Dual direct Z-scheme photocatalysts for overall water decomposition have demonstrated strong redox abilities and the efficient separation of photogenerated electron–hole pairs. Overall water splitting utilizing NiAl-LDH-based binary and ternary nanocomposites has been extensively investigated. The synthesized binary and ternary nanocomposites were characterized via XRD, FTIR, SEM, HRTEM, XPS, UV-DRS, and photoelectrochemical measurements. The surface wettability properties of the prepared nanocomposites were measured via contact angle measurements. The application of the NiAl-LDH/g-C₃N₄/Ag₃PO₄ ternary nanocomposite was investigated for photocatalytic overall water splitting under light irradiation. In this work, we found that in the presence of Ag₃PO₄, the evolution of H₂ and O₂ is high over LCN30, and 2.8- fold (O₂) and 1.4-fold (H₂) activity increases can be obtained compared with the use of LCN30 alone. It is proposed that Ag₃PO₄ is involved in the O₂ evolution reaction during water oxidation and g-C₃N₄ is involved in overall water splitting. Our work not only reports overall water splitting using NiAl-LDH-based nanocomposites but it also provides experimental evidence for understanding the possible reaction process and the mechanism of photocatalytic water splitting. Photoelectrochemical measurements confirmed the better H₂ and O₂ evolution abilities of NiAl-LDH/g-C₃N₄/Ag₃PO₄ in comparison with NiAl LDH, g-C₃N₄, Ag₃PO₄, and LCN30. The observed improvement in the gas evolution properties of NiAl LDH in the presence of Ag₃PO₄ is due to the formation of a dual direct Z-scheme, which allows for the easier and faster separation of charge carriers. More importantly, the LCNAP5 heterostructure shows high levels of H₂ and O₂ evolution, which are significantly enhanced compared with LCN30 and pure NiAl LDH.

Monodispersed CuO octahedral crystals were successfully synthesized using a low-temperature co-precipitation method. Zinc doping in CuO created surface defects that enhanced oxygen adsorption on the surface crucial for gas sensing applications. Pure and Zn-doped CuO sensor films were realized using the doctor blade method. The sensor films showed selective response towards a low concentration of NO₂ at a lower operating temperature of 150 °C. Doping with Zn causes the resistance of the sensor film to decrease due to the enhancement of charge carriers with an analogous improvement in the sensor response. The observed decrease in sensor resistance agreed well with the findings of the work function studies. Zinc doping resulted in an increase in work function by 180 meV which, after NO₂ exposure, was found to increase by a further 130 meV, attributed to the oxidizing behavior of the test gas.