Size‐Controlled Synthesis of Platinum–Copper Hierarchical Trigonal Bipyramid Nanoframes

Abstract

Mastery over the structure of materials at nanoscale can effectively tailor and control their catalytic properties, enabling enhancement in both activity and durability. We report a size-controlled synthesis of novel Pt-Cu hierarchical trigonal bipyramid nanoframes (HTBNFs). The obtained nanocrystals looked like a trigonal bipyramid on the whole, composed of similar ordered frame structural units. By varying the amount of KI involved in the reaction, HTBNFs with variable sizes from 110 to 250 nm could be obtained. In addition, the structure of HTBNFs could be preserved only in a limited range of the Pt/Cu feeding ratio. Relative to the commercial Pt/C, these Pt-Cu HTBNFs with different Pt/Cu ratio exhibited enhanced electrocatalytic activity toward formic acid oxidation reaction as much as 5.5 times in specific activity and 2.1 times in mass activity. The excellent electrocatalytic activity and better durability are due to the unique structure of HTBNFs and probably synergetic effects between Pt and Cu.

Fine‐Tuning Intrinsic Strain in Penta‐Twinned Pt–Cu–Mn Nanoframes Boosts Oxygen Reduction Catalysis

“…When the amount of NaI was 15 mg, hollow polyhedrons were prepared (Figure S10b, Supporting Information), indicating that NaI is the necessary factor to form hollow structure. As previously reported, the strong coordination interaction between I − and Pt 4+ could lead to the preferential reduction of Cu 2+ , and thus Pt precursor could replace Cu atoms to form the hollow structure. As the amount of NaI further increased, the structure of products could not be controlled precisely (Figure S10c, Supporting Information).…”

“…In this work, a series of control experiments was carried out to investigate the influences of reducing and stabilizing agents on reduction kinetics and structure for Pt–Cu–Mn UNFs. It was found that metal precursors have obvious interactions with threonine, NaI, and ethanolamine (see details in Figures S6–S8, Supporting Information), indicating that threonine, NaI, and ethanolamine all play significant roles in controlling the reduction kinetics and affecting the structure . To gain insight into the influence on structure, TEM was employed.…”

“…To date, numerous state‐of‐the‐art Pt‐based NFs have exhibited remarkably enhanced performance in fuel cells toward the cathodic ORR . Particularly, the Pt‐based NFs with abundant surface defects usually show superior catalytic activity . However, current researches on Pt‐based NFs mainly focus on their shape‐controlled synthesis and understanding of structure–property relationship.…”

Recent Advances in the Synthesis and Electrocatalytic Applications of Platinum‐Based Bimetallic Alloy Nanostructures

“…D and E): Reproduced with permission from Refs. , , respectively. F and G): Reproduced with permission from Ref.…”

“…Consequently, CTAB was proposed to promote the formation of Cu nanocrystals, and the subsequent galvanic replacement between preformed Cu nanocrystals with Pt species in the solution finally leads to PtCu 3 hollow nanocages. Another type of hollow PtCu nanoparticles, PtCu hierarchical trigonal bipyramid nanoframes (Figure D), has been generated by heating a mixed solution of aqueous, ethylene glycol (EG), CuCl 2 , H 2 PtCl 6 , KI, and PVP at 225 °C for 0.5 h . The obtained nanocrystals looked like a trigonal bipyramid as a whole and were composed of a series of similar frame structural units with sub‐5 nm branched tips.…”