Emerging Ruthenium-Based Electrocatalysts Towards Green Hydrogen: Current States, Challenges, and Opportunities

Since centuries, human development in industry has been regularly correlated with fossil fuel combustion and the release of greenhouse gases. As the overall demand for energy has risen drastically in the modern era, the problems related to the reduction of energy resources and increased environmental pollution cannot be ignored. It is required to seek novel energy sources to avoid the risks associated with the reduction of non-renewable energy resources and health issues due to the emission of dangerous gases. Among all the alternative resources for the demand of energy for various applications, hydrogen energy has been recognized as a superlative candidate for water electrolysis to produce cost-effective clean energy. This is called a sustainable strategy due to the immense abundance of resources (i.e., water), the only production of water, superior energy density, and net-zero carbon emissions (negligible air pollution). For electrocatalytic hydrogen evolution reactions (HER), the basic requirement is the choice of better electrocatalysts. Various electrocatalysts such as precious (e.g., Pt, Pd, Ir, and Ru etc.), earth-abundant metal (e.g., Fe, Co, Ni, and Cu etc.), and metal-free electrocatalysts are established for a practical HER progression. With them, ruthenium (Ru)-derived electrocatalysts hold opposite hydrogen bonding energy, have a rational price, and behave as an excellent alternative to platinum (Pt) for HER activity. Thus, this chapter delivers a perception of the current breakthroughs in the field of Ru-electrocatalysts, their synthesis strategies, and progress towards their utilization in green hydrogen production. With this, it also addresses the prospects of Ru-electrocatalysts towards their implementation in large-scale green hydrogen production.