Higher Reaction Rate Research Articles

Computational Modeling of a 2D Vanadium Redox Flow Battery Cell

These days, the implementation of sustainable power generation has led to a difference in propensity in the energy creation and capacity frameworks, compelling them to conquer the hardships that it addresses. Considering the entirety among the suggested technologies, vanadium redox flow batteries (VRFB) stand out as a wonderful choice regarding cyclability and versatility. The point of this study is to break down electrochemical performance of a vanadium redox flow battery cell in two dimensions. To accomplish this, a two-dimensional model comprising an ion exchange membrane, electrode and flow channel was created. A set of electrode compression and flow rates was tested to envision the impact on the velocity field, species concentration and potential and current distributions. As a result of compression, velocity profiles and reaction rates are both increased, by 12.7% and 9.2%, respectively, when applying 50% compression. Higher reaction rates and more stable concentration gradients were induced by higher electrolyte rates. Additionally, overpotential was reduced by 1.5% with the lowest flow rate.

Numerical Study on the Combustion Properties of Ammonia/DME and Ammonia/DMM Mixtures

Ammonia (NH3) is considered a promising zero-carbon fuel and was extensively studied recently. Mixing high-reactivity oxygenated fuels such as dimethyl ether (DME) or dimethoxymethane (DMM) with ammonia is a realistic approach to overcome the low reactivity of NH3. To study the combustion characteristics of NH3/DMM and NH3/DME mixtures, we constructed a NH3/DMM chemical mechanism and tested its accuracy using measured laminar burning velocity (LBV) and ignition delay time (IDT) of both NH3/DMM and NH3/DME mixtures from the literature. The kinetic analysis of NH3/DMM flames using this mechanism reveals that the CH3 radicals generated from the oxidation of DMM substantially affects the oxidation pathway of NH3 at an early stage of flame propagation. We investigated the formation of nitrogen oxides (NOx) in NH3/DMM and NH3/DME flames and little difference can be found in the NOx emissions. Using NH3/DMM flames as an example, the peak NOx emissions are located at an equivalence ratio (φ) of 0.9 and a DMM fraction of 40% in the conditions studied. Kinetic analysis shows that NOx emission is dominated by NO, which primarily comes from fuel nitrogen of NH3. The addition of DMM at 40% significantly promotes the reactive radical pool (e.g., H, O, and OH) while the maintaining a high concentration of NO precursors (e.g., HNO, NO2, and N2O), which results in a high reaction rate of NO formation reaction and subsequently generates the highest NO emissions.

Experimental investigation of multiple industrial wastes for carbon dioxide removal strategies

Industrial solid waste by-products are being increasingly employed for geochemical carbon dioxide removal (CDR) strategies due to their fine grain size, accessibility, and large annual production tonnages. Here, a range of such by-products has been tested experimentally for their reactivities with CO2 and water. Sample solutions were monitored for 100 h for changes in chemistry, and solid samples were characterised pre- and post-experiment. Samples rich in Ca- and Mg-bearing minerals, such as dunite, kimberlite, and ilmenite mine tailings, as well as marble quarry cuttings, were key cation sources. Ni sulphide, fluorite and borax tailings, coal-fired power plant fly ashes, and red mud samples showed high dissolution rates. The highest reaction rates were often observed during the initial few hours, and compared well to rates determined for rocks typically targeted for CDR purposes, such as basalt and gabbro. Several samples also showed secondary carbonate precipitation, suggesting opportunities for the development of single-step CDR technologies. Overall, the results of this study indicate that several industrial by-products can provide sufficient cations at favourable dissolution rates for geochemical CDR purposes. Any on-site or near-site conditions for reaction acceleration such as heat, concentrated CO2 or microbes, could further increase favourability for geochemical CDR opportunities.

