Figure 5.

(a) Time-dependent UV-visible spectrum showing the reduction of p-nitroaniline to 1,4-diaminobenzene with NaBH₄ in presence of urease reduced Au nanoparticles as catalyst. (b) Time-dependent UV-visible spectrum for the reduction of p-nitroaniline to 1,4-diaminobenzene with NaBH₄ catalyzed by Au@ZnO core-shell nanoparticles synthesized using urease. (c) Plot of ln (A) versus time for the reduction of p-nitroaniline to 1,4-diaminobenzene with NaBH₄ using urease reduced Au nanoparticles as catalyst (blue line and markers) and Au@ZnO core shell nanoparticles as catalyst (red line and markers).