Method For Synthesis Research Articles

Full-scale insight into high-entropy ceramics from basic concepts, synthesis technologies, structural characteristics, and properties to application prospects

High-entropy ceramics (HECs) are an emerging material system that has gained significant attention and become a focal point of research due to their unique structure and outstanding performance. This paper provides a comprehensive examination of the basic concepts, synthesis methods, structural characteristics, unique properties, and application prospects of HECs. It begins with an overview of the basic concepts and historical context, followed by a detailed comparison of synthesis techniques, including both traditional and innovative approaches. The paper then analyzes the structural characteristics and phase compositions of HECs, particularly focusing on oxide, carbide, boride, and other non-oxide ceramics. In addition, it delves into the mechanical, thermal, electrical, and magnetic properties of HECs. The article also reviews the applications of HECs in high-temperature structural materials, functional materials, high-performance coatings, and biomedical implants. Finally, it discusses the future challenges and development pathways for HECs. By highlighting new applications and transformative possibilities, this study not only sheds light on cutting-edge research but also emphasizes the significant impact of HECs on sustainable material development. The integration of machine learning and artificial intelligence can further unlock the unique structural capabilities of HECs, offering substantial potential for advancements in emerging fields like new energy and biomedicine.

From β-Carotene to Retinoids: A Review of Microbial Production of Vitamin A.

Vitamin A (retinoids) is crucial for human health, with significant demand across the food, pharmaceutical, and animal feed industries. Currently, the market primarily relies on chemical synthesis and natural extraction methods, which face challenges such as low synthesis efficiency and complex extraction processes. Advances in synthetic biology have enabled vitamin A biosynthesis using microbial cell factories, offering a promising and sustainable solution to meet the increasing market demands. This review introduces the key enzymes involved in the biosynthesis of vitamin A from β-carotene, evaluates achievements in vitamin A production using various microbial hosts, and summarizes strategies for optimizing vitamin A biosynthesis. Additionally, we outline the remaining challenges and propose future directions for the biotechnological production of vitamin A.

Adversarial Sample Synthesis for Visual Question Answering

Language prior is a major block to improving the generalization of visual question answering (VQA) models. Recent work has revealed that synthesizing extra training samples to balance training sets is a promising way to alleviate language priors. However, most existing methods synthesize extra samples in a manner independent of training processes, which neglect the fact that the language priors memorized by VQA models are changing during training, resulting in insufficient synthesized samples. In this paper, we propose an adversarial sample synthesis method, which synthesizes different adversarial samples by adversarial masking at different training epochs to cope with the changing memorized language priors. The basic idea behind our method is to use adversarial masking to synthesize adversarial samples that will cause the model to make wrong answers. To this end, we design a generative module to carry out adversarial masking by attacking the VQA model, and introduce a bias-oriented objective to supervise the training of the generative module. We couple the sample synthesis with the training process of the VQA model, which ensures that the synthesized samples at different training epochs are beneficial to the VQA model. We incorporated the proposed method into three VQA models including UpDn, LMH and LXMERT, and conducted experiments on three datasets including VQA-CP v1, VQA-CP v2 and VQA v2. Experimental results demonstrate that a large improvement of our method, such as 16.22% gains on LXMERT in the overall accuracy of VQA-CP v2.

In situ-grown nitrogen-sulfur co-doped carbon nanotubes encapsulated with FeS particles as cathode materials for zinc-air batteries

