Germanium sulfide (GeS) nanoparticles (NPs) were synthesized using hydrothermal method. The chemical composition was determined through energy-dispersive X-ray analysis, while scanning electron microscopy and transmission electron microscopy were employed to study the morphology. X-ray diffraction analysis confirmed the cubic structure of the GeS NPs. The crystallite size and lattice strain of cubic GeS NPs were found to be 29.65 nm and \(1.24 \times 10^{-3}\) respectively using Debye-Scherrer method. The energy levels of Ge and S were studied using X-ray photoelectron spectroscopy to determine the binding states and chemical composition. Thermo-gravimetric analysis was performed to calculate the kinetic parameters for thermal stability. Zeta potential of GeS NPs was \(-\) 22.4 mV indicating the prevention from aggregation. The optical band gap of the nanoparticles was measured to be 1.66 eV. Their photo-catalytic activity was evaluated at different powder concentrations, and the relevant parameters were estimated using the Langmuir-Hinshelwood kinetic model. The rate constant ‘kf’ was obtained to be 0.0018 min \(^{-1}\) , 0.0020 min \(^{-1}\) , 0.0035 min \(^{-1}\) for powder concentration of 1 g/L, 2 g/L and 3 g/L, respectively. Additionally, the potential applications of GeS NPs as pressure sensors and infrared sensors were comprehensively investigated.
