Electrocatalytic oxygen evolution reaction(OER)has been recognized as the bottleneck of overall water splitting,which is a promising approach for sustainable production of H_(2).Transition metal(TM)hydroxides are the ...Electrocatalytic oxygen evolution reaction(OER)has been recognized as the bottleneck of overall water splitting,which is a promising approach for sustainable production of H_(2).Transition metal(TM)hydroxides are the most conventional and classical non-noble metal-based electrocatalysts for OER,while TM basic salts[M^(2+)(OH)_(2-x)(A_(m^(-))_(x/m),A=CO_(3)^(2−),NO_(3)^(−),F^(−),Cl^(−)]consisting of OH−and another anion have drawn extensive research interest due to its higher catalytic activity in the past decade.In this review,we summarize the recent advances of TM basic salts and their application in OER and further overall water splitting.We categorize TM basic salt-based OER pre-catalysts into four types(CO_(3)^(2−),NO_(3)^(−),F^(−),Cl^(−)according to the anion,which is a key factor for their outstanding performance towards OER.We highlight experimental and theoretical methods for understanding the structure evolution during OER and the effect of anion on catalytic performance.To develop bifunctional TM basic salts as catalyst for the practical electrolysis application,we also review the present strategies for enhancing its hydrogen evolution reaction activity and thereby improving its overall water splitting performance.Finally,we conclude this review with a summary and perspective about the remaining challenges and future opportunities of TM basic salts as catalysts for water electrolysis.展开更多
Double slag process was adopted to produce low-phosphorus steel from middle-phosphorus hot metal.To achieve a stable dephosphorization operation,conventional process was modified as follows：the blowing time was exten...Double slag process was adopted to produce low-phosphorus steel from middle-phosphorus hot metal.To achieve a stable dephosphorization operation,conventional process was modified as follows：the blowing time was extended by approximately 1min by reducing the oxygen supply flow rate;calcium ferrite pellets were added to adjust the slag composition and viscosity;the dumping temperature was lowered by 30-50°C by the addition of calcium ferrite pellets during the double slag process to prevent phosphorus in the slag from returning to the molten steel;and the bottom-blown gas flow was increased during the blowing process.For 40 heats of comparative experiments,the rate of dephosphorization reached 91% and ranged between 87% and 95%;the phosphorus,sulfur,manganese,and oxygen contents calculated according to the compositions of molten steel and slag as well as the temperature of molten steel at the end-point of the basic oxygen furnace process were similar to the equilibrium values for the reaction between the slag and the steel.Less free calcium oxide and metallic iron were present in the final slag,and the surface of the slag mineral phase was smooth,clear,and well developed,which showed that the slag exhibited better melting effects than that produced using the conventional slag process.A steady phosphorus capacity in the slag and stable dephosphorization effects were achieved.展开更多
A traditional belief widespread across the biomedical community was that dietary habits and genetic predisposition were the basic factors causing colorectal cancer.In more recent times,however,a growing evidence has s...A traditional belief widespread across the biomedical community was that dietary habits and genetic predisposition were the basic factors causing colorectal cancer.In more recent times,however,a growing evidence has shown that other determinants can be very important in increasing(or reducing) incidence of this malignancy.The hypothesis that environmental and occupational risk factors are associated with colorectal cancer is gaining ground,and high risks of colorectal cancer have been reported among workers in some industrial branches.The aim of this study was to investigate the epidemiologic relationship between colorectal cancer and occupational exposures to several industrial activities,by means of a scientific literature review and meta-analysis.This work pointed out increased risks of colorectal cancer for labourers occupied in industries with a wide use of chemical compounds,such as leather(RR = 1.70,95%CI:1.24-2.34),basic metals(RR = 1.32,95%CI:1.07-1.65),plastic and rubber manufacturing(RR = 1.30,95%CI:0.98-1.71 and RR = 1.27,95%CI:0.92-1.76,respectively),besides workers in the sector of repair and installation of machinery exposed to asbestos(RR = 1.40,95%CI:1.07-1.84).Based on our results,the estimated crude excess risk fraction attributable to occupational exposure ranged from about 11% to about 15%.However,homogeneous pattern of association between colorectal cancer and industrial branches did not emerge from this review.展开更多
