Visible Light-Responsive Photocatalysts—From TiO2 to Carbon Nitrides and Boron Carbon Nitride

Abstract

Abstract It can be said that energy depletion and environmental pollution on a global scale are the most serious and urgent issues facing mankind in recent times. It is, thus, vital to design novel energy production and conversion systems that utilize natural energy and allow sustainable development without environmental destruction or pollution. In line with these objectives, the decomposition of H2O into H2 and O2, as well as the related reactions using visible light-responsive photocatalysts under sunlight irradiation, has been intensively investigated as one of the most promising environmentally benign energy production systems to address these issues. In the past half century, research on various photocatalytic systems using metal oxides has been carried out. However, to achieve higher efficiency in the production of H2, more innovative breakthroughs in the development of photocatalytic materials are strongly desired. To address such issues, graphitic carbon nitride (g-C3N4) and hexagonal boron carbon nitride (BCN) nano-materials have been investigated as promising visible light-responsive photocatalytic materials. In this chapter, we have highlighted the development of such g-C3N4 and hexagonal BCN photocatalytic nano-materials, focusing on their design, construction and optimization, as well as their applications to environmentally benign solar energy conversion systems, for the decomposition of H2O, reduction and fixation of CO2, and organic redox reactions. Such visible light-responsive photocatalytic materials are considered to be the most important research for the development of safe and clean energy production technologies for the 21st century and beyond.