Web application fingerprint recognition is an effective security technology designed to identify and classify web applications,thereby enhancing the detection of potential threats and attacks.Traditional fingerprint r...Web application fingerprint recognition is an effective security technology designed to identify and classify web applications,thereby enhancing the detection of potential threats and attacks.Traditional fingerprint recognition methods,which rely on preannotated feature matching,face inherent limitations due to the ever-evolving nature and diverse landscape of web applications.In response to these challenges,this work proposes an innovative web application fingerprint recognition method founded on clustering techniques.The method involves extensive data collection from the Tranco List,employing adjusted feature selection built upon Wappalyzer and noise reduction through truncated SVD dimensionality reduction.The core of the methodology lies in the application of the unsupervised OPTICS clustering algorithm,eliminating the need for preannotated labels.By transforming web applications into feature vectors and leveraging clustering algorithms,our approach accurately categorizes diverse web applications,providing comprehensive and precise fingerprint recognition.The experimental results,which are obtained on a dataset featuring various web application types,affirm the efficacy of the method,demonstrating its ability to achieve high accuracy and broad coverage.This novel approach not only distinguishes between different web application types effectively but also demonstrates superiority in terms of classification accuracy and coverage,offering a robust solution to the challenges of web application fingerprint recognition.展开更多
N-doped carbon materials,with their applications as electrocatalysts for the oxygen reduction reaction(ORR),have been extensively studied.However,a negletcted fact is that the operating potential of the ORR is higher ...N-doped carbon materials,with their applications as electrocatalysts for the oxygen reduction reaction(ORR),have been extensively studied.However,a negletcted fact is that the operating potential of the ORR is higher than the theoretical oxida-tion potential of carbon,possibly leading to the oxidation of carbon materials.Consequently,the infl uence of the structural oxidation evolution on ORR performance and the real active sites are not clear.In this study,we discover a two-step oxida-tion process of N-doped carbon during the ORR.The fi rst oxidation process is caused by the applied potential and bubbling oxygen during the ORR,leading to the oxidative dissolution of N and the formation of abundant oxygen-containing functional groups.This oxidation process also converts the reaction path from the four-electron(4e)ORR to the two-electron(2e)ORR.Subsequently,the enhanced 2e ORR generates oxidative H_(2)O_(2),which initiates the second stage of oxidation to some newly formed oxygen-containing functional groups,such as quinones to dicarboxyls,further diversifying the oxygen-containing functional groups and making carboxyl groups as the dominant species.We also reveal the synergistic eff ect of multiple oxygen-containing functional groups by providing additional opportunities to access active sites with optimized adsorption of OOH*,thus leading to high effi ciency and durability in electrocatalytic H_(2)O_(2) production.展开更多
Electrochemical water splitting,as a promising method for hydrogen production,has attracted significant attention.However,the lack of an electrocatalyst with a small energy loss and fast reaction kinetics has hindered...Electrochemical water splitting,as a promising method for hydrogen production,has attracted significant attention.However,the lack of an electrocatalyst with a small energy loss and fast reaction kinetics has hindered the development of this technology.Amorphous nanomaterials with short-range order and long-range disorder features have recently shown superior activity compared to their crystalline counterparts in water electrolysis.The enhanced activity arising from their intrinsic disordered structure results in more active sites and a higher intrinsic activity of such sites.In this regard,this review is aimed at summarizing the progress in amorphous electrocatalysts for water splitting.First,the synthesis strategies for amorphous electrocatalysts are discussed.Characterization tools for amorphous nanomaterials are then summarized.Moreover,the origin of the enhanced activity and stability of amorphous nanomaterials is analyzed.Finally,the current challenges and promising opportunities in this research area are discussed.This review aims to provide a guide for designing and developing amorphous nanomaterials with a fascinating electrocatalytic water splitting performance.展开更多