Theoretical Study on the Formation Mechanism of NOx Precursors During the Pyrolysis of 2,4-Imidazolinediketone

ABSTRACT The incineration technology of food waste is one of the effective technologies for achieving waste resource utilization and harmless utilization. As the most fundamental and important stage in the incineration process, it is necessary to conduct detailed research on the pyrolysis mechanism. Therefore, this article selects 2,4-imidazolidinedione as the representative chemical compound for food waste. Study the pyrolysis mechanism of 2,4-imidazolidinedione and the reaction pathway of NOx precursor generation by using density functional theory (DFT) calculation.The possible paths of NH3, HCN and HNCO formation from C-N/C-C bond fracture and C-N bond direct fracture caused by H-transfer are proposed. The formation path of NH3 has low energy barrier and high reaction rate constant at low temperature. At the same time, it explained that the release of HCN increases with the increase of temperature. In addition, this study has also theoretically demonstrated that the reaction path of NH3 is more prone to occur compared to HCN, which finely interprets the yield trend of NH3 and HCN in the experiment.

In-situ oxidation of Sn catalysts for long-term electrochemical CO2 reduction to formate

Electrochemical carbon dioxide (CO2) reduction (ECR) into valuable products such as formate is a compelling approach to managing excessive CO2 emissions. Tin (Sn)-based catalysts have been used for selective CO2 reduction to formate. However, they are often unstable for long-term ECR operation, especially at high reaction rates. In this work, we report highly selective Sn-based catalysts for CO2 reduction to formate at high current densities. The catalysts were prepared by depositing a layer of Sn nanoparticles on the surface of sputtered Ag on a polymer membrane. The catalysts exhibited over 90% Faradaic efficiency toward formate in the current density range of 50–300 mA/cm2 and were stable for over 20 h at a current density of 100 mA/cm2. Characterization of catalysts after ECR reaction reveals significant changes in catalyst morphology during ECR. To extend ECR operation time, we developed an in-situ catalyst regeneration strategy in which the catalysts are periodically oxidized during the reduction reaction. Using this approach, the operation time of Sn-catalysts was extended to more than 150 h with a selectivity over 90%, at the current density of 100 mA/cm2.

Insights into the catalytic performance of LDHs-derived CoAlO oxides with different anions intercalation for propane total oxidation

Constructing effective and stable non-noble metal catalysts is of great significance and prospect for catalytic oxidation of stable light alkanes at low temperature. Herein, the CoAlO oxide catalysts derived from the CoAl layered double hydroxides (LDHs) intercalated with CO32–, CH3COO– (Ac), SO42-, NO3– and citrate (CA) anions were prepared, and their catalytic performances for propane oxidation were investigated. Among all CoAlO catalysts, the CoAlO-Ac-3 catalyst (CH3COO– anion intercalation) exhibited better catalytic activity for propane oxidation (T90 = 300 °C), with the highest reaction rate (2.79 × 10-7 mol g−1 s−1) and TOF value (0.13 × 10-3 s−1) at 240 °C. Characterization results revealed that the interlayer anions affected the valence distribution of metals and surface active oxygen species, and CH3COO– anion intercalation CoAlO-Ac catalyst showed the highest Co3+/Co2+ molar ratio and active oxygen species. Combining with Raman and in-situ DRIFTS results, the lattice distortion of catalyst caused by the interlayer anions promoted the migration of active oxygen species, thus accelerating the propane adsorption and activation. Meanwhile, CoAlO-Ac-3 catalyst exhibited excellent stability and water resistance for propane oxidation.

The reactive flow evolution of the polymer-bonded explosive PBX 9502: Experiments and model validation in extreme pressure regimes

