Local reaction environment in electrocatalysis.

Beyond conventional electrocatalyst engineering, recent studies have unveiled the effectiveness of manipulating the local reaction environment in enhancing the performance of electrocatalytic reactions. The general principles and strategies of local environmental engineering for different electrocatalytic processes have been extensively investigated. This review provides a critical appraisal of the recent advancements in local reaction environment engineering, aiming to comprehensively assess this emerging field. It presents the interactions among surface structure, ions distribution and local electric field in relation to the local reaction environment. Useful protocols such as the interfacial reactant concentration, mass transport rate, adsorption/desorption behaviors, and binding energy are in-depth discussed toward modifying the local reaction environment. Meanwhile, electrode physical structures and reaction cell configurations are viable optimization methods in engineering local reaction environments. In combination with operando investigation techniques, we conclude that rational modifications of the local reaction environment can significantly enhance various electrocatalytic processes by optimizing the thermodynamic and kinetic properties of the reaction interface. We also outline future research directions to attain a comprehensive understanding and effective modulation of the local reaction environment.

Heterostructured WOx/W2C Nanocatalyst for Li2S Oxidation in Lithium-Sulfur Batteries with High-Areal-Capacity.

Lithium-sulfur (Li-S) batteries show extraordinary promise as a next-generation battery technology due to their high theoretical energy density and the cost efficiency of sulfur. However, the sluggish reaction kinetics, uncontrolled growth of lithium sulfide (Li2S), and substantial Li2S oxidation barrier cause low sulfur utilization and limited cycle life. Moreover, these drawbacks get exacerbated at high current densities and high sulfur loadings. Here, a heterostructured WOx/W2C nanocatalyst synthesized via ultrafast Joule heating is reported, and the resulting heterointerfaces contribute to enhance electrocatalytic activity for Li2S oxidation, as well as controlled Li2S deposition. The densely distributed nanoparticles provide abundant binding sites for uniform deposition of Li2S. The continuous heterointerfaces favor efficient adsorption and promote charge transfer, thereby reducing the activation barrier for the delithiation of Li2S. These attributes enable Li-S cells to deliver high-rate performance and high areal capacity. This study provides insights into efficient catalyst design for Li2S oxidation under practical cell conditions.

Interfacial Engineering of Zn Metal via a Localized Conjugated Layer for Highly Reversible Aqueous Zinc Ion Battery.

Aqueous zinc-ion batteries are regarded as promising and efficient energy storage systems owing to remarkable safety and satisfactory capacity. Nevertheless, the instability of zinc metal anodes, characterized by issues such as dendrite growth and parasitic side reactions, poses a significant barrier to widespread applications. Herein, we address this challenge by designing a localized conjugated structure comprising a cyclic polyacrylonitrile polymer (CPANZ), induced by a Zn2+-based Lewis acid (zinc trifluoromethylsulfonate) at a temperature of 120 °C. The CPANZ layer on the Zn anode, enriched with appropriate pyridine nitrogen-rich groups (conjugated cyclic -C=N-), exhibits a notable affinity for Zn2+ with ample deposition sites. This zincophilic skeleton not only serves as a protective layer to guide the deposition of Zn2+ but also functions as proton channel blocker, regulating the proton flux to mitigate the hydrogen evolution. Additionally, the strong adhesion strength of the CPANZ layer guarantees its sustained protection to the Zn metal during long-term cycling. As a result, the modified zinc electrode demonstrates long cycle life and high durability in both half-cell and pouch cells. These findings present a feasible approach to designing high performance aqueous anodes by introducing a localized conjugated layer.

High-Performance Alkaline Seawater Electrolysis with Anomalous Chloride Promoted Oxygen Evolution Reaction.

