Nitrogen-doped carbon-coated nanodiamonds for electrocatalytic applications

Abstract

Nitrogen-doped carbon hybridized nanodiamond (N-doped C@ND) materials have been developed and used as an electrocatalytic for oxygen reduction reactions (ORRs). The polymerized ionic liquids are employed to modify NDs and then subjected to thermal annealing at 600 °C, resulting in a high concentration of N-doped (9.33 at.%) carbon frameworks attached on the ND surface. This N-doped C@ND material provides a highly active mesoporous structure (4 nm pore) with a high surface area (366 m2 g−1) and allows for enhancement of catalytic performance compared to pure NDs. The N-doped C layers altered the electroneutrality of NDs, creating favourable charged sites for oxygen adsorption, thus weakening the O–O bond strength to facilitate ORR activity. Having a predominant four-electron transfer pathway with a total electron transfer number of 3.44–3.88 in the potential region of 0.1–0.8 VRHF, the N-doped C@ND-based catalyst materials performed well as a catalyst for the ORR in the alkaline medium. This affordable material and simple process will find potential application in clean energy generation and storage, durable fuel cells and metal–air batteries.

High-performance bifunctional oxygen electrocatalysts for zinc-air batteries over nitrogen-doped carbon encapsulating CoNi nanoparticles

“…theoretical capacity [1][2][3]. High-efficient oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) catalysts play a vital role during the charging and discharging process of the zinc-air battery [4][5][6]. At present, benchmark OER catalysts (IrO 2 and RuO 2 ) and ORR catalysts (Pt/C) can accelerate the sluggish reaction processes which exhibited super catalytic activity, but the high-cost and scarcity still significantly restricted their applications [7,8].…”