient electrocatalytic oxygen reduction

The utilization of sustainable green energies requires the energy conversion devices to enhance the convenience of use and storage. The oxygen reduction reaction (ORR), as one of the necessary steps in the operation of these devices, exhibits a slow reaction kinetic rate that seriously affects energy conversion and output efficiency. Due to the low abundance and poor stability of Pt, it is essential to develop high-performance oxygen reduction catalysts with low Pt loading. In this work, a composite precursor consisting of ZIF-8 coupled with ferrocene and chloroplatinic acid was prepared, and subsequently derived to obtain nitrogen-doped carbon nanoparticles with hollow capsule morphology on the surface. These hollow capsule structure formed with the assistance of Pt and Fe significantly enhances the performance of Pt/FC@ZIF-8-C nanoparticles as the ORR electrocatalyst, exhibiting superior catalytic activity and stability compared to Pt/C at a low Pt loading (0.7 wt%). This is very important for promoting the design and preparation of Pt-based catalysts, as well as the application of energy conversion and storage devices in the field of green energy sources.

Investigation of neutronic and thermal–electric coupling phenomenon in a 100 kWe-level nuclear silent heat pipe-cooled reactor

Heat pipe-cooled reactors are attractive because of their compact structure, high power capacity and reliability, and inherent safety features. These reactors are distinguished by the use of high-temperature heat pipes that directly bridge the reactor core and energy conversion devices, thus creating a tightly knit modular system. However, comprehensive coupled analysis of these reactors remains challenging because of the intricate multiphysics interactions involved. To address this, the neutronic and thermoelectric coupled phenomena of heat pipe-cooled reactors are investigated in this study. Models are introduced for the point reactor kinetics, core heat transfer, channel heat transfer, two-phase two-dimensional heat pipes, thermoelectric coupling, and cold plates. The channel heat transfer is refined in a 100 kWe-level nuclear silent heat pipe-cooled reactor and a model for the three-dimensional heat transfer process in its thermoelectric matrix established, which effectively resolves the calculation distortions of the lumped model. The maximum deviation between the calculation results from the proposed model and the verification data for a full-system coupled computation is less than 10 K. The core temperature difference from the three-dimensional model is five times that of the lumped model with a maximum average fuel temperature difference of 225.7 K. The maximum and average thermoelectric conversion efficiencies are 15.56 % and 14.43 %, respectively. The failures of one, five, and nine heat pipes are analysed. The failure of a single heat pipe has negligible effects with a peak fuel temperature surge of only 121 K. In contrast, a failure involving nine heat pipes leads to a peak fuel temperature spike of 778 K and a 47.1 % increase in the maximum heat transfer power, marking a critical operational threshold. It is therefore imperative to consider the safety margin in the potential failure of multiple central heat pipes during the preliminary design stages.

Research on electromagnetic energy absorption and conversion device with four-ring multi-resistance structure

A device for electromagnetic energy absorption and conversion was investigated as an electromagnetic energy harvester, which is based on a four-ring multi-resistance unit. The device can convert microwave energy to thermal energy and then to electrical energy through the Bi2Te3 thermoelectric material adhered to the load resistance. The energy harvesting efficiency, power loss distribution, and current density distribution of the harvester were analyzed. In addition, the energy harvesting efficiency of the unit under different incident angles and polarization angles was studied, and the effect of incident power on the temperature and energy conversion efficiency of the unit was analyzed. The simulation results showed that the energy harvesting efficiency of the harvester reaches 99.5% at 5.8 GHz. Each unit in the harvester can generate an output voltage of 171.8 mV under 7 W incident wave power, and the maximum output power is 9.71 mW. To verify the effectiveness of this method, a 5 × 5 unit array model was fabricated and measured, and the measurement results were consistent with the simulation results.

