Separate Reactions Research Articles

Hydrogen production for the synergistic catalytic of modified-titanium dioxide supported nickel catalyst with potassium carbonate catalyst by supercritical water gasification of coal

Supercritical water gasification (SCWG) is a novel energy utilization technology for converting coal into hydrogen (H2)-rich gas products. Constructing a synergistic catalytic system is crucial for the enhanced production of H2 in the SCWG of coal. This work constructed a novel synergistic catalytic system, Mo, Co, and Cu were employed to modify titanium dioxide-supported nickel (Ni/TiO2) catalysts which were added to separate reaction zones independent with potassium carbonate (K2CO3) to exhibit synergistic effects, thereby enhancing H2 yield. The modification of Ni/TiO2 can improve the stability of the catalyst by causing lattice shrinkage of TiO2, the synergistic catalytic system exerted much higher carbon gasification efficiency (CGE) and H2 yield than the non-catalytic condition in this way. Among all the Ni/TiO2 catalysts, synergistic Ni-Cu/TiO2 with K2CO3, which has the smallest Ni particle size, maximized the CGE and H2 yield from 30.82% and 15.48 mol·kg-1 to 95.43% and 81.42mol·kg-1, respectively. The synergistic catalytic mechanism was further revealed, providing theoretical support for the regulation of hydrogen production from SCWG of coal.

Multi-perspective kinetic analysis of plastic blends under thermogravimetric pyrolysis conditions.

Plastic blends were co-pyrolyzed under non-isothermal conditions in a thermogravimetric (TG) analyzer. The co-pyrolysis characteristics and kinetic triplet, i.e., apparent activation energies, reaction models, and preexponential factors, were investigated from different perspectives, including the overall, weight-loss stage, and overlapping complex reaction deconvolution perspective. Fraser Suzuki (FS) deconvolution was adopted for the peak fitting of the differential TG curves. A model-free method and the master plot theory were used to solve the kinetic equations and fit the reaction mechanism models, respectively. The results indicated that the co-pyrolysis of plastic blends (polyvinyl chloride (PVC)/polypropylene, PVC/polystyrene, PVC/acrylonitrile-butadiene-styrene) could not be adequately described using the overall approach or the weight-loss stage approach. The pyrolysis reaction exhibited a complex multistep overlapping reaction mechanism. FS deconvolution identified and separated four pseudo-reactions from the pyrolysis reaction. The kinetic triplet of the separated reactions was estimated and used to establish kinetic rate equations. Mathematical relations were established between the mass loss rate and pyrolysis temperature. The TG curves of the co-pyrolysis of plastic blends can be parameterized and predicted using the overlapping complex reaction deconvolution model. This study can act as a basis for the development of thermal conversion of mixed plastic waste.

Enhanced Photocatalytic H2 Evolution with Accelerating Surface Reaction via Ru‐Doped NiFe Hydroxide as Cocatalyst

AbstractPhotocatalytic hydrogen evolution via water splitting is considered as one of the most promising sustainable energy supply strategies. The cocatalyst loading method is widely applied to overcome the inefficient charge separation and sluggish surface hydrogen evolution reaction (HER) of photocatalysts. Herein, we prepared the Ru‐doped NiFe layered double hydroxide (NiFe‐LDH) as a cocatalyst for g‐C3N4. We found that the photocatalytic HER activity of g‐C3N4 is obviously enhanced by the loading of Ru‐doped NiFe‐LDH, the H2 evolution rate reaches 32 µmol/h about 5 times higher than original NiFe‐LDH loaded one. Our experimental and theoretical studies reveal that the synergistic effect of NiFe‐LDH matrix and Ru dopant is the key reason for the improved photocatalytic activity, where the NiFe‐LDH matrix promotes charge separation and transfer, the Ru dopant synergistically lowers the energy barrier for surface H2 evolution reaction, then achieving excellent photocatalytic H2 evolution activity.