A highly selective and durable oxygen evolution reaction (OER) electrocatalyst is the bottleneck for direct seawater splitting because of side reactions primarily caused by chloride ions (Cl- ). Most studies about OER catalysts in seawater focus on the repulsion of the Cl- to reduce its negative effects. Herein, we demonstrate that the absorption of Cl- on the specific site of a popular OER electrocatalyst, nickel-iron layered double hydroxide (NiFe LDH), does not have a significant negative impact; rather, it is beneficial for its activity and stability enhancement in natural seawater. A set of in situ characterization techniques reveals that the adsorption of Cl- on the desired Fe site suppresses Fe leaching, and creates more OER-active Ni sites, improving the catalyst's long-term stability and activity simultaneously. Therefore, we achieve direct alkaline seawater electrolysis for the very first time on a commercial-scale alkaline electrolyser (AE, 120 cm2 electrode area) using the NiFe LDH anode. The new alkaline seawater electrolyser exhibits a reduction in electricity consumption by 20.7 % compared to the alkaline purified water-based AE using commercial Ni catalyst, achieving excellent durability for 100 h at 200 mA cm-2 .

MXene Analogue: A 2D Nitridene Solid Solution for High-Rate Hydrogen Production.

Electrocatalysts for high-rate hydrogen evolution reaction (HER) are crucial to clean fuel production. Nitrogen-rich 2D transition metal nitride, designated "nitridene", has shown promising HER performance because of its unique physical/chemical properties. However, its synthesis is hindered by the sluggish growth kinetics. Here for the first time using a catalytic molten-salt method, we facilely synthesized a V-Mo bimetallic nitridene solid solution, V0.2 Mo0.8 N1.2 , with tunable electrocatalytic property. The molten-salt synthesis reduces the growth barrier of V0.2 Mo0.8 N1.2 and facilitates V dissolution via a monomer assembly, as confirmed by synchrotron spectroscopy and ex situ electron microscopy. Furthermore, by merging computational simulations, we confirm that the V doping leads to an optimized electronic structure for fast protons coupling to produce hydrogen. These findings offer a quantitative engineering strategy for developing analogues of MXenes for clean energy conversions.

Emerging Two-Dimensional Nanomaterials for Electrocatalysis.

Over the past few decades, the design and development of advanced electrocatalysts for efficient energy conversion technologies have been subjects of extensive study. With the discovery of graphene, two-dimensional (2D) nanomaterials have emerged as some of the most promising candidates for heterogeneous electrocatalysts due to their unique physical, chemical, and electronic properties. Here, we review 2D-nanomaterial-based electrocatalysts for selected electrocatalytic processes. We first discuss the unique advances in 2D electrocatalysts based on different compositions and functions followed by specific design principles. Following this overview, we discuss various 2D electrocatalysts for electrocatalytic processes involved in the water cycle, carbon cycle, and nitrogen cycle from their fundamental conception to their functional application. We place a significant emphasis on different engineering strategies for 2D nanomaterials and the influence these strategies have on intrinsic material performance, such as electronic properties and adsorption energetics. Finally, we feature the opportunities and challenges ahead for 2D nanomaterials as efficient electrocatalysts. By considering theoretical calculations, surface characterization, and electrochemical tests, we describe the fundamental relationships between electronic structure, adsorption energy, and apparent activity for a wide variety of 2D electrocatalysts with the goal of providing a better understanding of these emerging nanomaterials at the atomic level.

2D MoN-VN Heterostructure To Regulate Polysulfides for Highly Efficient Lithium-Sulfur Batteries.

Lithium-sulfur batteries hold promise for next-generation batteries. A problem, however, is rapid capacity fading. Moreover, atomic-level understanding of the chemical interaction between sulfur host and polysulfides is poorly elucidated from a theoretical perspective. Here, a two-dimensional (2D) heterostructured MoN-VN is fabricated and investigated as a new model sulfur host. Theoretical calculations indicate that electronic structure of MoN can be tailored by incorporation of V. This leads to enhanced polysulfides adsorption. Additionally, in situ synchrotron X-ray diffraction and electrochemical measurements reveal effective regulation and utilization of the polysulfides in the MoN-VN. The MoN-VN-based lithium-sulfur batteries have a capacity of 708 mA h g-1 at 2 C and a capacity decay as low as 0.068 % per cycle during 500 cycles with sulfur loading of 3.0 mg cm-2 .

