Template-Assisted Construction of Atomically Dispersed Fe-N-C Catalysts With Dense Fe-N4C Sites for Enhanced Oxygen Reduction Reaction

en This link goes to a English section zh This link goes to a Chinese section Atomically dispersed iron–nitrogen–carbon (Fe-N-C) catalysts have emerged as promising alternatives for oxygen reduction reaction (ORR) owing to their highly atomic utilization. However, maintaining both Fe atomic dispersion and dense Fe-N x sites (typically below 2 wt%) in Fe-N-C catalysts is still a key challenge. In this investigation, a template (1,2-dicyanobenzene; DCB) assisted strategy has been reported to achieve hierarchically porous Fe-N/C DCB0.2 -900°C catalysts, which have atomically dispersed Fe-N 4 C active sites with a 5.45 wt% Fe loading and served for robust ORR. 1,2-dicyanobenzene containing abundant nitrogen source not only efficiently enhances the coordinated environment for dense Fe sites, but also facilitates the formation of a hierarchical porous structure in Fe-N/C DCB0.2 -900°C catalyst. Computational analysis demonstrated that template-assisted structural modification effectively reduces the energy barrier associated with *OOH intermediate formation while simultaneously adjusting the d-band center position of Fe-N 4 C coordination sites within the Fe-N/C DCB0.2 -900°C system. This optimization enhances the stabilization of oxygen-bearing intermediates and promotes accelerated kinetics of the ORR. Consequently, the Fe-N/C DCB0.2 -900°C exhibited a half-potential of 0.9 V versus RHE when evaluated in 0.1 M KOH electrolyte and achieved a peak power density of 220 mW cm −2 in a zinc–air battery, surpassing commercial Pt/C (0.88 V vs. RHE, 194 mW cm −2 ). Such methodology provides a new avenue for constructing dense metal active sites for achieving functional, but not limited to, ORR, catalysts and applications. 摘要 en This link goes to a English section zh This link goes to a Chinese section 原子分散的铁-氮-碳(Fe-N-C)催化剂因其高原子利用率,已成为很有前景的氧还原反应(ORR)替代催化剂。然而,在Fe-N-C催化剂中同时保持铁的原子分散性和密集的Fe-N x 位点(通常低于2 wt%)仍是一个关键挑战。在本研究中,我们报道了一种模板(1,2-邻苯二甲腈; DCB)辅助策略,以制备具有分级多孔结构的Fe-N/C DCB0.2 -900°C催化剂,该催化剂具有原子分散的Fe-N 4 C活性位点,铁负载量为5.45 wt%,可用于高效的ORR。含有丰富氮源的1,2 -邻苯二甲腈不仅能有效改善密集铁位点的配位环境,还有助于在Fe-N/C DCB0.2 -900°C催化剂中形成分级多孔结构。理论计算分析表明,模板辅助的结构修饰有效降低了与*OOH中间体形成相关的能垒,同时调整了Fe-N/C DCB0.2 -900°C体系中Fe-N 4 C位点的d带中心位置。这种优化增强了含氧化合物中间体的稳定性,并促进了ORR的动力学反应速度。因此,在0.1 M KOH电解质中测试时,Fe-N/C DCB0.2 -900°C的半波电位为0.9 V,在锌空气电池中实现了220 mW cm −2 的峰值功率密度,超过了商用Pt/C(0.88 V,194 mW cm −2 )。这种方法为构建密集的金属活性位点提供了新途径,可用于制备功能性催化剂(不仅限于ORR)及相关应用。