Specificity of Photochemical Energy Conversion in Photosystem I from the Green Microalga <i>Chlorella ohadii</i>

Primary excitation energy transfer and charge separation reactions in photosystem I (PSI) from the extremophile desert green alga Chlorella ohadii, grown in low light, were studied using broadband femtosecond pump-probe spectroscopy in the spectral range from 400 to 850 nm and in the time range of 50 fs–500 ps. Photochemical reactions were induced by the excitation into the blue and red edges of the chlorophyll Qy absorption band, and compared with similar processes in PSI from the cyanobacterium Synechocystis sp. PCC 6803. When PSI from C. ohadii was excited at a wavelength of 660 nm, the processes of energy redistribution in the light-harvesting antenna of the complex were observed in a time interval of up to 25 ps, while the formation of a stable ion-radical pair P700+A1− was kinetically heterogeneous with characteristic times of 25 and 120 ps. With an alternative variant of excitation into the red edge of the Qy band at a wavelength of 715 nm, in half of the complexes, primary charge separation reactions were observed in the time range of 7 ps. In the rest of the complexes, the formation of the ion-radical pair P700+A1− was limited by energy transfer and occurred with a characteristic time of 70 ps. Similar photochemical reactions in PSI from Synechocystis 6803 were significantly faster: upon excitation at a wavelength of 680 nm, in ~30% of the complexes, the formation of primary ion-radical pairs occurred with a time of 3 ps. Upon excitation at 720 nm, kinetically unresolvable ultrafast primary charge separation was observed in half of the complexes, and the subsequent formation of a P700+A1− ion-radical pair was observed at 25 ps. The photodynamics of PSI from C. ohadii had a noticeable similarity with the processes of excitation energy transfer and charge separation in PSI from the microalga Chlamydomonas reinhardtii; however, in the PSI from C. ohadii slower components in the energy transfer dynamics were also observed.

Recent Strategies of Oxygen Carrier Design in Chemical Looping Processes for Inherent CO2 Capture and Utilization

AbstractChemical looping processes are considered a promising pathway for the efficient production of various fuels and chemicals. Temporally or spatially separated reduction and oxidation reaction in chemical looping can offer various advantages such as enhancing energy efficiency, surpassing equilibrium limitations, and eliminating the need for separation. However, the efficiency of the chemical looping process highly depends on the performance of the oxygen carrier. Higher gas conversion can increase separation efficiency and higher solid conversion can reduce the amount of cycled oxygen carrier. The performance indicators are highly related to the thermodynamic properties of the oxygen carriers and their redox kinetics. This review introduces some key articles and recent achievements for the enhancement of such properties. The different research strategies are discussed for enhancing the performance of stoichiometric and non-stoichiometric oxygen carriers. Through the rational design of oxygen carrier material, an energy-efficient chemical looping process is possible.

The Use of Gel Electrophoresis to Separate Multiplex Polymerase Chain Reaction Amplicons Allows for the Easy Identification and Assessment of the Spread of Toxigenic Clostridioides difficile Strains.

Clostridioides difficile is a common etiological factor of hospital infections, which, in extreme cases, can lead to the death of patients. Most strains belonging to this bacterium species synthesize very dangerous toxins: toxin A (TcdA) and B (TcdB) and binary toxin (CDT). The aim of this study was to assess the suitability of agarose gel electrophoresis separation of multiplex PCR amplicons to investigate the toxinogenic potential of C. difficile strains. Additionally, the frequency of C. difficile toxin genes and the genotypes of toxin-producing strains were determined. Ninety-nine C. difficile strains were used in the detection of the presence of genes encoding all of these toxins using the multiplex PCR method. In 85 (85.9%) strains, the presence of tcdA genes encoding enterotoxin A was detected. In turn, in 66 (66.7%) isolates, the gene encoding toxin B (tcdB) was present. The lowest number of strains tested was positive for genes encoding a binary toxin. Only 31 (31.3%) strains possessed the cdtB gene and 22 (22.2%) contained both genes for the binary toxin subunits (the cdtB and cdtA genes). A relatively large number of the strains tested had genes encoding toxins, whose presence may result in a severe course of disease. Therefore, the accurate diagnosis of patients, including the detection of all known C. difficile toxin genes, is very important. The multiplex PCR method allows for the quick and accurate determination of whether the tested strains of this bacterium contain toxin genes. Agarose gel electrophoresis is a useful tool for visualizing amplification products, allowing one to confirm the presence of specific C. difficile toxin genes as well as investigate their dissemination for epidemiological purposes.

