Chapter 10: Harnessing Both Light and Dark Conditions for Photocatalytic Hydrogen Production: Pathway for Ultimate Green Hydrogen

Hydrogen production methods span from carbon-intensive grey variants to cleaner blue and turquoise, with green variants being the most environmentally friendly. However, green hydrogen faces challenges due to the intermittent nature of solar energy and low efficiency. Photocatalysis, particularly using semiconductors, provides a promising paradigm shift for hydrogen production, by splitting water into hydrogen and oxygen when exposed to light, and offering a genuinely green and sustainable approach. Ionic carbon nitride, a semiconductor catalyst, demonstrates remarkable efficiency in hydrogen production, and in this chapter we present not only its ability to efficiently split seawater, but also showcase its unique ability for dark photocatalysis, generating hydrogen even without light. Understanding the structure–property relationships of carbon nitride can further enhance its potential for sustainable hydrogen production and revolutionize the energy landscape.