A lot of iron-bearing slags were produced,and whose grade is much more than that of industrial iron ore grade.Chemical analysis and phase identification shows that the iron-bearing slag is amorphous,has fayalite main ...A lot of iron-bearing slags were produced,and whose grade is much more than that of industrial iron ore grade.Chemical analysis and phase identification shows that the iron-bearing slag is amorphous,has fayalite main phase,iron grade is 36.10%,and is difficult to recover iron from the slag.Thermodynamic calculation indicates that CO cannot reduce fayalite at high temperature and carbon direct reduction can be effective.Moreover,the reaction begins at 770 ℃ and the temperature can be reduced down to 500℃ when CaO is added.On this basis,a method is put forward to making direct enrichment of iron by taking carbon contained pellets to realize the rapid reduction of fayalite,and the direct reduction process were studied in this paper.Experiments show that xC/xO should be less than 1.5 for the need of reduction and carburization,and CaO and Al2O3 can spur the reduction of fayalite.On conditions that xC/xO is 1.2,metallization rate can be 77% when temperature is 1 250 ℃ and only carbon is added,and metallization rate can be 74% when temperature is 1 200 ℃ and only CaO is added.Moreover the addition of Al2O3 can get a higher metallization rate（10% or so） than usual as R is between 0.4 and 1.0.Under the optimized condition of R equals to 0.6,temperature of 1 250 ℃,slag melting point of 1 320 ℃,and time of 30 min,the metallization rate can reach 88.43%.展开更多
Two types of layered hydroxide zinc m-aminobenzoate compounds with structures of layered basic metal salt （LBMS） were prepared by the reaction of zinc hydroxide with m-aminobenzoic acid solution in the temperature r...Two types of layered hydroxide zinc m-aminobenzoate compounds with structures of layered basic metal salt （LBMS） were prepared by the reaction of zinc hydroxide with m-aminobenzoic acid solution in the temperature range of 40----120℃. The formation reactions, structures, chemical compositions, and exfoliation reactions of the layered compounds in alcohol solvents were investigated by XRD, TG-DTA, SEM, and TEM. One layered phase with a basal spacing of 1.08 nm has a a-Ni（OH）2-1ike structure, and its chemical formula can be written as Zn（OH）0.67（m-NH2C6HaCOO）l.33. This phase has strip-like particle morphology and cannot be exfoliated into its nanosheets in alcohol solvents. The other layered phase with a basal spacing of 2.66 nm has a zinc hydrox- ide-nitrate-like structure, and can be exfoliated in alcohol solvents.展开更多
基金supported by the financial support from Natural Science Foundation of China(Nos.21871065,22209129 and 22071038)High-Level Innovation and Entrepreneurship(QCYRCXM-2022-123)+1 种基金support from the“Young Talent Support Plan”of Xi’an Jiaotong University(HG6J024)“Young Talent Lift Plan”of Xi’an city(095920221352).
文摘Electrocatalytic oxygen evolution reaction(OER)has been recognized as the bottleneck of overall water splitting,which is a promising approach for sustainable production of H_(2).Transition metal(TM)hydroxides are the most conventional and classical non-noble metal-based electrocatalysts for OER,while TM basic salts[M^(2+)(OH)_(2-x)(A_(m^(-))_(x/m),A=CO_(3)^(2−),NO_(3)^(−),F^(−),Cl^(−)]consisting of OH−and another anion have drawn extensive research interest due to its higher catalytic activity in the past decade.In this review,we summarize the recent advances of TM basic salts and their application in OER and further overall water splitting.We categorize TM basic salt-based OER pre-catalysts into four types(CO_(3)^(2−),NO_(3)^(−),F^(−),Cl^(−)according to the anion,which is a key factor for their outstanding performance towards OER.We highlight experimental and theoretical methods for understanding the structure evolution during OER and the effect of anion on catalytic performance.To develop bifunctional TM basic salts as catalyst for the practical electrolysis application,we also review the present strategies for enhancing its hydrogen evolution reaction activity and thereby improving its overall water splitting performance.Finally,we conclude this review with a summary and perspective about the remaining challenges and future opportunities of TM basic salts as catalysts for water electrolysis.
