本文以稻壳基多孔炭为载体,采用硼氢化钠为还原剂,制备了非贵金属负载复合材料,即Fe-AC、Co-AC和Ni-AC。采用XRD、SEM、BET和XPS分别表征复合材料的物理化学性质。将复合材料分别制成的复合电极,在1 M KOH的三电极体系中,利用循环伏安...本文以稻壳基多孔炭为载体,采用硼氢化钠为还原剂,制备了非贵金属负载复合材料,即Fe-AC、Co-AC和Ni-AC。采用XRD、SEM、BET和XPS分别表征复合材料的物理化学性质。将复合材料分别制成的复合电极,在1 M KOH的三电极体系中,利用循环伏安、交流阻抗、电化学活性表面积(ECSA)、塔菲尔斜率等方法研究复合电极电催化氧化肼(HzOR)的性能与机理。结果表明,成功地获得了非贵金属包膜多孔炭复合材料,并成功地应用于碱体系的电催化氧化肼中。综合性能推断,其中Co-AC比表面积可达到804.4 m^(2)/g,Co-AC表现出最高的ECSA为49.3 cm^(2),扫速为10 mV/s时反应速率最快,并且能在大于100 mA/cm^(2)的电流密度下保持持续稳定工作,说明具有良好的稳定性。展开更多
C1 chemistry is the essence of coal chemistry and natural gas chemistry. Catalytic methods to efficiently convert C1 molecules into fuels and chemicals have been extensively studied. Syngas（CO ＋H_2） conversion is t...C1 chemistry is the essence of coal chemistry and natural gas chemistry. Catalytic methods to efficiently convert C1 molecules into fuels and chemicals have been extensively studied. Syngas（CO ＋H_2） conversion is the most important industrial reaction system in C1 chemistry, and Fe and Co catalysts, two major industrial catalysts, have been the focus of fundamental research and industrial application. In the last decade, considerable research efforts have been devoted to discoveries concerning catalyst structure and increasing market demands for olefins and oxygenates. Since the development of efficient catalysts would strongly benefit from catalyst design and the establishment of a new reaction system, this review comprehensively overviews syngas conversion in three main reactions, highlights the advances recently made and the challenges that remain open, and will stimulate future research activities. The first part of the review summarizes the breakthroughs in Fischer-Tropsch synthesis regarding the optimization of activity and stability, determination of the active phase, and mechanistic studies. The second part overviews the modulation of catalytic structure and product selectivity for Fischer-Tropsch to olefins（FTO）. Catalysts designed to produce higher alcohols, as well as to tune product selectivity in C1 chemistry, are described in the third section. Finally, present challenges in syngas conversion are proposed, and the solutions and prospects are discussed from the viewpoint of fundamental research and practical application. This review summarizes the latest advances in the design, preparation, and application of Fe/Co-based catalysts toward syngas conversion and presents the challenges and future directions in producing value-added fuels.展开更多
Ingenious establishment of transition metal-nitrogen-carbon electrocatalysts with diverse catalytic active sites and hierarchically porous frameworks is highly significant to boost the oxygen reduction reaction(ORR)in...Ingenious establishment of transition metal-nitrogen-carbon electrocatalysts with diverse catalytic active sites and hierarchically porous frameworks is highly significant to boost the oxygen reduction reaction(ORR)in Zn-air batteries(ZABs).In this study,Fe/Co co-doped zeolitic imidazolium frameworks(ZIFs)and graphitic carbon nitride(g-C_(3)N_(4))were integrated and pyrolyzed to construct carbon-based electrocatalysts containing Fe,Co and N elements(labelled as Co-CoFe@NRPC),in which atomic-sc ale FeN_x and CoN_x,and nano scale metallic Co and CoFe alloy moieties were aligned with hierarchically porous N-doped carbon frameworks constructed by interconnected micropolyhedrons,nano tubes and nanosheets.The diverse active moieties guaranteed excellent intrinsic catalytic activity,while the hierarchically porous N-doped carbon frameworks ensured admirable accessibility of the catalytic active sites,excellent electrical conductivity,satisfactory mass transport and good durability.Expectedly,the optimized Co-CoFe@NRPC-90(with 90 mg g-C_(3)N_(4) added)electrocatalyst exhibited excellent ORR performance with a high half-wave potential of 885 mV(vs.reversible hydrogen electrode(RHE)),diffusion-limiting current density of 6.15 mA·cm^(-2),desirable durability and methanol tolerance.Simultaneously,the liquid ZAB established with Co-CoFe@NRPC-90 as an air-cathode electrocatalyst manifested an outstanding power density(281 mW·cm^(-2))and specific capacity(820.9 mAh·g_(Zn)^(-1)),transcending the liquid ZAB based on a commercial Pt/C electrocatalyst.展开更多
The experimental apparatus by self-designed was used,Fe/Co particles encapsulated in multi-walled carbon nanotubes(MWCNTs) were prepared by the method of anodic arc discharging plasma. The products were characterized ...The experimental apparatus by self-designed was used,Fe/Co particles encapsulated in multi-walled carbon nanotubes(MWCNTs) were prepared by the method of anodic arc discharging plasma. The products were characterized by transmission election microscopy,Raman spectroscopy and X-ray diffractometry. The magnetic properties of the products were characterized with vibration sample magnetometer. The TEM results show that MWCNTs have little impurity and good particles size,and Fe/Co with high continuity encapsulaties in carbon nanotubes. The saturated magnetization(σs),remanence(σm) and coercivity(Hc) of the sample are 17.30 A/(m·kg),3.96 A/(m·kg) and 31 521.60 A/m,showing better ferromagnetism compared with the bulk Fe/Co. The optimal conditions in this case are as follows:a helium gas atmosphere of 6.0×104 Pa,an arc current of 70 A,a voltage drop of 24 V,a constant distance of about 2 mm between the anodes and cathode,metallic powder contents of Fe and Co of 15.0%(mass fraction) and 15.0%,respectively,and well cooled electrodes and collector. This process is a convenient and effective that Fe/Co particles can be encapsulated in MWCNTs.展开更多
