Polyoxometalate‐Modified Sponge‐Like Graphene Oxide Monolith with High Proton‐Conducting Performance

Abstract

Graphene oxide (GO) contains abundant oxygen‐containing functional groups acting as hydrogen bond acceptors for proton conduction on its basal plane. However, the dilemma in realizing bulk in‐plane conduction and the metastability at room temperature of GO films both obstruct its application. Polyoxometalate‐modified sponge‐like GO monolith (PEGO) with 3D cross‐linking inner structure, which exhibits unique “shrink‐expand” effect to polar solvent, are synthesized. Owing to the introduction of polyoxometalates and the replacement of unstable epoxy groups by ethylenediamine, PEGO exhibits hitherto the highest proton conductivity under low relative humidity (1.02 × 10−2 S cm−1 at 60% relative humidity) and excellent long‐term stability (more than 1 month). The outstanding conductivity originates from 3D transporting pathways, high‐density hopping sites, and eliminated grain boundary resistance. This study provides a practical way to design GO‐based proton‐conducting material dominated by in‐plane diffusion.

Effects of Intercalated Molecules in Graphene Oxide on the Interlayer Channels for Anhydrous Proton Conduction

“…For instance, the conductivities increase from 1.4 × 10 –4 S cm –1 at 30 °C to 2.3 × 10 –4 S cm –1 at 60 °C for GO/BS, and from 2.2 × 10 –4 S cm –1 at 30 °C to 3.0 × 10 –4 S cm –1 at 60 °C for GO/PA, respectively. It should be noted that the conductivities obtained in this study are comparable to the data in the literature (as shown in Table S1), and the conductivities are speculated to be further increased with the improvement of relative humidity due to the strong acceleration effect of water on proton conduction. ,, …”

“…Proton conduction properties of GO and nanocomposites are measured and depicted in Figure 3c. Close to the values in literature, 26,32 GO attains a relatively low conductivity of 5 × 10 −5 S cm −1 at 30 °C, resulting from the insufficient loading amount of carrier sites and hydrogen bonds (inter-or intralayer). By comparison, the intercalation of organic molecules affords varied proton conduction properties for the nanocomposites (Figure 3c).…”

Understanding bond formation and its impact on the capacitive properties of SiW12 polyoxometalates adsorbed on functionalized carbon nanotubes

“…S14, the yellow regions on the isosurface show the loca- tions where the electronic charge was depleted and the blue regions show the sites where the charge is allocated. It is evident that the POM acts as an electronic sponge that may effectively retain charge after the cluster has been anchored to the substrate, and it is consistent with previous experimental works [53]. This may suggest that this effect is present in a POM@CNT composite system, independently of the presence of a functional group.…”

Heterotrimetallic Organic Framework Assembled with FeIII/BaII/NaI and Schiff Base: Structure and Visible Photocatalytic Degradation of Chlorophenols

“…The N 2 , CO 2 , and water vapor adsorption properties of 1 were studied under different conditions (Figure S2). Compound 1 assimilates a spot of N 2 (17.19 cm 3 /g) with a Brunauer–Emmett–Teller (BET) surface area of 47.83 m 2 /g at −196 °C as well as a low CO 2 uptake (11.89 cm 3 /g) at 20 °C. , As expected, 1 also shows very low water vapor adsorption at 20 °C (1.64 cm 3 /g) . These results suggest that the flexible framework of 1 tends to shrink upon the activation process.…”