钴单原子的双重限域制备策略及高效CO_(2)电还原性能

Construction of Cobalt Single Atoms via Double-confinement Strategy for High-performance Electrocatalytic Reduction of Carbon Dioxide

将锌钴双掺杂的金属有机框架(MOFs)纳米颗粒(ZnCo-ZIF)与聚丙烯腈(PAN)混溶形成前驱体溶液,通过静电纺丝与高温热化学反应,获得了一种多孔碳纳米纤维负载的钴单原子催化剂(A-Co@PCFs).高温热解时,聚丙烯腈分解碳化形成碳纳米纤维主体,MOFs纳米颗粒结构坍塌伴随锌组分的挥发,在纤维表面形成了丰富的多级孔结构.由于碳纳米纤维和孔道结构的双重限域作用,使钴组分不能聚集成钴纳米颗粒,而是形成高度分散的钴单原子.电化学测试结果表明,该钴单原子催化剂可将CO_(2)电还原为CO,在−0.66 V(vs.RHE)下,CO的法拉第效率可达94%.并且经过60 h的耐久性测试,其催化性能没有明显的性能衰减,显示出较高的稳定性.A-Co@PCFs的高活性与高稳定性可归因于材料的多孔结构和高度分散的钴原子,这也使其具有代替贵金属催化剂的可能性.

In this manuscript,zinc,cobalt co-doped metal organic frameworks(MOFs)nanoparticles(ZnCo-ZIF)were mixed with polyacrylonitrile(PAN)to form a precursor solution.After electrospinning and high temperature pyrolysis,a porous carbon nanofiber supported single-atom cobalt catalyst(A-Co@PCF)was obtained.During high-temperature pyrolysis,polyacrylonitrile decomposed and carbonized to form the main body of carbon nanofibers.The collapse of MOFs nanoparticle structure and the volatilization of zinc components created the hierarchically porous structure throughout the nanofibers.Due to the double confinement of carbon nanofibers and pore structure,cobalt components cannot aggregate into cobalt nanoparticles,but cobalt components generate highly dispersed cobalt single atoms.Electrochemical tests show that the cobalt monoatomic catalyst can successfully reduce carbon dioxide to carbon monoxide,and the Faraday efficiency of carbon monoxide can reach 94%at‒0.66 V(vs.RHE)cathode potential.And after 60 h of durability test,its catalytic performance has no obvious performance attenuation,showing high stability.The high activity and stability of A-Co@PCFs can be attributed to the porous structure of the material and highly dispersed cobalt atoms,which also makes it possible to replace precious metal catalysts.In addi⁃tion,this method also provides a reference for the synthesis of other transition metal single-atom catalysts.