The hydrogenation of petroleum resin(PR)is an effective process to prepare high value-added hydrogenated PR(HPR).However,the preparation of non-noble metal-based catalysts with high catalytic activity for PR hydrogena...The hydrogenation of petroleum resin(PR)is an effective process to prepare high value-added hydrogenated PR(HPR).However,the preparation of non-noble metal-based catalysts with high catalytic activity for PR hydrogenation still remains a challenge.Herein,a La promoted Ni-based catalyst is reported through the thermal reduction of quaternary Ni La Mg Al-layered double hydroxides(Ni La Mg Al-LDHs).The incorporation of La is beneficial to the reduction and stability of Ni particles with reduced particle size,and the increased alkalinity effectively mitigates the breakage of molecular chains of PR.As a result,the La promoted Ni-based catalyst exhibits high catalytic activity and excellent stability for PR hydrogenation.A hydrogenation degree of 95.4%and 96.1%can be achieved for HC_(5)PR and HC_(9) PR with less reduced softening point,respectively.Notably,the hydrogenation degree still maintains at 92.7%even after 100 hours’reaction,much better than that without La incorporation or prepared using conventional impregnation method.展开更多
The conventional ceramic synthesis of perovskite oxides involves extended high-temperature annealing in air and is unfavorable to the in situ hybridization of the conductive agent, thus resulting in large particle siz...The conventional ceramic synthesis of perovskite oxides involves extended high-temperature annealing in air and is unfavorable to the in situ hybridization of the conductive agent, thus resulting in large particle sizes, low surface area and limited electrochemical activities. Here we report a rapid gel auto-combustion approach for the synthesis of a perovskite/carbon hybrid at a low temperature of 180℃. The energy-saving synthetic strategy allows the formation of small and homogeneously dispersed LaxMnO3±6/C nanocomposites. Remarkably, the synthesized La0.99MnO3.03/C nanocomposite exhibits comparable oxygen reduction reaction （ORR） activity （with onset and peak potentials of 0.97 and 0.88 V, respectively） to the benchmark Pt/C due to the facilitated charge transfer, optimal eg electron filling of Mn, and coupled C-O-Mn bonding. Furthermore, the nanocomposite efficiently catalyzes a Zn-air battery that delivers a peak power density of 430 mW·cm^-2, an energy density of 837 W·h·kgzn^-1 and 340 h stability at a current rate of 10 mA·cm^-2.展开更多
Transition metal dichalcogenide nanodots （NDs） have received considerable interest. We report a facile bottom-up synthetic route for MoS2 NDs by using molybdenum pentachloride and L-cysteine as precursors in oleylam...Transition metal dichalcogenide nanodots （NDs） have received considerable interest. We report a facile bottom-up synthetic route for MoS2 NDs by using molybdenum pentachloride and L-cysteine as precursors in oleylamine. The synthesis of NDs with a narrow size distribution ranging from 2.2 to 5.3 nm, was tailored by controlling the reaction time. Because of its coating characteristics, oleyalmine leads to uniformity and monodispersity of the NDs. Moreover, the NDs synthesized have large specific surface areas providing active sites. Graphene possesses outstanding conductivity. Combining the advantages of the two materials, the 0D/2D material exhibits superior electrochemical performance because of the 2D permeable channels for ion adsorption, energy storage, and conversion. The as-prepared MoS2/rGO （-2.2 nm） showed a stable capacity of 220 mAh.g-1 after 10,000 cycles at the current density of 20 A.g-1. Furthermore, a reversible capacity -140 mAh·g-1 was obtained at a much higher current density of 40 A.g-L Additionally, this composite exhibited superior catalytic performance evidenced by a small overpotential （222 mV） to afford 10 mA.cm-2, and a small Tafel slope （59.8 mV-decade-1） with good acid-stability. The facile approach may pave the way for the preparation of NDs with these nanostructures for numerous applications.展开更多
Electrocatalysis provides various technologies for energy storage and conversion,which is an important part of realizing sustainable clean energy for the future.COFs,as emerging porous crystalline polymers,possess hig...Electrocatalysis provides various technologies for energy storage and conversion,which is an important part of realizing sustainable clean energy for the future.COFs,as emerging porous crystalline polymers,possess high specific surface areas,tunable pore structures,high crystallinity and tailorable functionalization.These features endow COFs with abundant active sites and fast electron transport channels,making them potentially efficient electrocatalysts.In recent years,COF-based electrocatalysts have been widely developed for hydrogen evolution reaction(HER),hydrogen oxidation reaction(HOR),oxygen evolution reaction(OER),oxygen reduction reaction(ORR),nitrogen reduction reaction(NRR)and carbon dioxide reduction reaction(CO_(2)RR).In this review,design strategies of COF-based electrocatalysts are briefly summarized,including applying COF as supports,introducing active metals in COF,constructing two-dimensional conductive COF,formation of COF-based hybrid and pyrolysis of COF to obtain carbon materials.Then,the recent research progress in COF-derived catalysts for specific electrocatalytic reactions is introduced systematically.Finally,the outlook and challenges of future applications of COFs in electrocatalysis are highlighted.展开更多
基金financially supported by the National Natural Science Foundation of China(22078064)Natural Science Foundation of Fujian Province for Distinguished Young Scholar(2018J06002)。
文摘The hydrogenation of petroleum resin(PR)is an effective process to prepare high value-added hydrogenated PR(HPR).However,the preparation of non-noble metal-based catalysts with high catalytic activity for PR hydrogenation still remains a challenge.Herein,a La promoted Ni-based catalyst is reported through the thermal reduction of quaternary Ni La Mg Al-layered double hydroxides(Ni La Mg Al-LDHs).The incorporation of La is beneficial to the reduction and stability of Ni particles with reduced particle size,and the increased alkalinity effectively mitigates the breakage of molecular chains of PR.As a result,the La promoted Ni-based catalyst exhibits high catalytic activity and excellent stability for PR hydrogenation.A hydrogenation degree of 95.4%and 96.1%can be achieved for HC_(5)PR and HC_(9) PR with less reduced softening point,respectively.Notably,the hydrogenation degree still maintains at 92.7%even after 100 hours’reaction,much better than that without La incorporation or prepared using conventional impregnation method.
