Abstract: Nitrogen is reduced to ammonia, hydrazine, and mixtures thereof by reaction with water on a solid metal oxide irradiated with ultraviolet light. Useful metal oxides include titanium dioxide and metal-doped titanium dioxide. Titanium dioxide doped with iron, cobalt, molybdenum or nickel is preferred. The metal oxide is irradiated in the presence of nitrogen and water with ultraviolet light from a source such as a mercury arc lamp or sunlight. The nitrogen and the water may be in the vapor phase, or they may be adsorbed on the metal oxide. In addition, liquid water may be present. The ammonia which is formed may be recovered in a number of ways, for example, by heating the metal oxide gently under vacuum, by water extraction, or by adsorption in an acid acceptor. The recovered ammonia may be used as an agricultural fertilizer either directly or in the form of ammonium nitrate, sulfate, or phosphate salts.