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This work focuses on the catalytic activity and surface modification of Vulcan XC 72R and Printex L6 toward the oxygen reduction reaction (ORR) after the carbon supports were subjected to a pre-treatment with nitric acid or ammonia. The results indicated that acid-treated Printex L6 was the bestsuited material toward the two-electron pathway of the ORR. This material contained the largest concentration of oxygenated acid species and hydrogen, as determined by XPS, the Boehm method, and elemental analysis. The enhanced formation of H 2 O 2 for acid-treated Printex L6 can be explained by the presence of oxygenated acid species increasing the hydrophilic character of the carbon support. The hydrophilicity of the material was investigated by contact angle measurements. However, the changes of the surface area, porosity, and the aliphatic chains of the carbons induced by the pre-treatments and the contributions of these factors to H 2 O 2 production cannot be disregarded.

Recently, there has been an increase in the demand for enzymes with modified activity, specificity, and stability. Enzyme engineering is an important tool to meet the demand for enzymes adjusted to different industrial processes. Knowledge of the structure and function of enzymes guides the choice of the best strategy for engineering enzymes. Each enzyme engineering strategy, such as rational design, directed evolution, and semi-rational design, has specific applications, as well as limitations, which must be considered when choosing a suitable strategy. Engineered enzymes can be optimized for different industrial applications by choosing the appropriate strategy. This review features engineered enzymes that have been applied in food, animal feed, pharmaceuticals, medical applications, bioremediation, biofuels, and detergents.

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In this work were used Sn and Ni as second metals with Pt to study both the electrochemical oxidation of ethanol using "in situ" ATR-FTIR and the oxygen reduction reaction which is assessed using a rotating ring disk electrode technique (RRDE). The onset potential of ethanol oxidation is 0.3 V for PtSn/C, and 0.4 V for PtNi/C. Acetic acid is the main product formed using PtSn/C while using PtNi/C CO2 is the main product. The current densities for ORR using PtSn/C were similar to those ones using PtNi/C in all potential regions, including the region of limit diffusion current. However, the peroxide production was smaller for PtNi/C than PtSn/C between -0.1 to -0.5 V. For PtNi/C, the reaction proceeds through the transfer of 3.7 electrons, while for PtSn/C about 3.8 electrons.

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