The most promising strategy for the efficient production of high purity hydrogen (and oxygen) is water electrolysis, while renewable sources (e.g. wind or solar) can provide the necessary power input for the electrolysis process. The hydrogen that is thus generated can either be used as fuel directly or in chemical processes as a reducing agent. Water splitting can be executable at both low temperatures (normally less than 100 °C), and at elevated temperatures (temperatures between 500 – 1500 °C via steam water electrolysis), while various ionic substances (intermediates) can be transmitted electrochemically during the process of electrolysis (OH−, H+, O2−). This electrolytic reaction needs additional energy to dissociate the water molecule, resulting in a more sluggish reaction system and kinetics than the progression of acidic electrolytic hydrogen evolution reaction. Knowing how the physical and chemical conditions of a catalyst-electrode material influence the adsorption of intermediates, energy barriers and activation energies on the efficiency of the electrolyzer is one of the major challenges in electrolysis. The temperature influence on the reactivity of alkaline potassium hydroxide (KOH) solution on a heterometallic NiFe surface was investigated with the aid of ReaxFF potential is performed using reactive molecular dynamics (RMD) simulations, with a particular focus on H2 generation. The analytical overview of the detailed hydrogen evolution response of a multifaceted chemical system from reactants to products through different intermediates is provided, in order to maximise the performance of the reactive processes to deliver the desired products and eliminate unnecessary side products. However, to understand completely the reactions at the catalyst surface, more basic information is required at the atomic level. In this investigation, therefore, we investigate the hydrogen generation in the presence of Ni and Ni-doped with transition metals such as Fe in the temperature range 500–1500 K through steam water electrolysis. Although some form of hydrogen is already detected at lower temperatures, significant formation of H2 is only achieved at preeminent temperatures of 1000 K or higher. Hydrogen molecules are also the most formed species at 1500 K. OH− diffusivity is also experiential in accordance with increasing dehydrogenation at higher temperatures, with increasing surface-to-subsurface diffusivity. Overall, the findings indicate that the optimum temperature for effective hydrogen generation on the NiFe heterometallic catalyst lies around 1000 K. In steam water electrolysis, the attained temperature 1000 K is characterised by the large numbers of reactive excited species. Hence, this reaction might generate a synergistic effect, which makes the process of steam water electrolysis an interesting technology. This study also highlights the significance of temperature in the process of steam water electrolysis, an important step towards successful H2 formation as a clean energy source

An Atomic-Scale Investigation of the Temperature Influence on the Reactivity of Alkaline Water Electrolysis on an Optimized Nickel-Iron Catalyst Surface for the Hydrogen Generation

Paper Proceedings: https://asmedigitalcollection.asme.org/IMECE/IMECE2021/volume/85543

ASME 2021 International Mechanical Engineering Congress and Exposition (IMECE2021)

Supporting the need among researchers worldwide for additional online and multimedia content, ASME now offers the ASME Conference Video Collection. This platform will collect and provide long-term access to conference presentation videos, encompassing all technology areas within ASME's technical conference and events program. About 30,000-40,000 engineers across all mechanical engineering and related disciplines participate in ASME conferences each year. This includes authors of approximately 6,000 to 8,000 technical papers published by ASME, the majority of whom also submit video presentations for our virtual conferences. The video collection will be available as an add-on to existing product packages or as a separate subscription.