文摘The conventional ceramic synthesis of perovskite oxides involves extended high-temperature annealing in air and is unfavorable to the in situ hybridization of the conductive agent, thus resulting in large particle sizes, low surface area and limited electrochemical activities. Here we report a rapid gel auto-combustion approach for the synthesis of a perovskite/carbon hybrid at a low temperature of 180℃. The energy-saving synthetic strategy allows the formation of small and homogeneously dispersed LaxMnO3±6/C nanocomposites. Remarkably, the synthesized La0.99MnO3.03/C nanocomposite exhibits comparable oxygen reduction reaction （ORR） activity （with onset and peak potentials of 0.97 and 0.88 V, respectively） to the benchmark Pt/C due to the facilitated charge transfer, optimal eg electron filling of Mn, and coupled C-O-Mn bonding. Furthermore, the nanocomposite efficiently catalyzes a Zn-air battery that delivers a peak power density of 430 mW·cm^-2, an energy density of 837 W·h·kgzn^-1 and 340 h stability at a current rate of 10 mA·cm^-2.
基金This work was supported by the National Key R＆D Program （No. 2016YFB0901502）, National NaturalScience Foundation of China （Nos. 51231003, 51271094, and 21231005）, Ministry of Education （Nos. B12015 and IRT13R30）, and the Fundamental Research Funds for the Central Universities.
文摘Transition metal dichalcogenide nanodots （NDs） have received considerable interest. We report a facile bottom-up synthetic route for MoS2 NDs by using molybdenum pentachloride and L-cysteine as precursors in oleylamine. The synthesis of NDs with a narrow size distribution ranging from 2.2 to 5.3 nm, was tailored by controlling the reaction time. Because of its coating characteristics, oleyalmine leads to uniformity and monodispersity of the NDs. Moreover, the NDs synthesized have large specific surface areas providing active sites. Graphene possesses outstanding conductivity. Combining the advantages of the two materials, the 0D/2D material exhibits superior electrochemical performance because of the 2D permeable channels for ion adsorption, energy storage, and conversion. The as-prepared MoS2/rGO （-2.2 nm） showed a stable capacity of 220 mAh.g-1 after 10,000 cycles at the current density of 20 A.g-1. Furthermore, a reversible capacity -140 mAh·g-1 was obtained at a much higher current density of 40 A.g-L Additionally, this composite exhibited superior catalytic performance evidenced by a small overpotential （222 mV） to afford 10 mA.cm-2, and a small Tafel slope （59.8 mV-decade-1） with good acid-stability. The facile approach may pave the way for the preparation of NDs with these nanostructures for numerous applications.
基金supported by the National Natural Science Foundation of China(52101268)Tianjin Natural Science Foundation(19JCQNJC05000)。
文摘Electrocatalysis provides various technologies for energy storage and conversion,which is an important part of realizing sustainable clean energy for the future.COFs,as emerging porous crystalline polymers,possess high specific surface areas,tunable pore structures,high crystallinity and tailorable functionalization.These features endow COFs with abundant active sites and fast electron transport channels,making them potentially efficient electrocatalysts.In recent years,COF-based electrocatalysts have been widely developed for hydrogen evolution reaction(HER),hydrogen oxidation reaction(HOR),oxygen evolution reaction(OER),oxygen reduction reaction(ORR),nitrogen reduction reaction(NRR)and carbon dioxide reduction reaction(CO_(2)RR).In this review,design strategies of COF-based electrocatalysts are briefly summarized,including applying COF as supports,introducing active metals in COF,constructing two-dimensional conductive COF,formation of COF-based hybrid and pyrolysis of COF to obtain carbon materials.Then,the recent research progress in COF-derived catalysts for specific electrocatalytic reactions is introduced systematically.Finally,the outlook and challenges of future applications of COFs in electrocatalysis are highlighted.
