In this work, we demonstrate the CoOOH/（Ti,C）-Fe2O3（CTCF） nanorods prepared by a facile approach as well as their implementation as photoanodes for photoelectrochemical（PEC） water splitting. The photocurrent den...In this work, we demonstrate the CoOOH/（Ti,C）-Fe2O3（CTCF） nanorods prepared by a facile approach as well as their implementation as photoanodes for photoelectrochemical（PEC） water splitting. The photocurrent density of CTCF photoanode is 1.85 m A cm-2 at ＋1.23 V vs. reversible hydrogen electrode（RHE）, which is more than 20 times higher than that of pristine α-Fe2O3 photoanode（0.08 m A cm-2）. The incident-photo-to-current conversion efficiency, applied bias photo-to-current efficiency and transfer efficiency of CTCF photoanode reaches 31.2% at 380 nm（＋1.23 V vs. RHE）,0.11%（＋1.11 V vs. RHE）, 68.2%（＋1.23 V vs. RHE） respectively, which are much higher than those of pristine α-Fe2O3 photoanode. Additionally, the longtime irradiation PEC water splitting of CTCF photoanode demonstrates its high stability at extreme voltage in NaOH（pH 14）.展开更多
Research on metal-organic framework(MOF)-based non-enzymatic glucose sensors usually ignores the impact of the surface reconstruction degree of MOF on the activity of catalyzing glucose oxidation.In this work,we choos...Research on metal-organic framework(MOF)-based non-enzymatic glucose sensors usually ignores the impact of the surface reconstruction degree of MOF on the activity of catalyzing glucose oxidation.In this work,we choose zeolitic imidazolate framework-67(ZIF-67),which is commonly used in glucose sensing,as a representative to investigate the influence of reconstruction degree on its structure and glucose catalytic performance.By employing the electrochemical activation strategy,the activity of ZIF-67 in catalyzing glucose gradually increased with the prolongation of the activation time,reaching the optimum after 2 h activation.The detection sensitivity of the activated ZIF-67 was 19 times higher than that of the initial ZIF-67,and the limit of detection(LOD)was lowered from 7 to 0.4μM.Our findings demonstrate that the oxidation degree of ZIF-67 deepened rapidly with continuously activation and was basically reconstructed to CoOOH after 2 h activation,accompanied by a morphological change from cuboctahedral to flower-like.Simultaneously,theoretical investigation revealed that ZIF-67 is not suitable as a stable glucose sensor electrode since the adsorbed glucose molecules hasten the dissociation of ligands and the breaking of Co-N bond in ZIF-67.Therefore,our work has important implications for the rational design of next-generation MOF-based glucose sensors.展开更多
Transition-metal oxyhydroxides are attractive catalysts for oxygen evolution reactions(OERs).Further studies for developing transition-metal oxyhydroxide catalysts and understanding their catalytic mechanisms will ben...Transition-metal oxyhydroxides are attractive catalysts for oxygen evolution reactions(OERs).Further studies for developing transition-metal oxyhydroxide catalysts and understanding their catalytic mechanisms will benefit their quick transition to the next catalysts.Herein,Mo-doped CoOOH was designed as a high-performance model electrocatalyst with durability for 20 h at 10 mAcm−2.Additionally,it had an overpotential of 260 mV(glassy carbon)or 215 mV(nickel foam),which was 78 mV lower than that of IrO_(2)(338 mV).In situ,Raman spectroscopy revealed the transformation process of CoOOH.Calculations using the density functional theory showed that during OER,doped Mo increased the spin-up density of states and shrank the spin-down bandgap of the 3d orbits in the reconstructed CoOOH under the electrochemical activation process,which simultaneously optimized the adsorption and electron conduction of oxygen-related intermediates on Co sites and lowered the OER overpotentials.Our research provides new insights into the methodical planning of the creation of transition-metal oxyhydroxide OER catalysts.展开更多
