Insight Observation of Simultaneously Enhanced CO Tolerance and Stability of Pt Electrocatalysts Decorated with Oxygen Vacancy Rich Cerium Oxide

Abstract

High and stable catalytic activity for the methanol oxidation reaction (MOR) and CO tolerance are essential for anodic electrocatalysts in direct methanol fuel cells (DMFCs). Here, we report a new method to simultaneously boost the CO tolerance as well as MOR stability of a Pt electrocatalyst by decoration with cerium oxide (CeOx). Detailed mechanistic investigations revealed that CeOx decoration can significantly improve the MOR stability of the Pt electrocatalyst due to the formation of Pt−O−Ce bonds ascribed to the high number of oxygen vacancies of CeOx. The simultaneously improved CO anti‐poisoning property of the CeOx decorated Pt electrocatalyst is resulting from Ce(OH)3, which is formed by the adsorption of water to CeOx. Ce(OH)3 could accelerate the formation of Pt(OH)ads species to recover CO poisoned Pt nanoparticles. At the same time, the CO species could also be oxidized by the lattice oxygen from CeOx. The fuel cell performance of the CeOx decorated Pt electrocatalyst is therefore higher than that of bare Pt electrocatalyst.

Tuning the Product Selectivity toward the High Yield of Glyceric Acid in Pt−CeO2/CNT Electrocatalyzed Oxidation of Glycerol

“…The backward anodic peak current density (I b ) corresponds to the removal of the intermediates from the Pt surface [48] . The I f /I b value for Pt−CeO 2 /CNT (4.9) with a CeO 2 :CNT ratio of 1.5 : 1 is much higher than that for Pt/CNT (2.8), which indicates a lower accumulation of intermediate residues on the catalyst surface during the glycerol electro‐oxidation process [49] . The CO stripping results further unveil the effect of CeO 2 on the desorption of intermediates from Pt/CNT.…”

“…[48] The I f /I b value for PtÀ CeO 2 / CNT (4.9) with a CeO 2 :CNT ratio of 1.5 : 1 is much higher than that for Pt/CNT (2.8), which indicates a lower accumulation of intermediate residues on the catalyst surface during the glycerol electro-oxidation process. [49] The CO stripping results further unveil the effect of CeO 2 on the desorption of intermediates from Pt/CNT. As shown in Figure 2a and Table S2, the onset potential of CO oxidation negatively shifts with the amount of CeO 2 .…”

“…The applied potential also plays the pivotal role in the glycerol conversion and the product distribution. [49] As displayed in Figure 3b and Table S4, when the applied potential increases from 0.4 V to 0.9 V vs. RHE, the glycerol conversion of PtÀ CeO 2 /CNT(1.5 : 1) rises from 17.2 % to 86.5 %, while the selectivity for C3 products drops from 100 % to 73 %. The GLYA selectivity also decreases from 62 % to 36 %, whereas the selectivities increase obviously for the further oxidation products of GLYA, including TAR, GLYCA, OXA, and FOR.…”

Carbon‐Free Nanocoral‐Structured Platinum Electrocatalyst for Enhanced Methanol Oxidation Reaction Activity with Superior Poison Tolerance

“…The synthesis and the design of anode/cathode catalyst at enhanced efficiency are still challenging issues . The noble metal (Ag/Au/Pt/Pd) nanoparticles are widely used as electrocatalysts due to their high‐energy conversion capability . Among those nanoparticles, Pt possesses enhanced catalytic activity for MOR both in alkaline and acidic media .…”

“…[5] The noble metal (Ag/Au/Pt/Pd) nanoparticles are widely used as electrocatalysts due to their highenergy conversion capability. [3,7,8] Among those nanoparticles, Pt possesses enhanced catalytic activity for MOR both in alkaline and acidic media. [9] Although Pt has the highest catalytic activity among noble metal catalysts, the use of Pt was demotivated due to the easier poisoning caused by the carbonaceous products produced during the MOR.…”