Highly selective electrocatalytic semihydrogenation of alkynes to alkenes with water as the hydrogen source over palladium-based electrocatalysts is significant but remains a great challenge because of the excessive h...Highly selective electrocatalytic semihydrogenation of alkynes to alkenes with water as the hydrogen source over palladium-based electrocatalysts is significant but remains a great challenge because of the excessive hydrogenation capacity of palladium.Here,we propose that an ideal palladium catalyst should possess weak alkene adsorption and inhibit subsurface hydrogen formation to stimulate the high selectivity of alkyne semihydrogenation.Therefore,sulfur-modified Pd nanowires(Pd-S NWs)are designedly prepared by a solid-solution interface sulfuration method with KSCN as the sulfur source.The introduction of S weakens the alkene adsorption and prevents the diffusion of active hydrogen(H^(*))into the Pd lattice to form unfavorable subsurface H^(*).As a result,electrocatalytic alkyne semihydrogenation is achieved over a Pd-S NWs cathode with wide substrate scopes,potential-independent up to 99%alkene selectivity,good fragile groups compatibility,and easily synthesized deuterated alkenes.An adsorbed hydrogen addition mechanism of this semihydrogenation reaction is proposed.Importantly,an easy modification of commercial Pd/C by in situ addition of SCN–enabling the gram-scale synthesis of an alkene with 99%selectivity and 95%conversion highlights the promising potential of our method.展开更多
Uncovering the structure evolution and real active species of energy catalytic materials under reaction conditions is important for both understanding structure-activity relationship and constructing electrocatalysts ...Uncovering the structure evolution and real active species of energy catalytic materials under reaction conditions is important for both understanding structure-activity relationship and constructing electrocatalysts for CO2 electroreduction(CO2ER).And integrating CO2ER with an anodic organic transformation to replace the oxygen evolution reaction is highly desirable.Here,In2O3 is selected as the model material to reveal the surface reconstruction under CO2ER condition.In situ and ex situ results reveal that the electrochemical in situ reconstruction of crystalline In2O3 leads to the formation of crystalline-In/amorphous In2O3-x heterostructure(In/In2O3-x).In/In2O3-xacts as the real active phase with Faradaic efficiency of^89.2%for the formate,outperforming In(~67.5%).The improved performance can be ascribed to electron-rich In rectified by Schottky effect of In2O3-xheterostructure.Impressively,formate and high-value octanenitrile can be simultaneously achieved by integrating CO2ER with octylamine oxidation in an In2O3-x||Ni2P two-electrode electrolyzer.展开更多
Syngas,a mixture of CO and H2 with a specific ratio,is of great necessity for the industrial production of olefins,liquid fuels,polymers,and drugs[1-4].Currently,syngas is mainly acquired under harsh conditions from t...Syngas,a mixture of CO and H2 with a specific ratio,is of great necessity for the industrial production of olefins,liquid fuels,polymers,and drugs[1-4].Currently,syngas is mainly acquired under harsh conditions from the ga-sification of solid coal and petroleum coke,as well as the steam reforming of natural gas[5,6],which accelerate the energy crisis and aggravate CO2 emission.展开更多
Understanding and manipulating synthetic progress for precisely controlling the components and defects of nanomaterials is an important and challenging task in materials synthesis and nanocatalysis.Metal phosphides(MP...Understanding and manipulating synthetic progress for precisely controlling the components and defects of nanomaterials is an important and challenging task in materials synthesis and nanocatalysis.Metal phosphides(MPs)have been explored as cheap advanced materials in various catalytic fields.MP materials are usually synthesized through gas-solid phosphorization reaction in a trial-to-error manner,but their formation mechanism and the origin of controlled synthesis remain unclear.Here,we combine in situ thermogravimetrc analysis-mass spectrometry(TG-MS)and quasi-in situ X-ray powder diffraction(XRD)analysis to probe the transformation mechanism from metal oxides(MOs)to MPs during the phosphorization process mediated by hypophosphite.Temperature,time,and the amount of hypophosphite are revealed as the driven forces while oxophilicity and crystallinity as the impeded forces,simultaneously control the component and defect level of a series of MP(M=Ni,Co,W,Mo,and Nb).The as-obtained WO2.9/WP is proved to be an efficient Z-scheme photocatalyst for oxidative coupling of methane with the total C2+production and C2H4 selectivity in C2+products reaching 10.75 pmolg-1 and 98.25%.Our work provides a fundamental understanding of the phosphorization treatment and thereby guides a viable synthetic route to the controlled synthesis of MOx-δ,MP,MOx-δ/MP,and MP/M heterostructured materials.展开更多
基金supported in part by the National Science Foundation of China under Grants U22B2027,62172297,62102262,61902276 and 62272311,Tianjin Intelligent Manufacturing Special Fund Project under Grant 20211097the China Guangxi Science and Technology Plan Project(Guangxi Science and Technology Base and Talent Special Project)under Grant AD23026096(Application Number 2022AC20001)+1 种基金Hainan Provincial Natural Science Foundation of China under Grant 622RC616CCF-Nsfocus Kunpeng Fund Project under Grant CCF-NSFOCUS202207.