The shock-to-detonation transition properties of the triaminotrinitrobenzene based PBX 9502 high explosive (HE) are experimentally and computationally explored in extremely high input pressure conditions. These include both slightly sub-Chapman–Jouguet and overdriven input pressure conditions, namely, ∼25 and ∼31 GPa, respectively. Our experiments capture the transient buildup of a shock-induced reaction via measurement of HE and polymethyl methacrylate window interface particle velocity profiles for a variety of sample thicknesses for this insensitive HE. These observations necessitate extremely thin explosive samples, and the high rates of reaction provide a considerable challenge to optical diagnostics. Samples at these thicknesses also provide an opportunity for evaluation of potential micro-structure effects on the resulting shock-to-detonation-transition measurements. To address this, the thin samples are also characterized via x-ray micro-computed tomography. Finally, a pair of previously established continuum-level detonation performance modeling approaches for PBX 9502 were used to analyze the experiments. The employed model variants crucially differ in their definition of each model’s empirical reaction rate functional form, utilization of shock state quantities, and local flow variable dependencies. As a result, the present experiments provide a novel platform to evaluate the quantitative and qualitative consequences stemming from these modeling choices in a challenging initiation scenario, largely beyond the chosen calibration range of either model. This new experimental information will provide a platform for both improved physics and model parameterizations for this well-studied explosive.

Polyol grafted thin film nanocomposite membrane: Enhanced pervaporation performance for isopropanol dehydration

Isopropanol is used as a cleaning agents especially in the semiconductor industry. Thus, recycling, and purifying alcohol can reduce the overall cost of production. To improve the separation performance of the thin-film nanocomposite (TFN) membrane, nanozeolite (NZ) was embedded in polyamide layer followed by post-treatment of polyols. The polyamide layer was fabricated through interfacial polymerization of diethylenetriamine (DETA) and trimesoyl chloride (TMC). NZ was dispersed in TMC in order to be embedded on the separation layer. Afterwards, the membrane was simultaneously post-treated using polyols. Different types of polyols were introduced: d-sorbitol (DST), erythritol (ERT), and pentaerythritol (PET). A higher number of hydroxyl groups can provide a denser separation layer. Their chemical structures also affects the reaction rate, where more linear structures (DST and ERT) had better reaction and crosslinking with acyl chloride. High reaction rate of DST gives the roughest surface and high crosslinking degree. Compared to other polyols, Using DST in post-treatment exhibited the highest separation performance. It had a permeation flux of 3,098 g·m−2·h−1 and 99.9 wt% water concentration in permeate (feed = 70 wt% aqueous isopropanol solution at 25℃). Therefore, post-treatment using polyols can further enhance the separation efficiency of TFN membranes with a stable performance over a long period of time.

Dual-function sensor based on NH2-MIL-101(Fe)@Cu/CeO2 nanozyme for colorimetric and fluorescence detection of heavy metals

Heavy metal ions exhibit significant toxicity and pose threats to ecosystems and human health. Therefore, the development of sensitive detection methods is crucial. Nanozyme-based heavy metal sensors have garnered attention, yet existing nanozymes often suffer from low catalytic activity, limited functionality, and unclear mechanisms. To address these issues, this study successfully synthesized an organic-inorganic hybrid nanozyme (NH2-MIL-101(Fe)@Cu/CeO2) using doping and composite techniques, creating a dual-functional sensor. It's worth noting that in NH2-MIL-101(Fe)@Cu/CeO2, copper doping and heterojunction formation may increase oxygen vacancy concentration, promoting electron transfer. Compared to individual components like amino-terephthalic acid iron (III) metal-organic framework (NH2-MIL-101(Fe)) and copper-doped cerium dioxide (Cu/CeO2), this composite material exhibited enhanced peroxidase-like activity (oxidase-like, peroxidase-mimic, catalase-mimic, and superoxide dismutase-mimic). Particularly, NH2-MIL-101(Fe)@Cu/CeO2 displayed outstanding peroxidase-like activity, with Km values of 0.02 mM for TMB and 0.49 mM for H2O2, surpassing most nanozymes, along with high reaction rate (Vmax = 3.82 × 10−5 mM/s). Leveraging NH2-MIL-101(Fe)@Cu/CeO2's peroxidase-like behavior, TMB oxidation turned blue, inhibited by glutathione causing fading. Importantly, Hg2+ complexed with glutathione's thiol group forming GSH-Hg2+, restoring the blue color. Utilizing these properties, a colorimetric sensor for Hg2+ detection was developed. Furthermore, NH2-MIL-101(Fe)@Cu/CeO2 also exhibited remarkable fluorescence performance; Cu2+ binding with amino groups quenched fluorescence. Exploiting this phenomenon, a fluorescent sensor for Cu2+ detection was devised. Results demonstrated this dual-functional sensor's advantages: high sensitivity (LODHg2+ = 0.7 nM, LODCu2+ = 0.1 µM), strong selectivity, wide linear range (0.01 ∼ 4 µM and 8 ∼ 600 µM), and robust stability (90 % activity retained after three cycles).

