Mn(IV) oxide/Mn(IV) sulfide/poly-2-amino-1-mercaptobenzene for green hydrogen generation from sewage water through the photoelectrocatalytic process

Abstract

The Mn(IV) oxide/Mn(IV) sulfide/poly-2-amino-1-mercaptobenzene (MnO 2 -MnS 2 /P2AMB) nanocomposite is prepared through a polymerization reaction (oxidation) and is utilized as a highly photo-electrocatalytic material for green hydrogen generation from sewage water. The MnO 2 -MnS 2 /P2AMB nanocomposite demonstrates remarkable optical properties, characterized by a bandgap of 1.81 eV. To promote the water splitting reaction by the synthesized MnO 2 -MnS 2 /P2AMB nanocomposite photoelectrode, sewage water is utilized as a sacrificial agent to effectively facilitate the generation of hydrogen gas through the evaluation of the current (J ph ). At −0.9 V, the J ph and J o values are determined to be −0.33 and −0.2 mA.cm -2 , correspondingly. Notably, the optimum J ph value of −0.26 mA.cm −2 is observed for incidence photons at 340 nm, indicating that light with higher frequency and energy leads to the generation of more electrons from the MnO 2 -MnS 2 /P2AMB nanocomposite and subsequent hydrogen production. Conversely, the lowest J ph value of −0.21 mA.cm −2 is obtained at 730 nm, suggesting the influence of infrared waves on the photoelectrode due to the small bandgap (1.86 eV) of the materials, as calculated in a previous analysis. This study represents an initial step towards the conversion of wastewater into hydrogen gas, which can serve as a sustainable fuel source for various industrial applications.