Search Results (630)

Nanostructured catalysts have become a core component of energy conversion in electrocatalysis and photocatalysis; however, successfully translating their performance from laboratory scale to industrial applications remains a long-standing challenge. This paper provides a critical assessment of the field, systematically tracing the entire development trajectory from catalyst design to practical application. We focus on five major classes of catalysts—monometallic catalysts, bimetallic/multimetallic alloy catalysts, metal compound catalysts, carbon-based composite catalysts, and single-atom catalysts—and explore synthetic strategies for achieving precise structural control, including hydrothermal/solvothermal methods, electrodeposition, template-assisted and MOF-derived syntheses, high-temperature pyrolysis, and post-treatment defect engineering. This paper delves into the mechanisms and performance descriptors governing the hydrogen evolution reaction (HER), oxygen evolution reaction (OER), oxygen reduction reaction (ORR), urea oxidation, photocatalytic water splitting, and CO₂ reduction. Based on the above analysis, this paper lays the mechanistic foundation for five core strategies to improve catalyst performance: morphology control, elemental doping, heterostructure and interface engineering, defect and vacancy engineering, and support modification. Furthermore, this paper provides an in-depth evaluation of the applications of these catalysts in water splitting, CO₂ valorization, fuel cells, metal–air batteries, and energy-saving electrolysis, with a particular focus on earth-abundant alternatives to precious metals. We argue that in many well-studied reactions, intrinsic activity may no longer be the primary bottleneck restricting their development; instead, the core challenge now lies in maintaining excellent catalytic performance under harsh and industrially relevant conditions, especially under high-current densities, impurity-containing feed systems, and long-term operating conditions. In response to this shift in research focus, this paper clearly identifies the key obstacles hindering the industrial application of catalysts and proposes practical directions for future research. Full article

The increasing worldwide demand for sustainable energy and effective waste management has heightened interest in solutions. Microbial fuel cells (MFCs) represent a potential category of bioelectrochemical systems that directly transform the chemical energy contained in organic waste into electrical energy via the metabolic processes of electroactive microorganisms. In the last twenty years, significant advancements have occurred in the comprehension of extracellular electron transfer (EET) mechanisms, biofilm formation, microbial community dynamics, electrode material engineering, and reactor design, resulting in marked enhancements in power density and wastewater treatment efficacy. Despite these breakthroughs, the extensive deployment and commercialization of MFC technology are constrained by various hurdles, including inadequate energy recovery, elevated material and fabrication expenses, operational instability, and the intricacies of system scale-up. This cutting-edge analysis offers a thorough evaluation of recent advancements in MFCs and their incorporation with sophisticated technology for waste management and energy generation. Focus is directed towards essential bioelectrochemical principles, microbial and biofilm engineering techniques, sophisticated electrode and membrane materials, reactor designs, and hybrid MFC systems integrated with anaerobic digestion, microbial electrolysis, and advanced oxidation methods. Ultimately, emerging trends, significant knowledge deficiencies, and future research goals are defined to inform the advancement of next-generation MFC systems that support circular economy and net-zero energy initiatives. Full article

This paper assesses the role of green hydrogen and green ammonia in the low-carbon reconstruction of Ukraine’s energy sector. The country, severely affected by war, has more than 70% of its energy infrastructure damaged or destroyed, which calls for novel solutions for not only reconstructing but also rethinking Ukraine’s energy sector shaped by the Soviet-era planning. In this context, decentralized and renewable energy solutions appear to be one of the best options to achieve this goal. This study combines four novel and mutually reinforcing methods: a Scopus-based literature review of highly cited green hydrogen publications, natural language processing (NLP) and bibliometric network analysis of Ukraine-related hydrogen research, a SWOT assessment, and a geospatial hydrogen production cost model (GEOH2). The novelty of this research lies in this integrated Ukraine-specific framework, which links research trends, wartime reconstruction constraints, hub-level policy choices, and financing risk-sensitive cost modeling. Therefore, the quantitative part of GEOH2 estimates the levelized cost of green hydrogen, while ammonia is treated as a downstream screening-level conversion and export pathway rather than as a full plant-level ammonia model. Our results show that Ukrainian green hydrogen research is concentrated on renewable-energy strategy, wind and solar electrolysis, water and desalination constraints, gas grid blending, underground storage, ammonia derivatives, and decentralized energy systems. The GEOH2 results indicate that southern Ukraine has strong physical potential for competitive green hydrogen production under de-risked financing, while war risk financing can make even resource-rich areas economically unattractive. Odesa and Dnipro emerge as important export-oriented and industrial hubs, whereas Zakarpattia remains strategically relevant as a safer western corridor linked to European markets. Our findings demonstrate that Ukraine’s hydrogen and ammonia development needs to follow a phased pathway: domestic renewable build-out and grid repair, pilot electrolysis projects and screening-level ammonia conversion pathways, targeted de-risking and insurance mechanisms, and only then broader export corridor development. This pathway can support decarbonization, energy security, industrial modernization, and Ukraine’s long-term integration into European clean energy value chains. Full article

