Electrochemical behavior of CoCrMo alloy for dental applications in acidic artificial saliva containing albumin.

The electrochemical properties of CoCrMo alloy immersed in different artificial saliva with or without Ca2+ and albumin were studied by open circuit potential (OCP), electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PP), and meanwhile the microstructures features, phase identification and chemical composition of the alloy were analyzed by SEM, EDS, XRD and RA-IR to further understand the electrochemical behavior of the alloy. The results indicated that the self-passivation behavior of the alloy occurred universally and was obviously distinct with each other in different acidic artificial saliva. No phase transformation was observed and the oxide layer and corrosion products exhibited amorphous nature. There was an obvious complexation of the adsorbed albumin with the alloy, and the adsorption capacity of albumin increased with the prolongation of immersion time. The adsorbed albumin presenting black stripped spots had a certain inhibition to the formation of passivation film, and Ca2+ in saliva promoted the further adsorption of albumin as an intermediate bridge, going against the improvement of the corrosion resistance of passivation film/alloy system. In addition, the passivation state of the alloy surface was changed by different methods to investigate the adsorption behavior of albumin and its influence on the further passivation behavior in depth. Hitherto, we tried to propose a model to explain the dynamic adsorption process of albumin and its influencing mechanism on the growth behavior of passivation film.

Novel perovskite-based composites, La1-x Nd x FeO3@activated carbon, as efficient catalysts for the degradation of organic pollutants by heterogeneous electro-Fenton reactions.

Perovskites, which have excellent electrocatalytic properties, are promising for use in heterogeneous catalysis. However, the design and development of green and effective electrocatalysts for environmental water treatment remains an arduous challenge. To overcome such difficulties, we present a facile sol-gel method for the design and preparation of a series of perovskite-activated carbon (AC) composites (La1-x Nd x FeO3@AC) for the degradation of methyl orange (MO) by heterogeneous electro-Fenton reactions. Furthermore, the as-made La0.6Nd0.4FeO3@AC composite anode had the strongest oxidation ability and stability, with MO wastewater and COD removal rates reaching 99.81% and 96.66% within 10 minutes, respectively. As far as we know, the La1-x Nd x FeO3@AC composites can be regarded as a series of the most effective catalysts for the degradation of MO to date.