ZIF-derived Fe,Co coordinated N/O-codoped three-dimensional tungsten–carbon matrix for the performance-enhanced zinc-air flow battery and water splitting

Constructing efficient and cost-effective electrocatalysts with oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER) for the development of zinc-air flow batteries (ZAFBs) and overall water splitting (OWS) is significant, but still challenging. Herein, we have fabricated a heterojunction catalyst (Fe,CoZn9+9-NO/WC) featuring uniformly dispersed Fe and Co coordinated with riched-nitrogen/oxygen codoped into a three-dimensional highly porous tungsten–carbon matrix modified carbon nanotube by a simple stepwise construction route using water as the solvent. The resultant Fe,CoZn9+9-NO/WC exhibits a positive half-wave potential (E1/2) of 0.889 V for ORR, a low overpotential at 10 mA·cm−2 for OER (290 mV) and HER (84 mV), and excellent electrochemical durability in alkaline electrolyte, outperforming even benchmark catalysts. Moreover, Fe,CoZn9+9-NO/WC as a bifunctional air cathode for ZAFBs delivers higher open circuit voltage, peak power density (190 mW·cm−2), and specific capacity (814 mAh·g−1), lower charge/discharge voltage gap and prolonged operational cycles durability, largely exceeding those of the hybrid Pt/C+RuO2 bifunctional catalyst. The alkaline OWS electrolyzer is constructed by Fe,CoZn9+9-NO/WC with good stability and requires only 1.556 V cell voltage at 10 mA·cm−2. Impressively, the self-constructed Fe,CoZn9+9-NO/WC electrodes were applied to practical ZAFBs and OWS devices, demonstrating superior performance to the recently reported ZIF/MOF-derived catalysts in organic solvents. This work offers an economical synthetic strategy to prepare highly efficient multifunctional catalysts with practical potential for commercial production, promising to facilitate the development of clean energy storage and conversion devices.

Smectic solid electrolytes containing lamellar conducting channels for solvent-free lithium-ion batteries with a thermal switch on/off performance

Developing electrolytes with desirable electrochemical performance and robust stability remains a huge challenge to meet the efficiency and durability demands of energy storage and conversion devices. Herein, the potential of ionic liquid crystals as high-performance electrolytes is demonstrated. Smectic ionic liquid crystals only consisting of conventional [C14Mim][BF4] and LiBF4 are designed and prepared as electrolytes for solvent-free lithium-ion batteries. [C14Mim][BF4] has good miscibility with LiBF4 to form smectic liquid crystals. LiBF4 is highly concentrated by [C14Mim][BF4] layers in the smectic electrolytes to form dynamic lamellar conducting channels, which enable considerable ion conductivities of 10–4 ∼ 10–3 S cm−1. The smectic electrolytes possess robust cyclic stability and energy conversion efficiency in Li/LiFePO4 batteries, which show a charge/discharge capacity of 154.7 mA h g−1 at a 1 C current density, as well as stable performance after 100 charge/discharge cycles even at 80 ℃. Additionally, the phase transition behavior of the electrolytes can be applied as a smart switch to thermally tune on/off the batteries. The electrolytes show almost no charge/discharge behavior under crystal phase, but automatically operate efficiently with charge/discharge capacities >150 mA h g−1 once entering the smectic phase. The present work sheds new light on developing high-performance and smart electrolytes for solvent-free Li-ion batteries.

Endplate effect in an open-cathode proton exchange membrane fuel cell stack: Phenomenon and resolution

Proton exchange membrane fuel cells (PEMFCs) have garnered substantial attention as highly promising devices for energy conversion. The operational lifespan and overall output performance of such stacks are inherently governed by the performance of the weakest fuel cell, a phenomenon often referred to as the “Bucket Effect.” Evidently, cells located proximate to the hydrogen inlet endplate exhibit poor performance in comparison to the remaining cells in a 95 cells open-cathode fuel cell stack. In response to this challenge, an innovative approach involving endplate heating has been proposed to mitigate the observed endplate effects. Experimental validation of this approach has been conducted, yielding pertinent results. Furthermore, the internal temperature distribution across the stack exhibits an asymmetric parabolic profile, largely attributed to the intricate interplay of the endplate effects. Comparative analysis against a counterpart stack without endplate heating indicates that an application of 80 W heating power leads to a prolongation of operational duration by 156 s, while 100 W heating extends the operational period by 333 s. 80 W heating increased stack power by 31.5 W while improving output power efficiency by 1.9%, and 100 W heating increased stack power by 45.6 W while improving output power efficiency by 2.74%.

Constructing FeS and ZnS Heterojunction on N,S-Codoped Carbon as Robust Electrocatalyst toward Oxygen Reduction Reaction.