Artificial Photosynthetic Assemblies Constructed by NH2-UiO-66 Decorated with Spatially Separated Dual Cocatalysts for Enhanced Photocatalytic Uranium Reduction.

The phenomenon of rapid migration of photogenerated charges in natural photosynthetic systems has motivated the design of efficient photocatalysts capable of fast charge separation and efficient reaction kinetics for photocatalytically assisted enrichment and separation of uranium U(VI) in uranium wastewater. In this study, we developed a biomimetic photocatalytic system MnOx/NH2-UiO-66-rGO (M/UiO-rGO) with spatially separated dual cocatalysts. Among them, rGO functions to capture electrons and participates in reduction reactions, while MnOx captures holes and participates in oxidation reactions. The M/UiO-rGO catalyst exhibits excellent performance in photocatalytic reduction of uranium (reaching 91.8% in 1 h), and even under natural light conditions, it exhibits excellent uranium removal ability (80.4%). Using multispectral coupling technology, we further confirmed that enriched uranium undergoes a continuous and complex reaction process of "capture-reduction-free radical oxidation-nucleation-crystallization". This work presents a viable strategy for designing biomimetic photocatalysts with efficient charge separation and rapid reaction kinetics for environmental purification purposes.

Electrochemical valorization of dilute reactive nitrogen compounds into ammonia: advances in catalysis and reactive separations.

The global demand for sustainable nitrogen management has brought attention to the challenge of efficiently converting dilute nitrogen compounds, such as nitrates and nitrogen oxides, into valuable ammonia. This review emphasizes on innovative catalyst designs, including homogeneous and heterogenous catalysts tailored to low-concentration reactive nitrogen species. Moreover it explores the integration of advanced separation and concentration techniques, such as electrosorption and dialysis, to overcome mass transport limitations and enable effective electrochemical valorization. This review also examines reactive separation strategies for post-purification, focusing on the integration of recovery processes with catalysis in a direct manner. By detailing these approaches, this work outlines pathways to scalable and energy-efficient solutions for converting waste nitrogen streams into ammonia, addressing critical challenges in nitrogen valorization and offering prospects for industrial applications.

Carbon-dot-induced oxygen vacancies in copper vanadate enabling persulfate photoactivation for tetracycline degradation.

Synchronously creating oxygen vacancies (OVs) and an internal electric field (IEF) in photocatalysts could be an ideal strategy to facilitate photogenerated charge separation and surface reactions but remain unexplored for this use. In this work, we report that low-cost and multifunctional CDs can involve in the nucleation reaction of copper vanadates (CuVs) to create OVs and proper IEF at the interface by modulating the valence states of coppers under hydrothermal conditions. Thus, CDs synergistically serve as oxygen vacancy inducer and charge separator in CuVs to extract photogenerated carriers to trigger persulfate (PS) activation for the degradation of tetracycline hydrochloride (TC). It turns out that CDs-modulated CuVs exhibit the expected photocatalytic capacity to activate PS in water and enable TC decomposition efficiency approximately 8 times higher than CDs-free CuVs under visible light irradiation. Our investigations elucidate that the oxidative breakdown of TC is dominated by the active species cooperation of 1O2 with h+ and OH formed in photocatalytic reaction system.

