Photoelectrochemical Water Splitting with Nitride-Based Photoelectrodes

Abstract

In semiconductor photoelectrochemical (PEC) cells, nitride-based materials have attained immense interest because of their suitable band position and bandgap, facile and low-cost synthesis, good thermal stability, and low toxicity. Mostly, two distinct classes of nitride materials have been explored in PEC cells-(i) metal nitrides and (ii) metal-free graphitic carbon nitride (g-CN). Although the use of g-CN in PEC cells is more promising due to its low photocorrosion and long-term stability, the development of photoelectrodes with g-CN is still in its primary stage. Besides, the low photocurrent density produced by g-CN photoelectrodes restricts its application. In contrast, metal-based nitrides are widely explored as photoelectrodes, and tremendous progress in the synthetic and application front has been achieved. Doping and substitution in the materials, integration with different cocatalysts, and fabrication of composite photoelectrodes have been demonstrated to substantially improve the photocurrent density. Moreover, efforts have been made for a thorough understanding of the photochemical and photoelectrochemical processes, including charge separation, recombination, charge transport, and interfacial processes. In this chapter, we describe the basic principles of designing nitride-based PEC cells, achievements, and deficiencies in nitride-based photoelectrodes. A detailed discussion on the application of the nitride-based photoelectrodes in photoelectrochemical water splitting is included, along with a perspective for the future application of this field. © 2022, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.