Ultrasound-assisted synthesis of electrocatalysts for hydrogen production

Hydrogen is a clean fuel that can be produced by means of hydrogen evolution reaction (HER) during water splitting process. HER requires the catalysts which could provide reversible binding of hydrogen that is energetically comparable with the process catalyzed by platinum (Pt). According to the most recent industrial reports, only 5 % of worldwide produced hydrogen is coming from electrolytic water splitting. One of the main obstacles is a very high onset overpotential which results in high energy consumption during hydrogen production process. Another problem is use of rather expensive precious metals and complicated multistep technological processes for synthesis of nanostructured materials. In this chapter, the main structural, compositional, and morphological aspects defining the efficiency of inorganic materials toward HER are summarized. Furthermore, materials containing earth-abundant transition and rare earth metals are highlighted as possible alternatives to Pt. It is demonstrated that alloys, nanoalloys, and near-surface alloys offer a number of potentially effective candidates toward HER. Use of high-intensity ultrasound for bottom-up synthesis of catalysts and especially for top-down structuring as well as activation of metal surfaces is discussed as a promising technological solution for the design of low-cost, robust, and efficient electrocatalysts.