The efficient electrocatalytic nitrate(NO_(3)^(−))reduction to ammonia(NRA)offers a sustainable alternative for both environmental remediation and ammonia synthesis.Developing advanced electrocatalysts with rationally...The efficient electrocatalytic nitrate(NO_(3)^(−))reduction to ammonia(NRA)offers a sustainable alternative for both environmental remediation and ammonia synthesis.Developing advanced electrocatalysts with rationally designed spatial arrangement of active sites and optimizing the synergetic effect among components are crucial for high efficiency and selectivity.Herein,we present Fe/N active sites decorated on porous carbon nanofibers(CNFs)with encapsulated FeCo nanoparticles(FeCo@CNFs-Fe/N)as electrocatalysts for NRA.The FeCo@CNFs-Fe/N catalyst demonstrates exceptional performance,achieving a high ammonia yield of 498.18μmol/(h·g_(cat)).Meanwhile,the enhanced reduction activity,especially the reduction in overpotential by 0.565 V,is 3–10 times higher than that of FeCo-encapsulated and Fe/N-modified CNFs-based catalysts.The enhanced catalytic activity is attributed to the efficient structure design and optimized spatial distribution of active sites,which enhance the electron transfer rate and decrease the reaction energy barrier.Mechanistic studies reveal that the synergetic effect between encapsulated nanoparticles and surface-modified Fe/N sites plays a crucial role in promoting efficient nitrate adsorption and selective ammonia production.These findings highlight the potential of strategically engineered CNF-based composites for nitrate reduction and other advanced electrocatalytic applications.展开更多
A ratiometric fluorescent probe for hypoxanthine(Hx)detection was established based on the mimic enzyme and fluorescence characteristics of cobalt-doped graphite-phase carbon nitride(Co doped g-C_(3)N_(4)).In addition...A ratiometric fluorescent probe for hypoxanthine(Hx)detection was established based on the mimic enzyme and fluorescence characteristics of cobalt-doped graphite-phase carbon nitride(Co doped g-C_(3)N_(4)).In addition to emitting strong fluorescence,the peroxidase activity of Co doped g-C_(3)N_(4)can catalyze the reaction of O-phenylenediamine and H_(2)O_(2)to produce diallyl phthalate which can emit yellow fluorescence at 570 nm.Through the decomposition of Hx by xanthine oxidase,Hx can be indirectly detected by the generating hydrogen peroxide based on the measurement of fluorescent ratio I(F_(570)/F_(370)).The linear range was 1.7-272.2 mg/kg(R^(2)=0.997),and the detection limit was 1.52 mg/kg(3σ/K,n=9).The established method was applied to Hx detection in bass,grass carp,and shrimp,and the data were verified by HPLC.The result shows that the established probe is sensitive,accurate,and reliable,and can be used for Hx detection in aquatic products.展开更多
Electrocatalytic reduction of nitrate to ammonia offers an environmentally friendly and sustainable approach for ammonia production,but it involves a multi-step reaction process with complex intermediates,and still fa...Electrocatalytic reduction of nitrate to ammonia offers an environmentally friendly and sustainable approach for ammonia production,but it involves a multi-step reaction process with complex intermediates,and still faces the challenge of high activity and high selectivity.Herein,a high-entropy nanoalloy was synthesized via high-temperature annealing of metal salt with dopamine as a carbon source for electrocatalytic reduction of nitrate to ammonia.The FeCoNiCuRu_(1.5)/C catalyst displays a conversion rate of 90.2%and an ammonia selectivity of 92.2% at-0.74 V(vs.RHE),significantly surpassing the performance of lowentropy alloys such as FeCo/C by 1.5–2 times.Moreover,FeCoNiCuRu_(1.5)/C maintains a consistent nitrate conversion rate of about 90.0% after 120 h of continuous operation(10 cycles),indicating high stability.The superior performance of FeCoNiCuRu_(1.5)/C can be attributed to the synergetic relay catalysis among Fe,Co,Ni,Cu,and Ru sites.This synergy enhances nitrate adsorption due to the optimized electronic structure of multiple active sites,which facilitates the nitrate reduction to intermediates.Subsequently,the effective active hydrogen produced at the Ru site,in conjunction with adjustments at other metal sites,promotes the selective transformation of the intermediates into ammonia.This work not only highlights the efficacy of synergetic relay electrocatalysis but also opens new avenues for developing highly efficient multi-site catalysts.展开更多