Synthesis and visible-light photocatalytic performance of Ce-BiVO4/SrTiO3Z-scheme heterojunction for H2 production and organic pollutant degradation

Ce-BiVO4/SrTiO3 (Ce-BVO/STO) Z-scheme heterojunction composites were synthesized through a hydrothermal method to address the dual challenges of the energy crisis and water pollution. The influences of Ce3+ doping in Ce-BVO and the composition ratio of Ce-BVO/STO on the photocatalytic degradation of methylene blue (MB) and water splitting for H2 production were systematically investigated. Notably, the Ce-BVO/STO-1/1 composite exhibited an H2 production capacity as high as 771.3 μmol/g under visible light irradiation for 5 h. Additionally, 96.65 % of MB (10 mg/L) was photodegraded under visible light within 150 min. Furthermore, after three cycles, the Ce-BVO/STO-1/1 composite maintained a stable H2 production yield and MB removal rate, demonstrating its high recyclability for practical application. The Z-scheme heterojunction structure effectively promoted the separation and redox reactions of photogenerated electrons (e-) and holes (h+), and the photoelectrochemical reaction mechanism responsible for the enhanced photocatalytic performance was verified. These findings indicate that the as-prepared Ce-BVO/STO-1/1 composite has significant potential for application in H2 production and pollutant degradation through visible-light-driven photocatalysis.

Reticular Materials for Photocatalysis.

Photocatalysis leverages solar energy to overcome the thermodynamic barrier, enabling efficient chemical reactions under mild conditions. It can greatly reduce reliance on traditional energy sources and has attracted significant research interest. Reticular materials, including metal-organic frameworks (MOFs) and covalent organic frameworks (COFs), represent a class of crystalline materials constructed from molecular building blocks linked by coordination and covalent bonds, respectively. Reticular materials function as heterogeneous catalysts, combining well-defined structures and high tailorability akin to homogeneous catalysts. In this review, the regulation of light absorption, charge separation, and surface reactions in the photocatalytic process through precise molecular-level design based on the features of reticular materials is elaborated. Notably, for MOFsmicroenvironment modulation around catalytic sites affects photocatalytic performance is delved, with emphasis on their unique dynamic and flexible microenvironments. For COFs, the inherent excitonic effects due to their fully organic nature is discussed and highlight the strategies to regulate excitonic effects for charge- and/or energy-transfer-mediated photocatalysis. Finally, the current challenges and future directions in this field, aiming to provide a comprehensive understanding of how reticular materials can be optimized for enhanced photocatalysis is discussed.

Enhancing Photoelectrochemical Water Splitting Efficiency of ZnO P-N Homojunction Nanorod Arrays By Piezotronics and Piezocatalyst

Due to the increasing demand for clean energy sources, hydrogen has received considerable attention due to its high energy density and only water byproduct. Among all the hydrogen generation methods, Photoelectrochemical (PEC) water splitting driven by solar light is promising for green hydrogen production. In this study, the efficiency of ZnO-nanorod arrays-based PEC systems is first enhanced by forming ZnO p-n homojunction via a two-step hydrothermal method with Sb doping, in favor of the separation of photo-generated carriers due to the built-in electric field. Additionally, in the context of piezotronics and piezocatalyst, applying external forces during water splitting could modulate the Schottky barrier height and the width of the depletion region, so that carrier separation and catalytic reaction is further improved. The synergistic effect between the built-in electric field and stress-induced Schottky barrier modulation leads to enhancement in photocurrent. This study provides a facile method for synthesizing ZnO p-n homojunctions and contributes to the improvement of output efficiency in PEC water splitting systems.