Combustion of micron-sized Al-Mg alloy wires in hot H2O/O2/N2 flows

The use of aluminum-magnesium (Al-Mg) alloy particle as energetic additive in solid propellants was previously shown to have many advantages over pure Al particle, such as relatively low ignition temperature, high reaction rate and low particle agglomeration rate. In this paper, the combustion of Al-Mg alloy in hot H2O/O2/N2 flows was experimentally studied using wires with a diameter of 200 µm. The employment of wires instead of particles provided a unique opportunity to obtain fundamental insights into the combustion process due to the spatial stabilization and large size of the sample. High-speed imaging showed that the combustion of Al-Mg alloy wire could be divided into three stages, namely pre-heating, ignition, and combustion. Spectral measurements suggested that the chemiluminescence emissions from Mg, MgO and MgOH dominated the collected spectra, in spite of only 3% Mg (by weight) existed in the alloy. Additionally, it was observed that moderate gaseous reactions could occur well before the breakup of the passive oxide coating, generating obvious fine oxide smokes. Moreover, consumption rates of the wire in different hot oxidizers were obtained and compared. It was shown that O2 featured more significant promotion of the reaction than H2O. Nevertheless, without O2, much less metal-oxide particles were generated. Temperature measurements indicated that the ignition temperature lied within 2160 ∼ 2220 K, which was lower than the melting points of Al2O3 (2350 K) and MgO (3125 K). Large single burning Al-Mg alloy droplets (∼200 µm diameter) were generated after the micro-explosion inside the wire. It was found that the combustion of Al-Mg alloy in both H2O/O2/N2 and H2O/N2 atmospheres were diffusion-controlled with a stand-off distance around 150 µm (stand-off ratios at ∼ 1.3). Finally, SEM and EDS measurements revealed that Al, Mg and O elements coexisted on the surface of the burnt wires. Nevertheless, it was observed that the oxidization of Mg started before Al, and the reaction of alloy was more intense when O2 existed. This led to the generation of much thicker oxide layers and larger number of nanoparticles.

Peculiarities of Fe penetration into the matrix of CaCO<sub>3</sub> ± olivine ± serpentine at a pressure of 4 GPa and temperature of 1400-1500°C (experimental data)

Research subject. We present the first results on modeling of the interaction of CaCO3 with metallic Fe in the presence of olivine and serpentine at high P-T parameters in comparison with the CaCO3-Fe system. The relevance of the study is related to the need to study decarbonatization reactions during subduction of crustal matter into the Earth's reduced mantle within the context of the global carbon cycle. Methods. The experiment was carried out using a BARS high-pressure apparatus at a pressure of 4.0 GPa and temperatures of 1400-1500°С with a subsequent study of the obtained samples on a scanning electron microscope equipped with a chemical microanalysis system. Results. CaCO3 was found to be unstable under the implemented conditions. The reaction products were iron carbide and Ca-wustite or Ca-magnesiowustite in the presence of silicate phases. Conclusions. The interaction of CaCO3 with metallic Fe at high pressure occurs even if the components are in the solid state. High reaction rates during interaction are provided by the appearance of liquid metal due to the relatively low melting temperature of the eutectic in Fe-C systems. The influence of gravity on the penetration of Fe into the carbonate matrix, which consists in the predominant infiltration of liquid metal between carbonate grains, was established. The presence of H2O significantly reduces the melting point of carbonate, which leads to an increase in the diffusion of components and decarbonization reaction rate, while the effect of gravity also takes place due to the difference in the density of liquid Fe in comparison with other components in a highly fluidized environment.