A visual colorimetric detection strategy is reported for total antioxidant capacity(TAC)assay by using 3,3',5,5'-tetramethylbenzidine(TMB)oxidation as chromogenic substrate based on gold nanoparticle-decorated...A visual colorimetric detection strategy is reported for total antioxidant capacity(TAC)assay by using 3,3',5,5'-tetramethylbenzidine(TMB)oxidation as chromogenic substrate based on gold nanoparticle-decorated MoSe_(2) nanosheets(Au@MoSe_(2)).Au@MoSe_(2) nanostructures exhibit high peroxidase-like activity and can catalyze H_(2)O_(2)to oxidize TMB.Based on inhibition effect of ascorbic acid(AA)on TMB oxidation,a facile and sensitive colorimetric method was developed for AA detection.Under optimal conditions,the proposed method showed a sensitivity for AA in a concentration range from 2 to 120μM and limit of detection was 0.41μM.Furthermore,the method was employed for TAC assay in actual samples,including commercial beverages and vitamin C tablets.This work represents a model in nanostructure design and will lead to further development of TAC assay in evaluation of antioxidant food quality.展开更多
We report a colorimetric method for glucose detection based on Au nanoparticle-decorated WSe_(2)(Au@WSe_(2))hybrid nanostructures.These hybrid structures are easily synthesized by simply stirring HAuCl_(4) precursor w...We report a colorimetric method for glucose detection based on Au nanoparticle-decorated WSe_(2)(Au@WSe_(2))hybrid nanostructures.These hybrid structures are easily synthesized by simply stirring HAuCl_(4) precursor with WSe_(2) nanosheets in aqueous solution.Owing to strong synergistic catalytic effects of Au nanoparticles and WSe_(2) nanosheets,the Au@WSe_(2) hybrid nanostructures exhibit enhanced peroxidase-like activity(about 2-fold higher compared to WSe_(2) nanosheets alone)for 3,3',5,5'-tetramethylbenzidine oxidation by H_(2)O_(2).Based on the highly catalytical property,the colorimetric method for glucose detection is established by coupling glucose oxidase(GOx).The detection limit of glucose is 3.66 pM.Moreover,the proposed colorimetric method is applicable to glucose detection in serum samples and is promising for applications in biomedical fields.展开更多
基金supported by Shanghai Science and Technology Plan Project(No.23ZR1467000)the Fundamental Research Funds for the Central University(No.22120240354)+1 种基金the National Natural Science Foundation of China(No.22131004)the Leading Scientific Research Project from China National Nuclear Corporation(No.CNNC–CXLM-202205).
文摘The efficient electrocatalytic nitrate(NO_(3)^(−))reduction to ammonia(NRA)offers a sustainable alternative for both environmental remediation and ammonia synthesis.Developing advanced electrocatalysts with rationally designed spatial arrangement of active sites and optimizing the synergetic effect among components are crucial for high efficiency and selectivity.Herein,we present Fe/N active sites decorated on porous carbon nanofibers(CNFs)with encapsulated FeCo nanoparticles(FeCo@CNFs-Fe/N)as electrocatalysts for NRA.The FeCo@CNFs-Fe/N catalyst demonstrates exceptional performance,achieving a high ammonia yield of 498.18μmol/(h·g_(cat)).Meanwhile,the enhanced reduction activity,especially the reduction in overpotential by 0.565 V,is 3–10 times higher than that of FeCo-encapsulated and Fe/N-modified CNFs-based catalysts.The enhanced catalytic activity is attributed to the efficient structure design and optimized spatial distribution of active sites,which enhance the electron transfer rate and decrease the reaction energy barrier.Mechanistic studies reveal that the synergetic effect between encapsulated nanoparticles and surface-modified Fe/N sites plays a crucial role in promoting efficient nitrate adsorption and selective ammonia production.These findings highlight the potential of strategically engineered CNF-based composites for nitrate reduction and other advanced electrocatalytic applications.
基金supported by the National Natural Science Foundation of China(21804050)the National Key R and D Program of China(2018YFD0901003)+2 种基金the Science and Technology Planning Project of Xiamen,China(3502Z20183031)the Fujian Provincial Fund Project(2018J01432)the Xiamen Science and Technology Planning Project,China(3502Z20183031)。
文摘A ratiometric fluorescent probe for hypoxanthine(Hx)detection was established based on the mimic enzyme and fluorescence characteristics of cobalt-doped graphite-phase carbon nitride(Co doped g-C_(3)N_(4)).In addition to emitting strong fluorescence,the peroxidase activity of Co doped g-C_(3)N_(4)can catalyze the reaction of O-phenylenediamine and H_(2)O_(2)to produce diallyl phthalate which can emit yellow fluorescence at 570 nm.Through the decomposition of Hx by xanthine oxidase,Hx can be indirectly detected by the generating hydrogen peroxide based on the measurement of fluorescent ratio I(F_(570)/F_(370)).The linear range was 1.7-272.2 mg/kg(R^(2)=0.997),and the detection limit was 1.52 mg/kg(3σ/K,n=9).The established method was applied to Hx detection in bass,grass carp,and shrimp,and the data were verified by HPLC.The result shows that the established probe is sensitive,accurate,and reliable,and can be used for Hx detection in aquatic products.
