<br>纳米级 TiO2 涂层提高了地球储量丰富的氧化钴催化剂在酸性水氧化过程中的稳定性,ACS Applied Materials & Interfaces

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纳米级 TiO2 涂层提高了地球储量丰富的氧化钴催化剂在酸性水氧化过程中的稳定性
ACS Applied Materials & Interfaces ( IF 8.3 ) Pub Date : 2022-07-15 , DOI: 10.1021/acsami.2c05849
Thanh Tran-Phu _{1,

2} , Hongjun Chen ₃ , Rahman Daiyan ₄ , Manjunath Chatti ₅ , Borui Liu ₂ , Rose Amal ₄ , Yun Liu ₆ , Douglas R Macfarlane ₅ , Alexandr N Simonov ₅ , Antonio Tricoli _{1,

2}

Affiliation

大规模部署用于高通量可持续制氢的质子交换膜水电解槽需要从贵金属阳极电催化剂过渡到低成本的地球丰富材料。然而，此类材料通常在低pH值下不够稳定和/或催化失活，并且需要正电势来维持阳极析氧反应(OER)的高速率。为了解决这个问题，我们探讨了由无定形 TiO ₂构成的介电纳米级薄层对基于低成本 Co ₃ O ₄的纳米结构 OER 阳极的稳定性和电催化活性的影响。我们证明了 OER 性能与原子层沉积 TiO ₂层的厚度之间的直接相关性。 4.4 nm 的最佳 TiO ₂层厚度可将阳极寿命延长约 1 倍。如图3所示，在pH值接近于零的情况下实现80小时的连续电解，同时保持裸Co ₃ O ₄表面的高OER催化活性。较薄和较厚的TiO ₂层分别降低稳定性和活性。这归因于最佳厚度的 TiO ₂层的点蚀，这允许接触具有催化活性的 Co ₃ O ₄表面，同时稳定其抗腐蚀。这些见解为用于酸性水分解以高通量制氢的活性和稳定复合材料的工程设计提供了方向。

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Nanoscale TiO2 Coatings Improve the Stability of an Earth-Abundant Cobalt Oxide Catalyst during Acidic Water Oxidation

The large-scale deployment of proton-exchange membrane water electrolyzers for high-throughput sustainable hydrogen production requires transition from precious noble metal anode electrocatalysts to low-cost earth-abundant materials. However, such materials are commonly insufficiently stable and/or catalytically inactive at low pH, and positive potentials required to maintain high rates of the anodic oxygen evolution reaction (OER). To address this, we explore the effects of a dielectric nanoscale-thin layer, constituted of amorphous TiO₂, on the stability and electrocatalytic activity of nanostructured OER anodes based on low-cost Co₃O₄. We demonstrate a direct correlation between the OER performance and the thickness of the atomic layer deposited TiO₂ layers. An optimal TiO₂ layer thickness of 4.4 nm enhances the anode lifetime by a factor of ca. 3, achieving 80 h of continuous electrolysis at pH near zero, while preserving high OER catalytic activity of the bare Co₃O₄ surface. Thinner and thicker TiO₂ layers decrease the stability and activity, respectively. This is attributed to the pitting of the TiO₂ layer at the optimal thickness, which allows for access to the catalytically active Co₃O₄ surface while stabilizing it against corrosion. These insights provide directions for the engineering of active and stable composite earth-abundant materials for acidic water splitting for high-throughput hydrogen production.

更新日期：2022-07-15

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