At high concentrations of nitrite and nitrate (0.1 M) no ammonia was detected. This is because at these concentrations part of the light is absorbed by the substrate itself and hence the light-absorbing capacity
of the semiconductor is decreased.
The optimum concentration was found to be 10 ppm. It was also observed that the equilibrium adsorption of the nitrite ions was maximum at this concentration.
In addition, the yield of ammonia was found to depend on the amount of Ru loading on the semiconductor.
The results on the yield of ammonia as function of the Ru content are given in Table 2.