Total arsenic and speciation analysis of saliva and urine samples from individuals living in a chronic arsenicosis area in China.

BACKGROUND: It is generally acknowledged that the determination of harmful chemical compounds excreted into saliva is useful for assessing their exposure levels. The aim of the present study was to compare the total arsenic and its species in saliva and urine samples collected from the people residing in an arsenic-contaminated area of China and to further verify the feasibility of using salivary arsenic as a new biomarker of arsenic exposure. METHODS: Total arsenic and speciation analyses in urine and saliva samples among 70 residents exposed to arsenic from drinking water in Shanxi, China were carried out by high-performance liquid chromatography-inductively coupled plasma-mass spectrometry (HPLC-ICP/MS). RESULTS: The result showed that, total arsenic concentration in saliva was relatively lower than in urine samples, but it existed a strong positive correlation with total urinary arsenic, drinking water arsenic and different skin lesions. For arsenic metabolism analyses, AsIII, AsV, MMA, and DMA were detected in all of the urine samples with the dominating species of DMA (73.2%). Different with urinary arsenic species, most arsenic species in saliva were not methylated. The major species in saliva was iAs (AsIII + AsV, 76.18%), followed by DMA (13.08%) and MMA (9.13%). And the primary methylation index (PMI), second methylation index (SMI) and proportion of the four different species (AsIII, AsV, MMA, and DMA) in saliva showed no significant positive relationship with that of in urine. CONCLUSIONS: These findings indicated saliva may be used as a useful tool for biological monitoring of total arsenic exposure in the crowd rather than an efficient tool for assessing arsenic metabolism in human body after exposed to arsenic.

A Bamboo-Inspired Nanostructure Design for Flexible, Foldable, and Twistable Energy Storage Devices.

Flexible energy storage devices are critical components for emerging flexible electronics. Electrode design is key in the development of all-solid-state supercapacitors with superior electrochemical performances and mechanical durability. Herein, we propose a bamboo-like graphitic carbon nanofiber with a well-balanced macro-, meso-, and microporosity, enabling excellent mechanical flexibility, foldability, and electrochemical performances. Our design is inspired by the structure of bamboos, where a periodic distribution of interior holes along the length and graded pore structure at the cross section not only enhance their stability under different mechanical deformation conditions but also provide a high surface area accessible to the electrolyte and low ion-transport resistance. The prepared nanofiber network electrode recovers its initial state easily after 3-folded manipulation. The mechanically robust membrane is explored as a free-standing electrode for a flexible all-solid-state supercapacitor. Without the need for extra support, the volumetric energy and power densities based on the whole device are greatly improved compared to the state-of-the-art devices. Even under continuous dynamic operations of forceful bending (90°) and twisting (180°), the as-designed device still exhibits stable electrochemical performances with 100% capacitance retention. Such a unique supercapacitor holds great promise for high-performance flexible electronics.

NNK-induced DNA methyltransferase 1 in lung tumorigenesis in A/J mice and inhibitory effects of (-)-epigallocatechin-3-gallate.

DNA methyltransferase 1 (DNMT1), a key enzyme mediating DNA methylation, is known to be elevated in various cancers, including the mouse lung tumors induced by the tobacco-specific carcinogen 4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). However, it is not known whether DNMT1 expression is induced right after NNK treatment and how DNMT1 expression varies throughout lung tumorigenesis. In the present study, we found that administration of NNK to A/J mice caused elevation of DNMT1 in bronchial epithelial cells at Days 1, 3, and 14 after NNK treatment. DNMT1 elevation at Day 1 was accompanied by an increase in phospho-histone H2AX (γ-H2AX) and phospho-AKT (p-AKT). At Weeks 5 to 20, NNK-induced DNMT1 in lung tissues was in lower levels than the early stages, but was highly elevated in lung tumors at Week 20. In addition, the early induction of p-AKT and γ-H2AX as well as cleaved caspase-3 in NNK-treated lung tissues was not detected at Weeks 5 to 20 but was elevated in lung tumors. In concordance with DNMT1 elevation, promoter hypermethylation of tumor suppressor genes Cdh13, Prdm2, and Runx3 was observed in lung tissues at Day 3 and in lung tumors. Treatment by EGCG attenuated DNMT1, p-AKT, and γ-H2AX inductions at Days 1 and 3 and inhibited lung tumorigenesis.

