The leaching behavior of main metallic sulphides in zinc concentrate under atmospheric oxygen-rich direct leaching conditions was studied through mineralogical analysis. The results show that the sulphides dissolve ob...The leaching behavior of main metallic sulphides in zinc concentrate under atmospheric oxygen-rich direct leaching conditions was studied through mineralogical analysis. The results show that the sulphides dissolve obviously except pyrite. Based on the relationship between elemental sulfur and the residual sulphides in the leaching residue, the dissolution of sphalerite, chalcopyrite, covellite and galena is assumed to follow the indirect oxidation reactions, where the acidic dissolution takes place firstly and then the released H2S transfers from the mineral surface into bulk solution and is further oxidized into elemental sulfur. The interface chemical reaction is further supposed as the controlling step in the leaching of these sulphides. The direct electrochemical oxidation reactions are assumed to contribute to the dissolution of pyrrhotite, which is controlled by the diffusion through elemental sulfur layer.展开更多
To achieve a new type of carbon-based quantum dots with unique photoluminescence PL a simple approach for fabrication of graphene quantum dots GQDs with oxygen-rich groups was developed via the hydrothermal reaction b...To achieve a new type of carbon-based quantum dots with unique photoluminescence PL a simple approach for fabrication of graphene quantum dots GQDs with oxygen-rich groups was developed via the hydrothermal reaction by using graphene oxides GOs as a precursor. Transmission electron microscope TEM and atomic force microscope AFM characterizations confirmed that the sizes and heights of GQDs were 5.02±0.92 nm and 0.6 nm respectively.A strong PL emission exhibited unique excitation wavelength dependent features.Also the carbene-like free zigzag edge sites were proposed to be the origin of the strong PL emission.The GQDs were demonstrated to be a superior probe for Fe3＋ detection in aqueous solution with a high sensitivity and feasibility due to the special coordinate interaction between Fe3＋and the phenolic hydroxyl group at GQDs.展开更多
In order to understand the evolution of oxygen-rich layer (ORL) on titanium alloys, the near α titanium alloy TA15 and α+β type titanium alloy TC4 were thermally exposed in air at 850 °C to evaluate the effect...In order to understand the evolution of oxygen-rich layer (ORL) on titanium alloys, the near α titanium alloy TA15 and α+β type titanium alloy TC4 were thermally exposed in air at 850 °C to evaluate the effect of α phase content on formation and evolution of ORL, and the stability and diffusion of oxygen in α- and β-Ti were investigated by first principles calculations to reveal the oxygen diffusion rate. TA15 with more α phases has a higher diffusion coefficient of ORL evolution than TC4, resulting in forming thicker ORL on TA15 under the same thermal exposure condition. The first principles calculations indicate that octahedral interstice of α-Ti is the most stable site for oxygen atom. The nearest neighbor diffusion between octahedral interstices along the [0001] direction in α-Ti presenting the lowest activation energy is the most favorable oxygen diffusion mechanism in α- and β-Ti.展开更多
The unique properties of metal oxide surfaces,crystal surfaces and defects play vital roles in biomass upgrading reactions.In this work,hierarchical porous bowl-shaped ZrO_(2)(HB-ZrO_(2))with mixed crystal phase was d...The unique properties of metal oxide surfaces,crystal surfaces and defects play vital roles in biomass upgrading reactions.In this work,hierarchical porous bowl-shaped ZrO_(2)(HB-ZrO_(2))with mixed crystal phase was designed and employed as the support for loading AuPd bimetal with different proportions to synthesize AuPd/HB-ZrO_(2) catalysts.The effects of surface chemistry,oxygen defects,bimetal interaction and metal-support interaction of AuPd/HB-ZrO_(2) on catalytic performance for the selective oxidation of 5-hydroxymethylfurfural(HMF)to 2,5-furandicarboxylic acid(FDCA)were systematically investigated.The Au 2 Pd1/HB-ZrO_(2) catalyst afforded a satisfactory FDCA yield of 99.9%from HMF oxidation using O_(2) as the oxidant in water,accompanied with an excellent FDCA productivity at 97.6 mmol g^(−1) h^(−1).This work offers fresh insights into rationally designing efficient catalysts with oxygen-rich defects for the catalytic upgrading of biomass platform chemicals.展开更多
The K metal batteries are emerged as promising alternatives beyond commercialized Li-ion batteries.However,suppressing uncontrolled dendrite is crucial to the accomplishment of K metal batteries.Herein,an oxygen-rich ...The K metal batteries are emerged as promising alternatives beyond commercialized Li-ion batteries.However,suppressing uncontrolled dendrite is crucial to the accomplishment of K metal batteries.Herein,an oxygen-rich treated carbon cloth(TCC)has been designed as the K plating host to guide K homogeneous nucleation and suppress the dendrite growth.Both density function theory calculations and experimental results demonstrate that abundant oxygen functional groups as K-philic sites on TCC can guide K nucleation and deposition homogeneously.As a result,the TCC electrode exhibits an ultra-long-life over 800 cycles at high current density of 3.0 mA·cm^(−2)for 3.0 mA·h·cm^(−2).Furthermore,the symmetrical cells can run stably for 2,000 h with low over-potential less than 20 mV at 1.0 mA·cm^(−2)for 1.0 mA·h·cm^(−2).Even at a higher current of 5.0 mA·cm^(−2),the TCC electrode can still stably cycle for 1,400 h.展开更多
基金Project (50964004) supported by the National Natural Science Foundation of China
文摘The leaching behavior of main metallic sulphides in zinc concentrate under atmospheric oxygen-rich direct leaching conditions was studied through mineralogical analysis. The results show that the sulphides dissolve obviously except pyrite. Based on the relationship between elemental sulfur and the residual sulphides in the leaching residue, the dissolution of sphalerite, chalcopyrite, covellite and galena is assumed to follow the indirect oxidation reactions, where the acidic dissolution takes place firstly and then the released H2S transfers from the mineral surface into bulk solution and is further oxidized into elemental sulfur. The interface chemical reaction is further supposed as the controlling step in the leaching of these sulphides. The direct electrochemical oxidation reactions are assumed to contribute to the dissolution of pyrrhotite, which is controlled by the diffusion through elemental sulfur layer.