Adiponitrile (ADN) serves as a critical intermediate for manufacturing polyamide 66. Electrochemical hydrodimerization of acrylonitrile (AN) offers a green and sustainable route for ADN production, yet conventional lead plate cathodes still suffer from high cell voltage, insufficient mechanical stability, and lead dust shedding during long-term operation. In this work, we developed a novel composite lead electrode in ambient air to overcome these drawbacks. Key preparation parameters, including calcination temperature, polytetrafluoroethylene (PTFE) content, substrate type, dispersion method, and dispersant dosage, were carefully screened and optimized. The optimal conditions were determined as follows: PTFE mesh as the substrate, 10% PTFE relative to lead powder, mechanical stirring dispersion, 0.5 wt% sodium hexametaphosphate as dispersant, air calcination at 325 °C, and subsequent electrochemical reduction. SEM, XRD, and XPS characterizations showed that the optimized electrode features a three-dimensional porous network assembled from interlaced rod-like and flower-like micro/nanostructures, which greatly elevates the specific surface area, enriches active sites, and facilitates electrolyte penetration and mass transport. After electrochemical reduction, the electrode surface was dominated by catalytically active Pb⁰. Electrochemical tests indicated that the composite electrode delivered a current density of 60–70 mA·cm⁻² at −1.6 to −2.0 V (vs. SCE) for AN reduction, nearly three times higher than that of a conventional lead plate. In addition, the composite electrode showed improved mechanical hardness and completely suppressed lead dust shedding, greatly enhancing operational safety and service life. Stable voltage was maintained during long-term electrolysis. This study provides a low-cost and scalable strategy for fabricating high-performance lead-based composite cathodes, which can support the industrial-scale green electrosynthesis of adiponitrile from acrylonitrile. Full article

Background/Objectives: Fixed orthodontic appliances interfere with oral hygiene and contribute to plaque retention, gingival inflammation and demineralization of enamel. Standard techniques for keeping oral hygiene (tooth brushing, mouthwashes, dental floss, interdental brush, etc.) are not sufficiently effective. The aim of this study was to investigate the effectiveness, safety, tolerability, and influence on quality of life of an electrolysis device being added to standard techniques of oral hygiene in orthodontic patients, compared to standard methods only. Methods: This 6-month study was designed as an observational prospective-cohort investigation. Primary outcomes of the study were indices of gingival inflammation and bleeding, dental plaque indices, the number of white spots on enamel, and safety (incidence of adverse events). Secondary outcomes were quality of life and overall costs of keeping oral hygiene. Results: The addition of the Neo Pill device to standard oral hygiene maintenance measures was associated with improvements in oral health indices after 6 months; however, given the non-randomized, preference-driven design, these findings reflect an association and should not be interpreted as evidence of causal efficacy. After 6 months, the primary outcomes of the study were significantly reduced compared to the application of only standard oral hygiene methods (from 21 to 55% reduction); the quality of life related to oral health was higher (for 14%), the tolerability of maintaining oral hygiene was the same as with standard measures and the costs of maintaining oral hygiene consumables were lower in the Neo Pill group (median difference 30%); however, this figure excludes the acquisition cost of the device itself, which was donated to all participants by the manufacturer, and the 95% confidence interval for this difference includes zero. Conclusions: The addition of an electrolysis device to standard oral hygiene maintenance measures in people wearing fixed orthodontic appliances was associated with improvements in gingival inflammation, papillary bleeding, and dental plaque indices—outcomes measured with established clinical instruments. Apparent reductions in white-spot lesion counts were also observed but should be considered exploratory given the absence of calibrated or blinded lesion assessment. These findings are preliminary and do not establish causal efficacy. Full article