Aqueous manganese dioxide ink for paper-based capacitive energy storage devices.

We report a simple approach based on a chemical reduction method to synthesize aqueous inorganic ink comprised of hexagonal MnO2 nanosheets. The MnO2 ink exhibits long-term stability and continuous thin films can be formed on various substrates without using any binder. To obtain a flexible electrode for capacitive energy storage, the MnO2 ink was printed onto commercially available A4 paper pretreated with multiwalled carbon nanotubes. The electrode exhibited a maximum specific capacitance of 1035 F g(-1) (91.7 mF cm(-2)). Paper-based symmetric and asymmetric capacitors were assembled, which gave a maximum specific energy density of 25.3 Wh kg(-1) and a power density of 81 kW kg(-1). The device could maintain a 98.9% capacitance retention over 10 000 cycles at 4 A g(-1). The MnO2 ink could be a versatile candidate for large-scale production of flexible and printable electronic devices for energy storage and conversion.

[Application of silk fibroin in biomedical areas].

For a long period of time, silk fibroin has been applied in biomedical areas. Along with the development of biotechnology, new functions of silk fibroin are being found and developed. From the suture of surgery to the therapeutic drug and the ordinary tissue engineering frame to high grade frame with drug buffer system, exploitation of silk fibroin is constantly introduced with something new from the old ones. In our review, we summarize the applications of silk fibroin in tissue engineering, drug buffer system and medical care.

Recent Advances in Electrocatalytic Hydrogenation Reactions on Copper-Based Catalysts.

Hydrogenation reactions play a critical role in the synthesis of value-added products within the chemical industry. Electrocatalytic hydrogenation (ECH) using water as the hydrogen source has emerged as an alternative to conventional thermocatalytic processes for sustainable and decentralized chemical synthesis under mild conditions. Among the various ECH catalysts, copper-based (Cu-based) nanomaterials are promising candidates due to their earth-abundance, unique electronic structure, versatility, and high activity/selectivity. Herein, recent advances in the application of Cu-based catalysts in ECH reactions for the upgrading of valuable chemicals are systematically analyzed. The unique properties of Cu-based catalysts in ECH are initially introduced, followed by design strategies to enhance their activity and selectivity. Then, typical ECH reactions on Cu-based catalysts are presented in detail, including carbon dioxide reduction for multicarbon generation, alkyne-to-alkene conversion, selective aldehyde conversion, ammonia production from nitrogen-containing substances, and amine production from organic nitrogen compounds. In these catalysts, the role of catalyst composition and nanostructures toward different products is focused. The co-hydrogenation of two substrates (e.g., CO2 and NOx n, SO3 2-, etc.) via C─N, C─S, and C─C cross-coupling reactions are also highlighted. Finally, the critical issues and future perspectives of Cu-catalyzed ECH are proposed to accelerate the rational development of next-generation catalysts.

Advanced Microwave Strategies Facilitate Structural Engineering for Efficient Electrocatalysis.

In the dynamic realm of energy conversion, the demand for efficient electrocatalysis has surged due to the urgent need to seamlessly integrate renewable energy. Traditional electrocatalyst preparation faces challenges like poor controllability, elevated costs, and stringent operational conditions. The introduction of microwave strategies represents a transformative shift, offering rapid response, high-temperature energy, and superior controllability. Notably, non-liquid-phase advanced microwave technology holds promise for introducing novel models and discoveries compared to traditional liquid-phase microwave methods. This review examines the nuanced applications of microwave technology in electrocatalyst structural engineering, emphasizing its pivotal role in the energy paradigm and addressing challenges in conventional methods. The ensuing discussion explores the profound impact of advanced microwave strategies on electrocatalyst structural engineering, highlighting discernible advantages in optimizing performance. Various applications of advanced microwave techniques in electrocatalysis are comprehensively discussed, providing a forward-looking perspective on their untapped potential to propel transformative strides in renewable energy research. It provides a forward-looking perspective, delving into the untapped potential of microwaves to propel transformative strides in renewable energy research.

