蔗糖基硬碳非贵金属催化剂的可控制备及电化学合成氨的性能研究

Controllable Preparation of Sucrose Based Hard Carbon Non Precious Metal Catalysts and Performance Study of Electrochemical Synthesis of Ammonia

本文以蔗糖为碳源,采用水热碳化法和硬模板法制备了碳微球,采用等体积浸渍法制备了新型铁基催化剂,研究了硬模板剂的加入顺序对催化剂活性的影响。结果表明,碳化时加入硬模板剂制备的Fe_(2)O_(3)/CMS2,表现出较高的初始活性,产氨速率和库伦效率最高时分别为1.22×10^(-8)mol·s^(-1)·cm^(-2)和70.33%。水热时加入硬模板剂制备的Fe_(2)O_(3)/CMS1,则表现出良好的稳定性,电解6h,Fe_(2)O_(3)/CMS1催化剂的产氨速率为4.3×10^(-9)mol·s^(-1)·cm^(-2),库伦效率为23.55%,相比初始的库伦效率下降了21.61%。XRD和SEM的表征分析结果证实,催化剂的载体碳微球的粒径约为8μm,活性物质主要是Fe_(2)O_(3)晶体和Fe_(3)O_(4)晶体。碳化时加入硬模板剂,有利于碳微球的碳化及活性物质Fe_(2)O_(3)晶体的形成。本方法有望为电化学合成氨提供一种低成本且绿色的载体碳材料。

Applied sucrose as a carbon source,carbon microspheres were prepared by hydrothermal carbonization and hard template methods.A novel iron-based catalyst was prepared by an equal volume impregnation method,and the effect of the order of adding hard template agents on the activity of the catalyst was studied.The results showed that Fe_(2)O_(3)/CMS2 prepared by adding a hard template agent during carbonization exhibited high initial activity,with ammonia production rate and coulombic efficiency of 1.22×10^(-8) mol/(s·cm^(2))and 70.33%,respectively.However,Fe_(2)O_(3)/CMS1 prepared by adding a hard template agent during hydrothermal treatment showed good stability.After 6h of electrolysis,the ammonia production rate of Fe_(2)O_(3)/CMS1 catalyst was 4.3×10^(-9) mol/(s·cm^(2)),and the coulombic efficiency of Fe_(2)O_(3)/CMS1 only decreased by 21.61%.The characterization analysis results of XRD and SEM confirmed that the diameter of the carbon microspheres supported by the catalyst was about 8μm,and the active substances were mainly Fe_(2)O_(3) crystals and Fe_(3)O_(4) crystals.Adding a hard template during carbonization was beneficial for the carbonization of the carbon microspheres and the formation of the active substance Fe_(2)O_(3) crystals.This method could provide a low-cost and green carrier carbon material for electrochemical synthesis of ammonia.