Porous platinum superparticles
Argonne researchers at the Center for Nanoscale Materials are entering a new frontier in the field of nanotechnology with the synthesis of Colloidal Superparticles (CSPs) of nanocrystals, a class of assembled nanocrystals in the form of colloidal particles.
A generalized strategy has been developed by a team from the Nanophotonics and NanoBio Interfaces Groups at Argonne’s Center for Nanoscale Materials (CNM) for the synthesis of mesoporous colloidal superparticles (CSPs) made of nanocrystals of platinum-group metals (e.g., Pt, Pd, Rh, and Ir) through self-limited growth of metal nanocrystals (or precursors) and silver halide in individual colloidal particles.
Synthesis of colloidal superparticles (CSPs) of nanocrystals, a class of assembled nanocrystals in the form of colloidal particles, has been emerging as a new frontier in the field of nanotechnology because of their potential novel properties originated from coupling of individual nanocrystals in CSPs. Here, a facile approach is reported for the controlled synthesis of mesoporous CSPs made of various platinum-group nanocrystals that exhibit high colloidal stability and ligand-free surfaces to significantly benefit their applications in solution-phase heterogeneous catalysis. The synthesis relies on self-limiting growth of composite particles through coprecipitation of both Pt-group nanocrystals (or their precursor compounds) and silver halides on sacrificial substrates of colloidal silver particles. The intermediate silver halides in the composite particles play the critical role in limiting the continuous growth (and/or coalescence) of individual Pt-group nanocrystals and they can be selectively dissolved to create nanoscale pores in the resulting CSPs.
Yongxing Hu, Yuzi Liu and Yugang Sun, “Mesoporous Colloidal Superparticles of Platinum-Group Nanocrystals with Surfactant-Free Surfaces and Enhanced Heterogeneous Catalysis,” Advanced Functional Materials, DOI: 10.1002/adfm.201403664. Published January 2015 Online, Published March 18, 2015 Print.