Department of Mechanical Engineering, Chonnam National University, Gwangju, Republic of Korea.
Sci Rep. 2017 Feb 27;7:43279. doi: 10.1038/srep43279.
3D and porous reduced graphene oxide (rGO) catalysts have been prepared with sp-hybridized 1,4-diaminobutane (sp-DABu, rGO-sp-rGO) and sp-hybridized 1,4-diaminobenzene (sp-DABe, rGO-sp-rGO) through a covalent amidation and have employed as a metal-free electrocatalyst for oxygen reduction reaction (ORR) in alkaline media. Both compounds have used as a junction between functionalized rGO layers to improve electrical conductivity and impart electrocatalytic activity to the ORR resulting from the interlayer charge transfer. The successful amidation and the subsequent reduction in the process of catalyst preparation have confirmed by X-ray photoelectron spectroscopy. A hierarchical porous structure is also confirmed by surface morphological analysis. Specific surface area and thermal stability have increased after successful the amidation by sp-DABu. The investigated ORR mechanism reveals that both functionalized rGO is better ORR active than nonfunctionalized rGO due to pyridinic-like N content and rGO-sp-rGO is better ORR active than rGO-sp-rGO due to higher pyridinic-like N content and π-electron interaction-free interlayer charge transfer. Thus, the rGO-sp-rGO has proven as an efficient metal-free electrocatalyst with better electrocatalytic activity, stability, and tolerance to the crossover effect than the commercially available Pt/C for ORR.
3D 多孔还原氧化石墨烯 (rGO) 催化剂已通过 sp 杂化 1,4-二氨基丁烷 (sp-DABu，rGO-sp-rGO) 和 sp 杂化 1,4-二氨基苯 (sp-DABe，rGO-sp-rGO) 的共价酰胺化制备，并用作碱性介质中氧还原反应 (ORR) 的无金属电催化剂。这两种化合物都用作官能化 rGO 层之间的连接物，以提高电导率并赋予 ORR 电催化活性，这是由于层间电荷转移。通过 X 射线光电子能谱证实了酰胺化和随后的催化剂制备过程中的还原成功。通过表面形貌分析也证实了分层多孔结构。通过 sp-DABu 的成功酰胺化，比表面积和热稳定性都得到了提高。所研究的 ORR 机制表明，由于吡啶型 N 含量，官能化 rGO 比非官能化 rGO 具有更好的 ORR 活性，而 rGO-sp-rGO 比 rGO-sp-rGO 具有更好的 ORR 活性，这是由于更高的吡啶型 N 含量和无π-电子相互作用的层间电荷转移。因此，rGO-sp-rGO 已被证明是一种高效的无金属电催化剂，与市售的 Pt/C 相比，具有更好的电催化活性、稳定性和对交叉效应的耐受性，用于 ORR。
