INDEX electrooxidations

Since oxidation of methanol is an electrocatalytic reaction with different adsorption steps, interactions of the adsorbed species with the metallic surface are important. Using platinum single-crystal electrodes, it has been proven that the electrooxidation of methanol is a surface-sensitive reaction. The initial activity of the Pt(llO) plane is much higher than that of the other low-index planes, but the poisoning phenomenon is so rapid that it causes a fast decrease in the current densities. The... 

Chang SC, Leung LWH, Weaver MJ. 1990. Metal crystallinity effects in electrocatalysis as prohed hy real-time ETIR spectroscopy electrooxidation of formic acid, methanol, and ethanol on ordered low-index platinum surfaces. J Phys Chem 94 6013-6021. 

Several approaches to the designing of efficient electrocatalysts for the electrooxidation of ethanol have been reported. Some of them focused on the structure of the catalytic particles. For instance, by generating high-index faceted Pt particles, the catalytic activity and selectivity to COg of Pt/C can be improved.The same is true for PtNi/C catalysts.However, high-index planes are not stable in nanoparticles, hence the mass activity of those catalysts is low. Most studies, however, deal with bimetallic particles, typically Pt-M (M = W, Pd, Rh, Re, with PtSn... 

Zhou ZY, Huang Z-Z, Chen D-J, Wang Q, Tian N, Sun S-G (2010) High-index faceted platinum nanocrystals supported on carbon black as highly ellicicmt catalysts for ethanol electrooxidation. Angew Chem Int Ed 49(2) 411-414... 

Bismuth has attracted significant interest as a Pt/C modifier for formic acid electrooxidation [21, 24, 26, 27]. A wide range of stable and well-characterized electrode surfaces modified by irreversible Bi adatom adsorption on Pt have been reported in the literature for a range of Bi coverages 6). Chen et al. have explored Bi adatom decoration on 81 nm tetrahexahedral Pt nanoparticles that while composed of (100) and (110) facets that are the least active for formic acid electrooxidation, they are boimd by 730 and vicinal high-index facets that are extremely active [18]. They have measured current densities of 10 mA cm for Bi coverages up to 0.9 at 0.4 V in 0.25 M formic acid and 0.5 M H2SO4 solution see Fig. 4.4. They also showed steady-state activity at 0.3 V of 2.8 mA cm after 1 min vs. 0.0003 mA cm for the non-modified Pt baseline. 

Tian N, Zhou ZY, Yu NF, Wang LY, Sun SG (2010) Direct electrodeposition of tetrahexahedral Pd nanocrystals with high index facets and high catalytic activity for ethanol electrooxidation. J Am (Them Soc 132 7580-7581... 

Synthesis of tetrahexahedral platinum nanocrystals with high-index facets and high electrooxidation activity. Science 316 732-735... 

Z.Y. Zhou, Z.Z. Huang, D.J. Chen, Q. Wang, N. TLan, S.G. Sun, High-index faceted platimun nanocrystals supported on carbon black as highly efficient catalysts for ethanol electrooxidation, Angew. Chem. Int. Ed. 49 (2010) 411-414. 

Prof. Zhao-Xiong Xie and co-workers at Xiamen University have developed a Cu " "-assisted synthesis process and obtained hexoctahedral (HOH) Au-Pd alloy nanocrystals enclosed with 431 high-index facets. In the shape-controlled synthesis, the Cu UPD was found to play a key role in formation of the HOH Au-Pd alloy NCs. It has tested that the as-prepared HOH Au-Pd alloy NCs exhibited excellent performance in terms of both formic acid electrooxidation and methanol tolerance due to synergism between the high-index facets and the alloy. 

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