Lanthanum sulfide-manganese sulfide/graphene oxide (La 2 S 3 -MnS/GO) composite thin film as an electrocatalyst for oxygen evolution reactions

In this study, the lanthanum sulfide-manganese sulfide (La2S3-MnS) nanosheet composite films with different thicknesses were grown on graphene oxide (GO) (LMS/GO) coated stainless steel substrate using binder-free successive ionic layer adsorption and reaction (SILAR) method, for the first time. The formation of crystal structure and chemical states was identified using X-ray diffraction analysis and X-ray photoelectron spectroscopy, respectively. The nitrogen sorption analysis showed the micro-/mesoporous structure of La2S3-MnS-90/GO thin film exhibiting a specific surface area of 170 m2 g-1 and hydrophilic nature. The scanning electron microscopic image showed microstructure with porous ultrathin interconnected nanosheets. Surface texture was examined using transmission electron microscopy. The resulting La2S3-MnS-90/GO thin film electrocatalyst showed oxygen evolution reaction (OER) overpotential as low at 263 mV to reach 10 mA cm-2 current density with Tafel slope of 48 mV dec-1 for in 1 M KOH solution and stability over 50 h. Consequently, it could be considered one of the alternate sulfide-based catalysts for highly efficient OER evolution.