High‐Dimensional MoO x Promotes Meta‐Stable Mo 5+ Active Site Regeneration for Efficient H 2 O 2 Electrosynthesis

Electrocatalytic two‐electron oxygen reduction reaction (2e − ORR) is a green method for H 2 O 2 synthesis, but its application is limited by insufficient catalyst selectivity, active site depletion, and low productivity. By regulating the crystal structure, high‐dimensional rod‐like molybdenum oxide (HDS‐MoO x ) was successfully synthesized, which is a non‐traditional phase distinct from the thermodynamically stable α‐MoO 3 . This unique high‐dimensional architecture not only exposes abundant meta‐stable Mo 5+ active sites but also enables reversible Mo 5+ /Mo 6+ valence cycling to stabilize active‐site regeneration. Compared with the conventional α‐MoO 3 , HDS‐MoO x showed a significant improvement in ORR performance, with a H 2 O 2 Faraday efficiency of 97% and a high average yield of 875 mmol g cat −1 h −1 , which is more than twice that of transition metal catalysts reported in the literature. Mechanistic studies reveal that the high‐dimensional structure promotes oxygen vacancy formation, exposing Mo 5+ active sites for O 2 activation. Meanwhile, the reversible Mo 5+ /Mo 6+ valence cycling effectively mitigates site depletion, ensuring long‐term catalytic stability. This work proposed a novel strategy for the efficient electroproduction of H 2 O 2 , offering valuable insights into the design of high‐performance 2e − ORR catalysts.