Transition metal sulfides as ideal oxygen reduction reaction (ORR) catalysts have great potential to regulate multiple reaction pathways and understand their corresponding internal reaction mechanisms at cathode in zinc-air batteries (ZABS), effectively. This work adopted a facile one-pot synthesis method based on chemical vapor deposition (CVD), which utilizes the synergistic effect of zeolite imidazolium ester skeleton (ZIF-8) and polypyrrole (PPY) to grow nitrogen-sulfur co-doped carbon nanotubes (NS-CNT) in the shape of colonic with a relatively uniform size and encapsulated with FeS nanoparticles as the main active sites. The synthesized purpose catalyst noted as FeS-NS-CNT-900, in which that the FeS nanoparticles were tightly encapsulated in carbon nanotubes, and this special structure ensures that the FeS particles do not detach during the reaction, thus greatly enhancing their electrochemical activity and stability. As expected, the FeS-NS-CNT-900 catalyst exhibited a half-wave potential of 0.877 V which is higher than that of commercial platinum charcoal (0.847 V), at 0.1 mol KOH. More importantly, the formation of abundant FeS catalytic active sites, the optimal conditions for NS-CNT growth, and the covered mechanisms of the enhanced ORR reaction activity of FeS-NS-CNT-900 were thoroughly investigated. Additionally, whileFeS-NS-CNT-900 was used as an air cathode material for the assembly of a zinc-air battery, it exhibited a peak power density and specific capacity of 123 mW cm−2 and 785.81 mA h g−1, respectively, which were significantly better than that of platinum-carbon cathode (92.8 mW cm−2 and 740.4 mA h g−1). And surprisingly, the battery with FeS-NS-CNT-900 cathode exhibited (delivered/showed) a high cycle stability of 260 h at 5 mA cm−2. Conclusively, present work provides a feasible method for in situ growth of sulfur and nitrogen co-doped carbon nanotube encapsulated transition metal sulfide nanoparticle catalysts, which may pave a new avenue for the preparation of high ORR performance air cathode material for ZABS.

FEATURES OF MARKETING ACTIVITIES ON THE BOOK MARKET OF UKRAINE

Goal. elucidation of the role and features of marketing activities in the book market of Ukraine. Achieving the goal will be facilitated by the achievement of the following tasks: 1) identification of factors influencing the behavior of consumers of book products; 2) disclosure of key aspects of marketing activity in the book market of Ukraine; 3) establishment of directions for increasing the effectiveness of marketing activities on buyers in the book market. Method. Methods of systematic and comparative analysis were used to identify factors influencing consumer behavior. The methods of analysis, synthesis and comparative analysis were used to reveal the marketing activity in the book market of Ukraine and to study the factors and the degree of their influence on the behavior of the buyer in the book market. Methods of synthesis and generalization were used to establish directions for improving the effectiveness of marketing activities on buyers in the book market. The results. The main aspects of the marketing activities of publishers and book distributors on the Ukrainian book market are outlined, the toolkit of the marketing mix used by market entities is highlighted, which made it possible to formulate the key areas of increasing the effectiveness of marketing activities for sellers of book products, which include: the need for market research; production of a quality marketing book; increasing the number of bookstores; application of merchandising and other methods of maximizing sales; improvement of the personnel policy due to the selection of personnel, systematic improvement of the qualifications of employees; implementation of logical pricing, use of price incentives; provision of activities for the popularization of reading and promotion of book products; development of effective state support measures for book publishing. Scientific novelty. Conducting a theoretical and practical analysis of the use of marketing mix tools in the book market of Ukraine and developed recommendations for increasing the effectiveness of marketing activities in the publishing industry. Practical significance. The results of the analysis are suitable for use in the development of effective marketing programs of Ukrainian book publishers and sellers of book products.

ORGANIZATIONAL AND ECONOMIC MECHANISMS FOR ADDRESSING WAR-INDUCED ENVIRONMENTAL ISSUES IN EUROPEAN POST-WAR CONTEXTS

Abstract: The article focuses on the development of organizational and economic mechanisms for addressing environmental problems caused by war in European post-war contexts and the implementation of the germinative development concept in these conditions. The tools for mitigating the negative environmental impact on business entities are identified. Overall, the article employs innovative approaches to effective management of environmental, resource-based, and germinative factors of economic development. The strengths and weaknesses of each approach are identified, and the appropriateness of their application to specific factors is demonstrated. Methodology: The study employs logical and dialectical methods; methods of synthesis, comparison, grouping, generalization of the systemic approach, as well as expert evaluation, questionnaires, planning, forecasting, and mathematical modeling methods. Scientific Novelty: A mechanism for managing the factors of ecological and resource influence on business activities is proposed, which ensures the efficiency of implemented innovations and the coordination of both material resources and financial flows, based on modeling these processes. Scientific approaches to their formation and post-conflict management tools are proposed, based on process modeling to ensure the stable functioning of business entities in post-war conditions, in accordance with EU requirements and standards.

