Template-free synthesis of non-noble metal single-atom electrocatalyst with N-doped holey carbon matrix for highly efficient oxygen reduction reaction in zinc-air batteries

Iridium‐Doped N‐Rich Mesoporous Carbon Electrocatalyst with Synthetic Macrocycles as Carbon Source for Hydrogen Evolution Reaction

“…The CB [6] possessing many carbonyl and amide groups is attractive for Ir 3+ binding through an ion-dipole effect, which is helpful for dispersing Ir 3+ in CB [6] self-assembly to form uniformly dispersed Ir sites and efficiently avoiding the particle gathering in the pyrolyzed samples. [30,44] Besides, the BET surface areas were 558.11, 116.68, 211.71, and 885.97 m 2 g −1 for CBC-Ir-800-1.2, CNT-Ir-800-1.2, GO-Ir-800-1.2, and ZIF-Ir-900-1.2, respectively. The corresponding pore diameter and total pore volume of CBC-Ir-800-1.2 were measured to be 4.61 nm and 0.994 cm 3 g −1 (Table S1, Supporting Information) by the Barrett-Joyner-Halenda (BJH) method.…”

“…Specifically, the N 1s spectra of the CBC-Ir-800-1.2 could be deconvoluted into four types of nitrogen species including pyridinic N (397.7 eV), pyrrolic N (399.2 eV), graphitic N (400.5 eV), and oxidized N (402.1 eV), respectively (Figure 3c). [44] Besides, the relative contents of four types of N were also analyzed. Compared with the pure CBC, the relative content of pyridinic N for CBC-Ir-800-1.2 was increased from 22.89% to 25.65% and from 20.39% to 22.52% for pyrrolic N, meanwhile, the active sites of pyridinic N and pyrrolic N can interact with Ir nanoclusters by electron coordination to generate Ir-N and result in a change of N 1s binding energy (Figure 3c).…”

“…And graphitic N plays a critical role in electronic transmission. [44,50,54] Furthermore, the chemical state of Ir existing in CBC-Ir-800-1.2 was also measured by the high-resolution spectra of Ir 4f (Figure 3d). The Ir 4f peaks at 60.6 and 63.8 eV were attributed to the 4f 7/2 and 4f 5/2 of Ir 0 , whereas the peaks located at 62.1 and 65.8 eV were assigned to 4f 7/2 and 4f 5/2 of Ir 4+ , confirming the coexistence of metallic Ir and Ir 4+ .…”

“…Compared with the most widely used carbon source precursors involving graphene, carbon nanotube, metal-organic frameworks (MOFs), and other carbonaceous materials, [40][41][42][43] CB [6] shows certain advantages: i) the heteroatom N is introduced into carbon framework by self-doping without any additional N sources duo to its extremely rich content of N; ii) the porous supramolecular self-assembly can produce ample inplane mesoporous structures during the pyrolysis without any addition tedious pre/post-treatments; [30,44] iii) the synthetic procedure of CB [6] is simple, environmental friendly, lowcost, and high-yielding. These unique structural characteristics of CB [6] greatly boost the electrical transfer and enhance the electrocatalytic activity of catalysts, [45] and thus using supramolecular macrocycle CB [6] as a deal carbon source precursor to produce efficient electrocatalysts is promising.…”

“…These unique structural characteristics of CB [6] greatly boost the electrical transfer and enhance the electrocatalytic activity of catalysts, [45] and thus using supramolecular macrocycle CB [6] as a deal carbon source precursor to produce efficient electrocatalysts is promising. However, up till now, CB [6] as the carbon source precursor has only attracted slight interest in supercapacitors [46] and oxygen reduction reaction, [44,47] while has not yet received enough attention in the exploration of electrocatalysis in HER.…”