Iron-based single-atom electrocatalysts: synthetic strategies and applications

Abstract

The performance and cost of electrocatalysts play an important role in the development and application prospects of energy conversion technology.

Recent Advances in Waste Plastic Transformation into Valuable Platinum‐Group Metal‐Free Electrocatalysts for Oxygen Reduction Reaction

“…Hence, the evolution of structural, morphological, chemical and interfacial modifications during pyrolysis must be investigated with state‐of‐the‐art in‐situ and ex‐situ techniques [139] . Furthermore, the single‐atom electrocatalysts (SAECs), owing to their definite structural coordination, outstanding intrinsic activity and highest possible atomic efficiency, are emerging as new frontiers in the field of electrocatalysis and can potentially substitute the PGM‐based electrocatalysts [101,102,140,141] . However, fabrication of SAECs with homogenous and heavily dense active moieties within the carbonaceous framework is still a technical issue.…”

“…Further insights into iron‐based species through Mössbauer spectroscopy confirmed the formation of different sorts of well‐dispersed Fe‐containing active sites at 800 °C (Figure 3I), [51] which are primarily important for the efficient ORR activity [89] . Recently, the iron‐based single‐atom electrocatalysts (SAECs) have emerged as a new frontier in the domain of Fe−N−C ORR electrocatalysis, where structural heterogeneity and adjacent coordination improve the catalytic performance [101,102] . Iron exhibits several empty d‐orbitals and allows various kinds of coordination, hence different types of iron‐containing monoatomic sites (Fe−N 4 , Fe−N 3 and Fe−N 2 ) are formed [88,101] .…”

“…Recently, the iron‐based single‐atom electrocatalysts (SAECs) have emerged as a new frontier in the domain of Fe−N−C ORR electrocatalysis, where structural heterogeneity and adjacent coordination improve the catalytic performance [101,102] . Iron exhibits several empty d‐orbitals and allows various kinds of coordination, hence different types of iron‐containing monoatomic sites (Fe−N 4 , Fe−N 3 and Fe−N 2 ) are formed [88,101] . Another interesting feature communicated by Daniel et al.…”

“…The scope of this Minireview is limited to the very recent research developments in the domain of plastic waste‐derived ORR electrocatalysts. Existing literature related to ORR mechanisms and reaction pathways [107— 110] and electrocatalysts [36,88,111–115] is reported for acidic media and alkaline media for PEMFCs and AEMFCs, respectively. As mentioned before, the electronic pathway of ORR reaction differs at different pH of the electrolyte [116] .…”

Synergistically enhanced single-atomic site catalysts for clean energy conversion

“…[12][13][14] Iron (Fe) and cobalt (Co) based SACs generally show a lower CO 2 RR onset potential, but *CO is difficult to desorb owing to the strong binding of the Fe or Co site with reaction intermediates. 15 Nickel (Ni) and copper (Cu) based SACs facilitate CO desorption, but they are oen limited by a larger initial potential due to the high energy barrier required to form the *COOH intermediate. 16,17 In addition, the too strong binding strength of transition metal (TM) sites with electron-donating intermediates also lowers the catalytic activity of OER and HER processes.…”