Fundamental Understanding and Figure of Merits for Electrocatalytic and Photoelectrocatalytic H 2 Production

Increasing global population and energy consumption are expected to rise further in the next few decades, making it crucial to develop a more sustainable energy system. There is a need of an energy source which can overcome the limitations associated with existing renewable energy sources, i.e., lack of sunlight, low wind speed, and so on. Hydrogen is projected as an ideal choice to store renewable energy in the form of chemical energy, which can be further utilized independent of the availability of sunlight and wind. Water splitting to make long-lasting green hydrogen is an appealing strategy for achieving a carbon-free future using hydrogen energy. However, in order for this technology to be realized and scaled up, efficient electrocatalysts (EC) and photo-electrocatalysts (PEC) are required to promote cathodic hydrogen evolution and anodic oxygen evolution. This chapter discusses the fundamentals of EC and PEC, as a process of green hydrogen generation. It further sheds light upon utilization of two-dimensional (2D) materials for producing hydrogen. The most recently produced 2D transition metal carbides and nitrides, known as “MXenes,” by Prof. Yury's group, are also discussed in this chapter.