Understanding the Activation and Concentration Overpotential of Negative and Positive Electrodes in Vanadium Redox Flow Batteries By Using Symmetric Cell Architecture

Renewable energy, represented by solar and wind energy, has made considerable progress. The vanadium redox flow battery (VRFB) has emerged as the premier option for large-scale energy storage to mitigate the fluctuations inherent in renewable energy sources, thus attracting growing interest [1]. However, the development of VRFB is hindered by their low energy density and current density [2]. Enhancing the electrochemical performance of VRFB is crucial for achieving high energy efficiency [3].In VRFB, the vanadium ions at the negative electrode (NE) are V2+ and V3+, while the vanadium ions at the positive electrode (PE) are VO2+ and VO2 +. In order to improve the electrochemical performance of VRFB, it is necessary to conduct in-depth analysis of the reaction rates of V2+/V3+ and VO2+/VO2 +. In this study, to clearly illustrate the respective reaction rates of different vanadium ions in NE and PE, symmetrical cells were used. Then, four different electrode combinations were used for symmetrical cell experiments (both electrodes were heated, NE was heated/ PE was not heated, PE was heated/NE was not heated, and both electrodes were not heated) to get more information of separated positive and negative reactions. Lastly, to further analyze the effect of vanadium ion concentration on the reaction rate, different state of charges (SOC) were also used, namely 20% SOC and 80% SOC.Fig. 1 showed the IV curves of symmetric cells under different electrode combination conditions. It showed that the overpotentials of negative electrolyte were always higher than those of positive electrolyte under the same electrode conditions, indicating that both the activation and concentration overpotential of the V2+/V3+ reaction were higher than those of the VO2+/VO2 + reaction.Fig. 1 (a) showed that at 20% SOC, the activation overpotential of the V3+ to V2 + reaction was higher than that of the V2+ to V3+ reaction at low current density under the NE not heated condition and PE not heated condition. However, the concentration overpotential of the V2+ to V3+ reaction was higher than that of the V3+ to V2+ reaction at high current density. At 80% SOC, both the activation and concentration overpotentials of the V3+ to V2 + reaction were higher. This was due to the decrease in V3+ concentration as SOC increased from 20% SOC to 80% SOC, resulting in an increase in the concentration overpotential for the V3+ to V2+ reaction.Fig.1 (b) showed that both the activation and concentration overpotentials of VO2 + to VO2+ reaction were higher than those of VO2+ to VO2 + reaction under both not heated conditions. However, the overpotential of the NE not heated condition at 20% SOC was higher than that of the PE not heated condition; but at 80% SOC, the results were opposite. This varaition could be attributed to the change in the concentration of VO2+ and VO2 +ions as SOC increased from 20% to 80%. Specifically, the decease in VO2+ concentration and the increase in VO2 + concentration significantly affected the activation and concentration overpotentials. That is, when the electrode was not heated, for the positive electrolyte, lower ion concentrations led to higher overpotentials.In summary, the experiment results showed that the activation overpotential was ordered as V3+>V2+>VO2 +>VO2+ reaction, and the concentration overpotential as V2+>V3+>VO2 +>VO2+ reaction.AcknowledgementThis work was supported by JSPS KAKENHI Grant Number 21H04540. The first author was supported by the China Scholarship Council.

Process simulation and economic evaluation of the industrial production of triacetin from glycerol: Comparing acetic acid and acetic anhydride as possible reagents

The objective of this work was to simulate, in Aspen HYSYS® v12.1, the process of obtaining triacetin from glycerol through three chemical routes: via acetic acid (Route 1), acetic anhydride (Route 2), and a combination of acetic acid and acetic anhydride in two separate reactors (Route 3). Additionally and as a novelty, it was investigated the technical and economic viability of a multipurpose plant to this end. It was verified that Route 1 resulted in the best triacetin breakeven prices, even though it would still not be competitive in the considered economic context. On the other hand, Route 2 presented the worst performance due to low conversion (11 %) and higher price of acetic anhydride. The combined route resulted in intermediate breakeven prices for triacetin, despite achieving the highest conversion (79 %) and highest final product purity (96 %). Yield/selectivity and the separation steps were identified as the main bottlenecks in these processes, with reactors and distillation columns accounting for more than 95 % of the equipment costs. The multipurpose plant proved technically possible, and it can be economically interesting depending on the market prices for acetic acid and acetic anhydride.

Balancing the Charge Separation and Surface Reaction Dynamics in Twin-Interface Photocatalysts for Solar-to-Hydrogen Production.

