کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
7737590 1497981 2014 8 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
The electrooxidation mechanism of formic acid on platinum and on lead ad-atoms modified platinum studied with the kinetic isotope effect
ترجمه فارسی عنوان
مکانیسم الکترو اکسیداسیون اسید فرمیک بر روی پلاتین و پلاتین اصلاح شده با آداپتورهای سرب با اثر ایزوتوپ جنبشی
کلمات کلیدی
الکترو اکسیداسیون، الکتروتالیز، سلول سوختی، اثر ایزوتوپ سینتیک، اسید فرمیک،
موضوعات مرتبط
مهندسی و علوم پایه شیمی الکتروشیمی
چکیده انگلیسی
Kinetics and mechanism of formic acid (FA) oxidation on platinum and upd-lead ad-atoms modified platinum electrodes have been studied using unlabelled and deuterated compounds. Poisoning of the electrode surface by CO-like species was prevented by suppression of dissociative chemisorption of FA due to a fast competitive underpotential deposition of lead ad-atoms on the Pt surface from an acidic solution containing Pb2+ cations. Modification of the Pt electrode with upd lead induced a catalytic effect in the direct electrooxidation of physisorbed FA to CO2. With increasing degree of H/D substitution, the rate of this reaction decreased in the order: HCOOH > DCOOH ≥ HCOOD > DCOOD. HCOOH was oxidized 8.5-times faster on a Pt/Pb electrode than DCOOD. This primary kinetic isotope effect proves that the C-H- and O-H-bonds are simultaneously cleaved in the rate determining step. A secondary kinetic isotope effect was found in the dissociative chemisorption of FA in the hydrogen adsorption-desorption range on a bare Pt electrode after H/D exchange in the C-H bond, wherein the influence of deuterium substitution in the O-H group was negligibly small. Thus the C-H bond cleavage is accompanied by the C-OH and not the O-H bond split in the FA decomposition, producing CO-like species on the Pt surface sites.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Power Sources - Volume 251, 1 April 2014, Pages 30-37
نویسندگان
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