Preliminary results from the Australian Genetics of Bipolar Disorder Study: A nation-wide cohort.

The Australian Genetics of Bipolar Disorder Study is a nation-wide cohort of adults living with bipolar disorder. The study aims to detect the relationships between genetic risk, symptom severity, and the lifetime prevalence of bipolar disorder, treatment response and medication side effects, and patterns and costs of health care usage. A total of 6682 participants (68.3% female; aged 44.8 ± 13.6 years [range = 18-90]) were recruited in three waves: a nation-wide media campaign, a mail-out based on prescriptions for lithium carbonate and through the Australian Genetics of Depression Study. Participants completed a self-report questionnaire. A total of 4706 (70%) participants provided a saliva sample and were genotyped and 5506 (82%) consented to record linkage of their Pharmaceutical and Medicare Benefits Schedule data. Most participants were living with bipolar I disorder (n = 4068) while 1622 participants were living with bipolar II disorder and 992 with sub-threshold bipolar disorder. The mean age of bipolar disorder diagnosis was 32.7 ± 11.6 years but was younger in bipolar I (p = 2.0E-26) and females (p = 5.7E-23). Excluding depression with onset prior to bipolar disorder diagnosis, 64.5% of participants reported one or more co-occurring psychiatric disorders: most commonly generalised anxiety disorder (43.5%) and posttraumatic stress disorder (20.7%). Adverse drug reactions were common and resulted in discontinuation rates ranging from 33.4% for lithium to 63.0% for carbamazepine. Our findings highlight the high rate of comorbidities and adverse drug reactions among adults living with bipolar disorder in the general Australian population. Future genomic analyses focus on identifying genetic variants influencing pharmacotherapy treatment response and side effects.

Application of the method of measuring deformation parameters under mechanical action on concrete beams using a fiber Bragg grating

In order to study the patterns of deformation and change of concrete structures, studies of the fiber Bragg lattice in the form of a measuring sensor were carried out. Fiber optic sensors have several advantages: small size, resistance to electromagnetic interference, high sensitivity, wide range, simple structure, high reaction rate, corrosion resistance, geometrically versatile and resistant to external influences. This work is related to the development of the characteristics and behavior of strain sensors acting on a fiber Bragg lattice using computer modeling. The work focuses on the analysis of the operational characteristics and behavior of strain sensors acting on the fiber Bragg lattice. The sensor is used to measure the deformation of an object whose resistance varies depending on the applied force. This is shown by an example of how a fiber Bragg lattice can demonstrate strain sensors. In the work, a simulation was carried out using a computer program to simulate the operation of a fiber Bragg lattice deformation sensor. When measuring the deformation, calculations with the Young's modulus formulas were used for a more accurate calculation of the data. When measured, the wavelength left from 1662 nm to 1666 nm, as well as a constant temperature from 20 °C to 40 °C. The results show the following, the values of the Young's modulus are 23.25 Pa, the Poisson's ratio is 0.167 br, the modulus of elasticity at shear is 9.96444 Pa. And in this regard, the results of this work show: the first is that changes in the magnitude, position and shape of the deformation can reflect the dynamic evolutionary process of deformation during bending on the structure. The following is the deformation curve has a good corresponding relationship with the change in the applied pressure, which shows software modeling in different types of deformation. The conclusion shows that the technology of monitoring fiber-Bragg lattice sensors has a good effect on internal deformation and control of mechanical stresses during model tests; it provides new methods and monitoring tools for model tests

Retrospective study on the association of human herpesvirus reactivation with severe DRESS: A description of blood and skin reactivations.

Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS) is a severe adverse event (mortality of 10%). Its pathophysiology involves herpesviruses, particularly HHV-6, but the exact mechanisms are still poorly understood. To describe severe cases of DRESS and especially their association with herpesvirus reactivation. This study was a multicentre case series conducted between 2007 and 2021 at five University Hospital Centres in France. The study included patients who had severe DRESS, which was defined as death, transfer to the intensive care unit (ICU), or severe damage to internal organs. We excluded patients without blood PCR sample, without a drug formally attributed or with RegiSCAR score < 6. We collected data on severity, causative drug, associated visceral damage and results of viral blood PCRs. HHV-6 reactivation was studied in skin biopsies by detection of small non-coding transcripts (HHV-6 miR-aU14) and a late viral protein (GP82/105). Fifty-two patients were included (29 female, median age 62, interquartile range (IQR) [37;72]). Eight patients (15%) died, 13 (27%) were admitted to ICU. Most patients (n = 34; 65%) had multisystem involvement: most frequent was liver (n = 46; 88%), then renal failure (n = 24; 46%). Forty patients (77%) had at least one blood viral reactivation among HHV-6, EBV or CMV, of which 21 (53%) had at least two. Median time of blood HHV-6 reactivation was 24 days (IQR [20;35]). HHV-6 reactivation was demonstrated in 15 out of 20 skin biopsies, with a median time of 11 days [9;17]. We confirmed the high rate of HHV-6 reactivation in severe DRESS and demonstrated cutaneous HHV-6 reactivation using small non-coding transcripts (HHV-6 miR-aU14), which preceded viral PCR positivity in blood. These results suggest that HHV-6 reactivation during DRESS may start in skin. Furthermore, search for miR-aU14 in skin biopsy could become a useful diagnostic tool for early detection of HHV-6 reactivation.

Metal-Supported Solid Oxide Cells for Energy Conversion, Electrolysis, and Chemical Synthesis

This talk will provide an overview and update of performance, durability, and applications of metal-supported solid oxide fuel cell (MS-SOFC) and electrolysis cell (MS-SOEC) technology developed at Lawrence Berkeley National Laboratory (LBNL). The unique LBNL symmetric cell architecture design, with thin zirconia ceramic backbones and electrolyte sandwiched between porous metal supports, offers a number of advantages over conventional all-ceramic cells, including low-cost structural materials (e.g. stainless steel), mechanical ruggedness, excellent tolerance to redox cycling, and extremely fast start-up capability. These features enable a wide variety of applications including vehicle range extenders, electrolysis for intermittent renewables, personal power generators, and distributed generation.With infiltrated catalysts, the catalyst compositions can be easily tailored to a variety of reactions, without re-optimizing the entire cell. Recent efforts have developed catalysts for internal reforming of natural gas and ethanol, steam electrolysis to produce hydrogen, oxidative coupling of methane to synthesize ethylene, and oxygen generation from air. A recent focus is 1000+ hour continuous operation with detailed post-mortem analysis. Progress on cell performance and durability for each of these applications will be discussed.Infiltrated catalysts, however, present a tradeoff between initial performance and long-term stability. Extremely high surface area promotes high electrochemical reaction rates, but also provides high surface energy leading to coarsening and facilitates Cr deposition. Recent approaches to mitigating catalyst coarsening and Cr deposition within the cathode include coatings to prevent Cr evaporation from the stainless steel components, and optimization of infiltrated catalyst processing to stabilize the microstructure during operation. The metal support structure has also been optimized for improved mass transport.

Computational Modeling of Photo-Electrochemical Reduction of CO2 Utilizing Concentrated Light