Solar-driven photocatalytic green hydrogen (H2) evolution reaction presents a promising route toward solar-to-chemical fuel conversion. However, its efficiency has been hindered by the desynchronization of fast photogenerated charge carriers and slow surface reaction kinetics. This work introduces a paradigm shift in photocatalyst design by focusing on the synchronization of charge transport and surface reactions through the use of twin structures as a unique platform. With CdS twin structure (CdS-T) as a model, the role of twin boundaries in modulating surface reactions and facilitating charge migration is systematically investigated. Utilizing transient absorption (TA) and time-resolved infrared (TRIR) spectroscopies, it is revealed that CdS-T achieves charge separation on a picosecond timescale and, importantly, the surface reaction at the twin boundary with the involvement of holes also occurs within 100ps to 3ns. This synchronization of charge donation and surface regeneration significantly enhances the hydrogen evolution process. Accordingly, CdS-T exhibits superior activity for visible light photocatalytic H2 production, withthe H2 production rate of 55.61mmol h-1 g-1 and remarkable stability (>30h), outperforming pristine CdS significantly. This study underscores the transformative potential of twin structures in photocatalysis, offering a new avenue to synchronize charge transport and surface reactions.

Prolonging Charge Carrier Lifetime via Intraband Defect Levels in S-Scheme Heterojunctions for Artificial Photosynthesis.

S-scheme heterostructure photocatalysts, distinguished by unique charge-transfer pathways and exceptional catalytic redox capabilities, have found widespread applications in addressing challenging chemical processes, including the photocatalytic reduction of CO2 with a high reaction barrier. Nevertheless, the influence of intraband defect levels within S-scheme heterojunctions on charge separation, carrier lifetime, and surface catalytic reactions has, for the most part, been overlooked. Herein, we develop a tunable defect-level-assisted strategy to construct an electron reservoir, effectively prolonging the lifetime of charge carriers through the rapid capture and gradual release of photoelectrons within WO3-x/In2S3 S-scheme heterojunctions, as authenticated by femtosecond transient absorption spectroscopy and theoretical simulations. The surface photoredox mechanism, unraveled by Gibbs free energy calculations, demonstrates that oxygen-vacancy-induced defect states in WO3-x/In2S3 heterojunctions unlock the rate-determining H2O oxidation into free oxygen molecules by forming metastable oxygen intermediates, contributing to the facilitation of H2O photooxidation. This distinct role, combined with the extended carrier lifetime, results in boosted CO2 photoreduction with nearly 100 % CO selectivity in the absence of any photosensitizer or scavenger. Our work sheds light on the role of controllable defect levels in governing charge transfer dynamics within S-scheme heterojunctions, thereby inspiring the development of more advanced photocatalysts for artificial photosynthesis.

Steering diffusion selectivity of chemical isomers within aligned nanochannels of metal-organic framework thin film

The movement of molecules (i.e. diffusion) within angstrom-scale pores of porous materials such as metal-organic frameworks (MOFs) and zeolites is influenced by multiple complex factors that can be challenging to assess and manipulate. Nevertheless, understanding and controlling this diffusion phenomenon is crucial for advancing energy-economic membrane-based chemical separation technologies, as well as for heterogeneous catalysis and sensing applications. Through precise assessment of the factors influencing diffusion within a porous metal-organic framework (MOF) thin film, we have developed a chemical strategy to manipulate and reverse chemical isomer diffusion selectivity. In the process of cognizing the molecular diffusion within oriented, angstrom-scale channels of MOF thin film, we have unveiled a dynamic chemical interaction between the adsorbate (chemical isomers) and the MOF using a combination of kinetic mass uptake experiments and molecular simulation. Leveraging the dynamic chemical interactions, we have reversed the haloalkane (positional) isomer diffusion selectivity, forging a chemical pathway to elevate the overall efficacy of membrane-based chemical separation and selective catalytic reactions.

Developmental Validation of a DIP-InDel/DIP-STR System for the Detection of Unbalanced DNA Mixtures.

