The influence of the electrochemical stressing (potential step and potential-static holding) on the degradation of polymer electrolyte membrane fuel cell electrocatalysts

Abstract The understanding of the degradation mechanisms of electrocatalysts is very important for developing durable electrocatalysts for polymer electrolyte membrane (PEM) fuel cells. The degradation of Pt/C electrocatalysts under potential-static holding conditions (at 1.2 V and 1.4 V vs. RHE) and potential step conditions with the upper potential of 1.4 V for 150 s and lower potential limits (0.85 V and 0.60 V) for 30 s in each period [denoted as Pstep(1.4V_150s–0.85V_30s) and Pstep(1.4V_150s–0.60V_30s), respectively] were investigated. The electrocatalysts and support were characterized with electrochemical voltammetry, transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS). Pt/C degrades much faster under Pstep conditions than that under potential-static holding conditions. Pt/C degrades under the Pstep(1.4V_150s–0.85V_30s) condition mainly through the coalescence process of Pt nanoparticles due to the corrosion of carbon support, which is similar to that under the conditions of 1.2 V- and 1.4 V-potential-static holding; however, Pt/C degrades mainly through the dissolution/loss and dissolution/redeposition process if stressed under Pstep(1.4V_150s–0.60V_30s). The difference in the degradation mechanisms is attributed to the chemical states of Pt nanoparticles: Pt dissolution can be alleviated by the protective oxide layer under the Pstep(1.4V_150s–0.85V_30s) condition and the potential-static holding conditions. These findings are very important for understanding PEM fuel cell electrode degradation and are also useful for developing fast test protocol for screening durable catalyst support materials.

[1]  Olivera Kesler,et al.  An oxidation-resistant indium tin oxide catalyst support for proton exchange membrane fuel cells , 2006 .

[2]  Hubert A. Gasteiger,et al.  Instability of Pt ∕ C Electrocatalysts in Proton Exchange Membrane Fuel Cells A Mechanistic Investigation , 2005 .

[3]  K. Sasaki,et al.  Stabilization of Platinum Oxygen-Reduction Electrocatalysts Using Gold Clusters , 2007, Science.

[4]  Edward F. Holby,et al.  Instability of Supported Platinum Nanoparticles in Low-Temperature Fuel Cells , 2007 .

[5]  Shohji Tsushima,et al.  Degradation Mechanism of PEMFC under Open Circuit Operation , 2006 .

[6]  Thomas F. Fuller,et al.  PEM Fuel Cell Pt ∕ C Dissolution and Deposition in Nafion Electrolyte , 2007 .

[7]  Jian Zhang,et al.  Comparative investigation of the resistance to electrochemical oxidation of carbon black and carbon nanotubes in aqueous sulfuric acid solution , 2006 .

[8]  Philip N. Ross,et al.  Improved Oxygen Reduction Activity on Pt3Ni(111) via Increased Surface Site Availability , 2007, Science.

[9]  Yuyan Shao,et al.  Multi-walled carbon nanotubes based Pt electrodes prepared with in situ ion exchange method for oxygen reduction , 2006 .

[10]  Yuyan Shao,et al.  Nitrogen-doped carbon nanostructures and their composites as catalytic materials for proton exchange membrane fuel cell , 2008 .

[11]  Yuyan Shao,et al.  In Situ Deposition of Highly Dispersed Pt Nanoparticles on Carbon Black Electrode for Oxygen Reduction , 2006 .

[12]  Robert M. Darling,et al.  Damage to the Cathode Catalyst of a PEM Fuel Cell Caused by Localized Fuel Starvation , 2006 .

[13]  Yuyan Shao,et al.  Proton exchange membrane fuel cell from low temperature to high temperature: Material challenges , 2007 .

[14]  Yong Wang,et al.  Supercritical fluid synthesis and characterization of catalytic metal nanoparticles on carbon nanotubes , 2004 .

[15]  Deyu Li,et al.  Well-dispersed high-loading pt nanoparticles supported by shell-core nanostructured carbon for methanol electrooxidation. , 2008, Langmuir : the ACS journal of surfaces and colloids.

[16]  Y. Xing,et al.  Electrochemical Durability of Carbon Nanotubes in Noncatalyzed and Catalyzed Oxidations , 2006 .

[17]  Qin Xin,et al.  Test on the degradation of direct methanol fuel cell , 2006 .

[18]  S. Ball,et al.  The Effect of Dynamic and Steady State Voltage Excursions on the Stability of Carbon Supported Pt and PtCo Catalysts , 2006 .

[19]  G. Swain,et al.  Preparation and characterization of boron-doped diamond powder : A possible dimensionally stable electrocatalyst support material , 2005 .

[20]  Geping Yin,et al.  Durability Study of Pt ∕ C and Pt ∕ CNTs Catalysts under Simulated PEM Fuel Cell Conditions , 2006 .

[21]  M. De Francesco,et al.  Comparison of high surface Pt/C catalysts by cyclic voltammetry , 2002 .

[22]  T. Jarvi,et al.  Electrocatalytic corrosion of carbon support in PEMFC cathodes , 2004 .

[23]  H. Tang,et al.  PEM fuel cell cathode carbon corrosion due to the formation of air/fuel boundary at the anode , 2006 .

[24]  J. Figueiredo,et al.  Modification of the surface chemistry of activated carbons , 1999 .

[25]  Mahlon Wilson,et al.  Scientific aspects of polymer electrolyte fuel cell durability and degradation. , 2007, Chemical reviews.

[26]  Deborah J. Myers,et al.  Effect of voltage on platinum dissolution : Relevance to polymer electrolyte fuel cells , 2006 .

[27]  T. Jarvi,et al.  Characterization of Vulcan Electrochemically Oxidized under Simulated PEM Fuel Cell Conditions , 2004 .

[28]  Vat Dam,et al.  The Stability of PEMFC Electrodes Platinum Dissolution vs Potential and Temperature Investigated by Quartz Crystal Microbalance , 2007 .

[29]  K. Yasuda,et al.  Imaging of highly oriented pyrolytic graphite corrosion accelerated by Pt particles , 2005 .

[30]  Geping Yin,et al.  Understanding and Approaches for the Durability Issues of Pt-Based Catalysts for PEM Fuel Cell , 2007 .

[31]  Zhongwei Chen,et al.  Durability investigation of carbon nanotube as catalyst support for proton exchange membrane fuel cell , 2006 .

[32]  R. Li,et al.  High Electrocatalytic Activity of Platinum Nanoparticles on SnO2 Nanowire-Based Electrodes , 2007 .

[33]  Yuehe Lin,et al.  PtRu/carbon nanotube nanocomposite synthesized in supercritical fluid: a novel electrocatalyst for direct methanol fuel cells. , 2005, Langmuir : the ACS journal of surfaces and colloids.

[34]  B. Popov,et al.  Durability study of Pt3Ni1 catalysts as cathode in PEM fuel cells , 2004 .

[35]  Hubert A. Gasteiger,et al.  Oxygen reduction on a high-surface area Pt/Vulcan carbon catalyst: a thin-film rotating ring-disk electrode study , 2001 .

[36]  L. J. Bregoli,et al.  A Reverse-Current Decay Mechanism for Fuel Cells , 2005 .

[37]  D. Wilkinson,et al.  Aging mechanisms and lifetime of PEFC and DMFC , 2004 .