On the basis of the values of E°, the standard Gibbs free energy
change ∆G° of reaction 1 could be estimated to be about -810
kJ mol-1, which implies a very strong tendency for reaction 1 to
progress toward the right-hand side.
Analytically pure bismuth nitrate [Bi(NO3)3, 0.01mol] and an
excess amount of aqueous hydrazine solution (N2H4‚H2O, 0.02mol)
were put in distilled water at room temperature to form a mixture
with insoluble precipitate. The pH value of the resulting solution
was adjusted to the range of 12-12.5 by addition of aqueous
NH3‚H2O. The mixture was stirred strongly for about 0.5 h and
then transferred into a Teflon-lined stainless steel autoclave. The
autoclave was sealed and maintained at 120 °C for 12 h. After
the reaction was completed, the resulting black solid product was
filtered, washed with diluted hydrochloric acid (1 M) for several
times to remove bismuth oxide or hydroxide possibly remnant in
the final products and then saturated NaBH4 solution to avoid