Extracting "masked" minor donor information from an unbalanced DNA mixture stain is important for the identification of the person of interest. In recent years, a series of compound markers genotyped based on allele-specific amplifications have been proposed to detect minor contributors of mixed stains. In this study, we selected out 18 DIP-InDel markers from previous literatures and established a multiplex system encompassing 18 DIP-InDel markers and 6 DIP-STR markers in two separate reactions. The allele frequencies were estimated based on 200 samples, and 23 of the 24 DIP-linked length polymorphic markers had a relatively high probability of informative markers (I value >0.267), which indicated their potential usefulness in the Chinese Han population. Moreover, the multiplex was highly sensitive (requiring >0.025ng) and specific to human DNA. This system is capable of detecting the minor contributor comprising 1% in unbalanced mixtures of two individuals. The capacity of profiling cell-free DNA was also analyzed in few cases. At least one paternal allele could be detected in maternal plasma samples with gestation periods ranging from 27 to 40 weeks. To conclude, the DIP-linked length polymorphic markers may serve as a convenient method for detecting the presence of a minor donor in unbalanced mixtures and show promise for noninvasive prenatal diagnosis.

Direct photoelectrochemical detection of ethanol in complex biological sample

The development of advanced photoelectrochemical (PEC) technology for the direct detection of ethanol in complex biological sample, has become a hot topic. However, the photo-active nanomaterials, which could generate the photo-induced carriers under illumination, are susceptible to biofouling and interference in complex bio-matrices. In this work, the silica nanochannel-protected TiO2 nanomaterials was reported for the first time that enables the direct sensing of ethanol in real fruits and untreated whole blood. The modification of SNC enhanced the sensitivity of ethanol detection by promoting light absorption, electron-hole separation, and surface reaction rate of photo-active materials. Meanwhile, the biofouling macromolecules and interference signals can be effectively excluded due to the hydrophilic properties, size, and electrostatic exclusion of nanochannels. As a result, without any complex sample pretreatments, the proposed PEC sensor can be directly immersed in complex biological samples for ethanol detection, exhibiting a broad linear range (1.775 μM-20 mM) and a low detection limit (1.2 μM), as well as excellent reproducibility and stability. This work paves a new path for PEC sensors in real biomedical applications.

Enabling Efficient Oxygen Evolution via Anchoring Carbon-Layer-Confined RuOx on a Well-Matched Substrate.

Oxygen evolution reaction (OER) is a multistep proton-coupled four-electron process with sluggish kinetics, which seriously limits the hydrogen production efficiency, thus it is of great importance to develop an efficient and stable OER catalyst. In this study, a two-step differential pyrolysis strategy is employed to design a three-dimensional porous microstructured material consisting of RuOx nanoparticles coated by a thin-layer carbon, where the active particles were isolated in separate chambers and the RuOx nanoparticles mainly existed in the form of a heterogeneous interface between RuO2 and partial metallic Ru. The preparation parameters of the catalysts are optimized via combining transient and steady-state polarization properties, and the target catalyst Cat-500-1.5t shows the best OER catalytic performance after ca. 60 h of a chronopotentiometry test in an acidic medium with a much smaller performance change than other samples. The unique design of adopting a carbon layer to form separate reaction chambers largely mitigates the excessive oxidation loss of the active components under strong oxidation potential. The suitability of the catalyst with the loaded substrate and test media is explored, and in an acidic medium, the carbon paper is much better than the titanium fiber, while in an alkaline medium, the titanium fiber is obviously superior to the carbon paper. On both carbon paper and titanium fiber, the performance in an alkaline medium outperforms that in an acidic medium, and the possible reasons for the performance difference are analyzed. Herein, to obtain the actual electrocatalytic performance, the optimal design of the catalyst structure and matching suitable conductive substrate in a specific medium are quite necessary, which provides a feasible strategy for the acquisition of efficient and stable electrocatalysts and the desirable presentation of performance.