Solar energy conversion of water and CO2 into H2/CO by an integrated photo-electrochemical (IPEC) cell and utilizing concentrated solar light allows for high power density and, if carefully designed, delivers high solar-to-fuel efficiency [1], [2]. In such devices, light absorption, charge generation/separation/transport, electrochemical reactions, and mass and ionic transport are required to occur simultaneously. Managing the coupled photon, charge, mass, and heat transport is central to a functioning and stable device. If not carefully designed, challenging operating conditions (high irradiation fluxes, critical thermal management) can induce irreversible damage to the IPEC cell and impact its performance. Thus, the optimal design of a high-performance device is conditioned by the development of a multi-dimensional and multi-physics computational model capable of estimating experimentally inaccessible quantities in complex porous geometries [3]. While such models have already been developed for water splitting, computational modeling of CO2 reduction under concentrated light is still missing.We present an IPEC cell computational model operating under highly concentrated radiation that accounts for both water splitting and CO2 reduction in a zero-gap gas diffusion electrode configuration. The continuum modeling is based on the solution of the coupled conservation and transport equations: species conservation and transport with electrochemical reactions, mass and momentum conservation, conservation and transport of electron and holes in the semiconductors, and Maxwell’s equations for the light propagation and absorption. We quantify spatially resolved non-uniform fields (local temperature, partial current densities, molar species fractions, etc.), inhomogeneities (e.g., local hotspots that could damage sealing), and CO2 conversion rates to demonstrate how such simulations can help to address engineering and operating conditions challenges. Finally, we show that the data obtained in experiments of an IPEC device operating under concentrated light are in agreement with our computational findings.Our simulations reveal that critical thermal management is required to improve IPEC cell efficiency. We provide evidence that challenging operating conditions (high solar irradiation concentration, low mass flow rate) can affect the CO partial current density, favor the competing hydrogen evolution reaction, lead to quartz window failure and decrease the photo-absorber efficiency.Overall, this work provides a validated multi-physics computational model of an IPEC cell operating with concentrated radiation that can be used to conduct feasibility studies and provide design guidelines for such thermally integrated IPEC devices for CO2 reduction at large solar irradiation concentrations. Keywords : Solar fuel, simulation, concentrated light, high power[1] S. Tembhurne, F. Nandjou, S. Haussener, A thermally synergistic photo-electrochemical hydrogen generator operating under concentrated solar irradiation, Nat. Energy. 4 (2019) 399–407. https://doi.org/10.1038/s41560-019-0373-7.[2] E. Boutin, M. Patel, E. Kecsenovity, S. Suter, C. Janáky, S. Haussener, Photo-Electrochemical Conversion of CO2 Under Concentrated Sunlight Enables Combination of High Reaction Rate and Efficiency, Adv. Energy Mater. 12 (2022). https://doi.org/10.1002/aenm.202200585.[3] S. Tembhurne, S. Haussener, Integrated Photo-Electrochemical Solar Fuel Generators under Concentrated Irradiation, J. Electrochem. Soc. 163 (2016) H999–H1007. https://doi.org/10.1149/2.0321610jes.

Important properties of anion exchange resins for efficient removal of PFOS and PFOA from groundwater

Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) present in various water sources have raised a serious concern on their health risk worldwide. Anion exchange is known to be one of the effective treatment methods but the resin properties suitable for theses contaminants have not been fully understood. We examined four commercially available anion exchange resins with different properties (DIAION™ PA312, HPA25M, UBA120, and WA30) and one polymer-based adsorbent (HP20), for their PFOA and PFOS removal in the batch experiment. All or a part of the selected resins were further characterized for their functional group, surface morphology and pore size distribution. The 72 h batch experiment with the 100 mg/L PFOA or PFOS in the laboratory pure water matrix showed a superior capacity of the strong base anion exchange resins, the porous-type HPA25M and PA312, and the gel-type UBA120, for PFOA removal (92.6–97.9%). Among those resins, the high porous HPA25M was suggested most effective due to its remarkably high reaction rate and effectiveness to PFOS (99.9%). In the groundwater matrix, however, the performance of the those anion exchange resins was generally suppressed, causing up to 71% decrease in their removal rates. The least matrix impact was observed for PFOS removal by HPA25M, which indicated the resin's high selectivity to the contaminant. The physiochemical analysis indicated that the presence of relatively large pores (1 nm–10 nm) over HPA25M played an important role in the PFAS removal.

