Nitrogen and Phosphorus Co‐doped Hollow Carbon Spheres as Efficient Metal‐Free Electrocatalysts for the Oxygen Reduction Reaction

Abstract

Replacement of rare‐ and noble‐metal catalysts with earth‐abundant, low‐cost, stable, and efficient metal‐free catalyst substitutes is highly desirable, but full of challenges for the oxygen reduction reaction (ORR). Herein, N, P co‐doped hollow carbon spheres (N,P‐HCS) are prepared through a simple pyrolysis method, using hollow carbon spheres (HCS), melamine, and phytic acid (PA) as the C, N, and P sources, respectively. Compared to the N‐doped HCS (N‐HCS) and P‐doped HCS (P‐HCS), the N, P co‐doped sample exhibited much higher ORR catalytic activity. Moreover, in comparison with commercial Pt/C, the as‐prepared N,P‐HCS showed comparable ORR activity, but stronger endurance to methanol and higher durability in alkaline solution. The high performance of N,P‐HCS can be primarily ascribed to the large surface area, high conductivity, porous carbon structure, and high content of heteroatoms (N and P). Considering the excellent catalytic activity and durability, after further structural optimization, N,P‐HCS could be a promising metal‐free catalyst candidate for the ORR in fuel cells.

In Situ Synthesis of Fe−N Co‐doped Porous Carbon Nanospheres by Extended Stöber Method for Oxygen Reduction in Both Alkaline and Acidic Media

“…The FeÀ NÀ Cs-1.0 catalyst showed the smallest semicircle diameter in high frequency region in 0.1 M KOH and 0.1 M HClO 4 solution, respectively, verifying that there was a faster charge transfer ability for FeÀ NÀ Cs-1.0 on ORR reaction. [71] In order to evaluate the structure stability of the FeÀ NÀ Cs-1.0 catalyst, we further investigated the morphology by SEM after electrochemical tests, the result was shown in Figure S4. It can be observed that FeÀ NÀ Cs-1.0 possessed a well-defined uniform spherical morphology after electrochemical tests, which confirmed that the excellent structure stability for FeÀ NÀ Cs-1.0 during electrocatalytic tests.…”

Nitrogen–phosphorus doped graphitic nano onion-like structures: experimental and theoretical studies

“…Graphitic materials have been doped with nitrogen, 18 boron, 19 sulfur, 20,21 beryllium, 22 and phosphorus. 23,24 The doping in graphitic materials can improve their electrochemical activity taking advantage of the different electronegativity of the dopants, which can polarize the adjacent atoms. 25 Recently, extensive investigations on the facile in situ synthesis of heteroatom doped carbon nanomaterials for effective catalytic applications have been reported.…”

Synthesis of Tangled Iron‐Nitrogen Co‐doped Carbon Nanosheets through a Dopamine Coordination Strategy for the Oxygen Reduction Reaction

“…Therefore, design and synthesis of low‐cost yet highly active PGM‐free electrocatalysts to boost the sluggish ORR is highly desirable. Single‐atom catalysts (SACs) with coordinated transition metal as catalytic centers can maximize the efficiency of metal utilization, thus achieving high activity and selectivity in relevant electrocatalytic reactions [11–14] . In particular, transition metal and nitrogen co‐doped carbon based single‐atom catalysts (M−N−C, where M represent Co, Fe, and Mn etc.)…”

“…Single-atom catalysts (SACs) with coordinated transition metal as catalytic centers can maximize the efficiency of metal utilization, thus achieving high activity and selectivity in relevant electrocatalytic reactions. [11][12][13][14] In particular, transition metal and nitrogen co-doped carbon based single-atom catalysts (MÀ NÀ C, where M represent Co, Fe, and Mn etc.) with optimal activity have been widely investigated as the promising candidates of PGM-free ORR catalysts.…”