High Entropy Alloys Enable Durable and Efficient Lithium-Mediated CO2 Redox Reactions.

Designing electrocatalysts with high activity and durability for multistep reduction and oxidation reactions is challenging. High-entropy alloys (HEAs) are intriguing due to their tunable geometric and electronic structure through entropy effects. However, understanding the origin of their exceptional performance and identifying active centers is hindered by the diverse microenvironment in HEAs. Herein, NiFeCoCuRu HEAs designed with an average diameter of 2.17 nm, featuring different adsorption capacities for various reactants and intermediates in Li-mediated CO2 redox reactions, are introduced. The electronegativity-dependent nature of NiFeCoCuRu HEAs induces significant charge redistribution, shifting the d-band center closer to Fermi level and forming highly active clusters of Ru, Co, and Ni for Li-based compounds adsorptions. This lowers energy barriers and simultaneously stabilizes *LiCO2 and LiCO3+CO intermediates, enhancing the efficiency of both CO2 reduction and Li2CO3 decomposition over extended periods. This work provides insights into specific active site interactions with intermediates, highlighting the potential of HEAs as promising catalysts for intricate CO2 redox reactions.

Acidic CO2-to-HCOOH electrolysis with industrial-level current on phase engineered tin sulfide.

Acidic CO2-to-HCOOH electrolysis represents a sustainable route for value-added CO2 transformations. However, competing hydrogen evolution reaction (HER) in acid remains a great challenge for selective CO2-to-HCOOH production, especially in industrial-level current densities. Main group metal sulfides derived S-doped metals have demonstrated enhanced CO2-to-HCOOH selectivity in alkaline and neutral media by suppressing HER and tuning CO2 reduction intermediates. Yet stabilizing these derived sulfur dopants on metal surfaces at large reductive potentials for industrial-level HCOOH production is still challenging in acidic medium. Herein, we report a phase-engineered tin sulfide pre-catalyst (π-SnS) with uniform rhombic dodecahedron structure that can derive metallic Sn catalyst with stabilized sulfur dopants for selective acidic CO2-to-HCOOH electrolysis at industrial-level current densities. In situ characterizations and theoretical calculations reveal the π-SnS has stronger intrinsic Sn-S binding strength than the conventional phase, facilitating the stabilization of residual sulfur species in the Sn subsurface. These dopants effectively modulate the CO2RR intermediates coverage in acidic medium by enhancing *OCHO intermediate adsorption and weakening *H binding. As a result, the derived catalyst (Sn(S)-H) demonstrates significantly high Faradaic efficiency (92.15 %) and carbon efficiency (36.43 %) to HCOOH at industrial current densities (up to -1 A cm-2) in acidic medium.

Emerging materials and technologies for electrocatalytic seawater splitting.

The limited availability of freshwater in renewable energy-rich areas has led to the exploration of seawater electrolysis for green hydrogen production. However, the complex composition of seawater presents substantial challenges such as electrode corrosion and electrolyzer failure, calling into question the technological and economic feasibility of direct seawater splitting. Despite many efforts, a comprehensive overview and analysis of seawater electrolysis, including electrochemical fundamentals, materials, and technologies of recent breakthroughs, is still lacking. In this review, we systematically examine recent advances in electrocatalytic seawater splitting and critically evaluate the obstacles to optimizing water supply, materials, and devices for stable hydrogen production from seawater. We demonstrate that robust materials and innovative technologies, especially selective catalysts and high-performance devices, are critical for efficient seawater electrolysis. We then outline and discuss future directions that could advance the techno-economic feasibility of this emerging field, providing a roadmap toward the design and commercialization of materials that can enable efficient, cost-effective, and sustainable seawater electrolysis.