n-Si,believed as a promising photoanode candidate,has suffered from sluggish oxygen evolution reaction(OER)kinetics and poor chemical stability when exposed to aqueous electrolyte.Herein,CoO_(x)/Ni:CoOOH bilayers were...n-Si,believed as a promising photoanode candidate,has suffered from sluggish oxygen evolution reaction(OER)kinetics and poor chemical stability when exposed to aqueous electrolyte.Herein,CoO_(x)/Ni:CoOOH bilayers were successfully deposited on n-Si substrate by atomic layer-deposition(ALD)and photoassisted electrochemical deposition(PED)for stabilizing and catalyzing photoelectrochemical(PEC)water oxidation.In comparison to the n-Si/CoO_(x)photoanode as reference,the prepared n-Si/CoO_(x)/Ni:CoOOH photoanode upon the optimized PED process presents a much improved PEC performance for water splitting,with the onset potential cathodically shifted to~1.03 V vs.reversible hydrogen electrode(RHE)and the photocurrent density much increased to 20 mA cm^(−2)at 1.23 V vs.RHE.It is revealed that the introduction of Ni dopants increases the work functions of the deposited Ni:CoOOH overlayers,which gives rise to the upward band bending weakened at the n-Si/CoO_(x)/Ni:CoOOH cascading interface while strengthened at the Ni:CoOOH/electrolyte interface(with the band bending shifted from downward to upward),contributing to the decreased and the increased driving forces for charge transfer at the interfaces,respectively.Then,the balanced driving forces at the interfaces would endow the n-Si/CoO_(x)/Ni:CoOOH photoanode with the best PEC performance.Moreover,PED has been evidenced superior to ED to dope Ni into CoOOH with the formed overlayer effectively catalyzing and stabilizing PEC water splitting.展开更多
Different sizes of layered CoOOH were synthesized by the molten-salt-assisted method at different temperatures.X-ray diffraction and scanning electron microscope studies reveal that CoOOH grew at(003)with increasing t...Different sizes of layered CoOOH were synthesized by the molten-salt-assisted method at different temperatures.X-ray diffraction and scanning electron microscope studies reveal that CoOOH grew at(003)with increasing temperature,and its size can reach dozens of microns.X-ray absorption near edge structure and XPS studies demonstrate that the Co valence state of CoOOH-750 is trivalent,and X-ray Absorption Fine Structure shows that it had a higher symmetry and lower disorder degree,indicating that CoOOH-750 has higher crystallinity and Co3+.The results of electrochemical tests show that CoOOH-750 exhibited the best oxygen-evolution-reaction(OER)catalytic activity.展开更多
As an antibiotic,tetracycline has been widely used against bacterial infection or as feed additives for growth promotion,which may lead to the enrichment of antibiotic residues in animals or their products.Therefore,t...As an antibiotic,tetracycline has been widely used against bacterial infection or as feed additives for growth promotion,which may lead to the enrichment of antibiotic residues in animals or their products.Therefore,the detection of tetracycline is closely related to human health.The morphological transformation of CoOOH nanoflakes induced by tetracycline was monitored by scanning electron microscope images,dark-field light scattering images and optical spectra,which found that tetracycline could decompose CoOOH nanoflakes into small nanoparticles with low light scattering signal.As a result,the reduced light scattering of CoOOH nanoflakes was proportional to the increased concentration of tetracycline in the range of 1.0-250μmol/L,and the limit of determination(LOD)was 0.23μmol/L(3σ/k).Most foreign substances did not interfere in the analysis of tetracycline.Furthermore,the concentration of tetracycline in different milk samples detected with the standard addition method was so low that it accorded with the safety regulation,which was similar to the detection result with high-performance liquid chromatography(HPLC).展开更多
基金preliminarily supported by the National Natural Science Foundation of China (21706295, 51772135 and 21376104)the Natural Science Foundation of Guangdong Province (2017A030313055 and 2014A030306010Jinan University (11617326 and 88017418)
文摘In this work, we demonstrate the CoOOH/（Ti,C）-Fe2O3（CTCF） nanorods prepared by a facile approach as well as their implementation as photoanodes for photoelectrochemical（PEC） water splitting. The photocurrent density of CTCF photoanode is 1.85 m A cm-2 at ＋1.23 V vs. reversible hydrogen electrode（RHE）, which is more than 20 times higher than that of pristine α-Fe2O3 photoanode（0.08 m A cm-2）. The incident-photo-to-current conversion efficiency, applied bias photo-to-current efficiency and transfer efficiency of CTCF photoanode reaches 31.2% at 380 nm（＋1.23 V vs. RHE）,0.11%（＋1.11 V vs. RHE）, 68.2%（＋1.23 V vs. RHE） respectively, which are much higher than those of pristine α-Fe2O3 photoanode. Additionally, the longtime irradiation PEC water splitting of CTCF photoanode demonstrates its high stability at extreme voltage in NaOH（pH 14）.
