Cobalt has excellent electrochemical,magnetic,and heat properties.As a strategic resource,it has been applied in many hightech products.However,the recent rapid growth of the battery industry has substantially deplete...Cobalt has excellent electrochemical,magnetic,and heat properties.As a strategic resource,it has been applied in many hightech products.However,the recent rapid growth of the battery industry has substantially depleted cobalt resources,leading to a crisis of cobalt resource supply.The paper examines cobalt ore reserves and distribution,and the recent development and consumption of cobalt resources are summarized as well.In addition,the principles,advantages and disadvantages,and research status of various methods are discussed comprehensively.It can be concluded that the use of diverse sources(Cu-Co ores,Ni-Co ores,zinc plant residues,and waste cobalt products)for cobalt production should be enhanced to meet developmental requirements.Furthermore,in recovery technology,the pyro-hydrometallurgical process employs pyrometallurgy as the pretreatment to modify the phase structure of cobalt minerals,enhancing its recovery in the hydrometallurgical stage and facilitating high-purity cobalt production.Consequently,it represents a promising technology for future cobalt recovery.Lastly,based on the above conclusions,the prospects for cobalt are assessed regarding cobalt ore processing and sustainable cobalt recycling,for which further study should be conducted.展开更多
The development of new catalytic techniques for wastewater treatment has long attracted much attention from industrial and academic communities.However,because of catalyst leaching during degradation,catalysts can be ...The development of new catalytic techniques for wastewater treatment has long attracted much attention from industrial and academic communities.However,because of catalyst leaching during degradation,catalysts can be short lived,and therefore expensive,and unsuitable for use in wastewater treatment.In this work,we developed a bimetallic CuO-Co3O4@γ-Al2O3 catalyst for phenol degradation with bicarbonate-activated H2O2.The weakly basic environment provided by the bicarbonate buffer greatly suppresses leaching of active Cu and Co metal ions from the catalyst.X-ray diffraction and X-ray photoelectron spectroscopy results showed interactions between Cu and Co ions in the CuO-Co3O4@γ-Al2O3 catalyst,and these improve the catalytic activity in phenol degradation.Mechanistic studies using different radical scavengers showed that superoxide and hydroxyl radicals both played significant roles in phenol degradation,whereas singlet oxygen was less important.展开更多
Electrochemical conversion of nitrate(NO_(3)~-) to ammonia(NH_(3)) can target two birds with one stone well, in NO_(3)^(-)-containing sewage remediation and sustainable NH_(3) production. However, single metalbased ca...Electrochemical conversion of nitrate(NO_(3)~-) to ammonia(NH_(3)) can target two birds with one stone well, in NO_(3)^(-)-containing sewage remediation and sustainable NH_(3) production. However, single metalbased catalysts are difficult to drive high-efficient NO_(3)~- removal due to the multi-electron transfer steps.Herein, we present a tandem catalyst with simple structure, Cu-Co binary metal oxides(Cu-Co-O), by engineering intermediate phases as catalytic active species for NO_(3)~- conversion. Electrochemical evaluation,X-ray photoelectron spectroscopy, and in situ Raman spectra together suggest that the newly-generated Cu-based phases was prone to NO_(3)~- to NO_(2)~- conversion, then NO_(2)~- was reduced to NH_(3) on Co-based species. At an applied potential of -1.1 V vs. saturated calomel electrode, the Cu-Co-O catalyst achieved NO_(3)~- -N removal of 90% and NH_(3) faradaic efficiency of 81% for 120 min in 100 m L of 50 mg/L NO_(3)~- -N,consuming only 0.69 k Wh/mol in a two-electrode system. This study provides a facile and efficient engineering strategy for developing high-performance catalysts for electrocatalytic nitrate conversion.展开更多