Investigating the broom-like inclusions in type Ib diamond single crystal synthesized by high pressure high temperature

The exceptional properties of diamonds enable diverse applications. However, the applications are significantly hindered by its inclusions. In this study, a specific type of inclusion, broom-like inclusions, has been investigated. The broom-like inclusions in diamonds were synthesized through various high-pressure high-temperature (HPHT) experiments. The synthesis methods were optimized by adjusting the metal catalyst composition, synthesis temperature, Mg(OH)2 content, and nitrogen getter (Ti). The broom-like inclusion morphology and composition were physically characterized and analyzed using various methods. Optical microscopy and SEM were utilized to characterize the morphology and shape of the inclusions, while Raman spectroscopy and Fourier Transform Infrared Spectroscopy were employed to analyze the influence of the defects on the properties of diamonds and investigate the composition of the broom-like inclusions. Gaseous inclusions emerged as crucial for broom-like inclusion formation. They probably originated from residual gases like H2 and CH4. The investigation of broom-like inclusions within diamond crystals has led to the development of various synthetic methods for producing inclusion-free crystals. The findings of this study offer valuable insights into the nature and origin of these inclusions in diamonds, as well as provide strategies to mitigate their formation during production.

The external assurance of ESG reports in Poland on the example of companies from the WIG20 index

Purpose: The article identifies the basic practices that audit companies use when auditing ESG reports in Poland after 2017. Methodology/approach: The study covered 120 ESG reports published by companies included in the WIG20 index between 2017 and 2022. The first stage of the research involved selecting companies from the research sample whose reports were externally audited. The second stage involved analyzing the contents of the assurance reports. The article also used bibliometric analysis, a critical literature review, comparative analysis, and induction and synthesis methods. Findings: The empirical research shows that out of 120 sustainability reports, only 36 were externally audited. A detailed analysis allowed the identification of audit firms’ basic practices: (1) the most common reference is to a report from an independent assurance service with limited certainty, (2) half of the reports were prepared by the “Big Four”, (3) all reports followed the International Standard for Assurance Services 3000, (4) the most common subject of the audits was GRI indicators, which were listed exhaustively in the report.Research limitations/implications: The research was conducted on a relatively small sample – only companies from the WIG20 index; additionally, the time scope of the research only covered reports from 2017–2022.Originality/value: The article contributes to the Polish literature on the subject but also has practical significance. The results of the empirical study indicate that audit reports are created with a large degree of freedom, which may negatively affect their cognitive value and comparability.

THEORETICAL AND METHODOLOGICAL PRINCIPLES OF PERSONNEL MANAGEMENT IN THE ASPECT OF RISK MANAGEMENT

The purpose of the article is to study the theoretical and methodological aspects of personnel management risks and the specifics of developing their management strategies in the context of modern dynamic business conditions. The work highlights the key aspects of personnel risks, methods of their analysis, methods of management and regulation, and gives practical recommendations for managers and managers. Method. To achieve the goal, the methods of analysis and synthesis, comparison, etc. are applied. The results. The theoretical aspects of risk management with human capital are studied. Analyzed and systematized methods aimed at reducing the impact of personnel risks on the productivity and stability of the enterprise. The result of the application of such strategies is an increase in the efficiency of personnel management, a reduction in the probability of problems, and the optimization of work processes. Scientific novelty. The article offers a comprehensive view of risk management in the context of personnel management. The use of modern methods of risk analysis and management allows in-depth solving of problems arising in personnel management and the development of effective strategies for their elimination, taking into account today's conditions. Practical significance. The results of the research can be useful for leaders and managers in the field of personnel management, contributing to the stability and efficiency of the organization. The considered strategies and methods can help to implement practical management solutions with the aim of reducing personnel risks and increasing labor productivity.

METHODOLOGICAL APPROACHES TO THE ECONOMIC ASSESSMENT OF THE INNOVATIVE ACTIVITIES OF RAILWAY TRANSPORT

Objective. Justification of the need to improve the economic assessment of the innovative activity of railway transport, the development of methodological approaches and practical recommendations for the assessment of the innovative activity of railway transport, the study of requirements and assessment indicators characterizing the results of the implementation of innovations. Methods. Various methods and approaches were used in the process of performing the tasks in this work. The abstract-logical method was used to determine the research objectives. Analytical and monographic approach was used in the analysis of literary sources. The method of data analysis and synthesis for the analysis of existing methodological approaches and indicators. A comprehensive review and strategic analysis to describe promising directions for the innovative development of railway transport. Systemic, analogical, and structural-functional research methods for determining indicators of economic evaluation of innovative activity. Results. The article examines the main methodological approaches and proposes a new approach to the economic assessment of innovative activity. Scientific novelty. Recommendations on the use of an additional system of indicators for evaluating the innovative activity of railway transport are given. Practical significance. The recommendations given in the article regarding the use of the indicator system can be applied in railway transport units to make a decision on the introduction of innovations.