Highly active and cost-efficient electrocatalysts for oxygen reduction reaction (ORR) are significant for developing renewable energy conversion devices. Herein, a nanocomposite Fe/ZnS-SNC electrocatalyst with an FeS and ZnS heterojunction on N,S-codoped carbon has been fabricated via a facile one-step sulfonating of the pre-designed Zn- and Fe-organic frameworks. Benefitting from the electron transfer from FeS to adjacent ZnS at the heterointerfaces, the optimized Fe/ZnS-SNC900 catalyst exhibits excellent ORR performances, featuring the half-wave potentials of 0.94 V and 0.81 V in alkaline and acidic media, respectively, which is competitive with the commercial 20 wt.% Pt/C (0.87 and 0.76 V). The flexible Zn-air battery equipping Fe/ZnS-SNC900 affords a higher open-circuit voltage (1.45 V) and power density of 30.2 mW cm-2. Fuel cells assembled with Fe/ZnS-SNC900 as cathodic catalysts deliver a higher power output of 388.3 and 242.8 mW cm-2 in H2-O2 and -air conditions. This work proposes advanced heterostructured ORR electrocatalysts that effectively promote renewable energy conversions.

Dual Single-Atomic Co-Mn Sites in Metal-Organic-Framework-Derived N-Doped Nanoporous Carbon for Electrochemical Oxygen Reduction.

Synthesizing dual single-atom catalysts (DSACs) with atomically isolated metal pairs is a challenging task but can be an effective way to enhance the performance for electrochemical oxygen reduction reaction (ORR). Herein, well-defined DSACs of Co-Mn, stabilized in N-doped porous carbon polyhedra (named CoMn/NC), are synthesized using high-temperature pyrolysis of a Co/Mn-doped zeolitic imidazolate framework. The atomically isolated Co-Mn site in CoMn/NC is recognized by combining microscopic as well as spectroscopic techniques. CoMn/NC exhibited excellent ORR activities in alkaline (E1/2 = 0.89 V) as well as in acidic (E1/2 = 0.82 V) electrolytes with long-term durability and enhanced methanol tolerance. Density functional theory (DFT) suggests that the Co-Mn site is efficiently activating the O-O bond via bridging adsorption, decisive for the 4e- oxygen reduction process. Though the Co-Mn sites favor O2 activation via the dissociative ORR mechanism, stronger adsorption of the intermediates in the dissociative path degrades the overall ORR activity. Our DFT studies conclude that the ORR on an Co-Mn site mainly occurs via bridging side-on O2 adsorption following thermodynamically and kinetically favorable associative mechanistic pathways with a lower overpotential and activation barrier. CoMn/NC performed excellently as a cathode in a proton exchange membrane (PEM) fuel cell and rechargeable Zn-air battery with high peak power densities of 970 and 176 mW cm-2, respectively. This work provides the guidelines for the rational design and synthesis of nonprecious DSACs for enhancing the ORR activity as well as the robustness of DSACs and suggests a design of multifunctional robust electrocatalysts for energy storage and conversion devices.

Designing Poly(3,4-ethylenedioxythiophene) Polystyrene Sulfonate/Graphene Oxide/Graphene Nanosheet/Polyethylene Glycol Phase-Change Composites with Superior Thermal Management for Photo-thermoelectric Generators.

Recently, growing interest in self-powered devices has led to the invention of new energy conversion devices. Photo-thermoelectric generators (PTEGs) have rapidly developed for their ability to harvest both light and thermal energy, but these devices are overly dependent on the continuity of energy input and cannot sustain output in an emergency situation. In the current study, poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS)/graphene oxide (GO)/graphene nanosheets (GNPs)/polyethylene glycol (PEG) phase-change composites (PCCs) were prepared with freeze-drying and vacuum-filling processes to acquire materials suitable for imparting energy storage characteristics to PTEGs. The melting and crystallization enthalpies of the PCCs fabricated based on the PEDOT:PSS/GO/GNP aerogels can reach 211.5 and 207.6 J g-1, respectively, which increase by nearly 5% compared with pure PEG, and the growth rate of thermal conductivity of the composites is as high as 262.7% (1.12 W m-1 K-1). Meanwhile, the excellent photothermal properties and high-temperature shape stability that pure PEG does not possess can also be imparted to PCCs by the aerogels. The PTEG assembled with PCCs and thermoelectric components can achieve a continuous output of over 1500 s after 300 s of light irradiation. After integrating the output of the device during the lamp on/off period, it is found that the total output of the device during the light-off period (8.4 V and 9.6 mW) can far exceed its total output during the light-on period (2.7 V and 4.4 mW). This work provides guidance for modulating the performance of PCCs and giving PTEGs the ability to operate under emergency or extremely harsh conditions and the prepared PTEGs are highly promising for practical use.

