Platinum-modified covalent triazine frameworks hybridized with carbon nanoparticles as methanol-tolerant oxygen reduction electrocatalysts

Abstract

Covalent triazine frameworks, which are crosslinked porous polymers with two-dimensional molecular structures, are promising materials for heterogeneous catalysts. However, the application of the frameworks as electrocatalysts has not been achieved to date because of their poor electrical conductivity. Here we report that platinum-modified covalent triazine frameworks hybridized with conductive carbon nanoparticles are successfully synthesized by introducing carbon nanoparticles during the polymerization process of covalent triazine frameworks. The resulting materials exhibit clear electrocatalytic activity for oxygen reduction reactions in acidic solutions. More interestingly, the platinum-modified covalent triazine frameworks show almost no activity for methanol oxidation, in contrast to commercial carbon-supported platinum. Thus, platinum-modified covalent triazine frameworks hybridized with carbon nanoparticles exhibit selective activity for oxygen reduction reactions even in the presence of high concentrations of methanol, which indicates potential utility as a cathode catalyst in direct methanol fuel cells.

Carbon- and Nitrogen-Based Porous Solids: A Recently Emerging Class of Materials

“…Indeed, very recently, Pt-CTF/ carbon nanoparticle composites proved to show a selective activity of electrochemical oxygen reduction reaction (ORR) in an acidic solution even in the presence of a high concentration of methanol (Figure 6c). 57 The reason for this interesting selective catalytic activity could originate from a Schottky metalsemiconductor heterojunction at the Pt/CTF interface, which can facilitate charged surface by a charge transfer and can trigger a different catalytic activity (Figure 7). 5861 …”

“…56,57 For example, platinum coordinated at CTF (Pt-CTF) shows a promising performance as a solid catalyst for direct low-temperature oxidation of methane to methanol with high selectivity, activity, and stability. This catalyst shows a turnover frequency of ca.…”

Conversion of amorphous polymer networks to covalent organic frameworks under ionothermal conditions: a facile synthesis route for covalent triazine frameworks

“…9 The abundant nitrogen atoms provide coordination sites, making CTFs attractive catalyst supports for metals. [9][10][11][12][13][14][15][16][17][18][19][20] CTFs have also been applied as solid base catalysts for the conversion of CO 2 21 and as metal free catalysts for ORR. 22,23 The high surface area and nitrogen amount make CTFs attractive for the storage of gases 6,[24][25][26][27][28] or generally as sorbent materials.…”

Spectroelectrochemical evidence of the role of viologen moiety as an electron transfer mediator from ITO substrate to a Pt complex acting as a confined molecular catalyst for hydrogen evolution reaction

“…Molecular catalysts are usually used as homogeneous catalyst in solution and are difficult to be separated from reactants and products after the reaction. It is very difficult to prepare single atom catalysts and to maintain their structures from aggregation without proper supports [9]. We have recently proposed that these problems can be overcome by confining a metal complex on and within molecular layers forming "confined molecular catalyst", which acts as heterogeneous catalysts, and reported that a Pt complex confined within viologen layer constructed on Si(111) electrode can act as electrocatalysts for both hydrogen evolution [10,11] and CO 2 reduction [12], demonstrating the effectiveness of the "confined molecular catalyst".…”