Peptide-directed Pd-decorated Au and PdAu nanocatalysts for degradation of nitrite in water

In this work, a palladium binding peptide, Pd4, has been used for the synthesis of catalytically active palladium-decorated gold (Pd-on-Au) nanoparticles (NPs) and palladium-gold (PdxAu100-x) alloy NPs exhibiting high nitrite degradation efficiency. Pd-on-Au NPs with 20% to 300% surface coverage (sc%) of Au showed catalytic activity commensurate with sc%. Additionally, the catalytic activity of PdxAu100-x alloy NPs varied based on palladium composition (x = 6-59). The maximum nitrite removal efficiency of Pd-on-Au and PdxAu100-x alloy NPs was obtained at sc 100% and x = 59, respectively. The synthesized peptide-directed Pd-on-Au catalysts showed an increase in nitrite reduction three and a half times better than monometallic Pd and two and a half times better than PdxAu100-x NPs under comparable conditions. Furthermore, peptide-directed NPs showed high activity after five reuse cycles. Pd-on-Au NPs with more available activated palladium atoms showed high selectivity (98%) toward nitrogen gas production over ammonia.

Automated summary

In this study, a palladium binding peptide, Pd4, was used to synthesize catalytically active palladium-decorated gold (Pd-on-Au) nanoparticles and palladium-gold alloy nanoparticles (PdxAu100-x) with high nitrite degradation efficiency. The catalytic activity of Pd-on-Au NPs correlated with the surface coverage of gold, while the activity of PdxAu100-x alloy NPs varied based on palladium composition. The highest nitrite removal efficiency was achieved at 100% surface coverage for Pd-on-Au NPs and x=59 for PdxAu100-x alloy NPs.