This paper describes the use of both atomically dispersed precursors (ADPs) and conductive carbon dispersion towards the synthesis of iron-based single atom electrocatalysts for the oxygen reduction reaction (ORR). For non-platinum group metal (non-PGM) catalysts, single iron, cobalt or manganese atoms coordinated with nitrogen are the most active structures towards the ORR. Achieving a high density of active sites made of single atoms is still challenging, requiring careful controls of pyrolysis to reduce the sintering of metal active sites. Herewith, we present a new strategy to synthesize iron-based single atom ORR electrocatalysts using a two-pronged approach. We first designed a dual-ligated metal organic framework (MOF) precursor. This MOF was then immobilized onto Ketjen black carbon that serves as a conductive dispersion medium for creating the highly dispersed single atom sites. We demonstrate a near complete dispersion of the iron sites without obvious formation of nanoparticles. The activity of the resulting electrocatalyst exhibited an onset potential of 0.96 V and a half-wave potential of 0.84 V vs. reversible hydrogen electrode (RHE).

本文描述了使用原子分散的前体 (ADP) 和导电碳分散体来合成铁基单原子电催化剂用于氧还原反应 (ORR)。对于非铂族金属（非 PGM）催化剂，与氮配位的单个铁、钴或锰原子是对 ORR 最活跃的结构。实现由单个原子组成的高密度活性位点仍然具有挑战性，需要仔细控制热解以减少金属活性位点的烧结。因此，我们提出了一种新的策略来使用双管齐下的方法合成铁基单原子 ORR 电催化剂。我们首先设计了一种双连接金属有机骨架 (MOF) 前驱体。然后将该 MOF 固定在作为导电分散介质的科琴黑碳上，以产生高度分散的单原子位点。我们证明了铁位点几乎完全分散，而没有明显形成纳米颗粒。所得电催化剂的活性表现出 0.96 V 的起始电位和 0.84 V 相对于可逆氢电极 (RHE) 的半波电位。