基金the National Natural Science Foundation of China(Nos.22102128 and 22279097)the Fundamental Research Funds for the Central Universities(No.WUT:2022IVA168).
文摘Research on metal-organic framework(MOF)-based non-enzymatic glucose sensors usually ignores the impact of the surface reconstruction degree of MOF on the activity of catalyzing glucose oxidation.In this work,we choose zeolitic imidazolate framework-67(ZIF-67),which is commonly used in glucose sensing,as a representative to investigate the influence of reconstruction degree on its structure and glucose catalytic performance.By employing the electrochemical activation strategy,the activity of ZIF-67 in catalyzing glucose gradually increased with the prolongation of the activation time,reaching the optimum after 2 h activation.The detection sensitivity of the activated ZIF-67 was 19 times higher than that of the initial ZIF-67,and the limit of detection(LOD)was lowered from 7 to 0.4μM.Our findings demonstrate that the oxidation degree of ZIF-67 deepened rapidly with continuously activation and was basically reconstructed to CoOOH after 2 h activation,accompanied by a morphological change from cuboctahedral to flower-like.Simultaneously,theoretical investigation revealed that ZIF-67 is not suitable as a stable glucose sensor electrode since the adsorbed glucose molecules hasten the dissociation of ligands and the breaking of Co-N bond in ZIF-67.Therefore,our work has important implications for the rational design of next-generation MOF-based glucose sensors.
基金The National Natural Science Foundation of China(Grant Nos.52072114 and 51922008)the 111 Project(Grant No.D17007),the Henan Center for Outstanding Overseas Scientists(Grant No.GZS2018003)+2 种基金Xinxiang Major Science and Technology Projects(Grant No.21ZD001)Guangdong Innovative and Entrepreneurial Research Team Program(2016ZT06N500)Guangdong Provincial Key Laboratory of Energy Materials for Electric Power(2018B030322001)all provided financial support for this work.
文摘Transition-metal oxyhydroxides are attractive catalysts for oxygen evolution reactions(OERs).Further studies for developing transition-metal oxyhydroxide catalysts and understanding their catalytic mechanisms will benefit their quick transition to the next catalysts.Herein,Mo-doped CoOOH was designed as a high-performance model electrocatalyst with durability for 20 h at 10 mAcm−2.Additionally,it had an overpotential of 260 mV(glassy carbon)or 215 mV(nickel foam),which was 78 mV lower than that of IrO_(2)(338 mV).In situ,Raman spectroscopy revealed the transformation process of CoOOH.Calculations using the density functional theory showed that during OER,doped Mo increased the spin-up density of states and shrank the spin-down bandgap of the 3d orbits in the reconstructed CoOOH under the electrochemical activation process,which simultaneously optimized the adsorption and electron conduction of oxygen-related intermediates on Co sites and lowered the OER overpotentials.Our research provides new insights into the methodical planning of the creation of transition-metal oxyhydroxide OER catalysts.