The hydrogenolysis of carbon–oxygen bonds is an important model reaction in upgrading biomass‐derived furanic compounds to transportation fuels.One of these model reactions,namelyconversion of5‐hydroxymethylfurfura...The hydrogenolysis of carbon–oxygen bonds is an important model reaction in upgrading biomass‐derived furanic compounds to transportation fuels.One of these model reactions,namelyconversion of5‐hydroxymethylfurfural(HMF)to the gasoline additive2,5‐dimethylfuran(DMF),isespecially attractive.In this study,bimetallic Cu‐Co catalysts supported on CeO2,ZrO2,and Al2O3were used for the selective hydrogenolysis of HMF to DMF.The structures of the fresh and usedcatalysts were studied using X‐ray diffraction,the Brunauer‐Emmett‐Teller method,transmissionelectron microscopy,temperature‐programmed reduction by H2,temperature‐programmed desorptionof NH3,and CHNS analysis.The structures were correlated with the catalytic activities.TheCu‐Co/CeO2catalyst produced mainly2,5‐bis(hydroxymethyl)furan via reduction of C=O bonds onlarge Cu particles.The Cu‐Co/Al2O3catalyst gave the best selectivity for DMF,as a result of a combinationof highly dispersed Cu,mixed copper–cobalt oxides,and suitable weak acidic sites.Cu‐Co/ZrO2had low selectivity for DMF and produced a combination of variousover‐hydrogenolysis products,including2,5‐dimethyltetrahydrofuran and5,5‐oxybis(methylene)‐bis(2‐methylfuran),because of the presence of strong acidic sites.The reaction pathways and effectsof various operating parameters,namely temperature,H2pressure,and time,were studied to enableoptimization of the selective conversion of HMF to DMF over the Cu‐Co/Al2O3catalyst.展开更多
A sulphuric acid bake–leach method for the treatment of mixed copper-cobalt oxide minerals was investigated as an alternative to the reductive leaching method. Sulphuric acid bake-leach process of the mixed copper-co...A sulphuric acid bake–leach method for the treatment of mixed copper-cobalt oxide minerals was investigated as an alternative to the reductive leaching method. Sulphuric acid bake-leach process of the mixed copper-cobalt oxide ore was carried out by mixing the sample with sulphuric acid followed by baking of the mixture in a muffle furnace. Baking tests were conducted at different conditions such as temperature, time, and varying amounts of acid. The reacted samples were then subjected to water leaching at room temperature to determine the leachability of copper and cobalt from the baked material. The dissolutions of copper and cobalt were dependent on acid concentration with cobalt showing more sensitivity to the amount of acid. Both copper and cobalt were extracted from the baked material within short leaching times and without the addition of reducing agents. The outcome of this work has shown that the sulphuric acid bake-leach process is a possible alternative to the reductive leaching method for copper-cobalt oxide ores.展开更多
Multilayer Cu-Co film has been produced from a single bath by the method of pulse electrodeposition. Its structure and some magnetic properties were analysed by TEM,AES, XRD and VSM. The results indicated that the fil...Multilayer Cu-Co film has been produced from a single bath by the method of pulse electrodeposition. Its structure and some magnetic properties were analysed by TEM,AES, XRD and VSM. The results indicated that the film was layed structure, consisted of alternating pure copper and copper-cobalt alloy layers. The results have shown the possibility of producing multilayer films with perpendicular magnetic anisotropy byelectrodeposition.展开更多
Developing cost-effective and high-performance oxygen evolution reaction(OER)electrocatalysts has become the intense research on pursuing emerging renewable energy conversion,in which exploring and investigating the i...Developing cost-effective and high-performance oxygen evolution reaction(OER)electrocatalysts has become the intense research on pursuing emerging renewable energy conversion,in which exploring and investigating the intrinsic nature of efficient and stable Cu Co spinel catalysts toward OER in alkaline media is highly desirable.Herein,Cu1–xCo2+xO4oxy-spinel nanoflakes are fabricated by a facile hydrothermal method with the oxidation of ammonia water.In the same condition,Cu1–xCo2+xS4thio-spinel nanospheres are formed without oxidation.In OER process,the as-obtained Cu1–xCo2+xO4nanoflakes and Cu1–xCo2+xS4nanospheres possess the anodic overpotential of 267 and 297 m V in alkaline media to drive the current density of 10 m A/cm^2,respectively,outperforming the state-of-the-art noble metal catalyst of RuO2.X-ray photoelectron spectroscopy analysis exhibits the higher ratio value of Co(Ⅲ)/Co(Ⅱ)in Cu1–xCo2+xO4than that in Cu1–xCo2+xS4,suggesting that the stronglyelectronegative oxygen efficiently predominates in regulating valence states of Co active sites in spinel structures.Remarkably,density functional theory simulation further reveals that the increased valence state of Co could accelerate the electron exchange between catalysts and oxygen adsorbates during electrocatalysis,thus contributing to the higher OER activity of Cu1–xCo2+xO4catalysts.This work provides deep insight regarding the significance of non-metal element(O and S)in Cu Co spinel structure catalysts,as well as presents a promising approach to exploit higher performance and grasp the mechanism of various non-noblemetal spinel catalysts for water oxidation.展开更多
