The splitting of water molecule to give hydrogen and oxygen gas is one of the most studied chemical reactions worldwide. An efficient, low cost and environment-friendly method of water splitting is urgently required as hydrogen is a potential clean fuel for the future.
2H2O → 2H2 + O2
Water splitting is an energy-intensive process. It requires energy to be supplied in the form of heat/light/chemical etc.
Electrolysis: The process of splitting a water molecule by passing electricity and collecting the H2 and O2 produced. This is usually done in containers called electrolyzers containing a cathode, an anode, and electrolyte. Depending on the type of electrolyte used, electrolyzers can be classified as:
Electrolysis can be an important method of Hydrogen production provided the electricity source is harmless to the environment. Hydrogen production via electrolysis using renewable electricity sources including solar, hydro, wind etc. are good options without creating any greenhouse gas emissions. The photovoltaic (PV) technology is a clean way to provide electricity to the electrolyzers for Hydrogen generation through water splitting. Photovoltaic effect is the conversion of light energy into electricity using semiconductors without any greenhouse gas emission. Therefore, it is considered a clean hydrogen generation technology. Electrochemical reaction initiated by light to give directly the Hydrogen gas is popularly known as photoelectrolytic water splitting.
Water splitting methods can be broadly classified into two types:
Photocatalytic Water Splitting: The process of water splitting using light, water, and a chemical only. The required voltage for water splitting is provided by a suitable band gap catalyst in presence of light.
Non-Photocatalytic Water Splitting: Water splitting without using light energy has been made possible by the breakthrough invention of the Hydroelectric Cell- A Revolutionary Green & Clean Energy device. The hydroelectric cell has been invented by Dr. R. K. Kotnala and Dr. Jyoti Shah at CSIR-NPL, India. This device generates electricity by dissociating water molecules at the specifically engineered oxygen deficient and nanoporous ferrite/metal oxide materials at room temperature. The ions created by water splitting are collected at the two dissimilar electrodes, zinc, and silver where an electrochemical reaction leads to the generation of electricity.