Fundamental understanding of the processes involved in that are behind the mechanism for electrochemical evolution of hydrogen and oxygen from water is considered critical in for further advancement of materials that could be implemented in electrolyzers,. Atomic scale insight at the electrified solid-liquid interfaces provides invaluable guidance to overcome limitations that cause a lower than desired operating efficiency of the devices. All of that highlights the need for development of more active, durable and cost effective oxygen evolution (OER) and hydrogen evolution (HER) reaction catalysts. While the majority of research is placed on the catalyst design and synthesis aiming to improve their efficiency, not too much less has been done to resolve and understand a the impact of the liquid phase of the interface at which reaction is taking place. In addition to surface structure, surface and subsurface composition and electronic properties, the role of liquid phase which is influencing the overall performance of an electrified interface is being investigated. Molecular species from the electrolyte and the nature of their interaction with the catalyst surface will be discussed. The knowledge acquired from two-dimensional surfaces has been employed to create real-world catalysts with superior properties.