Electrochemical production of hydrogen peroxide (H₂O₂) via the two-electron (2e⁻) pathway of oxygen reduction reaction (ORR) supplies an auspicious alternative to the current industrial anthraquinone process. Nonetheless, it still lacks efficient electrocatalysts to achieve high ORR activity together with 2e⁻ selectivity simultaneously. Herein, a boron-doped defective nanocarbon (B-DC) electrocatalyst is synthesized by using fullerene frameworks as the precursor and boric oxide as the boron source. The obtained B-DC materials have a hierarchical porous structure, befitting boron dopants, and abundant topological pentagon defects, exhibiting a high ORR onset potential of 0.78 V and a dominated 2e⁻ selectivity (over 95%). Remarkably, when B-DC electrocatalyst is employed in a real device, it achieves a high H₂O₂ yield rate (247 mg·L⁻¹·h⁻¹), quantitative Faraday efficiency (~ 100%), and ultrafast organic pollutant degradation rate. The theoretical calculation reveals that the synergistic effect of topological pentagon defects and the incorporation of boron dopants promote the activation of the O₂ molecule and facilitates the desorption of oxygen intermediate. This finding will be very helpful for the comprehension of the synergistic effect of topological defects and heteroatom dopants for boosting the electrocatalytic performance of nanocarbon toward H₂O₂ production.