文摘Web application fingerprint recognition is an effective security technology designed to identify and classify web applications,thereby enhancing the detection of potential threats and attacks.Traditional fingerprint recognition methods,which rely on preannotated feature matching,face inherent limitations due to the ever-evolving nature and diverse landscape of web applications.In response to these challenges,this work proposes an innovative web application fingerprint recognition method founded on clustering techniques.The method involves extensive data collection from the Tranco List,employing adjusted feature selection built upon Wappalyzer and noise reduction through truncated SVD dimensionality reduction.The core of the methodology lies in the application of the unsupervised OPTICS clustering algorithm,eliminating the need for preannotated labels.By transforming web applications into feature vectors and leveraging clustering algorithms,our approach accurately categorizes diverse web applications,providing comprehensive and precise fingerprint recognition.The experimental results,which are obtained on a dataset featuring various web application types,affirm the efficacy of the method,demonstrating its ability to achieve high accuracy and broad coverage.This novel approach not only distinguishes between different web application types effectively but also demonstrates superiority in terms of classification accuracy and coverage,offering a robust solution to the challenges of web application fingerprint recognition.
基金We acknowledge the National Natural Science Foundation of China(No.22275134)for fi nancial support.
文摘N-doped carbon materials,with their applications as electrocatalysts for the oxygen reduction reaction(ORR),have been extensively studied.However,a negletcted fact is that the operating potential of the ORR is higher than the theoretical oxida-tion potential of carbon,possibly leading to the oxidation of carbon materials.Consequently,the infl uence of the structural oxidation evolution on ORR performance and the real active sites are not clear.In this study,we discover a two-step oxida-tion process of N-doped carbon during the ORR.The fi rst oxidation process is caused by the applied potential and bubbling oxygen during the ORR,leading to the oxidative dissolution of N and the formation of abundant oxygen-containing functional groups.This oxidation process also converts the reaction path from the four-electron(4e)ORR to the two-electron(2e)ORR.Subsequently,the enhanced 2e ORR generates oxidative H_(2)O_(2),which initiates the second stage of oxidation to some newly formed oxygen-containing functional groups,such as quinones to dicarboxyls,further diversifying the oxygen-containing functional groups and making carboxyl groups as the dominant species.We also reveal the synergistic eff ect of multiple oxygen-containing functional groups by providing additional opportunities to access active sites with optimized adsorption of OOH*,thus leading to high effi ciency and durability in electrocatalytic H_(2)O_(2) production.
文摘Electrochemical water splitting,as a promising method for hydrogen production,has attracted significant attention.However,the lack of an electrocatalyst with a small energy loss and fast reaction kinetics has hindered the development of this technology.Amorphous nanomaterials with short-range order and long-range disorder features have recently shown superior activity compared to their crystalline counterparts in water electrolysis.The enhanced activity arising from their intrinsic disordered structure results in more active sites and a higher intrinsic activity of such sites.In this regard,this review is aimed at summarizing the progress in amorphous electrocatalysts for water splitting.First,the synthesis strategies for amorphous electrocatalysts are discussed.Characterization tools for amorphous nanomaterials are then summarized.Moreover,the origin of the enhanced activity and stability of amorphous nanomaterials is analyzed.Finally,the current challenges and promising opportunities in this research area are discussed.This review aims to provide a guide for designing and developing amorphous nanomaterials with a fascinating electrocatalytic water splitting performance.
