Co和Co_(9)S_(8)纳米颗粒均匀嵌入S、N共掺杂的多孔碳材料的电催化性能研究

Electrocatalytic performance of Co and Co_(9)S_(8) nanoparticles embedded uniformly in S,N co-doped porous carbon materials

热解金属有机骨架材料(MOFs)可以得到活性物质均匀嵌入的杂原子掺杂多孔碳材料,这种多孔碳材料在电催化领域具有重要的研究意义。对以Co^(2+)为中心离子,2,5-噻吩二羧酸和4,4-联吡啶为有机配体的Co基金属有机骨架材料([Co(tdc)(bpy)]^(2)_(n))进行热解处理,成功制备了Co和Co_(9)S_(8)纳米颗粒均匀嵌入的S、N共掺杂的多孔碳材料(Co/Co_(9)S_(8)@SNC)。其中700℃下热解得到的Co/Co_(9)S_(8)@SNC-700上形成的Co和Co_(9)S_(8)催化颗粒的比例适中,且多孔碳上的S和N掺杂的形式及比例也最佳。故Co/Co_(9)S_(8)@SNC-700在碱性电解液中表现出最佳的氧还原及氧析出双功能电催化性能和导电性。电化学测试结果表明,Co/Co_(9)S_(8)@SNC-700的氧还原极限电流密度为4.4mA/cm^(2),接近商用Pt/C(20wt%)。在氧析出测试中,Co/Co_(9)S_(8)@SNC-700在10mA/cm2处的过电位为0.37V,优于RuO_(2)。

Heteroatoms doped porous carbon materials with uniformly embedded active substances can be obtained by pyrolysis of metal-organic framework materials(MOFs).The porous carbon materials have important research significance in the field of electrocatalysis.Here,Co and Co_(9)S_(8) nanoparticles uniformly embedded in S,N-doped porous carbons(Co/Co_(9)S_(8)@SNC)were successfully fabricated by pyrolytic treatment of Co-based metal-organic framework materials([Co(tdc)(bpy)]~2_(n)).[Co(tdc)(bpy)]^(2)_(n) taking Co^(2+)as the central ion,2,5-thiophenedicarboxylic acid and 4,4-bipyridine as the organic ligands.The proportion of Co and Co_(9)S_(8) catalytic particles formed on Co/Co_(9)S_(8)@SNC-700 obtained from pyrolysis at 700℃was moderate,and the form and proportion of S and N doping on porous carbon were also the best.Therefore,Co/Co_(9)S_(8)@SNC-700 exhibited the best bifunctional electrocatalytic performance and electrical conductivity for oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)in alkaline electrolyte.Electrochemical test results showed that the ORR limit current density of Co/Co_(9)S_(8)@SNC-700 was 4.4mA·cm^(-2),which was close to commercial Pt/C(20wt.%).In the OER tests,the overpotential of Co/Co_(9)S_(8)@SNC-700 at 10mA·cm^(-2)was 0.37V,which was better than that of RuO_(2).