In recent years, we have experienced extreme climate changes due to the global warming, continuously impacting and changing our daily lives. To build a sustainable environment and society, various energy technologies have been developed and introduced. Among them, energy harvesting, converting ambient environmental energy into electrical energy, has emerged as one of the promising technologies for a variety of energy applications. In particular, a photo (electro) catalytic water splitting system, coupled with emerging energy harvesting technology, has demonstrated high device performance, demonstrating its great social impact for the development of the new water splitting system. In this review article, we introduce and discuss in detail the emerging energy-harvesting technology for photo (electro) catalytic water splitting applications. The article includes fundamentals of photocatalytic and electrocatalytic water splitting and water splitting applications coupled with the emerging energy-harvesting technologies using piezoelectric, piezo-phototronic, pyroelectric, triboelectric, and photovoltaic effects. We comprehensively deal with different mechanisms in water splitting processes with respect to the energy harvesting processes and their effect on the water splitting systems. Lastly, new opportunities in energy harvesting-assisted water splitting are introduced together with future research directions that need to be investigated for further development of new types of water splitting systems.
Surface Functionalization of Carbon Nanotubes for Energy Applications