Reaction Orders of the Hydrogenation of Nitrate and Nitrite in Water over a Nickel Catalyst

The hydrogenations of nitrate and nitrite in water were investigated using a Raney Ni catalyst and reduced Ni catalyst. For determination of the reaction orders, reduced Ni is more appropriate than Raney Ni due to the fact that Raney Ni has an intrinsic hydrogen on its surface and is more readily oxidized during the reaction. Based on the reaction orders of the reactants, it was revealed that the adsorption of hydrogen gas on the Ni surface was weaker than those of nitrate and nitrite. Graphic Abstract