Given its high energy density and environmentally benign nature, hydrogen has emerged as a sustainable alternative to conventional fossil fuels. Consequently, water electrolysis has attracted considerable attention as a hydrogen production method, with the design of efficient and durable catalytic materials representing a crucial research focus. Herein, we design a two-dimensional metal–organic framework (MOF) for hydrogen evolution electrocatalysis using density functional theory calculation. V₃(C₆O₆)₂, Cr₃(C₆O₆)₂ and Co₃(C₆O₆)₂ emerge as potentially viable, meeting dual criteria of thermodynamic stability and optimal catalytic activity. Notably, Cr₃(C₆O₆)₂ demonstrates unexpectedly high hydrogen evolution reaction (HER) activity comparable to Pt-based catalysts, owing to the moderate H-s/Cr-d-orbital hybridization that fine-tunes H binding. The findings provide substantial theoretical guidance for developing advanced electrocatalysts for sustainable hydrogen evolution. Full article

Hydrogen energy, as an important green energy source, is a crucial guarantee for achieving carbon neutrality and peak carbon emission. The anion exchange membrane (AEM) electrolysis cell combines the advantages of alkaline electrolysis cell and proton exchange membrane electrolysis cell and can employ non-precious metal catalysts combined with renewable energy, which is expected to break through the bottleneck of high production cost of green hydrogen. AEM water electrolysis combines the advantages of alkaline and proton exchange membrane water electrolysis for hydrogen production. It has the characteristics of high electrolysis efficiency, fast response rates, and low cost, and its considered one of the most promising renewable green energy hydrogen production technologies at present. AEM is a key component that provides OH^– ion conduction and blocks gas crossover, which directly affects the performance and service life of the AEM electrolysis water system. However, current AEMs face issues of low ion conductivity and poor stability. This review introduces the role of AEM in electrolytic cells, the performance requirements and evaluation parameters that high-performance AEM should meet, and focuses on the transport mechanism and influencing factors of OH^– in AEM. Furthermore, this review provides an overview of the structural composition of AEM, as well as common cationic groups and polymer backbone types. The degradation mechanism of various cationic groups and the characteristics of polymer main chains were elaborated, with a focus on the strategies for designing the stability of cationic functional groups, the methods for modifying and preparing polymer main chains, and the performance of AEMs. Finally, the future challenges and potential research directions of AEM membranes are discussed. It is suggested that high-performance AEMs meeting practical application needs should be developed through strategies such as crosslinking, block copolymerization, side chain grafting, and composite membrane technology, based on the design of alkali-resistant and stable AEM membranes. These insights provide reference and guidance for the further development of AEMs. Full article

The transition toward low-carbon energy systems has intensified interest in sustainable hydrogen production technologies. One of the most promising methods for producing green hydrogen is water electrolysis powered by renewable energy. This work reviews recent advances in electrode materials used in four major electrolysis technologies: alkaline (ALK), proton exchange membrane (PEM), solid oxide electrolysis cells (SOEC), and anion exchange membrane (AEM). A bibliometric analysis of scientific publications from 2021 to 2025 highlights the rapid growth of research and the increasing importance of electrode materials in improving electrolysis performance. Operating environments, material requirements, and catalytic properties are compared across these systems. Recent developments in electrocatalysts—including transition-metal alloys, heterostructured catalysts, defect-engineered materials, and nanostructured systems—are evaluated in terms of catalytic activity, durability, and scalability. Particular attention is given to reducing noble metal usage while maintaining high electrochemical performance. Results indicate that transition-metal-based catalysts and engineered interfaces can achieve activity comparable to noble-metal systems while offering better cost efficiency. However, challenges related to long-term durability, large-scale synthesis, and standardized testing persist. Continued interdisciplinary research in materials design and electrochemical engineering is essential to enable efficient, durable, and cost-effective green hydrogen production. Full article

