Converting Sewage Water into H₂ Fuel Gas Using Cu/CuO Nanoporous Photocatalytic Electrodes

This work reports on H₂ fuel generation from sewage water using Cu/CuO nanoporous (NP) electrodes. This is a novel concept for converting contaminated water into H₂ fuel. The preparation of Cu/CuO NP was achieved using a simple thermal combustion process of Cu metallic foil at 550 °C for 1 h. The Cu/CuO surface consists of island-like structures, with an inter-distance of 100 nm. Each island has a highly porous surface with a pore diameter of about 250 nm. X-ray diffraction (XRD) confirmed the formation of monoclinic Cu/CuO NP material with a crystallite size of 89 nm. The prepared Cu/CuO photoelectrode was applied for H₂ generation from sewage water achieving an incident to photon conversion efficiency (IPCE) of 14.6%. Further, the effects of light intensity and wavelength on the photoelectrode performance were assessed. The current density (J_ph) value increased from 2.17 to 4.7 mA·cm^-2 upon raising the light power density from 50 to 100 mW·cm^-2. Moreover, the enthalpy (ΔH*) and entropy (ΔS*) values of Cu/CuO electrode were determined as 9.519 KJ mol^-1 and 180.4 JK^-1·mol^-1, respectively. The results obtained in the present study are very promising for solving the problem of energy in far regions by converting sewage water to H₂ fuel.