Fast Cryomediated Dynamic Equilibrium Hydrolysates towards Grain Boundary-Enriched Platinum Scaffolds for Efficient Methanol Oxidation

Abstract

<jats:p>Although platinum nanocrystals have been considered as potential electrocatalysts for methanol oxidation reaction (MOR) in fuel cells, the large-scale practical implementation has been stagnated by their limited abundance, easy poisoning, and low durability. Here, grain boundary-enriched platinum (GB-Pt) scaffolds are produced in large scale via facilely reducing fast cryomediated dynamic equilibrium hydrolysates of platinum salts. Such plentiful platinum grain boundaries are originated from the fast fusion of short platinum nanowires during reduction of the individually and homogeneously dispersed platinum intermediates. These grain boundaries can provide abundant active sites to efficiently catalyze MOR and meanwhile enable to oxidize the adsorbed poisonous CO during the electrocatalytic process. As a consequence, the as-synthesized GB-Pt scaffolds exhibit an impressively high mass activity of 1027.1 mA mg<jats:sub>Pt</jats:sub><jats:sup>−1</jats:sup> for MOR, much higher than that of commercial Pt/C (345.2 mA mg<jats:sub>Pt</jats:sub><jats:sup>−1</jats:sup>), as well as good stability up to 5000 cycles. We are confident that this synthetic protocol can be further extended to synthesize various grain boundary-enriched metal scaffolds with broad applications in catalysis.</jats:p>

Polyelectrolyte-Induced Stereoassembly of Grain Boundary-Enriched Platinum Nanoworms on Ti3C2Tx MXene Nanosheets for Efficient Methanol Oxidation

“…Besides, the Ti 3 C 2 T x -supported Pt nanoworms were found to possess abundant grain boundaries at the junctions (Figure F). Notably, the appearance of these grain boundary sites on the Pt worms was commonly accompanied by a large number of twin defects, such as corner or edge atoms and high-index facets, which were able to reduce the activation energy for alcohol oxidation and simultaneously provide plentiful active sites for the elimination of CO byproducts. , Moreover, the interplanar crystal spacings on the Pt nanoworms were about 2.21 and 1.98 Å (Figure G), verifying that the Pt(111) and Pt(200) are the most common crystal planes in the worm-shaped Pt structures. Additionally, high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) and elemental analysis (Figure H–M) demonstrate the coexistence of C, N (from PDDA), O, Ti, and Pt components in the Pt NW/PDDA-Ti 3 C 2 T x hybrid, which are all homogeneously dispersed over the Ti 3 C 2 T x nanosheet.…”

“…Notably, the appearance of these grain boundary sites on the Pt worms was commonly accompanied by a large number of twin defects, such as corner or edge atoms and high-index facets, which were able to reduce the activation energy for alcohol oxidation and simultaneously provide plentiful active sites for the elimination of CO byproducts. 38,39 Moreover, the interplanar crystal spacings on the Pt nanoworms were about 2. 3.2.…”

Harnessing Electrostatic Interactions for Enhanced Conductivity in Metal-Organic Frameworks

“…Exploration of electrically conductive metal-organic frameworks (MOFs) [1] offers exciting opportunities for fabricating electronic materials with the advantages of tunable structure, high crystallinity, and permanent porosity [2]. This would greatly expand the prospective applications of MOF materials [3][4][5][6][7][8][9][10][11][12][13]. Although increasing endeavors have been devoted to this field [14][15][16][17], MOFs with high conductivity are still rare, and the preparation of conductive MOFs has remained a big challenge to date.…”