Increased Green Electricity Generated in Carbon-Doped TiO₂-Based Hydroelectric Cell

The most efficient way to mitigate the degradation of the environment and global warming is to generate clean, sustainable green energy. A hydroelectric cell (HEC) is a green energy device that employs oxygen-deficient, mesoporous metal oxides to produce electricity through water splitting at room temperature. In this work, carbon doping is explored to create oxygen vacancies in TiO₂. The solid-state reaction method was used to process titanium dioxide (TiO₂) with 0.1 wt.% and 0.5 wt.% of carbon (C). Photoluminescence (PL) spectroscopy confirmed the presence of microstructural defects and optical defects in the carbon-doped TiO₂. The enhancement in microstrain and dislocation density due to the incorporation of carbon atoms in the TiO₂ lattice was confirmed by x-ray diffraction (XRD) analysis. The HEC was fabricated by applying silver paste in a comb-like pattern to one face of the sample pellet and attaching a zinc sheet to the other face. The surface of the C-TiO₂ pellet was moistened with water to generate voltage and current. The fabricated 2 × 2 cm² TiO₂ and 0.1 wt.% and 0.5 wt.% C-doped TiO₂ HECs generated short-circuit current of 5.0 mA, 6.3 mA, and 7 mA with open-circuit voltage of 0.76 V, 0.81 V, and 0.74 V, respectively. The cells delivered off-load output power of 3.8 mW, 5.10 mW, and 5.2 mW, respectively. Nyquist curves obtained for the HECs in the wet state confirmed the ionic conduction process within the material and charge transfer to the electrodes. Carbon-doped TiO₂ processed at low temperature generated enhanced power output in comparison to pure TiO₂. Therefore, C-doped TiO₂ is a cost-effective material for producing green electricity at a large scale.