基金the financial support of Guangxi Science and Technology Major Project(Guike AA22068078)the Natural Science Foundation of Henan Province(No.222300420548)+2 种基金Henan Province Science and Technology Research and Development plan joint Fund(No.232301420043)the Key Project of the National Key Research and Development Program of China(No.2021YFC2902604)Modern Analysis and Computing Centre in Zhengzhou University。
文摘Cobalt has excellent electrochemical,magnetic,and heat properties.As a strategic resource,it has been applied in many hightech products.However,the recent rapid growth of the battery industry has substantially depleted cobalt resources,leading to a crisis of cobalt resource supply.The paper examines cobalt ore reserves and distribution,and the recent development and consumption of cobalt resources are summarized as well.In addition,the principles,advantages and disadvantages,and research status of various methods are discussed comprehensively.It can be concluded that the use of diverse sources(Cu-Co ores,Ni-Co ores,zinc plant residues,and waste cobalt products)for cobalt production should be enhanced to meet developmental requirements.Furthermore,in recovery technology,the pyro-hydrometallurgical process employs pyrometallurgy as the pretreatment to modify the phase structure of cobalt minerals,enhancing its recovery in the hydrometallurgical stage and facilitating high-purity cobalt production.Consequently,it represents a promising technology for future cobalt recovery.Lastly,based on the above conclusions,the prospects for cobalt are assessed regarding cobalt ore processing and sustainable cobalt recycling,for which further study should be conducted.
基金supported by the National Natural Science Foundation of China(21273086)Chutian Scholar Foundation from Hubei Province,China~~
文摘The development of new catalytic techniques for wastewater treatment has long attracted much attention from industrial and academic communities.However,because of catalyst leaching during degradation,catalysts can be short lived,and therefore expensive,and unsuitable for use in wastewater treatment.In this work,we developed a bimetallic CuO-Co3O4@γ-Al2O3 catalyst for phenol degradation with bicarbonate-activated H2O2.The weakly basic environment provided by the bicarbonate buffer greatly suppresses leaching of active Cu and Co metal ions from the catalyst.X-ray diffraction and X-ray photoelectron spectroscopy results showed interactions between Cu and Co ions in the CuO-Co3O4@γ-Al2O3 catalyst,and these improve the catalytic activity in phenol degradation.Mechanistic studies using different radical scavengers showed that superoxide and hydroxyl radicals both played significant roles in phenol degradation,whereas singlet oxygen was less important.
基金supported by National Natural Science Foundation of China (Nos.52131003 and 42007180)Special Research Assistant Program of Chinese Academy of Science, Natural Science Foundation of Chongqing (No.cstc2020jcyj-msxm X0775)+1 种基金Scientific Research Instrument Development Project of Chinese Academy of Sciences (No.YJKYYQ20200044)Outstanding Scientist of Chongqing Talent Program (No.CQYC20210101288)。
文摘Electrochemical conversion of nitrate(NO_(3)~-) to ammonia(NH_(3)) can target two birds with one stone well, in NO_(3)^(-)-containing sewage remediation and sustainable NH_(3) production. However, single metalbased catalysts are difficult to drive high-efficient NO_(3)~- removal due to the multi-electron transfer steps.Herein, we present a tandem catalyst with simple structure, Cu-Co binary metal oxides(Cu-Co-O), by engineering intermediate phases as catalytic active species for NO_(3)~- conversion. Electrochemical evaluation,X-ray photoelectron spectroscopy, and in situ Raman spectra together suggest that the newly-generated Cu-based phases was prone to NO_(3)~- to NO_(2)~- conversion, then NO_(2)~- was reduced to NH_(3) on Co-based species. At an applied potential of -1.1 V vs. saturated calomel electrode, the Cu-Co-O catalyst achieved NO_(3)~- -N removal of 90% and NH_(3) faradaic efficiency of 81% for 120 min in 100 m L of 50 mg/L NO_(3)~- -N,consuming only 0.69 k Wh/mol in a two-electrode system. This study provides a facile and efficient engineering strategy for developing high-performance catalysts for electrocatalytic nitrate conversion.
