摘要
以泡沫镍(NF)为基底,采用一步水热法制备了主晶相为CoS_(2)、夹杂少量NiO相、具有三维多孔风叶结构的CoS_(2)/NF电极材料。当溶液中钴硫物质的量之比为1∶5时,在140℃下保温18 h,获得了由10 nm厚度的纳米片构成的三维风叶结构的晶态CoS_(2)/NF电催化剂。CoS_(2)/NF在肼氧化及析氢反应中均表现出优异的催化性能,在水合肼碱性介质中,获得-10 mA·cm^(-2)的析氢电流密度时,需要的过电势仅为83 mV,获得50 mA·cm^(-2)的氧化电流密度时,需要的肼氧化电位仅为51 mV(vs RHE);在水合肼辅助电解水双功能电解槽中,获得100 mA·cm^(-2)的电流密度时,需要的分解槽压仅为0.550 V,远低于其在同条件下全水分解的2.075 V,大幅减小了电能消耗,极大地提高了电解水产氢效率。无论在三电极体系还是双电极体系,CoS_(2)/NF均表现出优异的长效稳定性及耐用性。分析认为,电极表面多孔风叶结构的形成,使其电化学活性面积增加了24倍,为催化反应的发生提供了海量的活性位点及物质传递通道。CoS_(2)及NiO相的形成,在一定程度上协同改善了本征析氢活性。CoS_(2)/NF的组成、结构特性共用造就了其优异催化性能,其中结构优势起主导作用。通过机理研究,提出了CoS_(2)/NF在析氢及肼氧化过程中的反应路径。
Here,we report a three-dimensional blade-like nanosheet cobalt disulfide electrocatalyst with CoS_(2) as the main crystal phase with a small amount of the mixed NiO phase,which is fabricated in situ on nickel foam(NF)by one-step hydrothermal synthesis.When the molar ratio of cobalt and sulfur in the solution was 1∶5,the crystalline CoS_(2)/NF electrocatalyst with a three-dimensional porous blade-like structure composed of 10 nm nanosheets was obtained at 140℃for 18 h.During hybrid water electrolysis in an alkaline medium containing hydrazine hydrate,CoS_(2)/NF electrode merely need 83 mV overpotential to deliver-10 mA·cm^(-2) towards hydrogen evolution reaction(HER),while 51 mV(vs RHE)oxidation potential to drive 50 mA·cm^(-2) towards hydrazine oxidation reaction(HzOR).Integrated into a hybrid cell towards hydrazine hydrate assisted water electrolysis,the CoS_(2)/NF couple required a cell voltage of only 0.550 V to afford 100 mA·cm^(-2) current density,far lower than that of overall water splitting(2.075 V),giving rise to the significant decrease of power consumption and the great improvement of hydrogen-producing efficiency.As-prepared CoS_(2)/NF displayed excellent stability and durability towards HER or HzOR both in three-electrode and two-electrode systems.The formation of a nanoporous blade-like structure created a large number of micropores on the electrode surface,which led to the nearly 24-fold increased electrochemical active area(ECSA),and provided a huge amount of active sites and material transfer channels for the catalytic reaction.The formation of cobalt disulfide and nickel oxide phase synergically improved the intrinsic hydrogen evolution activity to a certain extent.The composition and structural characteristics of CoS_(2)/NF contribute to superior catalytic performance,and the structural advantage played the predominant role in outstanding catalytic performances.Using mechanism research,the reaction paths of CoS_(2)/NF in HER and HzOR are proposed,respectively.
作者
孙强强
赵鹏程
吴若雨
曹宝月
王毅梦
樊雪梅
SUN Qiang-Qiang;ZHAO Peng-Cheng;WU Ruo-Yu;CAO Bao-Yue;WANG Yi-Meng;FAN Xue-Mei(Research Centre of Grapheme Technology and Application,Shaanxi Key Laboratory of Comprehensive Utilization of Tailings Resources,School of Chemical Engineering and Modern Materials,Shangluo University,Shangluo,Shaanxi 726000,China)
出处
《无机化学学报》
SCIE
CAS
CSCD
北大核心
2023年第3期422-432,共11页
Chinese Journal of Inorganic Chemistry
基金
陕西高校青年创新团队(No.20JCS062)
商洛市科技计划项目(No.2020-Z-0041)
商洛学院应用催化科研团队(No.19SCX01)资助。
关键词
CoS_(2)
析氢反应
肼氧化反应
协同催化
反应路径
cobalt disulfide
hydrogen evolution reaction
hydrazine oxidation
synergistic catalysis
reaction path
