Photo-electrochemical green-hydrogen generation: Fundamentals and recent developments

Scalable, cost-effective production and earth-abundant material platforms for clean energy sources such as green hydrogen are key research problems. Understanding the fundamentals is the basis of the advancement of research in green hydrogen production. Quantum materials such as two-dimensional materials are emerging material platforms for green-hydrogen generation. Quantum mechanical tools such as density functional theory play a crucial role in understanding quantum phenomena hence improving the efficiency of hydrogen production from the quantum materials. In this review article, we discuss the basic principles of green hydrogen generation using photo-electrochemical water splitting. The methods to evaluate the catalytic activity of the catalysts are discussed in detail. A broad classification of the photo/electro-catalysts for water splitting is further elaborated. We discuss methods to enhance the performance of the catalysts by doping the hetero-atoms, and the synergic effects of using other nanomaterials such as quantum dots and plasmonic nanostructures. The concept of electron transfer enhancement due to magnetic nanostructures is also discussed in detail. The introduction and application of surface plasmons for enhanced hydrogen generation are also discussed. Finally, we discuss the application of hydrogen in a fuel cell for the generation of electricity.