文摘The hydrogenolysis of carbon–oxygen bonds is an important model reaction in upgrading biomass‐derived furanic compounds to transportation fuels.One of these model reactions,namelyconversion of5‐hydroxymethylfurfural(HMF)to the gasoline additive2,5‐dimethylfuran(DMF),isespecially attractive.In this study,bimetallic Cu‐Co catalysts supported on CeO2,ZrO2,and Al2O3were used for the selective hydrogenolysis of HMF to DMF.The structures of the fresh and usedcatalysts were studied using X‐ray diffraction,the Brunauer‐Emmett‐Teller method,transmissionelectron microscopy,temperature‐programmed reduction by H2,temperature‐programmed desorptionof NH3,and CHNS analysis.The structures were correlated with the catalytic activities.TheCu‐Co/CeO2catalyst produced mainly2,5‐bis(hydroxymethyl)furan via reduction of C=O bonds onlarge Cu particles.The Cu‐Co/Al2O3catalyst gave the best selectivity for DMF,as a result of a combinationof highly dispersed Cu,mixed copper–cobalt oxides,and suitable weak acidic sites.Cu‐Co/ZrO2had low selectivity for DMF and produced a combination of variousover‐hydrogenolysis products,including2,5‐dimethyltetrahydrofuran and5,5‐oxybis(methylene)‐bis(2‐methylfuran),because of the presence of strong acidic sites.The reaction pathways and effectsof various operating parameters,namely temperature,H2pressure,and time,were studied to enableoptimization of the selective conversion of HMF to DMF over the Cu‐Co/Al2O3catalyst.
文摘A sulphuric acid bake–leach method for the treatment of mixed copper-cobalt oxide minerals was investigated as an alternative to the reductive leaching method. Sulphuric acid bake-leach process of the mixed copper-cobalt oxide ore was carried out by mixing the sample with sulphuric acid followed by baking of the mixture in a muffle furnace. Baking tests were conducted at different conditions such as temperature, time, and varying amounts of acid. The reacted samples were then subjected to water leaching at room temperature to determine the leachability of copper and cobalt from the baked material. The dissolutions of copper and cobalt were dependent on acid concentration with cobalt showing more sensitivity to the amount of acid. Both copper and cobalt were extracted from the baked material within short leaching times and without the addition of reducing agents. The outcome of this work has shown that the sulphuric acid bake-leach process is a possible alternative to the reductive leaching method for copper-cobalt oxide ores.
文摘Multilayer Cu-Co film has been produced from a single bath by the method of pulse electrodeposition. Its structure and some magnetic properties were analysed by TEM,AES, XRD and VSM. The results indicated that the film was layed structure, consisted of alternating pure copper and copper-cobalt alloy layers. The results have shown the possibility of producing multilayer films with perpendicular magnetic anisotropy byelectrodeposition.
基金the support from the National Natural Science Foundation of China(91750112,51801075)Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX191591).D Rao gratefully acknowledges the support of Jiangsu Overseas Visiting Scholar Program for University Prominent Young and Mid-aged Teachers and Presidents.
文摘Developing cost-effective and high-performance oxygen evolution reaction(OER)electrocatalysts has become the intense research on pursuing emerging renewable energy conversion,in which exploring and investigating the intrinsic nature of efficient and stable Cu Co spinel catalysts toward OER in alkaline media is highly desirable.Herein,Cu1–xCo2+xO4oxy-spinel nanoflakes are fabricated by a facile hydrothermal method with the oxidation of ammonia water.In the same condition,Cu1–xCo2+xS4thio-spinel nanospheres are formed without oxidation.In OER process,the as-obtained Cu1–xCo2+xO4nanoflakes and Cu1–xCo2+xS4nanospheres possess the anodic overpotential of 267 and 297 m V in alkaline media to drive the current density of 10 m A/cm^2,respectively,outperforming the state-of-the-art noble metal catalyst of RuO2.X-ray photoelectron spectroscopy analysis exhibits the higher ratio value of Co(Ⅲ)/Co(Ⅱ)in Cu1–xCo2+xO4than that in Cu1–xCo2+xS4,suggesting that the stronglyelectronegative oxygen efficiently predominates in regulating valence states of Co active sites in spinel structures.Remarkably,density functional theory simulation further reveals that the increased valence state of Co could accelerate the electron exchange between catalysts and oxygen adsorbates during electrocatalysis,thus contributing to the higher OER activity of Cu1–xCo2+xO4catalysts.This work provides deep insight regarding the significance of non-metal element(O and S)in Cu Co spinel structure catalysts,as well as presents a promising approach to exploit higher performance and grasp the mechanism of various non-noblemetal spinel catalysts for water oxidation.
