Research on ORR and OER Bifunctional Carbon Nanotubes Catalysts with Cobalt Encapsulated at the Tips

The development of non-precious metal-based electrocatalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is of great significance for fuel cell and water electrolysis technologies. Carbon-based materials loaded with transition metals exhibit outstanding catalytic performance. In this study, we developed bamboo-like bifunctional carbon nanotubes (CNT) catalysts with cobalt for ORR and OER via a straightforward and effective synthesis technique. Characterization revealed that the metal Co was encapsulated in the tips of CNT with Co@CNT-100 exhibiting the most uniform distribution of CNT, a significantly larger specific surface area (107.51 m 2 g −1 ) along with the highest degree of structural disorder (I D /I G = 1.43). The electrochemical tests showed that Co@CNT-100 exhibited excellent catalytic activity with an onset potential of 0.92 V, a half-wave potential of 0.82 V, and a limiting diffusion current density of 4.64 mA cm −2 , and outperforming 20% commercial Pt/C in terms of kinetic potential and constant potential lifetime tests and methanol resistance. Additionally, the OER overpotential was 1.56 V at 10 mA cm −2 , and the potential difference (ΔE) between the OER overpotential (E j @10 mA cm −2 ) and the ORR half-wave potential (E 1/2 ) was just 0.74 V, highlighting its strong potential application as a dual-function catalyst for ORR and OER.