Search

Your search keyword '"Ma, Yimeng"' showing total 4 results
Start Over Author "Ma, Yimeng" Publisher american chemical society
4 results on '"Ma, Yimeng"'

3. Kinetics of photoelectrochemical oxidation of methanol on hematite photoanodes

Author

Mesa, Camilo A., Kafizas, Andreas, Francas, Laia, Pendlebury, Stephanie R., Pastor, Ernest, Ma, Yimeng, Le Formal, Florian, Mayer, Matthew T., Gratzel, Michael, Durrant, James R., and Commission of the European Communities

Subjects
TRANSIENT ABSORPTION-SPECTROSCOPY, PHOTOGENERATED HOLES, DYNAMICS, Science & Technology, Chemistry, Multidisciplinary, ELECTRODES, General Chemistry, SEMICONDUCTORS, Article, WATER OXIDATION, Chemistry, REDUCTION, Physical Sciences, ANATASE, TIO2, PHOTOOXIDATION, 03 Chemical Sciences
Abstract

The kinetics of photoelectrochemical (PEC) oxidation of methanol, as a model organic substrate, on alpha-Fe2O3 photoanodes are studied using photoinduced absorption spectroscopy and transient photocurrent measurements. Methanol is oxidized on alpha-Fe2O3 to formaldehyde with near unity Faradaic efficiency. A rate law analysis under quasi-steady-state, conditions of PEC methanol oxidation indicates that rate of reaction is second order in the density of surface holes on hematite and independent of the applied potential. Analogous data on anatase TiO2 photoanodes indicate similar second-order kinetics for methanol oxidation with a second-order rate constant 2 orders of magnitude higher than that on alpha-Fe2O3. Kinetic isotope effect studies determine that the rate constant for methanol oxidation on alpha-Fe2O3 is retarded similar to 20-fold by H/D substitution. Employing these data, we propose a mechanism for methanol oxidation under 1 sun irradiation on these metal oxide surfaces and discuss the implications for the efficient PEC methanol oxidation to formaldehyde and concomitant hydrogen evolution.

Published
2017

4. Kinetics of Photoelectrochemical Oxidation of Methanol on Hematite Photoanodes.

Author

Mesa CA, Kafizas A, Francàs L, Pendlebury SR, Pastor E, Ma Y, Le Formal F, Mayer MT, Grätzel M, and Durrant JR

Abstract

The kinetics of photoelectrochemical (PEC) oxidation of methanol, as a model organic substrate, on α-Fe 2 O 3 photoanodes are studied using photoinduced absorption spectroscopy and transient photocurrent measurements. Methanol is oxidized on α-Fe 2 O 3 to formaldehyde with near unity Faradaic efficiency. A rate law analysis under quasi-steady-state conditions of PEC methanol oxidation indicates that rate of reaction is second order in the density of surface holes on hematite and independent of the applied potential. Analogous data on anatase TiO 2 photoanodes indicate similar second-order kinetics for methanol oxidation with a second-order rate constant 2 orders of magnitude higher than that on α-Fe 2 O 3 . Kinetic isotope effect studies determine that the rate constant for methanol oxidation on α-Fe 2 O 3 is retarded ∼20-fold by H/D substitution. Employing these data, we propose a mechanism for methanol oxidation under 1 sun irradiation on these metal oxide surfaces and discuss the implications for the efficient PEC methanol oxidation to formaldehyde and concomitant hydrogen evolution.

Published
2017
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results