## 1 Introduction
In order to make water splitting viable for large-scale H\({}_{2}\) production the electrocatalysts must also be stable and low cost [14]. Currently, Pt-based catalysts for the HER and Ru- and Ir-based catalysts for the OER are benchmarks when it comes to the performance evaluation of the other catalysts reported in the literature [15, 16, 17]. However, their scarcity and high cost are significant obstacles for large-scale applications, making the identification of non-noble materials that are both highly efficient and stable a main concern. The scientific literature contains a large number of functional materials that have been studied regarding their electrocatalytic water-splitting properties, ranging from noble metal-based to non-noble metal-based and metal-free ones [18, 19, 20]. Perovskite oxides are a category of functional materials that have been revealed to be very promising for the water-splitting domain [21,22]. These compounds share a crystal structure characterized by the chemical formula ABO\({}_{3}\), where the A-site is occupied by a bigger metal cation than the one occupying the B-site, and they possess properties such as piezoelectricity, superconductivity, ferroelectricity, and enormous magnetoresistivity which make them useful for various industrial and commercial domains [23]. The full potential of perovskite oxides in the water-splitting field has yet to be revealed, but the evaluation of their relevant catalytic properties is of current interest to researchers, as reflected in the recent publications of [PERSON] et al. [24,25]. In one of the studies, hybrid materials based on montmorillonite functionalized with LaMnO\({}_{3}\) perovskite were obtained for the first time and were tested regarding their water-splitting electrocatalytic activity in alkaline media, which led to the identification of the modified electrode possessing the best properties for the HER [24]. A subsequently published investigation outlines the HER electrocatalytic properties in alkaline media of unsubstituted, Ca-substituted, and Pd-substituted LaMnO\({}_{3}\). The most significant results were obtained for the electrodes modified with compositions containing the Pd-substituted perovskite oxide [25]. The current paper continues the work of [PERSON] et al. [25] concerning the water electrolysis catalytic properties of perovskite oxide-based modified electrodes via the study of two new materials--LaMnO\({}_{3}\):Ag/PVP (P11) and LaMnO\({}_{3}\):Pd/PVP (P14)--in a strongly alkaline medium. The modified samples whose OER and HER activity were evaluated experimentally were obtained using four different procedures. The results show that while both perovskite compounds display negligible electrocatalytic activity for the HER, the electrode modified with a composition containing P11 and manufactured with one of the procedures (designated as Procedure 4) is more active toward the OER than the rest of the investigated samples. In terms of novelty, the study of the water-splitting electrocatalytic properties of P11 and P14 has not been previously performed, and the materials have not been previously characterized with the physico-chemical methods mentioned in the paper.