2D MXenes Nanosheets for Advanced Energy Conversion and Storage Devices: Recent Advances and Future Prospects.

Since the initial MXenes were discovered in 2011, several MXene compositions constructed using combinations of various transition metals have been developed. MXenes are ideal candidates for different applications in energy conversion and storage, because of their unique and interesting characteristics, which included good electrical conductivity, hydrophilicity, and simplicity of large-scale synthesis. Herein, we study the current developments in two-dimensional (2D) MXene nanosheets for energy storage and conversion technologies. First, we discuss the introduction to energy storage and conversion devices. Later, we emphasized on 2D MXenes and some specific properties of MXenes. Subsequently, research advances in MXene-based electrode materials for energy storage such as supercapacitors and rechargeable batteries is summarized. We provide the relevant energy storage processes, common challenges, and potential approaches to an acceptable solution for 2D MXene-based energy storage. In addition, recent advances for MXenes used in energy conversion devices like solar cells, fuel cells and catalysis is also summarized. Finally, the future prospective of growing MXene-based energy conversion and storage are highlighted.

Incorporating graphene oxide into COF membranes enables ultrahigh proton conductivity and ultralow H2 crossover

Proton exchange membranes (PEMs) are the core components of electrochemical hydrogen energy production, storage and conversion devices. It is a great challenge to develop PEMs with a combination of high proton conductivity, minimal H2 crossover and mechanical robustness for achieving high efficiency and long-term stability in these devices. Here, a co-assembled PEM composed of ionic covalent organic framework (iCOF) nanosheets and functionalized graphene oxide (GO) nanosheets was presented. The iCOF (TpPa-SO3H) nanosheets and polydopamine-modified graphene oxide (DGO) nanosheets were co-assembled into TpPa-SO3H/DGO mixed nanosheets with ultrahigh aspect ratio, which were readily further processed into TpPa-SO3H/DGO co-assembled membranes. The abundant and uniformly distributed –SO3H groups on TpPa-SO3H nanosheets and the acid-base pairs formed between TpPa-SO3H and DGO nanosheets promoted proton conduction significantly. Additionally, the dense structured DGO nanosheets inhibited H2 crossover remarkably, and the multiple interactions between TpPa-SO3H and DGO nanosheets enhanced mechanical strength. The resultant TpPa-SO3H/DGO co-assembled membrane exhibited an ultrahigh proton conductivity of 916.4 mS cm−1 (80 °C, 100% RH), an unprecedently low H2 crossover of 9.7 barrer and a sufficient tensile stress of 87.8 MPa. The enhanced proton conduction and H2 barrier property led to enhanced performance in both electrochemical hydrogen compression and single hydrogen fuel cells.

Review on Microfluidic Technology Based Synthesis of Fe-based Nanoparticles for Catalyst in Fuel Cell

Conventional combustion based energy generations, reliant on fossil fuels, poses significant environmental harm. In contrast, fuel cells offer an efficient and eco-friendly energy conversion method, capable of integrating with renewable sources and contemporary energy carriers to support sustainable development and energy security. Consequently, fuel cells are considered the promising energy conversion devices of the future. However, extensive research reveals that the cost of catalysts constitutes the most substantial portion of the overall fuel cell cost. To tackle this cost constraint, considerable advancements have been achieved in the development of cost-effective, precious metal-free electrocatalysts. Common methods for the preparation of metal nanomaterials (NPs) have more stringent requirements, lower deposition efficiency and higher costs. In addition, conventional preparation methods without precisely control of reagent concentration, mixing and temperature during the preparation process, makes it difficult to obtain the same results with poor reproducibility, restricting the industrial fabrication of high performance nanomaterials. Microfluidic reactors have advantages of efficient mixing, high heat and mass transfer, low reagent consumption, precise control of reactant components, residence time, reaction temperature and other parameters. They can also be coupled with multi-step reactions, greatly reducing the preparation time while obtaining composite nanomaterials with excellent dimensional homogeneity. In this review, we mainly discuss the microfluidic technology-based synthesis of PGM-free catalyst used in fuel cell.

