Heterogeneous catalysts with ultra-small clusters and atomically dispersed(USCAD)active sites have gained increasing attention in recent years.However,developing USCAD catalysts with high-density metal sites anchored ...Heterogeneous catalysts with ultra-small clusters and atomically dispersed(USCAD)active sites have gained increasing attention in recent years.However,developing USCAD catalysts with high-density metal sites anchored in porous nanomaterials is still challenging.Here,through the template-free S-assisted pyrolysis of low-cost Fe-salts with melamine(MA),porous alveolate Fe/g-C3N4 catalysts with high-density(Fe loading up to 17.7 wt%)and increased USCAD Fe sites were synthesized.The presence of a certain amount of S species in the Fe-salts/MA system plays an important role in the formation of USCAD S-Fe-salt/CN catalysts;the S species act as a"sacrificial carrier"to increase the dispersion of Fe species through Fe-S coordination and generate porous alveolate structure by escaping in the form of SO2 during pyrolysis.The S-Fe-salt/CN catalysts exhibit greatly promoted activity and reusability for degrading various organic pollutants in advanced oxidation processes compared to the corresponding Fe-salt/CN catalysts,due to the promoted accessibility of USCAD Fe sites by the porous alveolate structure.This S-assisted method exhibits good feasibility in a large variety of S species(thiourea,S powder,and NH4SCN)and Fe salts,providing a new avenue for the low-cost and large-scale synthesis of high-density USCAD metal/g-C3N4 catalysts.展开更多
4f chemistry studies the chemical bonding characteristics of fifteen lanthanide (Ln) elements in the periodic table and their wide applications in materials sciences and engineering, which forms the scientific fundame...4f chemistry studies the chemical bonding characteristics of fifteen lanthanide (Ln) elements in the periodic table and their wide applications in materials sciences and engineering, which forms the scientific fundamentals ofⅥperiodic elements in the periodic table of elements. Orbital hybridization modes of Ln elements clarify their chemical bonding nature in all reaction systems. Wide coordination number (CN) option, ranging from 2 to 16, is the reason why Ln elements are the treasure of new materials, therefore, searching for novel materials may be well carried out via the rational design of coordination environment of central Ln cations to stabilize their variable energy states. Balance utilization of Ln elements is dependent on their coordination architecture in the crystallographic frame, Ln elements can be replaced by non-Ln elements when CN <10, and when CN≥10 expensive Ln elements can be replaced by those cheaper ones.展开更多
文摘Heterogeneous catalysts with ultra-small clusters and atomically dispersed(USCAD)active sites have gained increasing attention in recent years.However,developing USCAD catalysts with high-density metal sites anchored in porous nanomaterials is still challenging.Here,through the template-free S-assisted pyrolysis of low-cost Fe-salts with melamine(MA),porous alveolate Fe/g-C3N4 catalysts with high-density(Fe loading up to 17.7 wt%)and increased USCAD Fe sites were synthesized.The presence of a certain amount of S species in the Fe-salts/MA system plays an important role in the formation of USCAD S-Fe-salt/CN catalysts;the S species act as a"sacrificial carrier"to increase the dispersion of Fe species through Fe-S coordination and generate porous alveolate structure by escaping in the form of SO2 during pyrolysis.The S-Fe-salt/CN catalysts exhibit greatly promoted activity and reusability for degrading various organic pollutants in advanced oxidation processes compared to the corresponding Fe-salt/CN catalysts,due to the promoted accessibility of USCAD Fe sites by the porous alveolate structure.This S-assisted method exhibits good feasibility in a large variety of S species(thiourea,S powder,and NH4SCN)and Fe salts,providing a new avenue for the low-cost and large-scale synthesis of high-density USCAD metal/g-C3N4 catalysts.
基金supported by the National Natural Science Foundation of China(22278056)Liaoning Revitalization Talent Program(XLYC2008032)the Fundamental Research Funds for the Central Universities(DUT22LAB602)。
基金supported by the National Key Research and Development Program of China(2016YFB0701004)Jilin Province Science and Technology Development Project(20170101092JC)
文摘4f chemistry studies the chemical bonding characteristics of fifteen lanthanide (Ln) elements in the periodic table and their wide applications in materials sciences and engineering, which forms the scientific fundamentals ofⅥperiodic elements in the periodic table of elements. Orbital hybridization modes of Ln elements clarify their chemical bonding nature in all reaction systems. Wide coordination number (CN) option, ranging from 2 to 16, is the reason why Ln elements are the treasure of new materials, therefore, searching for novel materials may be well carried out via the rational design of coordination environment of central Ln cations to stabilize their variable energy states. Balance utilization of Ln elements is dependent on their coordination architecture in the crystallographic frame, Ln elements can be replaced by non-Ln elements when CN <10, and when CN≥10 expensive Ln elements can be replaced by those cheaper ones.
