Secondary-Atom-Doping Enables Robust Fe–N–C Single-Atom Catalysts with Enhanced Oxygen Reduction Reaction

Abstract

• Secondary-atom-doped strategy was proposed to synthesize single-atom electrocatalyst. • The increase in both the density of active sites and their intrinsic activity was achieved simultaneously. • The resultant single-atom catalyst shows outstanding ORR activity in acidic media. ABSTRACT Single-atom catalysts (SACs) with nitrogen-coordinated nonprecious metal sites have exhibited inimitable advantages in electrocatalysis. However, a large room for improving their activity and durability remains. Herein, we construct atomically dispersed Fe sites in N-doped carbon supports by secondary-atom-doped strategy. Upon the secondary doping, the density and coordination environment of active sites can be efficiently tuned, enabling the simultaneous improvement in the number and reactivity of the active site. Besides, structure optimizations in terms of the enlarged surface area and improved hydrophilicity can be achieved simultaneously. Due to the beneficial microstructure and abundant highly active FeN 5 moieties resulting from the secondary doping, the resultant catalyst exhibits an admirable half-wave potential of 0.81 V versus 0.83 V for Pt/C and much better stability than Pt/C in acidic media. This work would offer a general strategy for the design and preparation of highly active SACs for electrochemical energy devices.

Neutral Zn‐Air Battery Assembled with Single‐Atom Iridium Catalysts for Sensitive Self‐Powered Sensing System

“…N 1s of SA‐Ir/NC with five peaks at 398.3, 399.1, 400.1, 401.0, and 403.9 eV correspond to pyridinic N, Ir‐N, pyrrolic N, graphitic N, and oxidized N, respectively. [ 14 ] Compared with NC, SA‐Ir/NC has an additional Ir‐N peak, further confirming the existence of IrN x . As shown in Figure 2b, Ir 4f could be deconvoluted into four components, assigned to Ir 4+ 4f 7/2 (61.5 eV), Ir 4+ 4f 5/2 (64.5 eV), Ir 3+ 4f 7/2 (62.2 eV), and Ir 3+ 4f 5/2 (65.2 eV).…”

Engineering the Coordination Sphere of Isolated Active Sites to Explore the Intrinsic Activity in Single-Atom Catalysts

“…ORR plays a crucial role in the energy storage and conversion systems such as fuel cells and some other renewable energy technologies [ 137 – 139 ]. So far, Pt and its alloys are typically regarded as the most efficient ORR catalysts [ 140 – 143 ].…”

Fine-Tuning Pyridinic Nitrogen in Nitrogen-Doped Porous Carbon Nanostructures for Boosted Peroxidase-Like Activity and Sensitive Biosensing

“…As a control, N-CMNs-2 were synthesized in the same manner without nitrogen sources. Given that dicyandiamide is decomposed to ammonia (NH 3 ) gas during annealing, the released NH 3 can benefit the transformation of N species, achieving the modulation of nitrogen doping [ 33 , 34 ]. The transmission electron microscopy (TEM) image of the as-prepared N P -CMNs is shown in Figure 1(b) , which clearly displays the chiseled spherical pores with a diameter of 20 nm, deriving from the silica templates.…”