A wind-solar energy harvester based on airflow enhancement mechanism for rail-side devices

A significant challenge arising from the rugged climate and environment is the provision of power to isolated railway-side equipment on the Plateau. Emerging renewable energy harvesting technologies present a promising solution. This paper proposes and confirms a Wind-Solar Energy Harvester (WSEH) founded on an Airflow Enhancement Mechanism (AFEM) for powering rail-side equipment. The proposed WSEH comprises of Vertical Axis Wind Turbine (VAWT), Flexible Photovoltaic Deflectors (FPVDs), and energy conversion and storage devices. The AFEM is executed founded on the FPVD that amplifies the airflow energy blown towards the VAWT due to the Blockage effect. The FPVD, grounded on an umbrella-like mechanism, unfolds as a PV panel for solar energy collection; and folds as a deflector to raise the wind energy collection potential for the VAWT. Through CFD simulation, the VAWT’s maximum power coefficient attains 0.387, and the optimum gain effect of FPVD is 66.54%. The prototypes, comprising VAWT and FPVDs, are scrutinized in a wind tunnel to authenticate the practicable effects illustrated by the no-load speed and load output of VAWT. The case study demonstrates that the WSEH creates 1566.82 kWh of electrical energy per year, sufficient for powering rail-side equipment on the Plateau.

Functional Alkali Metal-Based Ternary Chalcogenides: Design, Properties, and Opportunities.

The search for novel materials has recently brought research attention to alkali metal-based chalcogenides (ABZ) as a new class of semiconducting inorganic materials. Various theoretical and computational studies have highlighted many compositions of this class as ideal functional materials for application in energy conversion and storage devices. This Perspective discusses the expansive compositional landscape of ABZ compositions that inherently gives a wide spectrum of properties with great potential for application. In the present paper, we examine the technique of synthesizing this particular class of materials and explore their potential for compositional engineering in order to manipulate key functional properties. This study presents the notable findings that have been documented thus far in addition to outlining the potential avenues for implementation and the associated challenges they present. By fulfilling the sustainability requirements of being relativity earth-abundant, environmentally benign, and biocompatible, we anticipate a promising future for alkali metal chalcogenides. Through this Perspective, we aim to inspire continued research on this emerging class of materials, thereby enabling forthcoming breakthroughs in the realms of photovoltaics, thermoelectrics, and energy storage.

Spatial separation strategy to construct N/S co-doped carbon nanobox embedded with asymmetrically coupled Fe-Co pair-site for boosted reversible oxygen electrocatalysis

The fabrication of a remarkably efficient iron-metal-based pair-site, constrained within carbon support, presents a significant and intricate undertaking, primarily attributable to the propensity of proximate metallic entities to amalgamate into the alloy state. In response to this challenge, a spatial segregation approach was conceptualized, aiming to synthesize an N/S co-doped carbon nanobox hosting an asymmetrically coupled Fe-Co pair-site. This engineered nanostructure manifested remarkable electrocatalytic properties, notably featuring a superb half-wave potential of 0.903 V for the oxygen reduction reaction (ORR) and a commendable overpotential of 0.296 V at 10 mA/cm2 for the oxygen evolution reaction (OER). Additionally, a homemade Zn-air battery incorporating this nanohybrid catalyst demonstrated a discharge capacity of 737 mAh/g, a specific maximum power density of 239 mW/cm2 as well as notable durability. Work-function calculations suggested that the electronic interaction between Fe and Co phases, along with the synergetic catalysis of N/S co-doped carbon substrate, could facilitate charge redistribution at the interface, create abundant active sites, and optimize the adsorption–desorption energy of oxygen species on the active center, thus markedly reducing the ORR/OER catalytic reaction barriers. These findings highlight a new strategy for designing and synthesizing efficient bifunctional carbon-based catalysts for energy storage and conversion devices.

Achieving Solar-Thermal-Electro Integration Evaporator Nine-Grid Array with Asymmetric Strategy for Simultaneous Harvesting Clean Water and Electricity.

