Facile fabrication of polypyrrole/NiOx core-shell nanocomposites for hydrogen production from wastewater

This work highlights testing the polymer nanocomposite for hydrogen gas production from wastewater (sewage water). The in-situ polymerization technique is used to prepare polypyrrole (PPy) and PPy/NiOx nanocomposite films on a glass substrate. The film's ability to generate hydrogen from sewage water is then evaluated. The XRD and XPS confirmed the formation of two types of NiOX: NiO and Ni2O3. The optical property of the composite is greater than the polymer under the insertion of NiOx as a core for the polymer coating shell, in which the band gap values are 2.25 and 1.81 eV, respectively. The TEM confirmed the PPy/NiOx core-shell formation, in which the polymer shell (20 nm) coated the NiOX core (170 nm). The electrochemical testing for H-2 gas production is carried out through a three-electrode cell. The effect of light on/off, wavelengths, and temperature on the H-2 production is applied. Under off/on light, the produced current density (J(ph)) value is enhanced from 5 to 16 mu A, respectively. The effect of monochromatic light: 440, 540, and 730 nm are tested, and the produced J(ph) values are -1.28, -1.16, and -1.14 mu A cm(-2), respectively. In which, the decreasing J(ph) value with increasing of the monochromatic light confirmed the behavior of the photoelectrode under different optical regions. The J(ph) values increase from -1.6 to -5.8 mu A cm(-2) with a rise in temperature from 30 to 55?. Moreover, enthalpy (delta H*), activation energy (E-a), and entropy (delta S*) of thermodynamic processes are determined using the photoelectrode response at different temperatures.