Sea urchin-like nickel nanoparticles encapsulated in nitrogen-doped carbon nanotubes for improved hydrogen peroxide electrosynthesis

Electrosynthesis of hydrogen peroxide (H 2 O 2 ) via the two-electron oxygen reduction reaction (2e − ORR) route is regarded as a promising substitute for the conventional anthraquinone method. In this study, a core–shell Ni@carbon material with adjustable shell thickness was synthesized using a simple hydrothermal-calcination method with the formation of metal organic framework (MOF) as the intermediate. During the calcination process, sea-urchin like morphology was obtained with nickel nanoparticles as the core and nitrogen-doped carbon nanotubes (NCNTs) as the shell. The optimized [email protected] material exhibits a high H 2 O 2 selectivity of >90 % in a wide potential range of 0.2–0.6 V, and a H 2 O 2 concentration of 797 mg/L can be achieved within 120 min in 0.1 M KOH. The generated H 2 O 2 can maintain almost 100 % degradation of 10 ppm Rhodamine B within 12 h. Theoretical calculations unveil that the synergistic effect between encapsulated nickel nanoparticles (Ni NPs) and N-doped carbon layers effectively regulates the charge distribution, resulting in optimal binding strength of *OOH intermediate, thus leading to the high selectivity of H 2 O 2 . This work provides an efficient strategy for the synthesis of electrocatalysts with high performance for 2e − ORR.