Nanomaterials and energy applications
Special Issue Information
Dear colleagues,
Energy is a key commercial, diplomatic, and globalization issue during the last century, and the energy demand will continue to be so in the next century. At this time, the global energy consumption stands at almost 18.5 TW. Energy demand is expected to exceed, due to rising in global population and economic activities. The majority of today's energy is derived from fossil fuels. Because fossil fuels emit carbon dioxide, their consumption has an unpredictable impact on the global environment. A clean renewable energy source is required to meet global energy demand while also protecting the environment from carbon dioxide emissions . Hydrogen makes up the majority of the cosmos and water is the most common form of hydrogen. Water electrolysis can be used to extract hydrogen. The endergonic reaction of water splitting requires energy to split the water molecule and neutralize the activation energy. Water molecules can be split into hydrogen and oxygen molecules via photocatalysis using an efficient photocatalyst. Metal oxides semiconductors are cheap, nontoxic, and easily available on earth and they are thought to be the finest candidate for usage as a photocatalyst. Unfortunately, metal oxides are large band gap semiconductors and they can absorb only UV light of solar radiation For better solar light to hydrogen conversion efficiency, photocatalyst should absorb maximum solar light. It can be achieved by decreasing the bandgap of the semiconductor that is used as a photocatalyst.
Energy is needed during the electrolysis process to break the molecule of water into H2 and O. Water splitting is a reaction that is carried out. The change in Gibbs free energy for water electrolysis is 237 kJmole-1. Water electrolysis is a non-spontaneous and uphill reaction. As a result, sunlight must be stored using photon energy as output and resist the activation energy. The optical bandgap of the semiconductor material varies from 2.0 to 2.4 eV. The energy for the separation of a water molecule is 237 kJ mole-1, so a semiconductor material that has a bandgap of 1.23 eV is considered optimum for the electrolysis of water.
Looking forward to your contributions.
Dr Muhammad Junaid
Section Editor