基金financially supported by the Beijing Natural Science Foundation of China(No.2172057)
文摘Double slag process was adopted to produce low-phosphorus steel from middle-phosphorus hot metal.To achieve a stable dephosphorization operation,conventional process was modified as follows：the blowing time was extended by approximately 1min by reducing the oxygen supply flow rate;calcium ferrite pellets were added to adjust the slag composition and viscosity;the dumping temperature was lowered by 30-50°C by the addition of calcium ferrite pellets during the double slag process to prevent phosphorus in the slag from returning to the molten steel;and the bottom-blown gas flow was increased during the blowing process.For 40 heats of comparative experiments,the rate of dephosphorization reached 91% and ranged between 87% and 95%;the phosphorus,sulfur,manganese,and oxygen contents calculated according to the compositions of molten steel and slag as well as the temperature of molten steel at the end-point of the basic oxygen furnace process were similar to the equilibrium values for the reaction between the slag and the steel.Less free calcium oxide and metallic iron were present in the final slag,and the surface of the slag mineral phase was smooth,clear,and well developed,which showed that the slag exhibited better melting effects than that produced using the conventional slag process.A steady phosphorus capacity in the slag and stable dephosphorization effects were achieved.
文摘A traditional belief widespread across the biomedical community was that dietary habits and genetic predisposition were the basic factors causing colorectal cancer.In more recent times,however,a growing evidence has shown that other determinants can be very important in increasing(or reducing) incidence of this malignancy.The hypothesis that environmental and occupational risk factors are associated with colorectal cancer is gaining ground,and high risks of colorectal cancer have been reported among workers in some industrial branches.The aim of this study was to investigate the epidemiologic relationship between colorectal cancer and occupational exposures to several industrial activities,by means of a scientific literature review and meta-analysis.This work pointed out increased risks of colorectal cancer for labourers occupied in industries with a wide use of chemical compounds,such as leather(RR = 1.70,95%CI:1.24-2.34),basic metals(RR = 1.32,95%CI:1.07-1.65),plastic and rubber manufacturing(RR = 1.30,95%CI:0.98-1.71 and RR = 1.27,95%CI:0.92-1.76,respectively),besides workers in the sector of repair and installation of machinery exposed to asbestos(RR = 1.40,95%CI:1.07-1.84).Based on our results,the estimated crude excess risk fraction attributable to occupational exposure ranged from about 11% to about 15%.However,homogeneous pattern of association between colorectal cancer and industrial branches did not emerge from this review.
基金Item Sponsored by National Science and Technology Support Program for 11th Five-Year Plan of China(2009BAB45B05)
文摘A lot of iron-bearing slags were produced,and whose grade is much more than that of industrial iron ore grade.Chemical analysis and phase identification shows that the iron-bearing slag is amorphous,has fayalite main phase,iron grade is 36.10%,and is difficult to recover iron from the slag.Thermodynamic calculation indicates that CO cannot reduce fayalite at high temperature and carbon direct reduction can be effective.Moreover,the reaction begins at 770 ℃ and the temperature can be reduced down to 500℃ when CaO is added.On this basis,a method is put forward to making direct enrichment of iron by taking carbon contained pellets to realize the rapid reduction of fayalite,and the direct reduction process were studied in this paper.Experiments show that xC/xO should be less than 1.5 for the need of reduction and carburization,and CaO and Al2O3 can spur the reduction of fayalite.On conditions that xC/xO is 1.2,metallization rate can be 77% when temperature is 1 250 ℃ and only carbon is added,and metallization rate can be 74% when temperature is 1 200 ℃ and only CaO is added.Moreover the addition of Al2O3 can get a higher metallization rate（10% or so） than usual as R is between 0.4 and 1.0.Under the optimized condition of R equals to 0.6,temperature of 1 250 ℃,slag melting point of 1 320 ℃,and time of 30 min,the metallization rate can reach 88.43%.
基金Project supported by the Shaanxi Provincial Natural Science Foundation （No. 2007B24）, and the Education Office of Shaanxi Province （No. 2010JK409） of China.
文摘Two types of layered hydroxide zinc m-aminobenzoate compounds with structures of layered basic metal salt （LBMS） were prepared by the reaction of zinc hydroxide with m-aminobenzoic acid solution in the temperature range of 40----120℃. The formation reactions, structures, chemical compositions, and exfoliation reactions of the layered compounds in alcohol solvents were investigated by XRD, TG-DTA, SEM, and TEM. One layered phase with a basal spacing of 1.08 nm has a a-Ni（OH）2-1ike structure, and its chemical formula can be written as Zn（OH）0.67（m-NH2C6HaCOO）l.33. This phase has strip-like particle morphology and cannot be exfoliated into its nanosheets in alcohol solvents. The other layered phase with a basal spacing of 2.66 nm has a zinc hydrox- ide-nitrate-like structure, and can be exfoliated in alcohol solvents.