文摘C1 chemistry is the essence of coal chemistry and natural gas chemistry. Catalytic methods to efficiently convert C1 molecules into fuels and chemicals have been extensively studied. Syngas（CO ＋H_2） conversion is the most important industrial reaction system in C1 chemistry, and Fe and Co catalysts, two major industrial catalysts, have been the focus of fundamental research and industrial application. In the last decade, considerable research efforts have been devoted to discoveries concerning catalyst structure and increasing market demands for olefins and oxygenates. Since the development of efficient catalysts would strongly benefit from catalyst design and the establishment of a new reaction system, this review comprehensively overviews syngas conversion in three main reactions, highlights the advances recently made and the challenges that remain open, and will stimulate future research activities. The first part of the review summarizes the breakthroughs in Fischer-Tropsch synthesis regarding the optimization of activity and stability, determination of the active phase, and mechanistic studies. The second part overviews the modulation of catalytic structure and product selectivity for Fischer-Tropsch to olefins（FTO）. Catalysts designed to produce higher alcohols, as well as to tune product selectivity in C1 chemistry, are described in the third section. Finally, present challenges in syngas conversion are proposed, and the solutions and prospects are discussed from the viewpoint of fundamental research and practical application. This review summarizes the latest advances in the design, preparation, and application of Fe/Co-based catalysts toward syngas conversion and presents the challenges and future directions in producing value-added fuels.
基金financially supported by the National Natural Science Foundation of China (No.51972109)the Natural Science Foundation of Hunan Province (No.2023JJ30276)+1 种基金the Scientific Research Fund of Hunan Provincial EducationDepartment,China (Nos.22A0473 and 20A225)the Postgraduate Research Innovation Fund of Hunan Institute of Science and Technology (No.2022-38)。
文摘Ingenious establishment of transition metal-nitrogen-carbon electrocatalysts with diverse catalytic active sites and hierarchically porous frameworks is highly significant to boost the oxygen reduction reaction(ORR)in Zn-air batteries(ZABs).In this study,Fe/Co co-doped zeolitic imidazolium frameworks(ZIFs)and graphitic carbon nitride(g-C_(3)N_(4))were integrated and pyrolyzed to construct carbon-based electrocatalysts containing Fe,Co and N elements(labelled as Co-CoFe@NRPC),in which atomic-sc ale FeN_x and CoN_x,and nano scale metallic Co and CoFe alloy moieties were aligned with hierarchically porous N-doped carbon frameworks constructed by interconnected micropolyhedrons,nano tubes and nanosheets.The diverse active moieties guaranteed excellent intrinsic catalytic activity,while the hierarchically porous N-doped carbon frameworks ensured admirable accessibility of the catalytic active sites,excellent electrical conductivity,satisfactory mass transport and good durability.Expectedly,the optimized Co-CoFe@NRPC-90(with 90 mg g-C_(3)N_(4) added)electrocatalyst exhibited excellent ORR performance with a high half-wave potential of 885 mV(vs.reversible hydrogen electrode(RHE)),diffusion-limiting current density of 6.15 mA·cm^(-2),desirable durability and methanol tolerance.Simultaneously,the liquid ZAB established with Co-CoFe@NRPC-90 as an air-cathode electrocatalyst manifested an outstanding power density(281 mW·cm^(-2))and specific capacity(820.9 mAh·g_(Zn)^(-1)),transcending the liquid ZAB based on a commercial Pt/C electrocatalyst.
基金Project (ZS-011-A25-007) supported by the Natural Science Foundation of Gansu province, China
文摘The experimental apparatus by self-designed was used,Fe/Co particles encapsulated in multi-walled carbon nanotubes(MWCNTs) were prepared by the method of anodic arc discharging plasma. The products were characterized by transmission election microscopy,Raman spectroscopy and X-ray diffractometry. The magnetic properties of the products were characterized with vibration sample magnetometer. The TEM results show that MWCNTs have little impurity and good particles size,and Fe/Co with high continuity encapsulaties in carbon nanotubes. The saturated magnetization(σs),remanence(σm) and coercivity(Hc) of the sample are 17.30 A/(m·kg),3.96 A/(m·kg) and 31 521.60 A/m,showing better ferromagnetism compared with the bulk Fe/Co. The optimal conditions in this case are as follows:a helium gas atmosphere of 6.0×104 Pa,an arc current of 70 A,a voltage drop of 24 V,a constant distance of about 2 mm between the anodes and cathode,metallic powder contents of Fe and Co of 15.0%(mass fraction) and 15.0%,respectively,and well cooled electrodes and collector. This process is a convenient and effective that Fe/Co particles can be encapsulated in MWCNTs.