基金financially supported by the Shanghai Science and Technology Plan Project(No.23ZR1467000)Basic Research Project of Tongji University(No.22120240354)+2 种基金State Key Laboratory of Treatments and Recycling for Organic Effluents by Adsorption in Petroleum,Chemical Industry(No.SDHY2206)National Natural Science Foundation of China(No.21976134)the Fundamental Research Funds for the Central Universities。
文摘Electrocatalytic reduction of nitrate to ammonia offers an environmentally friendly and sustainable approach for ammonia production,but it involves a multi-step reaction process with complex intermediates,and still faces the challenge of high activity and high selectivity.Herein,a high-entropy nanoalloy was synthesized via high-temperature annealing of metal salt with dopamine as a carbon source for electrocatalytic reduction of nitrate to ammonia.The FeCoNiCuRu_(1.5)/C catalyst displays a conversion rate of 90.2%and an ammonia selectivity of 92.2% at-0.74 V(vs.RHE),significantly surpassing the performance of lowentropy alloys such as FeCo/C by 1.5–2 times.Moreover,FeCoNiCuRu_(1.5)/C maintains a consistent nitrate conversion rate of about 90.0% after 120 h of continuous operation(10 cycles),indicating high stability.The superior performance of FeCoNiCuRu_(1.5)/C can be attributed to the synergetic relay catalysis among Fe,Co,Ni,Cu,and Ru sites.This synergy enhances nitrate adsorption due to the optimized electronic structure of multiple active sites,which facilitates the nitrate reduction to intermediates.Subsequently,the effective active hydrogen produced at the Ru site,in conjunction with adjustments at other metal sites,promotes the selective transformation of the intermediates into ammonia.This work not only highlights the efficacy of synergetic relay electrocatalysis but also opens new avenues for developing highly efficient multi-site catalysts.
基金the National Natural Science Foundation of China(Nos.21804050 and 22004032)Hunan Provincial Natural Science Foundation of China(No.2021JJ20020).
文摘A visual colorimetric detection strategy is reported for total antioxidant capacity(TAC)assay by using 3,3',5,5'-tetramethylbenzidine(TMB)oxidation as chromogenic substrate based on gold nanoparticle-decorated MoSe_(2) nanosheets(Au@MoSe_(2)).Au@MoSe_(2) nanostructures exhibit high peroxidase-like activity and can catalyze H_(2)O_(2)to oxidize TMB.Based on inhibition effect of ascorbic acid(AA)on TMB oxidation,a facile and sensitive colorimetric method was developed for AA detection.Under optimal conditions,the proposed method showed a sensitivity for AA in a concentration range from 2 to 120μM and limit of detection was 0.41μM.Furthermore,the method was employed for TAC assay in actual samples,including commercial beverages and vitamin C tablets.This work represents a model in nanostructure design and will lead to further development of TAC assay in evaluation of antioxidant food quality.
基金supported by the National Natural Science Foundation of China(Nos.22004032 and 21804050)the Fundamental Research Funds for the Central Universities(No.531118010569)the Natural Science Foundation of Fujian Province of China(No.2019J05098).
文摘We report a colorimetric method for glucose detection based on Au nanoparticle-decorated WSe_(2)(Au@WSe_(2))hybrid nanostructures.These hybrid structures are easily synthesized by simply stirring HAuCl_(4) precursor with WSe_(2) nanosheets in aqueous solution.Owing to strong synergistic catalytic effects of Au nanoparticles and WSe_(2) nanosheets,the Au@WSe_(2) hybrid nanostructures exhibit enhanced peroxidase-like activity(about 2-fold higher compared to WSe_(2) nanosheets alone)for 3,3',5,5'-tetramethylbenzidine oxidation by H_(2)O_(2).Based on the highly catalytical property,the colorimetric method for glucose detection is established by coupling glucose oxidase(GOx).The detection limit of glucose is 3.66 pM.Moreover,the proposed colorimetric method is applicable to glucose detection in serum samples and is promising for applications in biomedical fields.
