碳纸自支撑N掺杂碳纳米管复合MoC/NiCo异质结构的电解水析氧性能

Carbon paper self-supported N-doped carbon nanotubes with MoC/NiCo heterostructures for electrolytic water oxygen evolution reaction

电催化分解水是当今最有成效的产氢方法之一,而析氧反应是水分解的决速步,但其动力学缓慢,因此,开发能有效加速析氧反应的电催化剂成为研究者关注的焦点。首先,选择以碳纸(CP)为自支撑基底,原位水热生长氧化锌(ZnO)纳米针,后进一步通过水热在其上生长NiCoMo的层状氢氧化物(NiCoMo-LDH)纳米片,制得NiCoMo-LDH/ZnO/CP。最后,以双氰胺(DCDA)作为碳源和氮源,与NiCoMo-LDH/ZnO/CP在N_(2)气氛下共退火2 h,制备出CP自支撑的封装有MoC和NiCo纳米粒的N掺杂碳纳米管(NCNT)阵列MoC-NiCo@NCNT/CP。由于MoC和NiCo的协同作用、高电导性以及无黏合剂的自支撑电极构建,使得所研制电极MoC-NiCo@NCNT/CP在1 mol·L^(-1)KOH溶液中具有很好的电解水析氧活性,过电位仅需243 mV时即可获得50 mA·cm^(-2)的电流密度,比RuO_(2)催化剂析氧过电位更低。此外,MoC-NiCo@NCNT/CP还显示出较好的稳定性。

Electrocatalytic water splitting is one of the most effective strategies for hydrogen production.Oxygen evolution reaction(OER)is the decisive step for water splitting.In view of the slow kinetics for OER,developing electrocatalysts that can effectively accelerate OER kinetics has become the research hots.Here,carbon paper(CP)was firstly chosen as the self-supporting substrate,and zinc oxide nanoneedles(ZnO)was in situ hydrothermally grown onto it.After that,NiCoMo-layered hydroxide(NiCoMo-LDH)nanosheets were further generated on it by the hydrothermal treatment to obtain the NiCoMo-LDH/ZnO/CP composite.Finally,NiCoMo-LDH/ZnO/CP was annealed in the presence of dicyandiamide(DCDA)as the carbon and nitrogen sources for 2 h in nitrogen atmosphere,preparing the MoC and NiCo-encapsulated N-doped carbon nanotubes(NCNT)constructed on CP(i.e.MoC-NiCo@NCNT/CP).Due to the synergistic effect between MoC and NiCo,high electrical conductivity,and binder-free electrode configuration,the self-supported MoC-NiCo@NCNT/CP electrode exhibited the excellent activities in 1 mol·L~(-1)KOH solution with only 243 mV overpotential to drive a current density of 50 mA·cm~(-2).Moreover,MoC-NiCo@NCNT/CP still showed good stability for 20 h at 20 mA·cm~(-2).