Electrocatalysis, scanning electrochemical

Among other advances, the nanostructuration of electrochemically synthesized conducting polymers has raised a lot of interest. To achieve this, one of the most straightforward and common way is the use of a scanning electrochemical microscope (SECM). Since the pioneering work of Bard, several authors have refined the conditions, improving the resolution. Heinze et al. used a PMMA matrix to confine more cleanly the electrodeposition of PPy [24], and in a further work, they could deposit micropatterns of poly(dimethoxybithiophene) with the help of electrocatalysis by a ruthenium complex, obtaining well-defined plots [25,26]. 

Sanchez-Sanchez CM, Vidal-Iglesias FJ, Solla-Gullon J, Montiel V, Aldaz A, Feliu JM, Herrero E (2010) Scanning electrochemical microscopy for studying electrocatalysis on shape-controlled gold nanoparticles and nanorods. Electrochim Acta 55(27) 8252-8257... 

Application of Scanning Electrochemical Microscopy (SECM) to Study Electrocatalysis of Oxygen Reduction by MN4-Macrocyclic Complexes... 

Zhou, J., Y. Zu, and A. J. Bard, Scanning electrochemical microscopy. Part 39. The proton/hydrogen mediator system and its application to the study of the electrocatalysis of hydrogen oxidation, J. Electroanal. Chem., Vol. 491, 2000 pp. 22-29. 

Lin, C. L., Rodriguez-Lopez, J., Bard, A. J. Micropipet delivery-substrate collection mode of scanning electrochemical microscopy for the imaging of electrochemical reactions and the screening of methanol oxidation electrocatalysis. Anal. Chem. 2009, 81, 8868-8877. 

Electrochemical data recorded under no steady-state conditions can also be used for studying electrocatalytic processes involving porous materials. In cases where the catalytic system can be approached by homogeneous electrocatalysis in solution phase, variation of cyclic voltammetric profiles with potential scan rate (Nicholson and Shain, 1964) and/or, for instance, square-wave voltammetric responses with square-wave frequency (O Dea et al., 1981 O Dea and Osteryoung, 1993 Lovric, 2002) can be used. This situation can, in principle, be taken for highly porous materials where substrate transport, as well as charge-balancing ion transport, is allowed. On first examination, the catalytic process can be approached in the same manner... 

Figure 17.7 (A) Cyclic voltammogram of catechol on a platinum electrode. (B) Effect of poly(aniline-co-o-aminophenol) fiber diameter on the electrochemical oxidation of catechol, at a scan rate of 60 mV Average fiber diameter ( ) 70 nm, (2) 90 nm, (3) 100 nm, (4) 107 nm, in a solution consisting of 5 mM catechol and 0.3 M Na2S04 with pH 5.0. (Reprinted with permission from Electrochimica Acta, Poly(aniline-co-o-aminophenol) nanostructured network Electrochemical controllable synthesis and electrocatalysis byShaolin Mu, 51, 17, 3434-3440. Copyright (2006) Elsevier Ltd)...

Besides SECM, other speetroseopie mefliods, such as scanning differential electrochemical mass spectrometry (SDEMS) and IR thermography, were also used as combinatorial screening methods for fuel cell electrocatalysis. The principle of SDEMS is to use mass spectrometry to locally measure dissolved gases and volatile liquid species near flie surfaces of catalyst arrays. IR thermography is based on reaction heat mapping. The heat results from the fuel cell electrochemical reactions on the catalyst arrays. Both methods can obtain reaction... 

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