基金The National Basic Research Program of China(973Program)(No.2013CB932902)the National Natural Science Foundation of China(No.21201034,21173042)the Fundamental Research Funds for the Central Universities(No.3207044403)
文摘To achieve a new type of carbon-based quantum dots with unique photoluminescence PL a simple approach for fabrication of graphene quantum dots GQDs with oxygen-rich groups was developed via the hydrothermal reaction by using graphene oxides GOs as a precursor. Transmission electron microscope TEM and atomic force microscope AFM characterizations confirmed that the sizes and heights of GQDs were 5.02±0.92 nm and 0.6 nm respectively.A strong PL emission exhibited unique excitation wavelength dependent features.Also the carbene-like free zigzag edge sites were proposed to be the origin of the strong PL emission.The GQDs were demonstrated to be a superior probe for Fe3＋ detection in aqueous solution with a high sensitivity and feasibility due to the special coordinate interaction between Fe3＋and the phenolic hydroxyl group at GQDs.
基金Project(51701128) supported by the National Natural Science Foundation of China
文摘In order to understand the evolution of oxygen-rich layer (ORL) on titanium alloys, the near α titanium alloy TA15 and α+β type titanium alloy TC4 were thermally exposed in air at 850 °C to evaluate the effect of α phase content on formation and evolution of ORL, and the stability and diffusion of oxygen in α- and β-Ti were investigated by first principles calculations to reveal the oxygen diffusion rate. TA15 with more α phases has a higher diffusion coefficient of ORL evolution than TC4, resulting in forming thicker ORL on TA15 under the same thermal exposure condition. The first principles calculations indicate that octahedral interstice of α-Ti is the most stable site for oxygen atom. The nearest neighbor diffusion between octahedral interstices along the [0001] direction in α-Ti presenting the lowest activation energy is the most favorable oxygen diffusion mechanism in α- and β-Ti.
基金financially supported by the Natural Science Foundation of Jiangsu Province(No.BK20200917)the China Postdoctoral Science Foundation(No.2021M701474)+1 种基金Youth Talent Cultivation Plan of Jiangsu UniversityCollaborative Innovation Center for Water Treatment Technology and Materials.
文摘The unique properties of metal oxide surfaces,crystal surfaces and defects play vital roles in biomass upgrading reactions.In this work,hierarchical porous bowl-shaped ZrO_(2)(HB-ZrO_(2))with mixed crystal phase was designed and employed as the support for loading AuPd bimetal with different proportions to synthesize AuPd/HB-ZrO_(2) catalysts.The effects of surface chemistry,oxygen defects,bimetal interaction and metal-support interaction of AuPd/HB-ZrO_(2) on catalytic performance for the selective oxidation of 5-hydroxymethylfurfural(HMF)to 2,5-furandicarboxylic acid(FDCA)were systematically investigated.The Au 2 Pd1/HB-ZrO_(2) catalyst afforded a satisfactory FDCA yield of 99.9%from HMF oxidation using O_(2) as the oxidant in water,accompanied with an excellent FDCA productivity at 97.6 mmol g^(−1) h^(−1).This work offers fresh insights into rationally designing efficient catalysts with oxygen-rich defects for the catalytic upgrading of biomass platform chemicals.
基金supported by the Innovation Program of Central South University(No.2019zzts249),and the authors would like to appreciate Xiaobin Zhou for the help of XPS tests from Shiyanjia Lab(http://www.shiyanjia.com).
文摘The K metal batteries are emerged as promising alternatives beyond commercialized Li-ion batteries.However,suppressing uncontrolled dendrite is crucial to the accomplishment of K metal batteries.Herein,an oxygen-rich treated carbon cloth(TCC)has been designed as the K plating host to guide K homogeneous nucleation and suppress the dendrite growth.Both density function theory calculations and experimental results demonstrate that abundant oxygen functional groups as K-philic sites on TCC can guide K nucleation and deposition homogeneously.As a result,the TCC electrode exhibits an ultra-long-life over 800 cycles at high current density of 3.0 mA·cm^(−2)for 3.0 mA·h·cm^(−2).Furthermore,the symmetrical cells can run stably for 2,000 h with low over-potential less than 20 mV at 1.0 mA·cm^(−2)for 1.0 mA·h·cm^(−2).Even at a higher current of 5.0 mA·cm^(−2),the TCC electrode can still stably cycle for 1,400 h.
