Pt Immobilization within a Tailored Porous-Organic Polymer–Graphene Composite: Opportunities in the Hydrogen Evolving Reaction

Abstract

A facile, postsynthetic treatment of a designed composite of pyrimidine-based porous-organic polymer and graphene (PyPOP@G) with ionic Pt, and the subsequent uniform electrodeposition of Pt metallic within the pores, led to the formation of a composite material (PyPOP-Pt@G). The pyrimidine porous-organic polymer (PyPOP) was selected because of the abundant Lewis-base binding sites within its backbone, to be combined with graphene to produce the PyPOP@G composite that was shown to uptake Pt ions simply upon brief incubation in H2PtCl6 solution in acetonitrile. The XPS analysis of PyPOP@G sample impregnated with Pt ions confirmed the presence of Pt­(II/IV) species and did not show any signs of metallic nanoparticles, as further confirmed by transmission electron microscopy. Immediately upon electrochemical reduction of the Pt­(II/IV), metallic Pt (most likely atomistic Pt) was observed. This approach stands out, as compared to Pt monolayer deposition techniques atop metal foams, or a recently reported atomic layer deposition (ALD), as a way of depositing submonolayer coverage of precious catalysts within the 1–10 nm pores found in microporous solids. The prepared catalyst platform demonstrated large current density (100 mA/cm2) at 122 mV applied overpotential for the hydrogen evolution reaction (HER), with measured Faradaic efficiency of 97(±1)%. Its mass activity (1.13 A/mgPt) surpasses that of commercial Pt/C (∼0.38 A/mgPt) at the overpotential of 100 mV. High durability has been assessed by cyclic and linear sweep voltammetry, as well as controlled potential electrolysis techniques. The Tafel plot for the catalyst demonstrated a slope of ∼37 mV/decade, indicating a Heyrovsky-type rate-limiting step in the observed HER.

Exfoliation of amorphous phthalocyanine conjugated polymers into ultrathin nanosheets for highly efficient oxygen reduction

“…S4 in the ESI †). 49 The elemental mapping veri es the homogenous surface distribution of Co, Fe, C, and N throughout the whole Fe0.5Co0.5Pc-CP NSs (Fig. 1f).…”

“…Meanwhile, hetero-assemblies of 2D nanolayers such as transition metal dichalcogenides/diseleniums, 46 layered double hydroxides, 47 and metal-organic frameworks 48 with various graphene NSs (including graphene, nitrogen doped graphene, and defective graphene) have been recently received increasing interest in fabricating versatile high performance electrocatalysts including oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER) catalysts. The high activity is due to the combination of the highly exposed active centers presented on 2D nanolayers [27][28][29][30] and high electron transfer capability of graphene NSs [49][50][51][52] together with strong interaction between these components to reform the electronic distribution. Thanks to the ultrathin nature, the as-prepared bimetallic Fe0.5Co0.5Pc-CP NSs were used to fabricate a heterostructure Fe0.5Co0.5Pc-CP NS@G with graphene NSs, which exhibits high ORR catalytic activity in an alkaline medium.…”

Synthesis of CNTs@POP‐Salen Core‐Shell Nanostructures for Catalytic Epoxides Hydration

“…The direct mixing of the monomers and non‐functionalized CNTs resulted in the formation of composite materials with phase separated POPs and CNTs (denoted as CNTs‐POP‐salen) on the basis of TEM characterization (Figure B). Alkordi and co‐workers reported the one‐pot synthesis of POP@G composite using different POPs and graphene . The phase separated POPs and CNTs was possibly caused by the fast precipitation of POP‐salen in our case.…”

Phosphate Doped Ultrathin FeP Nanosheets as Efficient Electrocatalysts for the Hydrogen Evolution Reaction in Acid Media

“…It has been generally recognized that hydrogen evolution reaction (HER) is a very promising method for achieving efficient water‐splitting and consequently the production of high‐purity H 2 . In the last few decades, the state‐of‐the‐art HER catalysts are mainly based on noble metal of Pt . The scarcity and high cost of Pt, however, greatly restrict the use of Pt‐based electrocatalysts in mass industrial production.…”

“…[3][4][5] In the last few decades, the state-of-the-art HER catalysts are mainly based on noble metal of Pt. [6][7][8] The scarcity and high cost of Pt, however, greatly restrict the use of Pt-based electrocatalysts in mass industrial production. To solve this issue, a variety of transition-metal-based HER catalysts have been developed, [9,10] including metal carbides, [11][12][13] selenides, [14,15] phosphides [16,17] and chalcogenides.…”