Nanocompartment-confined polymerization in living systems

Polymerization in living systems has become an effective strategy to regulate cell functions and behavior. However, the requirement of high concentrations of monomers, the existence of complicated intracorporal interferences, and the demand for extra external stimulations hinder their further biological applications. Herein, a nanocompartment-confined strategy that provides a confined and secluded environment for monomer enrichment and isolation is developed to achieve high polymerization efficiency, reduce the interference from external environment, and realize broad-spectrum polymerizations in living systems. For exogenous photopolymerization, the light-mediated free-radical polymerization of sodium 4-styrenesulfonate induces a 2.7-fold increase in the reaction rate with the protection of a confined environment. For endogenous hydrogen peroxide-responsive polymerization, p‑aminodiphenylamine hydrochloride embedded in a nanocompartment not only performs a 6.4-fold higher reaction rate than that of free monomers, but also activates an effective second near-infrared photoacoustic imaging-guided photothermal immunotherapy at tumor sites. This nanocompartment-confined strategy breaks the shackles of conventional polymerization, providing a universal platform for in vivo synthesis of polymers with diverse structures and functions.

Transport phenomena of bubble growth coupled with chemical reaction during laser-induced photothermal reduction and deposition processes

Laser assisted low-temperature nano/microfabrication of functional materials on a flexible or rigid substrate using water-based liquid precursor have gained significant attention owing to its high process efficiency and low environment impact. Both of which are essential for the green and low-carbon manufacturing technologies needed for the next generation of electronic devices. Laser induced photo-hydrothermal synthesis (LIPHS) utilizes thermally induced reductive reaction in a liquid precursor to synthesize and deposit nano/micro-patterns on temperature sensitive substrates. During LIPHS, microbubble generation is inevitable as a result of byproduct gas formation and liquid-vapor phase change of the precursor. Transport phenomena of the laser-induced reduction reaction coupled with microbubble dynamics on the liquid-vapor-solid triple contact interface significantly affects the quality of fabricated nano/microstructures. Herein, we investigated microbubble formation and growth on the substrate surface during a LIPHS process for silver on a polyimide substrate surface. Framewise growth of microbubble was captured for different laser powers and solute concentrations to reveal the time dependent bubble diameter variation. It was found that the bubble size and growth rate decreased with increasing solute concentration owing to increased boiling point of the precursor. Bubble temperature and reduction reaction rate were obtained by theoretical analyses on the microbubble growth rate. Transient solid-liquid-vapor triple contact point temperature of the microbubble during the LIPHS process was obtained from a numerical simulation to develop a comprehensive model the first time for predicting the chemical reaction rate. The proposed model was validated experimentally with a relative error of 6.2% at the highest reaction rate.

Insight into the Physicochemical Properties of Co-Based Catalysts in Fischer–Tropsch Synthesis

The effect of the different supports and catalyst-reducing agents on the Fischer–Tropsch (FT) reaction was investigated. The large surface area SiO2 support with a smaller pore volume deposited fine, evenly distributed Co3O4. Cubic-shaped Co3O4 appeared in clusters on the TiO2 support, whereas Co3O4 existed as single large particles on the Al2O3 support. The activity data obtained were discussed in terms of cluster size, particle size, particle shape, and mass transport limitations. The SiO2-supported catalysts showed a higher activity for the formation of paraffinic products when reduced in H2 at 250 °C. This is attributed to the formation of the CoO-Co active bond, which enhanced the activation of CO and the hydrogenation reactions. A higher activity was observed for the TiO2-supported catalyst at a higher reduction temperature (350 °C) when the mass of Co metal was higher. It afforded more paraffinic products due to enhanced secondary hydrogenation of olefins at higher reaction rates. The large Co3O4 supported on Al2O3 showed the least activity at both reduction temperatures due to strong metal-support interactions. The H2-reduced catalysts exhibited superior activity compared to all the syngas-reduced catalysts. Syngas reduction led to surface carbon deposition and the formation of surface carbides which suppressed the hydrogenation reactions and are selective to olefinic products.