Green Synthesis of a Highly Efficient and Stable Single-Atom Iron Catalyst Anchored on Nitrogen-Doped Carbon Nanorods for the Oxygen Reduction Reaction

Abstract

The synthesis of inexpensive and efficient electrocatalysts with an excellent stability for the electrochemical oxygen reduction reaction (ORR) in both alkaline and acid media through a facile environment-friendly strategy is extremely desirable but remains challenging. In this study, a single-atom iron electrocatalyst with exclusively Fe–N4 moieties anchored on nitrogen-doped carbon nanorods (denoted as Fe–SA/NCS) is synthesized through a one-step pyrolysis of Fe-doped zeolitic imidazole framework-8 (ZIF8) nanorods that are synthesized in an aqueous system without acid leaching assistance. Profiting from the synergistic effect of the hierarchically porous carbon support with a rodlike structure and the large number of Fe–N4 moieties, the newly prepared Fe–SA/NCS exhibits excellent ORR catalysis activities with a half-wave potential of 0.91 V vs RHE in 0.1 M KOH as well as 0.77 V vs RHE in 0.1 M HClO4. Furthermore, better stability in alkaline or acid conditions was also observed for Fe–SA/NCS compared with Pt/C. The high open-circuit voltage of 1.53 V and high power density of 141.6 mW cm–2 of a zinc–air battery (ZAB) with Fe–SA/NCS as the cathode material indicate excellent electrochemical performances. The ZAB with the Fe–SA/NCS catalysts exhibits a remarkable cycling performance for more than 300 h with a high voltaic efficiency of 78.6%. The present work could pave the way for the rational construction of highly efficient and stable single-atom electrocatalysts through green synthesis for sustainable energy technologies.

Strategies for boosting the activity of single-atom catalysts for future energy applications

“…[86][87][88][89] Zhang et al developed MOF-derived Fe-N 4 sites on N-doped carbon materials (denoted as Fe-SA/NCS), which exhibited excellent activity and long-term durability in the ORR process. 90 2.2.7. Ball-milling.…”

“…Metal loadings of SACs reach as high as 10 wt%. 90 Because of the high-density Pt centers, the noble SACs show 30 times higher activity in HCOOH oxidation than the commercial Pt/C. Xia et al reported an ultrahigh Ir metal loading of 41.6 wt% (3.84 at%) by a graphene quantum dot (GQD)-assisted synthesis strategy (Fig.…”

Tailoring Single-Atom Fen4 Moieties as a Robust Heterogeneous Catalyst for High-Performance Electro-Fenton Treatment of Organic Pollutants

“…The XRD patterns of Fe-SAC/NC and ZIF-8-derived Ndoped carbon matrices, as shown in Fig. 2a, exhibited only two peaks centered at 24.3° and 44.5°, which were assigned to (002) and (004) crystal planes of carbon, respectively [44,45]. No diffraction peak related to Fe-based species (iron oxides, iron nitrides or iron carbides) appeared, evidencing that Fe sites were atomically dispersed in Fe-SAC/NC.…”

Atomic-Scale Engineered Fe Single-Atom Electrocatalyst Based on Waste Pig Blood for High-Performance AEMFCs

“…To overcome these drawbacks, many types of Pt-replacement catalysts have been studied, with non-precious metals (especially transition metals) and metal-coordinated-to-nitrogen in carbon material (metal–nitrogen–carbon, M–N–C) catalysts being the most promising. − Among these Pt-replacement catalysts, it has been reported that M–N–C catalysts are abundant and inexpensive, are composed of commercial Pt catalyst components, and have similar activity and durability to Pt catalysts. Generally, most of the existing M–N–C catalysts are synthesized using a top–down approach because it is difficult to prevent the sintering of the metal in a high-temperature heat treatment process.…”