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.

Polyaniline (PANI) and PANI/Ag₂O/Ag composites I and II were prepared under different AgNO₃ oxidant concentrations using the oxidative photopolymerization method. The chemical structure and optical, electrical, and morphological properties were determined for the prepared nanocomposite. The PANI/Ag₂O/Ag composite II has the optimum optical properties, in which the bandgaps of PANI, composite I, and composite II are 3.02, 1.71, and 1.68 eV, respectively, with the morphology of a bunch of grape-like shapes with average particles sizes of 25 nm. Under the optimum optical properties, glass/PANI/Ag₂O/Ag composite II electrode is used for hydrogen generation from sewage water. The measurements are carried out from a three-electrode cell under a xenon lamp. The effects of light wavelengths and temperature on the produced current density ([ ]) are mentioned. Under the applied voltage (at 30°C), the current density values ([ ]) increase from 0.003 to 0.012 mA.cm^-2 in dark and light, respectively. While increasing the temperature, [ ] values increase to 0.032 mAcm^-2 at 60°C. The thermodynamic parameters are calculated, in which the activation energy ([ ]), enthalpy ([ ]), and entropy ([ ]) values are 27.1 kJ·mol^-1, 24.5 J mol^-1, and 140.5 J K^-1 mol^-1, respectively. Finally, a simple mechanism for the produced hydrogen generation rate is mentioned. The prepared electrode is a very cheap (1$ for [ ]) electrode.

In this review, the transformative role of polymer nanocomposites in hydrogen production from challenging water sources is explored. Their catalytic efficiency and unique properties are highlighted, making them vital for overcoming complexities in hydrogen generation. Polymer nanocomposites demonstrate exceptional adaptability to various water compositions, including wastewater and saline water, enhancing efficiency, stability, and compatibility. In this review, the significance of these nanomaterials in the sustainable energy landscape is underscored, showcasing their ability to outperform conventional methods. Key breakthroughs in catalytic efficiency and adaptability are emphasized, illustrating their crucial role in clean hydrogen production. Looking forward, in this review, potential applications of polymer nanocomposites in diverse fields, from industrial processes to energy sector advancements, are identified. This synthesis of findings not only enhances the understanding but also sets the stage for the widespread adoption of polymer nanocomposites in meeting the global demand for sustainable hydrogen production.

This study provides H₂ gas as a renewable energy source from sewage water splitting reaction using a PMT/Au photocathode. So, this study has a dual benefit for hydrogen generation; at the same time, it removes the contaminations of sewage water. The preparation of the PMT is carried out through the polymerization process from an acid medium. Then, the Au sputter was carried out using the sputter device under different times (1 and 2 min) for PMT/Au-1 min and PMT/Au-2min, respectively. The complete analyses confirm the chemical structure, such as XRD, FTIR, HNMR, SEM, and Vis-UV optical analyses. The prepared electrode PMT/Au is used for the hydrogen generation reaction using Na₂S₂O₃ or sewage water as an electrolyte. The PMT crystalline size is 15 nm. The incident photon to current efficiency (IPCE) efficiency increases from 2.3 to 3.6% (at 390 nm), and the number of H₂ moles increases from 8.4 to 33.1 mmol h⁻¹ cm⁻² for using Na₂S₂O₃ and sewage water as electrolyte, respectively. Moreover, all the thermodynamic parameters, such as activation energy (E_a), enthalpy (ΔH*), and entropy (ΔS*), were calculated; additionally, a simple mechanism is mentioned for the water-splitting reaction.