In-situ immobilization of CoNi nanoparticles into N-doped carbon nanotubes/nanowire-coupled superstructures as an efficient Mott-Schottky electrocatalyst toward electrocatalytic oxygen reduction

The ingenious design and feasible fabrication of affordable, active and robust electrocatalysts toward the oxygen reduction reaction (ORR) is imperative importance for the advancement of advanced sustainable energy technologies. The electronic structure modulation via the establishment of Mott- Schottky heterojunctions offers a powerful leverage to realize the boosted electrocatalytic intrinsic activity, yet remaining challenging. Herein, an ingenious self-sacrificial template strategy is developed for the fabrication of an advanced hybrid Mott-Schottky electrocatalyst composed of CoNi alloyed nanoparticles in-situ implanted within N-doped carbon nanotube/nanowire-integrated hierarchical superstructures (CoNi@N-CNT/NWs). The combinations of experimental and theoretical studies demonstrate that the rectifying contact of CoNi nanoalloys and N-CNT/NWs can induce the self- driven charge transfer across the Mott-Schottky heterojunctions, giving rise to the improved electron transfer rate, reconfigured charge distribution, and boosted intrinsic activity. Moreover, the "branches"/"trunk"- structured carbon substrates can offer the tight structural interconnectivity and highly accessible channels for active site exposure, thus dramatically facilitating the mass transfer during the electrocatalytic process. As anticipated, the as-prepared CoNi@N-CNT/NWs exhibit prominent ORR performance with a half-wave potential (E1/2) of 0.86 V and exceptional long-term stability in 0.1 mol L−1 KOH. The innovational manipulation of electronic state via the of Mott-Schottky heterojunctions can enlighten the rational design of electrocatalysts with excellent performance.