•Maleimide is proposed as building blocks for the design of proton exchange membranes.•We studied the proton transfer between maleimide by DFT calculations.•We reduced the proton transfer barrier by phosphonic acid.•We observed synergetic effect of the overall conductivity in the MI-MPA composite.•We studied the proton transfer between the homologues of maleimide.Density functional theory (DFT) calculations are applied to the study of proton transport in maleimide and its homologues, succinimide and phthalimide. The calculations reproduce correctly their structural characteristics and reveal the hydrogen bonding and proton hopping properties. Specifically, the calculations show that the potential barrier for proton transfer between two maleimide molecules is about 30.60 kcal mol−1 mediated by one or two water molecules with correction of solvation effect by water, and will decrease to about 13.22 kcal mol−1 if ethylphosphonic acid molecule is used as mediator with correction of solvation effect by phosphoric acid. In addition, the calculations also show that succinimide and phthalimide possess similar characteristics compared to maleimide. Finally, it is concluded that maleimide and its homologues are building block candidates for the design of high-temperature proton exchange membranes.

The synergetic proton conducting effect with three orders of magnitude improvement in proton conductivity was observed in an acid–base composite composed of phosphonic acid functionalized polystyrene (PS-PA) and triazolyl functionalized polystyrene (PS-Tri). In addition, a new method for the development of proton conducting materials by the combination of different acidic and basic polymers is proposed. The PS-PA was synthesized by the bromination of polystyrene on the para-position of the phenyl ring followed by phosphonation and hydrolysis. The PS-Tri was synthesized by the chloromethylation of polystyrene on the para-position of the phenyl ring followed by azidation and 1,3-dipolar cycloaddition or ‘click’ reaction. A maximum proton conductivity of 11.2 mS cm−1, which is three orders of magnitude higher than that of pristine PS-PA or PS-Tri, a tensile strength of 16.3 MPa, and a minimum water uptake of 15.1% (90 °C, 90% RH) were observed in the PS-PA/PS-Tri composite composed of 66.7% PS-PA. Finally, a mosaic-like morphology model and space-charge effects were proposed to explain the synergetic proton conducting effect.

The effects of Y addition to Pd/Ce-Zr/Al2O3 catalyst have been investigated for the combustion of methane. The supported Pd catalysts are characterized by XPS, TPR, TPO and TPSR techniques in order to study the oxidation/reduction properties. Activity tests in methane combustion show that addition of Y to Pd/Ce-Zr/Al2O3 catalyst remarkably promotes its low-temperature and total conversion activity. In addition, the introduction of Y also greatly suppresses deactivation of Pd/Ce-Zr/Al2O3 and endows Pd/Ce-Zr-Y/Al2O3 with higher thermal stability than Pd/Ce-Zr/Al2O3. The characterization results of catalysts indicate that the addition of Y to Pd/Ce-Zr/Al2O3 catalyst can effectively inhibit the decomposition of PdO particles and improve the reduction–reoxidation properties of the active PdO species, which increases the catalytic activity and thermal stability of the Pd/Ce-Zr/Al2O3 catalyst.

Promotional effect of Ca on the catalytic property of Pd/Ce–Zr/Al2O3 catalyst towards methane combustion is examined. The surface properties and the oxidation/reduction behavior of these catalysts are investigated by BET, TEM, XPS, TPR, TPO and TPSR techniques. Activity tests in methane combustion show that addition of Ca to Pd/Ce–Zr/Al2O3 can promote remarkably its low-temperature activity. The thermal stability of the Pd/Ce–Zr/Al2O3 catalyst to the exposure at high temperature is also enhanced by Ca loading. XPS and TEM results show that the addition of Ca to Pd/Ce–Zr/Al2O3 catalyst generates well-dispersed PdO particles on support. H2–TPR, O2–TPO and CH4/O2–TPSR experiments show that the addition of Ca improves the reduction/reoxidation properties and thermal stability of the active PdO species, which increases the catalytic activity and thermal stability of the Pd/Ce–Zr/Al2O3 catalyst.