Nanostructured HoFeO_(3)powders were obtained by solution combustion method at various glycinenitrate ratios(G/N=0.2,0.4,...,1.4).According to X-ray powder diffractometry data,the presence of two modifications of HoFe...Nanostructured HoFeO_(3)powders were obtained by solution combustion method at various glycinenitrate ratios(G/N=0.2,0.4,...,1.4).According to X-ray powder diffractometry data,the presence of two modifications of HoFeO_(3)in the synthesized samples was established:orthorhombic(Pbnm)and hexagonal(P63/mmc).The crystallite size of the obtained compositions varies from 62±6 to 29±3 nm,depending on the G/N ratio.From magnetic structure studies,it is found that HoFeO_(3)obtained with a stoichiometric amount of glycine in the reaction solution is in the magnetically ordered state and is represented by a sextet with quadrupole splitting(QS)=0 mm/s,isomeric shift(IS)=0.36 mm/s and effective field strength(Heff)=497 kOe.According to the results of vibrational magnetometry,it is found that the orthoferrites obtained have a ferromagnetic structure,the main parameters of which(Ms,Mr and Hc)systematically change with a change in the redox ratio of the reaction mixture and,as a consequence,their phase composition,and reach maximum values at a G/N ratio=0.6.In the samples obtained with a significant excess and lack of glycine(G/N=0.2 and 1.4),despite their amorphous nature,hysteresis loops characteristic of the ferromagnetic state of the substance is observed.It is hopeful to obtain a pure hexagonal modification of HoFeO_(3)via heat treatment on amorphous products of glycine-nitrate combustion.展开更多
The catalytic transferred of small molecules into high-value chemical products in green methods are highly perused,and has obtained huge attention.In this field,great progress has been achieved during the past five ye...The catalytic transferred of small molecules into high-value chemical products in green methods are highly perused,and has obtained huge attention.In this field,great progress has been achieved during the past five years.Followed by the roadmap(Chinese Chemical Letters,2019,30,2089-2109)written by us before five years,we think that it should be updated to give more insights in this field.Thus,we write the present roadmap based on the fast changed background.In this roadmap,oxygen and carbon dioxide reduction reactions(including at high temperature),photocatalytic hydrogen generation and carbon dioxide reduction reactions,(photo)electrocatalytic reduction of O_(2)to H_(2)O_(2)and NH_(3)generated from N_(2) are discussed.The progress and challenges in above catalytic processes are given.We believe this manuscript will give the researchers more suggestions and help them to obtain useful information in this field.展开更多
文摘Nanostructured HoFeO_(3)powders were obtained by solution combustion method at various glycinenitrate ratios(G/N=0.2,0.4,...,1.4).According to X-ray powder diffractometry data,the presence of two modifications of HoFeO_(3)in the synthesized samples was established:orthorhombic(Pbnm)and hexagonal(P63/mmc).The crystallite size of the obtained compositions varies from 62±6 to 29±3 nm,depending on the G/N ratio.From magnetic structure studies,it is found that HoFeO_(3)obtained with a stoichiometric amount of glycine in the reaction solution is in the magnetically ordered state and is represented by a sextet with quadrupole splitting(QS)=0 mm/s,isomeric shift(IS)=0.36 mm/s and effective field strength(Heff)=497 kOe.According to the results of vibrational magnetometry,it is found that the orthoferrites obtained have a ferromagnetic structure,the main parameters of which(Ms,Mr and Hc)systematically change with a change in the redox ratio of the reaction mixture and,as a consequence,their phase composition,and reach maximum values at a G/N ratio=0.6.In the samples obtained with a significant excess and lack of glycine(G/N=0.2 and 1.4),despite their amorphous nature,hysteresis loops characteristic of the ferromagnetic state of the substance is observed.It is hopeful to obtain a pure hexagonal modification of HoFeO_(3)via heat treatment on amorphous products of glycine-nitrate combustion.
基金supported by the National Natural Science Foundation of China(Nos.22268003,22102095,52204320,U20A20246 and 12275199,U22A20418,22075196,21972110,52202208)National Key Research and Development Program of China(Nos.2023YFA1507903,2022YFB3803600,2022YFB4002501)+9 种基金SINOPEC(Beijing)Research Institute of Chemical Industry Co.,Ltd.(No.223239)the Fundamental Research Funds for the Central Universities(No.CCNU22JC017)the Postdoctoral Science Foundation of China(No.2021M692535)the Natural Science Foundation of Shaanxi Province(No.2022JQ-095)the Basic Research Project Foundation of Xi’an Jiaotong University(No.xzy012024012)the Youth Foundation of State Key Laboratory of Electrical Insulation and Power Equipment(No.EIPE2131)the Russian Science Foundation(No.22-13-00035)the Ministry of Science and Higher Education within the framework of a State Assignment of the Ioffe Institute,Russian Academy of Sciences(No.FFUG-2024-0036)Yunnan Fundamental Research Projects(No.202305AF150116)the Research Project Supported by Shanxi Scholarship Council of China(No.2022-050)。
文摘The catalytic transferred of small molecules into high-value chemical products in green methods are highly perused,and has obtained huge attention.In this field,great progress has been achieved during the past five years.Followed by the roadmap(Chinese Chemical Letters,2019,30,2089-2109)written by us before five years,we think that it should be updated to give more insights in this field.Thus,we write the present roadmap based on the fast changed background.In this roadmap,oxygen and carbon dioxide reduction reactions(including at high temperature),photocatalytic hydrogen generation and carbon dioxide reduction reactions,(photo)electrocatalytic reduction of O_(2)to H_(2)O_(2)and NH_(3)generated from N_(2) are discussed.The progress and challenges in above catalytic processes are given.We believe this manuscript will give the researchers more suggestions and help them to obtain useful information in this field.
