In this paper we present a study on stable radicals and short-lived species generated in anion-exchange membrane (AEM) fuel cells (AEMFCs) during operation. The in-situ measurements are performed with a micro-AEMFC inserted into a resonator of an electron paramagnetic resonance (EPR) spectrometer, which enables separate monitoring of radicals formed on the anode and cathode sides. The creation of radicals is monitored by the EPR spin trapping technique. For the first time, we clearly show the formation and presence of stable radicals in AEMs during and after long-term AEMFC operation. The main detected adducts during the operation of the micro-AEMFC are DMPO-OOH and DMPO-OH on the cathode side, and DMPO-H on the anode side. These results indicate that oxidative degradation involving radical reactions have to be taken into account when stability of AEMFC is investigated.

Single Cu( ii ) and Fe( iii ) surface catalytic sites dramatically enhance the activity of rutile TiO ₂ in photocatalytic degradation of 4-chlorophenol.

Using acid–base-type doping of polyaniline with H₃PMo₁₂O₄₀, two series of catalyst samples were prepared. In series Sl the doping and polymerization were carried out simultaneously, leading to a uniform distribution of the dopant over the whole volume of the polymer. In series SII the doping was achieved by protonation of already formed polyemeraldine base with H₃PMo₁₂O₄₀. Since this process must involve diffusion in the solid matrix, the surface becomes enriched in heteropolyanions (Keggin units) due to their limited diffusivity. The examination of physicochemical properties of the samples by XP, EPR and FTIR spectroscopies indicated that the Keggin units incorporated into the polymer matrix retain their identity and represent catalytically active centres. The insertion of the dopant species increases the electrical conductivity of the polymer by several orders of magnitude. The catalytic activity was tested in ethyl alcohol conversion and both the products of acid–base [C₂H₄ and (C₂H₅)₂O] and redox (CH₃CHO) type reactions were observed. Owing to the surface enrichment of the SII series of catalysts their catalytic activity was much higher than that of samples of the Sl series nominally doped to the same level. In both types of catalysts the selectivity to the redox reaction product (CH₃CHO) was greatly enhanced in comparison with unsupported H₃PMo₁₂O₄₀.

The cyano-bridged [Cu^II(tetrenH₂)]₂[W^IV(CN)₈]₂·5H₂O (tetren = tetraethylenepentaamine) (1), [Cu^II(tetrenH₂)][Cu^II(tetrenH)][W^V(CN)₈][W^IV(CN)₈]·2.5H₂O (2), [Cu^II(dien)]₂[W^IV(CN)₈]·4H₂O (dien = diethylenetriamine) (3) and its isomorphous molybdenum(IV) analogue (4) have been prepared and structurally characterised. 1 and 2 are built from the W₂Cu₂(μ-CN)₄ squares extended into 1-D structure by cyano-bridges. 2-D 3 and 4 form a square grid pattern with tungsten atoms in the corners and –CN–Cu(dien)–NC– linkages on the edges of the squares. The magnetic behaviour of 1 and 3 indicates the presence of two isolated Cu^II spins S = 1/2 with a very weak antiferromagnetic coupling through the diamagnetic NC–W^IV–CN bridges in the low temperatures. Assembly 2 exhibits a weak ferromagnetic interaction between Cu^II and W^V isolated by diamagnetic [W^IV(CN)₈]⁴⁻ spacer from another Cu^II centre within W^V–CN–Cu^II–NC–W^IV–CN–Cu^II unit and the antiferromagnetic interaction between the Cu^II ₂W^VW^IV units.