Due to the non-renewability of fossil fuels, hydrogen is considered to be a promising alternative choice. The main advantage of hydrogen fuel is the lack of CO₂ and other pollutant emissions such as NO_x and SO_x. At present, 98% of hydrogen at present is derived from the reformation of fossil fuels. Water is the most abundant hydrogen resource on the earth, thus, hydrogen production from water splitting would be one of most promising approaches for sustainable development in energy and environment. Hydrothermal reaction has played an important role in the formation of fossil fuels because of some unique inherent properties of high-temperature water, such as a high ion product and a low dielectric constant. High-temperature water acts not only as a reaction medium but also as a hydrogen source. In this paper, a high efficiently hydrogen production from water splitting with Fe as a reducing agent is presented, which mainly include an enhanced hydrogen production from water by using CO₂ or H₂S. Further, the CO₂ reduction with the hydrogen formed in-site is also reported. In addition, the discussion of possible reaction mechanism for hydrogen production and CO₂ reduction is presented.