The selective oxidative transformation of 5-hydroxymethylfurfural (HMF) is a key route toward producing a wide variety of chemicals in the biorefinery industry. Herein, we report a NiAl layered double hydroxide (NiAl-LDH) catalyst as a highly effective electrocatalytic oxidation catalyst for the transformation of HMF into 2,5-diformylfuran (DFF), a valuable furan-based chemical, with about 75.53% DFF selectivity under neutral conditions. It demonstrated good stability without deactivation after 9 cycles of repeated electrolysis. The NiAl-LDH electrocatalyst was deposited on a nickel foam support via a hydrothermal method, and its structural properties and surface morphology were extensively investigated. Systematic studies of reaction temperature, current intensity, and electrolyte concentration revealed that the neutral electrolyte plays a critical role in achieving high DFF selectivity by suppressing aldehyde over-oxidation. Mechanistic investigations with electrochemically active surface area (ECSA), electrochemical impedance spectroscopy (EIS), Tafel slope and density functional theory (DFT) calculations revealed that the reversible transformation between Ni(OH)₂ and active NiOOH species in the NiAl-LDH electrocatalyst was the main reason for the oxidation of HMF, while the incorporation of Al provided structural support to the electrode, enabling the catalyst to exhibit excellent stability during electrolysis. Overall, this work demonstrates an active, earth-abundant metal electrocatalyst for the valorization of biomass-derived 5-HMF to DFF. Full article

Hydrogen energy is an important carrier for achieving China’s “dual carbon” goals, and one of the sources of green hydrogen is to develop better water electrolysis catalysts. This paper reviews the current research status of water electrolysis hydrogen production catalysts, analyzes the role and significance of advanced hydrogen energy catalysts in achieving the “dual carbon” goals, and conducts an in-depth analysis of the difficulties in moving from the laboratory to large-scale application, namely, how to bridge the “four gaps”, including catalyst performance evaluation, long-term application of catalysts, macro-scale preparation, and device integration. It also proposes overall improvement ideas and measures. In this paper, effective improvement methods are proposed for these “four gaps”, which can improve the relevant indicators and service life of water electrolysis hydrogen production catalysts, further promote the large-scale production and industrial application of green hydrogen, and provide a strong guarantee for solving China’s “dual carbon” problems. Full article

Currently, hydrogen has become an indispensable topic when discussing the energy transition. Determining the amount of hydrogen produced or lost through leaks is a critical issue. Recently, with the emergence of the low-cost MQ-8 resistive semiconductor sensor, which is sensitive to hydrogen and responds with an output voltage $V_{out}$, there has been considerable interest in its use in small laboratory experiments. The combination of the volumetric method, the MQ-8 sensor, and the BME280 sensor (for temperature, pressure, and humidity) is of significant interest and has industrial applications. This work presents an in-depth study of the combination of the traditional volumetric method with the MQ-8 and BME sensors. Sensor validation metrics were evaluated to ensure the reliability of the results. The pressure remained approximately constant due to the system configuration. The results indicate that for a current of 1 A, it is possible to determine the approximate volume of hydrogen as a function of the sensor’s output voltage. For low currents ranging from 0.76 to 250 mA, the results indicate that it is possible to determine the approximate hydrogen flow rate as a function of the voltage detected by the sensor. With further investigation, it will be possible to propose the use of MQ-8 and BME280 sensors in environments containing hydrogen. Full article

