Thermally Activated Carbon Cloth Toward Efficient Two‐Electron Oxygen Reduction for H₂O₂ Electrosynthesis

The thermal activation of carbon represents a pivotal strategy in developing high‐performance oxygen reduction reaction (ORR) electrocatalysts. However, the fundamental influence of annealing atmospheres on ORR activity remains elusive. Herein, flexible carbon cloth (CC) is thermally activated under various atmospheres, including air, N 2 , and H 2 /Ar. Comprehensive characterizations reveal that the oxidative air atmosphere introduces oxygen functionalized sp 3 defects that synergistically enhance the 2e − pathway for hydrogen peroxide (H 2 O 2 ) generation. In stark contrast, the inert (N 2 ) or reductive (H 2 /Ar) atmospheres largely preserve graphitic domains, resulting in inferior catalytic activity. Benefiting from the oxidative thermal activation, the optimized CC achieves unprecedented H 2 O 2 selectivity of 94.7–97.6% and a half‐wave potential ( E 1/2 ) of 0.69 V. The excellent electrochemical performance is ensured by the good balance between the surface defect density ( I D /I G = 1.042), oxygen content (11.07 at.%), and overall structure integrity. The demonstrated methodology provides a scalable blueprint for tailoring carbon electrocatalysts for sustainable energy conversion and storage technologies.