IrOx·nH2O with lattice water-assisted oxygen exchange for high-performance proton exchange membrane water electrolyzers.

The trade-off between activity and stability of oxygen evolution reaction (OER) catalysts in proton exchange membrane water electrolyzer (PEMWE) is challenging. Crystalline IrO2 displays good stability but exhibits poor activity; amorphous IrOx exhibits outstanding activity while sacrificing stability. Here, we combine the advantages of these two materials via a lattice water-incorporated iridium oxide (IrOx·nH2O) that has short-range ordered structure of hollandite-like framework. We confirm that IrOx·nH2O exhibits boosted activity and ultrahigh stability of >5700 hours (~8 months) with a record-high stability number of 1.9 × 107 noxygen nIr-1. We evidence that lattice water is active oxygen species in sustainable and rapid oxygen exchange. The lattice water-assisted modified OER mechanism contributes to improved activity and concurrent stability with no apparent structural degradation, which is different to the conventional adsorbate evolution mechanism and lattice oxygen mechanism. We demonstrate that a high-performance PEMWE with IrOx·nH2O as anode electrocatalyst delivers a cell voltage of 1.77 V at 1 A cm-2 for 600 hours (60°C).

Dynamic rhenium dopant boosts ruthenium oxide for durable oxygen evolution.

Heteroatom-doping is a practical means to boost RuO2 for acidic oxygen evolution reaction (OER). However, a major drawback is conventional dopants have static electron redistribution. Here, we report that Re dopants in Re0.06Ru0.94O2 undergo a dynamic electron accepting-donating that adaptively boosts activity and stability, which is different from conventional dopants with static dopant electron redistribution. We show Re dopants during OER, (1) accept electrons at the on-site potential to activate Ru site, and (2) donate electrons back at large overpotential and prevent Ru dissolution. We confirm via in situ characterizations and first-principle computation that the dynamic electron-interaction between Re and Ru facilitates the adsorbate evolution mechanism and lowers adsorption energies for oxygen intermediates to boost activity and stability of Re0.06Ru0.94O2. We demonstrate a high mass activity of 500 A gcata.-1 (7811 A gRe-Ru-1) and a high stability number of S-number = 4.0 × 106 noxygen nRu-1 to outperform most electrocatalysts. We conclude that dynamic dopants can be used to boost activity and stability of active sites and therefore guide the design of adaptive electrocatalysts for clean energy conversions.

[Comparison of the total arsenic concentration between saliva and blood after oral administration of sodium arsenite to rats].

OBJECTIVE: To compare the total arsenic concentration between blood and saliva after oral administration of sodium arsenite to SD rats. METHODS: A single oral gavage dose of sodium arsenite (20mg/kg) was administrated to 21 adult male Sprague-Dawley rats. Then collected blood and saliva samples at 0, 1-2, 4-5, 7-8, 11-12, 17-18, 23-24 hour for total arsenic detection. The blood samples were detected for total arsenic concentration by Atomic Fluorescence Spectrometry (AFS-230) and the salivary arsenic were detected by inductively coupled plasma mass spectrometry (ICP-MS). RESULTS: After intake of 20 mg/kg BW sodium arsenite, the total arsenic concentration in blood of SD rats was increased rapidly, and reached the peak value at the 1-2 hour, then descended gradually. However, there was a second peak value at the 7-8 hour. The upward trend of salivary arsenic was more slowly than blood arsenic, and reached the peak value at the 7-8 hour, then descended gradually. The variation tendency of salivary arsenic and blood arsenic with time were basically the same. Besides, there was an obvious positive association between them, the correlation coefficient was 0.678, P < 0.01. CONCLUSION: The excretion of arsenic in saliva was slower than that of blood samples after administrated a single oral gavage dose of sodium arsenite (20 mg/kg) to SD rate, but the metabolism mode of arsenic in saliva was similar with that in blood, suggested that salivary arsenic can also well reflect the exposure level of arsenic in the body.