The 316L stainless steel is widely utilized as structural material in hydrogen production industry due to its excellent combination of corrosion resistance and mechanical properties. However, it remains susceptible to localized pitting corrosion in chloride-containing high-temperature environments. Especially, the main electrolysis byproduct sodium chlorate (NaClO₃) also has complicated effect on pitting corrosion. Therefore, evaluating and predicting the pitting severity grades of 316L steel in NaClO₃ and NaCl environment is essential for controlling operation risks. In recent years, machine learning (ML) methods have gained significant attention in the field of corrosion prediction; however, existing research has primarily focused on the regression prediction of continuous parameters, while studies dedicated to the classification and evaluation of pitting severity grades remain relatively limited. Furthermore, experimental datasets are commonly constrained by small sample sizes and imbalanced class distributions, which hinder the performance enhancement of classification models. Based on experimental pitting data of 316L stainless steel, this study employs ADASYN (Adaptive Synthetic Sampling) to mitigate data imbalance and develops a Feedforward Neural Network (FFNN) for pitting rate classification. The proposed model is compared and analyzed against several commonly used machine learning models. Through a comprehensive evaluation of predictive performance, the feasibility of the developed model in pitting severity grading is verified, thereby providing a novel approach for the predictive evaluation of the pitting corrosion of 316L stainless steel. Full article

Proton exchange membrane water electrolysis (PEMWE) is currently limited by the sluggish kinetics and poor durability of the oxygen evolution reaction (OER). In this work, a structurally uniform IrB_160-4 catalyst was synthesized through a simple, scalable one-pot aqueous method. This template-free method enables near-quantitative yields and gram-scale preparation, with products rapidly separated via simple filtration. The catalyst consists of uniform, nanoclusters self-assembled from highly crystalline ~3 nm Ir nanoparticles. The optimized catalyst exhibits superior OER activity over commercial Ir-Black. The assembled proton exchange membrane electrolyzer, utilizing a low anodic iridium loading of 0.5 mg cm⁻², demonstrates excellent performance (2.0 A cm⁻² @ 1.79 V) and high durability (>1500 h). This synthesis strategy provides a feasible method for achieving efficient and stable PEM water electrolysis for hydrogen production. Full article

A layered bimetallic CoMo-LDH precursor was prepared on nickel foam via a hydrothermal method, and a 3D hierarchical flower-like nanosheet CoMoP/NF electrocatalyst with a crystalline–amorphous heterostructure was constructed in situ through low-temperature phosphidation. The water electrolysis performance was optimized by adjusting the Co/Mo molar ratio. The 3D hierarchical porous structure provides a large specific surface area and abundant active sites, and Mo doping effectively modulates the electronic structure. The catalyst exhibits superior HER performance with overpotentials of only 37 mV and 65 mV at 10 mA·cm⁻² in acidic and alkaline media and shows a lower HER overpotential than commercial Pt/C at current densities above 426 mA·cm⁻² in acidic conditions. Meanwhile, this catalyst delivers an OER overpotential of 729 mV at 500 mA·cm⁻² in alkaline media and can operate stably for 50 h. The assembled two-electrode overall water splitting cell only requires 1.42 V at 10 mA·cm⁻², outperforming Pt/CǁRuO₂ (1.52 V). This work offers a promising strategy for designing low-cost and high-efficiency overall water splitting electrocatalysts for high-current-density applications. Full article

The treatment of high-salinity wastewater generated from the use of sodium hydroxide (NaOH) in rare-earth metallurgy poses significant environmental and resource-recovery challenges. Conventional methods are often economically unfeasible due to their high energy consumption and limited value recovery. To address these limitations, this study proposes an innovative integrated electrochemical process designed not only to desalinate the wastewater efficiently but also to valorize it through the simultaneous co-production of NaOH, chlorine (Cl₂), and hydrogen (H₂). Systematic optimization reveals a critical trade-off between ion transport efficiency and side reactions, with optimal performance achieved at 2 mol L⁻¹ NaCl, 80 mA cm⁻² current density, 2 mm electrode spacing, 30 mL min⁻¹ flow rate, and 5000 mg L⁻¹ initial NaOH concentration. The system maintains exceptional long-term stability, sustaining 97.5% Cl⁻ removal over 4410 min of continuous operation without membrane fouling, a key advantage over conventional processes. Validation with authentic rare earth wastewater achieves 90.3% desalination within 5 h. Techno-economic analysis shows that the market value of recovered NaOH nearly offsets the energy cost, achieving near-cost-neutrality. This work establishes electrolysis–membrane coupling as a technically viable and economically attractive strategy for transforming high-salinity industrial waste streams into valuable resources. Full article