Hydrolytically Stable Phosphorylated Hybrid Silicas for Proton Conduction

Abstract

A new approach to the synthesis of fully immobilized phosphorus functionalized hybrid proton conductive gels based on phosphonic acid grafting is presented in this paper. The hybrid silicas with different amounts of phosphonic acid have been prepared and characterized using Fourier‐transform infrared spectroscopy, X‐ray photoelectron spectroscopy, Brunauer–Emmett–Teller surface area analysis, thermogravimetric analysis, and electrochemical techniques. The proton conductivity of the materials depend strongly on hydration, which increases by four orders of magnitude over the relative humidity (RH) range of 20 to 100 %, up to a maximum of 0.027 S cm–1 at 100 °C and 100 % RH. For the reported samples, proton conduction is believed to occur within a dynamic hydrogen‐bond network formed by functionalized P–OH groups and water molecules by the Grotthuss mechanism. However, the proton conductive sites (P–OH) are likely to be partially immobilized by strong protonic receptors (N atoms in amines), which reduces the free P–OH groups and restricts proton transfer. Hydration may cause a bonding structural rearrangement, which results in more free P–OH groups as active proton conductive sites and, therefore, greatly increased proton conductivity is observed.

Toward improved mechanical strength, oxidative stability and proton conductivity of an aligned quadratic hybrid (SPEEK/FPAPB/Fe3O4-FGO) membrane for application in high temperature and low humidity fuel cells

“…Considering that the E a for Grotthuss mechanism is in the range of 9.65-38.59 kJ mol À1 and for vehicle mechanism is only about 16.4 kJ mol À1 . 58,59 The obtained results indicate that both Grotthuss and vehicle mechanisms coexist in membranes under 100% RH, while Grotthuss mechanism dominates more under 20% RH, due to the lack of free water molecules. Overall, the incorporation of …”

Artificial synapse network on inorganic proton conductor for neuromorphic systems

“…Proton conductivity of the nanogranular P-doped SiO 2 film was estimated to be B10 À 4 Scm À 1 at room temperature 24 . High proton conductivity is due to the sequence of proton hopping between hydroxyl groups and water molecules under applied electric field 24,26,27 . Accumulation of protons at the interface of SiO 2 electrolyte/IZO electrode will result in a large EDL capacitance and a strong lateral electrostatic coupling, which is meaningful for building artificial synaptic network [28][29][30] .…”

Functionalized Mesoporous Silica with Very Large Pores for Cellulase Immobilization

“…35 Figure 4 shows the XPS survey spectra of nonfunctionalized and organo-functionalized FDU-12 materials that were used to determine the chemical structure and the elemental compositions (Table 1). In general, the spectra of organo-functionalized silica samples show relatively strong C1s and Si2s peaks which indicate the presence of organosilanes.…”