Creatinine is an amino acid derived from creatine catabolism at different steps of the body's organs, and its detection is significant because levels out of normal values are linked to some diseases like kidney failure.

In the present study, three different structures with preferentially exposed crystal faces were supported on commercial carbon black by the polyol method (nanoparticles (NP/C), nanobars (NB/C) and nanorods (NR/C)). The electrocatalysts were characterized by XRD, TEM, TGA and cyclic voltammetry at three different ethanol concentrations. Considerable differences were found in terms of catalytic electroactivity. At all ethanol concentrations, the trend observed for the ethanol oxidation peak potential was preserved as follows: NB/C < NP/C< NR/C < commercial Pd/C. This result indicates that, from a thermodynamics point of view, the NB/C catalyst enclosed by Pd(100) facets presented the highest activity with respect to ethanol electro-oxidation among all of the catalysts studied.

The glucose electro-oxidation reaction typically involves several steps and it is strongly influenced by the crystalline structure. In this paper, gold with typical {111} defects (namely Au_{111}) and gold with defects enclosed in the (200) plane (Au_{200}) were used to determine the effect of the surface energy in the adsorption and electro-oxidation of D-(+)-glucose. To this end, an electrokinetic analysis of surface species was made by means of zeta potential (ζ) measurements and was correlated with an electrochemical study. At low glucose concentration (0.1 mM), the system Au_{200} showed a positive and large ζ value of 261.26 mV related to protons from the glucose dehydrogenation. Au_{111} presented a negative ζ value of −98.11 mV associated to the glucose chemisorption plus OH⁻ adsorption from the electrolyte. At a higher concentration (>20 mM) both systems exhibited positive ζ values (from 40 to 60 mV) related to the glucose dehydrogenation because of saturation of the electrical double layer by glucose molecules. Through cyclic voltammetry, it was observed that at low glucose concentration (<20 mM), both materials had preference for oxidation of glucose by-products. However, at higher concentrations, Au_{111} favors glucono-lactone oxidation (0.4 V vs. NHE); meanwhile Au_{200} favors glucose oxidation (−0.43 V vs. NHE). Through the electrokinetic analysis, the behavior of Au_{111} can be related to its affinity toward the chemisorption of glucose molecules, and that of Au_{200} to weak glucose chemisorption, which allows the desorption of glucose by-products renewing the gold surface for the further oxidation of glucose molecules.

Well-ordered, homogenous cube-shaped highly ordered Pd, without other geometries, was obtained by chemical reduction in aqueous media by employing ascorbic acid, polyvinylpyrrolidone and sodium bromide as the reducing agent, surfactant and additive, respectively. The X-ray diffraction (XRD) patterns exhibited a face-centred cubic structure with an average crystallite size of 11.5 nm. Transmission electron microscopy (TEM) images showed a homogeneous distribution of cubic Pd nanoparticles (namely Pd nanocubes) with a preferential (200) crystallographic plane and a particle size of approximately 10.6 ± 1.2 nm. The electrocatalytic activity of the Pd nanocubes was evaluated in terms of the current density attributed to the oxidation reaction of the following three common fuels: methanol, ethanol and formic acid. The results obtained showed that the current density achieved with the Pd nanocube electrocatalyst is 4, 3 and 3.5 (12, 10 and 8.7 mA mg⁻¹ cm⁻², respectively) times higher than that reached with commercial Pd at similar oxidation potential values. Furthermore, the Pd nanocube catalyst exhibited higher catalytic activity for formic acid oxidation than that reported for Pd-based materials. The oxygen reduction reaction using the Pd nanocubes in basic media was also tested.

AuPd/polyaniline was used for the first time, for ethylene glycol electrooxidation in a microfluidic fuel cell operated at room temperature.