Developing high-efficiency and low-cost catalysts towards oxygen evolution reaction(OER)is extremely important for overall water splitting and rechargeable metal-air batteries.Herein we propose a promising organometal...Developing high-efficiency and low-cost catalysts towards oxygen evolution reaction(OER)is extremely important for overall water splitting and rechargeable metal-air batteries.Herein we propose a promising organometallic coordination polymer(OCP)induced strategy to construct hierarchical N-doped carbon framework with NiFe nanoparticles encapsulated inside(NxFe@N-C)as a highly active and stable OER catalyst.The synthesis of OCP precursor depends on the unique molecular structure of iminodiacetonitrile(IDAN),which can coordinate with metal ions to form Ni2Fe(CN)6 with prussian blue analogs(PBA)structure.Unlike previous PBA-induced methods,the thickness of the carbon layer covering the surface of the metal core can be well controlled during the pyrolysis through adjusting the amount of IDAN,which builds a wonderful bridge for investigating the relationship between carbon layer thickness and catalytic performance.Both the experimental characterizations and theoretical studies validate that a suitable carbon layers thickness leads to optimal OER activity and stability.By optimizing the structure and composition,the optimized Ni_(3)Fe@N-C with hierarchical framework exhibits the low overpotentials(260 mV at 10 mA cm^(-2);320 mV at 50 mA cm^(-2)),improved kinetics(79 mV dec^(-1)),and robust long-term stability,which exceeds those of benchmark RuO_(2).展开更多
A novel coordination polymer, [Fe(C 5H 4NCOO) 2] n, was synthesized by hydrothermal reaction and characterized by elemental analysis as well as IR spectroscopy. The crystal structure (with a novel 3-D network) of this...A novel coordination polymer, [Fe(C 5H 4NCOO) 2] n, was synthesized by hydrothermal reaction and characterized by elemental analysis as well as IR spectroscopy. The crystal structure (with a novel 3-D network) of this compound belongs to monoclinic, space group P2 1/n, a=0.49544(1) nm, b=1.32443(2) nm, c=1.04983(1) nm, β=101.586(1)°. The diffuse reflectance spectra (200～2500 nm) showed that the polymer had strong absorbance in 375～563 nm (E g≈2.5 eV) region and weak absorbance from 720 to 2500 nm (near infrared spectra).展开更多
The kinetics of gellation reaction between amphoteric polyacrylamide(APAM) and water soluble phenol-formaldehyde resin has been studied. The whole gelation process could be divided into three periods:induction period,...The kinetics of gellation reaction between amphoteric polyacrylamide(APAM) and water soluble phenol-formaldehyde resin has been studied. The whole gelation process could be divided into three periods:induction period, acceleration period and steady period. The accelerative increase period ranged in 3～17 days determines the incremental amount of gelling velocity and gel viscosity, and its gelling kinetics equation is η=η 0+kt 0.9(25 ℃). There are two factors which are the doses of water soluble phenol formaldehyde resin as crosslinker and the molecular weight of APAM affecting the gelling velocity at temperature 40～70 ℃, the former is the more prominent. The gelling reaction rate constant k could be controlled in 1 57～3 13 Pa·s/d 0.9 for reaction of 0 4% APAM solution with 0 2%～0 8% resol as crosslinker at reaction temperature 50 ℃ and the gel viscosity being reached to the maximum values of 16 2～29 0 Pa·s.展开更多
基金the financial supported by the National Natural Science Foundation of China(Nos.22109073,22072067 and 21875112)the Natural Science Foundation of Jiangsu Province(No.BK20200711)+2 种基金supported from the National and Local Joint Engineering Research Center of Biomedical Functional Materials and a project sponsored by the Priority Academic Program Development of Jiangsu Higher Education InstitutionsZ.Li thanks Postgraduate Research&Practice Innovation Program of Jiangsu Province(No.KYCX21_1326)China Scholarship Council(No.202006860026).
文摘Developing high-efficiency and low-cost catalysts towards oxygen evolution reaction(OER)is extremely important for overall water splitting and rechargeable metal-air batteries.Herein we propose a promising organometallic coordination polymer(OCP)induced strategy to construct hierarchical N-doped carbon framework with NiFe nanoparticles encapsulated inside(NxFe@N-C)as a highly active and stable OER catalyst.The synthesis of OCP precursor depends on the unique molecular structure of iminodiacetonitrile(IDAN),which can coordinate with metal ions to form Ni2Fe(CN)6 with prussian blue analogs(PBA)structure.Unlike previous PBA-induced methods,the thickness of the carbon layer covering the surface of the metal core can be well controlled during the pyrolysis through adjusting the amount of IDAN,which builds a wonderful bridge for investigating the relationship between carbon layer thickness and catalytic performance.Both the experimental characterizations and theoretical studies validate that a suitable carbon layers thickness leads to optimal OER activity and stability.By optimizing the structure and composition,the optimized Ni_(3)Fe@N-C with hierarchical framework exhibits the low overpotentials(260 mV at 10 mA cm^(-2);320 mV at 50 mA cm^(-2)),improved kinetics(79 mV dec^(-1)),and robust long-term stability,which exceeds those of benchmark RuO_(2).
文摘A novel coordination polymer, [Fe(C 5H 4NCOO) 2] n, was synthesized by hydrothermal reaction and characterized by elemental analysis as well as IR spectroscopy. The crystal structure (with a novel 3-D network) of this compound belongs to monoclinic, space group P2 1/n, a=0.49544(1) nm, b=1.32443(2) nm, c=1.04983(1) nm, β=101.586(1)°. The diffuse reflectance spectra (200～2500 nm) showed that the polymer had strong absorbance in 375～563 nm (E g≈2.5 eV) region and weak absorbance from 720 to 2500 nm (near infrared spectra).
文摘The kinetics of gellation reaction between amphoteric polyacrylamide(APAM) and water soluble phenol-formaldehyde resin has been studied. The whole gelation process could be divided into three periods:induction period, acceleration period and steady period. The accelerative increase period ranged in 3～17 days determines the incremental amount of gelling velocity and gel viscosity, and its gelling kinetics equation is η=η 0+kt 0.9(25 ℃). There are two factors which are the doses of water soluble phenol formaldehyde resin as crosslinker and the molecular weight of APAM affecting the gelling velocity at temperature 40～70 ℃, the former is the more prominent. The gelling reaction rate constant k could be controlled in 1 57～3 13 Pa·s/d 0.9 for reaction of 0 4% APAM solution with 0 2%～0 8% resol as crosslinker at reaction temperature 50 ℃ and the gel viscosity being reached to the maximum values of 16 2～29 0 Pa·s.