Water evaporation is a ubiquitous and spontaneous phase transition process. The utilization of solar-driven interface water evaporation that simultaneously obtains clean water and power generation can effectively alleviate people's concerns about fresh water and energy shortages. However, it remains a great challenge to efficiently integrate the required functions into the same device to reduce the complexity of the system and alleviate its dependence on solar energy to achieve full-time operation. In this work, a multifunctional device based on reduced graphene oxide (RGO)/Mn3 O4 /Al2 O3 composite nanomaterials is realized by an asymmetric strategy for effective solar-thermal-electro integration that can induce power generation by water evaporation in the presence/absence of light. Under one sun irradiation, the solar-driven evaporation rate and output voltage are 1.74kgm-2 h-1 and 0.778V, respectively. More strikingly, the nine-grid evaporation/power generation array integrated with multiple devices in series has the advantages of small volume, large evaporation area, and high power generation, and can light up light-emitting diodes (LEDs), providing the possibility for large-scale production and application. Based on the high photothermal conversion efficiency and power production capacity of the RGO/Mn3 O4 /Al2 O3 composite evaporation/generator, it will be a promising energy conversion device for future sustainable energy development and applications.

Two-dimensional phthalocyanine-based covalent organic frameworks as high-performance electrocatalysts for oxygen reduction and oxygen evolution

It is crucial to use efficient catalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) in energy conversion devices, aiming to mitigate energy crises. The catalytic activity of MPc-PI-COF-1 and MPc-PI-COF-2 (M = Mn, Fe, Co) towards ORR and OER is investigated systematically based on DFT methods. Different M-N4 sites can adjust the binding strength of oxygen-containing intermediates to effect catalysis activity, while the different linkers have only a minor effect. FePc-PI-COF-1 and MnPc-based COFs have low ORR overpotential (ηORR) values, even lower than Pt(111). For OER, CoPc-based COFs have comparable OER overpotential (ηOER) values to that on RuO2(110). To sum up, MnPc-based COFs are efficient ORR catalysts, and CoPc-based COFs have high OER activity. FePc-PI-COF-1 could be served as an effective bifunctional catalyst with a ηORR value of 0.38 V and ηOER value of 0.56 V. Moreover, FePc-PI-COF-1 exhibits exceptional resistance to various impurity gases, indicating its strong tolerance against poisoning. These study offer valuable insights for the rational discovery of reticular materials as highly efficient electrocatalysts.

Refining the chain-branching process in the low-temperature oxidation of 1-hexene with synchrotron-based PEPICO spectroscopy

Understanding the chemical reactions that occur during the low-temperature oxidation of alkenes is crucial for developing advanced energy conversion devices, as alkenes are significant components of realistic fuels. Despite extensive experimental and theoretical studies, the oxidation chemistry of alkenes remains less understood compared to that of alkanes. The present study investigates the low-temperature oxidation of 1-hexene in a jet-stirred reactor, using synchrotron-based PEPICO spectroscopy at a fixed temperature (T = 625 K) and an equivalence ratio (ϕ=0.5). Previous studies in the literature have suggested that the discrepancy between experiments and predictions from kinetic models might be due to the kinetics considered for the chain branching process. The sensitivity of the PEPICO technique to molecular structure allowed for a comprehensive examination of the conformational landscape, facilitating the differentiation of isomers among the main intermediates: hydroperoxides, cyclic ethers, and ketohydroperoxides. Other intermediates and primary products were also quantified and compared to the predictions of a kinetic model from the literature. The results confirm that kinetic models overpredict the formation of hydroxyl ketohydroperoxides and that alkenyl hydroperoxides are the primary chain-branching agents during 1-hexene oxidation. This work underscores the need for a reassessment of the branching ratio between O2-addition and the isomerization of hydroxy alkyl radicals.

Recent Advances in Phosphorene: Structure, Synthesis, and Properties.

Phosphorene is a 2D phosphorus atomic layer arranged in a honeycomb lattice like graphene but with a buckled structure. Since its exfoliation from black phosphorus in 2014, phosphorenehas attracted tremendous research interest both in terms of synthesis and fundamental research, as well as in potential applications. Recently, significant attention in phosphorene is motivated not only by research on its fundamental physical properties as a novel 2D semiconductor material, such as tunable bandgap, strong in-plane anisotropy, and high carrier mobility, but also by the study of its wide range of potential applications, such as electronic, optoelectronic, and spintronic devices, energy conversion and storage devices. However, a lot of avenues remain to be explored including the fundamental properties of phosphorene and its device applications. This review recalls the current state of the art of phosphorene and its derivatives, touching upon topics on structure, synthesis, characterization, properties, stability, and applications. The current needs and future opportunities for phosphorene are also discussed.