具有高效氧还原反应催化活性的共轭三嗪骨架材料负载的单原子钴催化剂

Atomic cobalt anchored on covalent triazine frameworks with ultra-high performance towards oxygen reduction reaction

单原子钴是一种理想的代替铂催化氧还原反应(ORR)的非贵金属催化剂,然而制备低成本、高稳定性且高效的此类催化剂仍面临挑战.这需要高效的制备策略以及强健的支撑材料以稳定单原子钴.因此,我们提出了一种适于大量制备的三嗪骨架材料负载的单原子钴ORR催化剂(Co-CTF/KB).其单原子钴负载量达4 wt%,在碱性介质中ORR催化性能超过商用Pt/C和大部分已报道的非贵金属催化剂:半波电位(E_(1/2))达0.830 V,截止电流为6.14 mA cm^(-2),且具有极高的甲醇耐受性.得益于CTF对钴单原子的强稳定性,Co-CTF/KB催化循环10000圈后,电位偏移仅5 mA,展现出极好的循环稳定性.此外,Co-CTF/KB还能催化析氧反应(OER),是一种高效、高稳定的ORR/OER双功能催化剂.此工作为规模化制备高质量的单原子催化剂提供了新思路.

Single cobalt atom is promising non-precious metal catalyst instead of Pt in the oxygen reduction reaction(ORR).However,it is still a great challenge to develop a costeffective,ultrastable and efficent single-atom cobalt catalyst for ORR,requiring efficient fabrication strategies and robust support to stabilize the single cobalt atom.Here,we prepared a highly active and stable atomically isolated cobalt catalyst via covalent triazine framework(CTF)support with Ketjen Black(KB)hybridization in scale.The prepared single Co catalyst(Co-CTF/KB)possesses high metal loading over 4 wt%and shows superior ORR performance with a half-wave potential(E1/2)of 0.830 V and a limiting current density of 6.14 mA cm-2 as well as high tolerance of methanol in an alkaline medium,which outperforms commercial Pt/C and most non-precious-metal catalysts reported to date.Benefiting from strong stabilization of Co atoms on CTF,Co-CTF/KB shows outstanding stability with only 5 mV negative shifts after 10,000 cycles.Moreover,it also displays high catalytic activity for oxygen evolution reaction(OER),suggesting it is an efficient ORR/OER bifunctional catalyst.The present work provides a facile strategy for preparing single-atom catalysts in bulk quantity and contributes to development of catalysts for electrochemical conversion and storage devices.