In situ construction of N-doped hollow carbon nanotubes anchored Co nanoparticles for bifunctional ORR/OER electrocatalyst

The development of efficient, inexpensive, and stable bifunctional non-noble metal catalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is of practical significance for the large-scale application of zinc-air batteries. Here, a novel bifunctional Co-based nano-catalyst (Co@CxNyC) is fabricated by complexation-reduction and high-temperature pyrolysis method. Co nanoparticles were loaded in nitrogendoped hollow irregular carbon nanotubes derived from natural fibers and carbon quantum dots. Remarkably, the unique hollow structure and the Co-Nx active site make the screened Co@C1N3C have efficient ORR&OER catalytic performance. Co@C1N3C with onset potential (0.90 V) and half-wave potential (0.84 V) exhibited an efficient 4e � transfer path and favorable stability and methanol tolerance. Moreover, the overpotential of Co@C1N3C needed to achieve 100 mA cm-2 is 625 mV, which is 31 mV better than that of RuO2. In conclusion, this work not only provides deep insights into the catalytic activity of Co@CxNyC nanocomposite as ORR&OER bifunctional electrocatalysts but also guides the growth of Co-based bifunctional catalysts.