Arch-shaped Triboelectric Nanogenerator with Ni/Cu Bimetallic MOFengineered Intermediate layer for Self-Powered Electrochemical Clean Hydrogen Production and Environmental Remediation

Abstract

Electrochemistry has evolved as an affordable and effective approach for clean energy conversion and for the mitigation of environmental pollution. However, its reliance on external power for its operation has become a limiting factor in its widespread usage. Triboelectric nanogenerators (TENGs) offer a promising green alternative for energy harvesting but suffer from rapid charge decay, reducing practical effectiveness. Addressing this, we report an arch-shaped TENG with nylon cloth and ecoflex as triboelectric layers and Ni/Cu bimetallic MOF@PDMS composite as an intermediate layer to drive an electrochemical cell and demonstrate two applications, namely, electrolyte-free water splitting for hydrogen production and wastewater purification through dye degradation. The intermediate layer lowers the charge recombination process, thereby enhancing the device’s output by 77% (from 49.3 V to 87.3 V). Under periodic finger tapping, the device delivers an output voltage of 87.3 V, a short-circuit current of 0.29 µA, and a power density of 0.05 W/m2 at 40 MΩ. The large surface area and conductivity of Ni/Cu bimetallic MOF create effective charge-trapping sites inside the intermediate layer, increasing charge storage capacity as confirmed through dielectric measurements. Moreover, the arch-shaped device achieves a mechanical energy conversion efficiency of 23.6% and exhibits excellent environmental robustness with stable output under varying ambient conditions. To reduce energy loss during the electrochemical process, a unique strategy is employed by coupling the output performance and durability (over 5000 cycles) of the device with a half-wave rectifying circuit, resulting in 1.4 times faster hydrogen production and degradation of two organic dyes, like Rhodamine B and Atrazine. Overall, this research showcases the dual functionality of the device for self-powered green energy conversion and environmental remediation.