GENESIS OF THE CONCEPT OF «GOODWILL»

Goal. The problem of defining the essence of goodwill lies in its complex and multifaceted nature. Goodwill formation occurs constantly, but as a fully-fledged accounting object, disclosed in consolidated financial statements, it arises during business combinations. Various stakeholders have subjective perceptions of goodwill, complicating its definition, evaluation, and accounting. The relevance and purpose of the research lie in the necessity of formulating a comprehensive approach to understanding the essence of goodwill, considering its etymology, analysis of domestic and foreign contemporary and historical sources, existing approaches to interpretation, and highlighting key categories. Method. The research utilized methods of systemic analysis, synthesis, comparison, systematization, analogy, and generalization. Results. The global economy witnesses an increase in the value of intangible assets and goodwill. The change in the dominance of approaches to understanding the essence of goodwill, analysis, and systematization of existing sources allowed identifying that for the current stage of development of this concept, the recognition of its complexity and diversity is characteristic. This necessitates the identification of key components of goodwill, analyzing their role in business value management, brand value enhancement, and capital accumulation. The main focus is on using goodwill to measure consumer trust, shape the company's reputation, and assess its performance. The proposed comprehensive definition of goodwill as a special intangible asset that reflects the added value of the business, potential for future income generation, shaped by the interaction of components such as reputation, brand, recognition, image, corporate style, customer loyalty, corporate culture, technological advantages, customer base, trade secrets, know-how, research, development, innovation, patents, licenses, copyrights, government grants, partnerships, competencies, managerial qualities, social and environmental responsibility, collectively providing business with competitive advantages, investment attractiveness, and contributing to its successful operation. The proposed definition will most fully account for the key components of goodwill expression and generation, helping to comprehensively understand its essence and positively impact the market capitalization of the business. Practical significance. Correct understanding of goodwill is important for accurate assessment, completeness of disclosure in consolidated financial statements, and for effective management and justification of investor decisions.

Facile synthesis of novel acidic modified magnetic graphene oxide and its application in the green synthesis of pyrimido[4,5-b]quinolines

This study aimed to create an innovative acidic nano catalyst capable of producing pyrimido[4,5-b]quinolines under environmentally friendly conditions. To achieve this objective, 1,3-benzenedisulfonyl amide (BDSA) was immobilized onto the surface of magnetic graphene oxide (GO/Fe3O4@PTRMS@BDSA@SO3H), and its surface was acidified using chlorosulfonic acid. The synthesized catalyst's structure was thoroughly examined and verified through various analyses, including FTIR, EDX, elemental mapping, FESEM, XRD, TGA, and DSC. This novel nano catalyst exhibited exceptional activity and selectivity in synthesizing pyrimido[4,5-b]quinoline derivatives under solvent-free conditions, at low temperatures, and with high efficiency. Its catalytic effectiveness stemmed from features such as easy and eco-friendly synthesis methods, abundant accessible catalytic sites, a high surface area, remarkable selectivity, and facile separation from the reaction medium. Additionally, the catalyst proved to be cost-effective, safe, scalable, and reusable for up to four times.

KSCN molten salt synthesis of hierarchical MoS2/NPC for rapid and durable sodium storage

MoS2 boasts high capacity but often encounters issues such as poor electrical conductivity, limited cycling stability due to volume expansion, and polysulfide shuttling when applied as the anode in sodium-ion batteries (SIBs). To this end researchers have developed MoS2/carbon composites, which enhance electronic conductivity, ion diffusion, and structural stability. Herein, we develop a new synthesis method using a KSCN molten salt to produce hierarchical MoS2 on nitrogen and phosphorus co-doped carbon (NPC). The molten KSCN acts both as the sulfur source and the reaction medium, facilitating the creation of hierarchical MoS2 structures with a high loading of 85.8 wt%. These structures optimize ion diffusion channels and enhance electrochemical reaction kinetics. Additionally, the NPC framework improves electron transport and reduces polysulfide shuttling. With its superior structural stability and accelerated electrode kinetics, MoS2/NPC exhibits an impressive rate capacity of 468 mAh g−1 at 10 A g−1 and maintains a long lifespan of 1300 cycles at 2 A g−1. Moreover, full cells equipped with a NaNi1/3Fe1/3Mn1/3O2 cathode retain 98 % capacity retention after 400 cycles. This study presents a promising approach for fabricating advanced MoS2/carbon anodes with dedicate nanostructures for SIBs.

