Highly Dispersed and Crystalline Ta2O5 Anchored Pt Electrocatalyst with Improved Activity and Durability Toward Oxygen Reduction: Promotion by Atomic-Scale Pt–Ta2O5 Interactions,ACS Catalysis

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Highly Dispersed and Crystalline Ta2O5 Anchored Pt Electrocatalyst with Improved Activity and Durability Toward Oxygen Reduction: Promotion by Atomic-Scale Pt–Ta2O5 Interactions
ACS Catalysis ( IF 11.3 ) Pub Date : 2019-03-06 00:00:00 , DOI: 10.1021/acscatal.8b04505
Wenbin Gao _{1,

2} , Zhengping Zhang _{1,

2} , Meiling Dou _{1,

2} , Feng Wang _{1,

2}

Affiliation

Developing highly active and durable Pt-based electrocatalysts for the oxygen reduction reaction (ORR) is a crucial target if actual commercial application of proton exchange membrane fuel cells (PEMFCs) is to be realized. Herein we show that utilizing highly dispersed and crystalline Ta₂O₅-modified carbon nanotubes (CNTs) as a support can stabilize Pt nanoparticles (NPs) by strengthening the metal–support interactions at the atomic scale, and furthermore, we show that this offers an efficient strategy to improve the ORR catalytic activity and durability of the Pt NPs. These were found to be selectively anchored on the interface of well-dispersed Ta₂O₅ NPs and CNTs, showing an atomic-coupled interfacial structure between Pt and Ta₂O₅ with lattice overlap of Pt (200) and Ta₂O₅ (001). X-ray absorption near edge structure (XANES) analysis shows that the electronic structure of Pt is perturbed by Ta₂O₅ by virtue of the formation of strong Pt–O–Ta bonds. The presence of highly crystalline Ta₂O₅ also induces the growth of polyhedral-structured Pt NPs with the exposure of abundant (111) and (100) facets, leading to an improved ORR activity for Pt–Ta₂O₅/CNT. As a result, our Pt–Ta₂O₅/CNT electrocatalyst exhibits high ORR activity with a large electrochemical surface area of 78.4 m² g^–1 and a mass activity of 0.23 A mg^–1_Pt at 0.9 V (this represents a 3.4- and 2.2-fold improvement over the corresponding activities of commercial Pt/C and Pt/CNT catalysts, respectively). Most importantly, Pt–Ta₂O₅/CNT possesses superior long-term durability without any obvious degradation after 10 000 cycles and thus outperforms both of the commercial Pt/C and Pt/CNT catalysts. Our strategy of using highly dispersed and crystalline Ta₂O₅ to stabilize Pt NPs, resulting in strengthened metal–support interactions, should facilitate the development of high-performance Pt-based ORR electrocatalysts for use in fuel cells.

中文翻译：

高分散性和结晶态Ta ₂ O ₅固定的Pt电催化剂，具有改善的活性和降低氧的耐久性：通过原子尺度的Pt–Ta ₂ O ₅相互作用促进

如果要实现质子交换膜燃料电池（PEMFC）的实际商业应用，开发用于氧还原反应（ORR）的高活性和耐用性的Pt基电催化剂是至关重要的目标。本文中，我们证明了利用高度分散和结晶的Ta ₂ O ₅修饰的碳纳米管（CNT）作为载体，可以通过在原子尺度上增强金属与载体的相互作用来稳定Pt纳米颗粒（NPs），此外，我们证明了这一点一种有效的策略来提高Pt NPs的ORR催化活性和耐久性。发现它们被选择性地锚定在分散良好的Ta ₂ O ₅ NP和CNT的界面上，显示出Pt和Ta之间的原子耦合界面结构₂ O ₅与Pt（200）和Ta ₂ O ₅（001）的晶格重叠。X射线吸收法的近边缘结构（XANES）分析表明，由于形成了坚固的Pt-O-Ta键，Ta ₂ O ₅扰动了Pt的电子结构。高度结晶的Ta ₂ O ₅的存在还诱导了多面体结构的Pt NP的生长，同时暴露了丰富的（111）和（100）面，从而提高了Pt–Ta ₂ O ₅ / CNT的ORR活性。结果，我们的Pt–Ta ₂ O ₅/ CNT电催化剂具有高ORR活性，在0.9 V时的电化学表面积为78.4 m ² g ^–1，质量活性为0.23 A mg ^–1_Pt（这比其相应的活性分别提高了3.4倍和2.2倍）分别使用市售的Pt / C和Pt / CNT催化剂）。最重要的是，Pt-Ta ₂ O ₅ / CNT具有卓越的长期耐久性，在经过10 000次循环后没有任何明显的降解，因此其性能优于市售的Pt / C和Pt / CNT催化剂。我们使用高度分散和结晶的Ta ₂ O _5的策略为了稳定Pt NPs，从而增强金属与载体之间的相互作用，应该促进用于燃料电池的高性能Pt基ORR电催化剂的开发。

更新日期：2019-03-06

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