Cotton-derived carbon fiber-supported Ni nanoparticles as nanoislands to anchor single-atom Pt for efficient catalytic reduction of 4-nitrophenol

Excessive price and scarcity of Pt species make it very necessary to enhance the atom utilization and catalytic efficiency of Pt catalysts for implementing their industrial practicality. Here, natural cotton is adopted as the precursor to in-situ support well-dispersed and uniform-sized Ni nanoparticles, which then work as nanoislands to effectively deposit single-atom Pt via the galvanic replacement reaction. On the resulting fibrous carbon matrix, the monocrystalline Ni particles are verified to tightly anchor isolated Pt atoms to form the alloyed PtNi nanoparticles. In the 4-nitrophenol (4-NP) reduction to 4-aminophenol (4-AP), the catalytic activity of the bimetallic PtNi/C catalyst with the low Pt loading (0.81%) maximally reaches 25 times as high as the primary Ni/C product. Simulated calculations demonstrate that the single-atom Pt centers on PtNi nanoparticles rapidly capture and split H-2 molecules, while Ni atoms strongly adsorb 4-NP molecule to activate the -NO2 group. Therefore, the trapped H atom could easily attack the -NO2 and reduce 4-NP.

Automated summary

In this study, PtNi nanoparticles were prepared by depositing single-atom Pt on nickel nanoparticles via galvanic replacement reaction using natural cotton as the precursor. The bimetallic PtNi/C catalyst with low Pt loading showed enhanced catalytic activity in the reduction of 4-nitrophenol. Simulated calculations demonstrated that the single-atom Pt centers on PtNi nanoparticles efficiently captured and split H-2 molecules, while the Ni atoms interacted strongly with 4-NP molecules to activate the reaction.