The role of spectral matching in enhancing photocatalytic performance with TiO2-rGO catalysts for metronidazole wastewater elimination

The role of spectral matching in enhancing the photocatalytic degradation of metronidazole using TiO2-reduced graphene oxide (TiO2-rGO) systems is investigated in this study. A rapid, one-step microwave synthesis method was utilized to produce TiO2-rGO composites with varying proportions of graphene oxide. Characterization techniques, including X-ray diffraction (XRD), Raman spectroscopy, and transmission electron microscopy (TEM), were employed to elucidate the morphological and structural attributes of the photocatalysts, thereby facilitating their application in photocatalysis. Spectral matching between the photocatalytic material and the irradiation source was identified as critical to the methodology. Experiments conducted under LED light tailored to the absorption spectra of the catalysts demonstrated that the TiO2-rGO system with a 2 % GO composition achieved the highest metronidazole degradation efficiency, reaching 95 % degradation after 120 min of irradiation. Furthermore, the catalyst maintained high reusability, with only a 5 % decrease in efficiency after five cycles of reuse. The Electrical Energy per Order (EEO) was determined to be 3.51 kWh/m3, indicating the system’s high energy efficiency. The study emphasizes the real-world applicability of TiO2-rGO composites for wastewater treatment, particularly in terms of environmental sustainability and operational cost-effectiveness.

Machine Learning Enables Reliable Colorimetric Detection of pH and Glucose in Wearable Sweat Sensors

AbstractIn healthcare, blood pH and glucose levels are critical indicators, especially for chronic conditions like diabetes. Although taking blood samples is accurate, it is invasive and unaffordable for many. Wearable sensors offer non‐invasive and continuous detection methods, yet face major challenges, such as high cost, inaccuracies, and complex interpretation. Colorimetric wearable sensors integrated with machine learning (ML) are introduced for accurately detecting pH values and glucose concentrations in sweat. These battery‐free and cost‐effective biosensors, made of cotton textiles, are designed to work seamlessly with smartphones for data collection and automated analysis. A new pH indicator is synthesized with enhanced sensitivity and two types of glucose sensors are developed by depositing enzymatic solutions onto cotton substrates. The sensors' performance is assessed using standard solutions with known pH levels ranging from 4 to 10 and glucose concentrations between 0.03 to 1 mm. The photos captured from these sensors are then analyzed by image processing and three different ML algorithms, achieving an accuracy of 90% in pH and glucose detection. These findings provide effective synthesis methods for textile‐based sweat sensors and demonstrate the significance of employing different ML algorithms for their colorimetric analysis, thus eliminating the need for human intervention in the process.

One-Step-Modified Biochar by Natural Anatase for Eco-Friendly Cr (VI) Removal

The global serious pollution situation urgently needs green, efficient, and sustainable development methods to achieve heavy metal pollution control. The photocatalytic properties of anatase are sufficient to achieve pollution control by providing photoelectrons to harmful heavy metals. However, since natural anatase particles tend to agglomerate and deactivate in water, most studies have been conducted to prepare TiO2–biochar nanocomposites using chemical synthesis methods. In the present study, we utilized pyrolytic sintering to load natural anatase onto biochar to obtain natural anatase–biochar (TBC) composites. Characterization tests, such as X-ray diffraction (XRD), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS), showed that anatase was uniformly partitioned into the surface and pores of biochar without destroying the lattice structure. Due to its photocatalytic properties, TBC degraded Cr (VI) by 99.63% under light conditions. This is 1.58 times higher than the dark condition. Zeta potential showed that the surface of the TBC was positively charged under acidic conditions. The charge attraction between TBC and chromium salt was involved in the efficient degradation of Cr (VI). Different sacrificial agents as well as gas purge experiments demonstrated that photoelectrons (e−) and superoxide radicals (O2−) dominated the degradation of Cr (VI). TBC has the characteristics of high efficiency, stability, and sustainability. This may provide a new idea for the preparation of photocatalytic materials and the realization of environmental protection and sustainable development through heavy metal pollution control.

Black titanium oxide: synthesis, modification, characterization, physiochemical properties, and emerging applications for energy conversion and storage, and environmental sustainability.

