A Self‐Powered Ocean Energy Platform Enabling Green Hydrogen Production and Smart Ocean Monitoring From Irregular Wave Energy

ABSTRACT Triboelectric nanogenerators (TENGs) are promising for harvesting low‐frequency, stochastic ocean‐wave energy, yet their limited power output and inefficient energy utilization hinder practical marine applications. Here, we present an in‐phase dual‐layer oscillating float triboelectric nanogenerator (IDOF‐TENG) that directly converts irregular ocean‐wave energy into electricity for simultaneous green hydrogen production and smart ocean monitoring. The IDOF‐TENG integrates synchronized dual‐layer polytetrafluoroethylene (PTFE) triboelectric interfaces for constructive charge superposition with a noncontact reciprocating rotation mechanism combining helical transmission and planetary gearing to efficiently harvest multidirectional wave energy. Under 1.0 Hz mechanical excitation, the device delivers a maximum output current of 0.48 mA and a peak volumetric power density of 81.23 W m −3 , while maintaining stable operation over 60 h. Coupled with a power management circuit and a hydrothermally synthesized MoS 2 /NiCo 2 O 4 /NF electrocatalyst, the harvested energy drives self‐powered water splitting with a hydrogen evolution rate of 56.22 µL min −1 under realistic wave conditions. The stored electrical energy also continuously powers marine Internet‐of‐Things devices, including navigation beacons, wireless water‐quality monitoring, and temperature‐humidity sensing. This work establishes a scalable self‐powered ocean energy platform that bridges ocean‐wave energy harvesting with green hydrogen production and autonomous marine sensing, providing a practical strategy for sustainable offshore energy systems.