The distribution of He in η-Fe2C has been studied by first-principles calculations.The formation energies of interstitial He and substitutional He（replacing Fe） are 3.76 eV and 3.49 eV,respectively,which are remark...The distribution of He in η-Fe2C has been studied by first-principles calculations.The formation energies of interstitial He and substitutional He（replacing Fe） are 3.76 eV and 3.49 eV,respectively,which are remarkably smaller than those in bcc Fe,indicating that He is more soluble in η-Fe2C than in bcc Fe.The binding potencies of both a substitutionalinterstitial He pair（1.28 eV） and a substitutional-substitutional He pair（0.76 eV） are significantly weaker than those in bcc Fe.The binding energy between the two He atoms in an interstitial-interstitial He pair（0.31 eV） is the same as that in bcc Fe,but the diffusion barrier of interstitial He（0.35 eV） is much larger than that in bcc Fe,suggesting that it is more difficult for the interstitial He atom to agglomerate in η-Fe2C than in bcc Fe.Thus,self-trapping of He in η-Fe2C is less powerful than that in bcc Fe.As a consequence,small and dense η-Fe2C particles in ferritic steels might serve as scattered trapping centers for He,slow down He bubble growth at the initial stage,and make the steel more swelling resistant.展开更多
Fenton or photocatalytic degradations of organic contaminants are recognized as promising approaches to address the increasing environmental pollution issues.Herein,we develop the effective synergistic catalysis react...Fenton or photocatalytic degradations of organic contaminants are recognized as promising approaches to address the increasing environmental pollution issues.Herein,we develop the effective synergistic catalysis reaction of Fenton and photocatalysis based on a loofah sponge-like Fe_(2)O_(x)/C nanocomposite,which exhibits excellent nitrobenzene photocatalytic degradation property.It is noted that Fe2O3 nanoparticles with surface Fe^(2+) species were encapsulated with an ultrathin carbon layer(denoted as Fe_(2)O_(x)/C)via a supramolecular self-sacrificing template and following thermal treatment process.The experimental results indicated that the thin layer carbon coating not only inhibited the Fe iron leaching from the Fe_(2)O_(x)but also prompted the separation and transferring of electrons–hole pairs.The introduction of Fe_(2)O_(x)/C enables the Fenton reaction to induce a rapid Fe^(2+)/Fe^(3+)cycle,and meanwhile,together with the photocatalytic reaction to produce continuous active substances for the subsequent degradation catalytic reaction without successive H2O2,resulting in the inexpensive and the effective photocatalytic procedure.As a result,100%nitrobenzene(100 mg/L)was degraded and 97%of the organic carbon was mineralized in 90 min using the Fe_(2)O_(x)/C(0.1 g/L)at a low H_(2)O_(2) dosage(0.50 mM),under air mass(AM)1.5 irradiation.Theoretical calculations confirmed that the Fe_(2)O_(x)/C-600 with thin carbon layer promoted the dissociation of H2O2 and the·OH desorption.The synergistic catalysis of this work may provide new ideas for low-cost and more efficient treatment of pollutants.展开更多
基金Project supported by the Research Key Project of Science and Technology of Education Bureau of Henan Province,China(Grant Nos.14A140030,15A140032,15B150010,and 15A430037)the Innovation Talents Program of Science and Technology of Institution of Higher Education of Henan Province,China(Grant No.14HASTIT044)
文摘The distribution of He in η-Fe2C has been studied by first-principles calculations.The formation energies of interstitial He and substitutional He（replacing Fe） are 3.76 eV and 3.49 eV,respectively,which are remarkably smaller than those in bcc Fe,indicating that He is more soluble in η-Fe2C than in bcc Fe.The binding potencies of both a substitutionalinterstitial He pair（1.28 eV） and a substitutional-substitutional He pair（0.76 eV） are significantly weaker than those in bcc Fe.The binding energy between the two He atoms in an interstitial-interstitial He pair（0.31 eV） is the same as that in bcc Fe,but the diffusion barrier of interstitial He（0.35 eV） is much larger than that in bcc Fe,suggesting that it is more difficult for the interstitial He atom to agglomerate in η-Fe2C than in bcc Fe.Thus,self-trapping of He in η-Fe2C is less powerful than that in bcc Fe.As a consequence,small and dense η-Fe2C particles in ferritic steels might serve as scattered trapping centers for He,slow down He bubble growth at the initial stage,and make the steel more swelling resistant.
基金the National Key R&D Program of China(No.2018YFE0201704)the National Natural Science Foundation of China(No.21771061)the Outstanding Youth Fund of Heilongjiang Province(No.JQ 2020B002).
文摘Fenton or photocatalytic degradations of organic contaminants are recognized as promising approaches to address the increasing environmental pollution issues.Herein,we develop the effective synergistic catalysis reaction of Fenton and photocatalysis based on a loofah sponge-like Fe_(2)O_(x)/C nanocomposite,which exhibits excellent nitrobenzene photocatalytic degradation property.It is noted that Fe2O3 nanoparticles with surface Fe^(2+) species were encapsulated with an ultrathin carbon layer(denoted as Fe_(2)O_(x)/C)via a supramolecular self-sacrificing template and following thermal treatment process.The experimental results indicated that the thin layer carbon coating not only inhibited the Fe iron leaching from the Fe_(2)O_(x)but also prompted the separation and transferring of electrons–hole pairs.The introduction of Fe_(2)O_(x)/C enables the Fenton reaction to induce a rapid Fe^(2+)/Fe^(3+)cycle,and meanwhile,together with the photocatalytic reaction to produce continuous active substances for the subsequent degradation catalytic reaction without successive H2O2,resulting in the inexpensive and the effective photocatalytic procedure.As a result,100%nitrobenzene(100 mg/L)was degraded and 97%of the organic carbon was mineralized in 90 min using the Fe_(2)O_(x)/C(0.1 g/L)at a low H_(2)O_(2) dosage(0.50 mM),under air mass(AM)1.5 irradiation.Theoretical calculations confirmed that the Fe_(2)O_(x)/C-600 with thin carbon layer promoted the dissociation of H2O2 and the·OH desorption.The synergistic catalysis of this work may provide new ideas for low-cost and more efficient treatment of pollutants.