Since its advent in 2011, black titanium oxide (B-TiOx) has garnered significant attention due to its exceptional optical characteristics, notably its enhanced absorption spectrum ranging from 200 to 2000 nm, in stark contrast to its unmodified counterpart. The escalating urgency to address global climate change has spurred intensified research into this material for sustainable hydrogen production through thermal, photocatalytic, electrocatalytic, or hybrid water-splitting techniques. The rapid advancements in this dynamic field necessitate a comprehensive update. In this review, we endeavor to provide a detailed examination and forward-looking insights into the captivating attributes, synthesis methods, modifications, and characterizations of B-TiOx, as well as a nuanced understanding of its physicochemical properties. We place particular emphasis on the potential integration of B-TiOx into solar and electrochemical energy systems, highlighting its applications in green hydrogen generation, CO2 reduction, and supercapacitor technology, among others. Recent breakthroughs in the structure-property relationship of B-TiOx and its applications, grounded in both theoretical and empirical studies, are underscored. Additionally, we will address the challenges of scaling up B-TiOx production, its long-term stability, and economic viability to align with ambitious future objectives.

Comparative Studies of Benzimidazoles Synthetic Routes and its Biological Activity

<p> Benzimidazole, discovered in 1872, is a heterocyclic compound noted for its pharmacological activities. It and its derivatives can be synthesized through methods such as condensation reactions and using nano-based nanoparticles as catalysts. Recent environmentally friendly methods include microwaves, ultrasound, and photochemical reactions. its derivatives are known for their diverse medicinal applications </p> <p> Benzimidazole and its derivatives are versatile compounds with a wide range of pharmacological activities. Their synthesis has evolved over time, incorporating various environmentally friendly methods such as microwave, ultrasound, and photochemical reactions. The continued exploration of these compounds and their synthesis methods holds great promise for the development of new and effective medicinal applications. </p> <p> Here, we provide an overview of benzimidazole, highlighting its historical significance, various synthesis methods, and extensive range of pharmacological activities. It aims to emphasize the importance of benzimidazole and its derivatives in medicinal chemistry and their potential therapeutic applications. The review also notes the development of environmentally friendly synthesis techniques, reflecting advancements in the field.</p>

Porous Silicon-Supported Catalytic Materials for Energy Conversion and Storage.

Porous silicon (Si) has a tetrahedral structure similar to that of sp3- hybridized carbon atoms in a typical diamond structure, which affords it unique chemical and physical properties including an adjustable intrinsic bandgap, a high-speed carrier transfer efficiency. It has shown great potential in photocatalysis, rechargeable batteries, solar cells, detectors, and electrocatalysis. This review introduces various porous Si-supported electrocatalysts and analyzes the reasons why porous Si is used as a new carrier/active sites from the perspectives of its molecular structure, electronic properties, synthesis methods, etc. The electrochemical applications of porous Si-based electrocatalysts in energy conversion reactions such as hydrogen evolution reaction, oxygen evolution reaction, oxygen reduction reaction, and total water decomposition together with lithium-ion batteries (LIBs) and supercapacitors in energy storage are summarized. The challenges and future research directions for porous Si are also discussed. This review aims to deepen the understanding of porous Si and promote the development and applications of this new type of Si material.

Design and regulation of defective electrocatalysts.

Electrocatalysts are the key components of electrochemical energy storage and conversion devices. High performance electrocatalysts can effectively reduce the energy barrier of the chemical reactions, thereby improving the conversion efficiency of energy devices. The electrocatalytic reaction mainly experiences adsorption and desorption of molecules (reactants, intermediates and products) on a catalyst surface, accompanied by charge transfer processes. Therefore, surface control of electrocatalysts plays a pivotal role in catalyst design and optimization. In recent years, many studies have revealed that the rational design and regulation of a defect structure can result in rearrangement of the atomic structure on the catalyst surface, thereby efficaciously promoting the electrocatalytic performance. However, the relationship between defects and catalytic properties still remains to be understood. In this review, the types of defects, synthesis methods and characterization techniques are comprehensively summarized, and then the intrinsic relationship between defects and electrocatalytic performance is discussed. Moreover, the application and development of defects are reviewed in detail. Finally, the challenges existing in defective electrocatalysts are summarized and prospected, and the future research direction is also suggested. We hope that this review will provide some principal guidance and reference for researchers engaged in defect and catalysis research, better help researchers understand the research status and development trends in the field of defects and catalysis, and expand the application of high-performance defective electrocatalysts to the field of electrocatalytic engineering.