A half-wave rectifying triboelectric nanogenerator for self-powered water splitting towards hydrogen production

Ocean energy is one of promising energy candidates in addressing energy crisis and environmental pollution issues. How to make practical use of ocean energy to produce sustainable energy still poses challenges. In this work, a half-wave rectifying water flow-driven triboelectric nanogenerator (HRWF-TENG) is fabricated to collect water wave energy towards hydrogen production via self-powered electrochemical water splitting. The HRWF-TENG achieves large voltage and low loss direct current (DC) output using a half-wave rectifying circuit, which enables the open-circuit voltage and short-circuit current to reach 100 V and 90 μA at 140 rpm, respectively. The RuOx/CNT catalyst was prepared for the hydrogen evolution reaction (HER), and the HRWF-TENG provided electrons for water molecules to generate hydrogen at the cathode. By connecting the HRWF-TENG with a water splitting unit directly, the whole system can a hydrogen production rate of 12.32 μL min-1, with a sustainable hydrogen energy conversion efficiency of 2.38%. The entire design simplifies the traditional self-powered water splitting system by a half-wave rectifying TENG, providing a more practical strategy for conversion of ocean energy into renewable hydrogen energy. A self-powered energy conversion system that can convert the kinetic energy of irregular water flow into hydrogen has been proposed. It consists of two main components: a half-wave rectifying water flow-driven triboelectric nanogenerator that converts the kinetic energy of water flow into electrical energy and the electrolytic cell that utilizes electrocatalytic water splitting to prepare hydrogen. • The whole system with half-wave rectifying property does not need extra transformer, rectifier bridge or capacitor. • The water flow kinetic energy can be converted into large DC output to power the water splitting without extra battery. • The HRWF-TENG system can achieve a high hydrogen energy conversion efficiency of 2.38%.