Yaling Wu,Zhaopeng Sun,Yingying Chen,Dan Liu,Yan Meng,Zheng Yan
Metal synergy can enhance the catalytic performance, and a prefabricated solid precursor can guide the ordered embedding, of secondary metal source ions for the rapid synthesis of bimetallic organic frameworks (MM’-MOFs) with a stoichiometric ratio of 1:1. In this paper, Co-MOF-1D containing well-defined binding sites was synthesized by mechanical ball milling, which was used as a template for the induced introduction of Fe ions to successfully assemble the ordered bimetallic Co 1 Fe 1 -MOF-74@2 (where @2 denotes template-directed synthesis of MOF-74). Its electrocatalytic performance is superior to that of the conventional one-step-synthesized Co 1 Fe 1 -MOF-74@1 (where @1 denotes one-step synthesis of MOF-74), and the ratio of the two metal sources, Co and Fe, is close to 1:1. Meanwhile, the iron valence states (Fe II and Fe III ) in Co 1 Fe 1 -MOF-74@2 were further regulated to obtain the electrocatalytic materials Co 1 Fe 1 (II)-MOF-74@2 and Co 1 Fe 1 (III)-MOF-74@2 . The electrochemical performance test results confirm that Co 1 Fe 1 (II)-MOF-74@2 regulated by valence state has a better catalytic performance than Co 1 Fe 1 (III)-MOF-74@2 in the oxygen evolution reaction (OER) process. This phenomenon is related to the gradual increase in the valence state of Fe ions in Co 1 Fe 1 (II)-MOF-74@2 , which promotes the continuous improvement in the performance of the MOF before reaching the optimal steady state and makes the OER performance reach the optimum when the Fe II /Fe III mixed-valence state reaches a certain proportion. This provides a new idea for the directed synthesis and optimization of highly efficient catalysts.
Kaixin Zhu,Changzi Jin,Chunxiao Zhao,Ruisheng Hu,Zoltán Klencsár,Ganeshraja Ayyakannu Sundaram,Dávid F. Srankó,Rile Ge,Junhu Wang
Simple-controlled synthesis of multiple porous and monodisperse cobalt-iron oxides were realized by varying the prepared conditions via a template-assisted glycol solvothermal process. The obtained materials were characterized by X-ray diffraction, transmission electron microscopy, scanning electron microscopy, Mössbauer spectroscopy and nitrogen adsorption/desorption measurement. It was found that the amounts of metal precursors and the Co:Fe ratio significantly influenced the morphology, the crystallinity, as well as the textural and electronic properties of the cobalt-iron products. The different cobalt-iron oxides with various shells were employed into the catalytic activation of peroxymonosulfate (PMS) for Orange II degradation, among which, multi-shelled cobalt ferrite microsphere was certified to perform the best activity due to the coefficient contribution of higher content of octahedral Co 2+ , more exposed active sites and the reservoir effect. Sulfate and hydroxyl radicals were crucial reactive species in Orange II degradation, proved by the scavenger quenching test. This work shows that cobalt-iron oxide microspheres with such architecture make differences in the PMS-mediated aqueous organics degradation system, which extends the perspective and application of such functional oxides in the environmental field.
危险品化学品经营许可证（带存储）