Encapsulation of Janus-structured Ni/Ni2P nanoparticles within hierarchical wrinkled N-doped carbon nanofibers: Interface engineering induces high-efficiency water oxidation

The exploration of efficient and economical electrocatalysts towards the oxygen evolution reaction (OER) is highly imperative for the development of OER-associated sustainable energy technologies. Interface engineeringenabled electronic regulation represents a powerful leverage to improve the intrinsic activity of earth-abundant electrocatalysts. Herein, we report a scalable hydroxycarbonate-assisted pyrolysis strategy to immobilize Janusstructured fine Ni/Ni2P nanoparticles onto hierarchical N-doped carbon nanosheet-grafted nanofibers (denoted as Ni/Ni2P@N-CNIF hereafter) for high-efficiency electrocatalytic OER. The strong coupling of fine Ni/Ni2P hetem-nanoparticles with the superstructured carbon substrate renders Ni/Ni2P@N-CNIF with regulated electronic state, sufficient anchored active sites, shortened distance for mass transport and enhanced structural stability. Consequently, the optimized Ni/Ni2P@N-CNIF exhibits extraordinary electrocatalytic OER activity and durability in KOH medium. As a proof-of-concept demonstration, when pairing Ni/Ni2P@N-CNIF with commercial Pt/C catalyst for overall water splitting, the assembled two-electrode electrolyzer outperforms the stateof-the-art RuO2 parallel to Pt/C-equipped counterpart. The concept of interface engineering and carbon hybridization herein may provide new inspirations for the future design of affordable and efficient electrocatalysts for various sustainable energy conversions.

Automated summary

Efficient and economical electrocatalysts for the oxygen evolution reaction (OER) are crucial for sustainable energy technologies. Interface engineering and carbon hybridization were used to immobilize Janus-structured Ni/Ni2P nanoparticles onto hierarchical N-doped carbon nanosheet-grafted nanofibers, resulting in high-efficiency Ni/Ni2P@N-CNIF catalyst for electrocatalytic OER.