基金supported by the National Key Research and Development Program of China (2018YFB1502003)the National Natural Science Foundation of China (21875183)+3 种基金the Natural Science Basic Research Program of Shaanxi Province (2019JCW-10)the National Program for the Support of Top-notch Young Professionalsthe Fundamental Research Funds for the Central UniversitiesThe Youth Innovation Team of Shaanxi Universities
文摘n-Si,believed as a promising photoanode candidate,has suffered from sluggish oxygen evolution reaction(OER)kinetics and poor chemical stability when exposed to aqueous electrolyte.Herein,CoO_(x)/Ni:CoOOH bilayers were successfully deposited on n-Si substrate by atomic layer-deposition(ALD)and photoassisted electrochemical deposition(PED)for stabilizing and catalyzing photoelectrochemical(PEC)water oxidation.In comparison to the n-Si/CoO_(x)photoanode as reference,the prepared n-Si/CoO_(x)/Ni:CoOOH photoanode upon the optimized PED process presents a much improved PEC performance for water splitting,with the onset potential cathodically shifted to~1.03 V vs.reversible hydrogen electrode(RHE)and the photocurrent density much increased to 20 mA cm^(−2)at 1.23 V vs.RHE.It is revealed that the introduction of Ni dopants increases the work functions of the deposited Ni:CoOOH overlayers,which gives rise to the upward band bending weakened at the n-Si/CoO_(x)/Ni:CoOOH cascading interface while strengthened at the Ni:CoOOH/electrolyte interface(with the band bending shifted from downward to upward),contributing to the decreased and the increased driving forces for charge transfer at the interfaces,respectively.Then,the balanced driving forces at the interfaces would endow the n-Si/CoO_(x)/Ni:CoOOH photoanode with the best PEC performance.Moreover,PED has been evidenced superior to ED to dope Ni into CoOOH with the formed overlayer effectively catalyzing and stabilizing PEC water splitting.
文摘利用工艺简单,成本低廉的共沉淀法制得Co OOH,并用作非水性锂-氧气电池阴极催化剂。通过恒流充放电、线性伏安扫描(LSV)和电化学阻抗(EIS)测试研究了电极的电化学性能。结果表明:由于Co OOH能够明显提高氧气还原反应(ORR)的催化活性,与未使用Co OOH的电极相比较,使用Co OOH为催化剂的电极首次放电容量高达5 093 m Ah·g^(-1),提高了1.7倍。电池的充电过电压降低了约460 m V,充电可逆性得到增强,充放电可逆性提高,使得循环性能得到显著改善。
基金This work was supported by“Transformational Technologies for Clean Energy and Demonstration”,Strategic Priority Research Program of the Chinese Academy of Sciences(Grant no.XDA21080200).
文摘Different sizes of layered CoOOH were synthesized by the molten-salt-assisted method at different temperatures.X-ray diffraction and scanning electron microscope studies reveal that CoOOH grew at(003)with increasing temperature,and its size can reach dozens of microns.X-ray absorption near edge structure and XPS studies demonstrate that the Co valence state of CoOOH-750 is trivalent,and X-ray Absorption Fine Structure shows that it had a higher symmetry and lower disorder degree,indicating that CoOOH-750 has higher crystallinity and Co3+.The results of electrochemical tests show that CoOOH-750 exhibited the best oxygen-evolution-reaction(OER)catalytic activity.
基金the National Natural Science Foundation of China(No.21405123)the Innovation and Entrepreneurship Project of Southwest University(20172902008)+1 种基金the College of Pharmaceutical Sciences Innovation and Entrepreneurship Project of Southwest University(YX2017-CXYB-10)the Open Funding Project of the State Key Laboratory of Bioreactor Engineering.
文摘As an antibiotic,tetracycline has been widely used against bacterial infection or as feed additives for growth promotion,which may lead to the enrichment of antibiotic residues in animals or their products.Therefore,the detection of tetracycline is closely related to human health.The morphological transformation of CoOOH nanoflakes induced by tetracycline was monitored by scanning electron microscope images,dark-field light scattering images and optical spectra,which found that tetracycline could decompose CoOOH nanoflakes into small nanoparticles with low light scattering signal.As a result,the reduced light scattering of CoOOH nanoflakes was proportional to the increased concentration of tetracycline in the range of 1.0-250μmol/L,and the limit of determination(LOD)was 0.23μmol/L(3σ/k).Most foreign substances did not interfere in the analysis of tetracycline.Furthermore,the concentration of tetracycline in different milk samples detected with the standard addition method was so low that it accorded with the safety regulation,which was similar to the detection result with high-performance liquid chromatography(HPLC).