文摘Highly selective electrocatalytic semihydrogenation of alkynes to alkenes with water as the hydrogen source over palladium-based electrocatalysts is significant but remains a great challenge because of the excessive hydrogenation capacity of palladium.Here,we propose that an ideal palladium catalyst should possess weak alkene adsorption and inhibit subsurface hydrogen formation to stimulate the high selectivity of alkyne semihydrogenation.Therefore,sulfur-modified Pd nanowires(Pd-S NWs)are designedly prepared by a solid-solution interface sulfuration method with KSCN as the sulfur source.The introduction of S weakens the alkene adsorption and prevents the diffusion of active hydrogen(H^(*))into the Pd lattice to form unfavorable subsurface H^(*).As a result,electrocatalytic alkyne semihydrogenation is achieved over a Pd-S NWs cathode with wide substrate scopes,potential-independent up to 99%alkene selectivity,good fragile groups compatibility,and easily synthesized deuterated alkenes.An adsorbed hydrogen addition mechanism of this semihydrogenation reaction is proposed.Importantly,an easy modification of commercial Pd/C by in situ addition of SCN–enabling the gram-scale synthesis of an alkene with 99%selectivity and 95%conversion highlights the promising potential of our method.
基金the National Natural Science Foundation of China (21871206 and 21701122)。
文摘Uncovering the structure evolution and real active species of energy catalytic materials under reaction conditions is important for both understanding structure-activity relationship and constructing electrocatalysts for CO2 electroreduction(CO2ER).And integrating CO2ER with an anodic organic transformation to replace the oxygen evolution reaction is highly desirable.Here,In2O3 is selected as the model material to reveal the surface reconstruction under CO2ER condition.In situ and ex situ results reveal that the electrochemical in situ reconstruction of crystalline In2O3 leads to the formation of crystalline-In/amorphous In2O3-x heterostructure(In/In2O3-x).In/In2O3-xacts as the real active phase with Faradaic efficiency of^89.2%for the formate,outperforming In(~67.5%).The improved performance can be ascribed to electron-rich In rectified by Schottky effect of In2O3-xheterostructure.Impressively,formate and high-value octanenitrile can be simultaneously achieved by integrating CO2ER with octylamine oxidation in an In2O3-x||Ni2P two-electrode electrolyzer.
基金the National Natural Science Foundation of China(21871206 and 21901180)China Postdoctoral Science Foundation(2019TQ0226)for the financial support。
文摘Syngas,a mixture of CO and H2 with a specific ratio,is of great necessity for the industrial production of olefins,liquid fuels,polymers,and drugs[1-4].Currently,syngas is mainly acquired under harsh conditions from the ga-sification of solid coal and petroleum coke,as well as the steam reforming of natural gas[5,6],which accelerate the energy crisis and aggravate CO2 emission.
基金the National Natural Science Foundation of China(Nos.21422104 and 21373149)for financial support.
文摘Understanding and manipulating synthetic progress for precisely controlling the components and defects of nanomaterials is an important and challenging task in materials synthesis and nanocatalysis.Metal phosphides(MPs)have been explored as cheap advanced materials in various catalytic fields.MP materials are usually synthesized through gas-solid phosphorization reaction in a trial-to-error manner,but their formation mechanism and the origin of controlled synthesis remain unclear.Here,we combine in situ thermogravimetrc analysis-mass spectrometry(TG-MS)and quasi-in situ X-ray powder diffraction(XRD)analysis to probe the transformation mechanism from metal oxides(MOs)to MPs during the phosphorization process mediated by hypophosphite.Temperature,time,and the amount of hypophosphite are revealed as the driven forces while oxophilicity and crystallinity as the impeded forces,simultaneously control the component and defect level of a series of MP(M=Ni,Co,W,Mo,and Nb).The as-obtained WO2.9/WP is proved to be an efficient Z-scheme photocatalyst for oxidative coupling of methane with the total C2+production and C2H4 selectivity in C2+products reaching 10.75 pmolg-1 and 98.25%.Our work provides a fundamental understanding of the phosphorization treatment and thereby guides a viable synthetic route to the controlled synthesis of MOx-δ,MP,MOx-δ/MP,and MP/M heterostructured materials.