Herein, we report the performance of Pd nanoparticles (NPs) prepared by Atomic Layer Deposition (ALD) as a catalyst for methanol electro-oxidation. Pd NPs were decorated onto anodic TiO₂ nanotube (TNT) layers as supporting material that possess a large available surface area and direct electrical contact via the underlying titanium foil. Different Pd loadings (150 – 300 – 450 – 600 ALD cycles) show different particles sizes ranging between 7 and 12 nm, as revealed by transmission electron microscopy. Coalescence dominated visibly from 450 ALD cycles, which led to a porous Pd layer all along the TNT walls rather than the growth of individual particles. Electrocatalytic performance was investigated by cyclic voltammetry (CV), where the catalytic activity increased proportional with Pd loading up to the highest values for 400 and 450 cycles, whereas a further increase in the number of ALD cycles (N_ALD) did not show any additional improvement in methanol oxidation current densities. TNT layers decorated with 400, 450 and 600 Pd ALD cycles show featureless curves suggesting complete anti-poisoning ability or possibly a proof of a direct conversion from CH₃OH to CO₂ (without any intermediate byproducts). The lack of an oxidation peak during the anodic scan and therefore a reduction peak during the cathodic scan, confirms Pd NPs (stabilized by TiO₂) efficiently utilize OH_ads and chemisorbed CH₃OH in a way that its CO poisoning was inhibited. As a result, the tuned high surface area TNT layers exhibited excellent performance as a supporting material for Pd NPs against formation of electrochemical poisoning species. Finally, the mechanism of the TNT layers interaction with Pd NPs, which led to the propelling methanol oxidation reaction without loss in performance over cycling is postulated.

在此，我们报告了通过原子层沉积 (ALD) 制备的 Pd 纳米颗粒 (NPs) 作为甲醇电氧化催化剂的性能。Pd NPs 装饰在阳极 TiO _2上纳米管 (TNT) 层作为支撑材料，具有大的可用表面积和通过下面的钛箔直接电接触。正如透射电子显微镜所揭示的，不同的 Pd 负载量（150 – 300 – 450 – 600 次 ALD 循环）显示出 7 到 12 nm 之间的不同粒径。在 450 次 ALD 循环中聚结明显占主导地位，这导致整个 TNT 壁上形成多孔 Pd 层，而不是单个颗粒的生长。通过循环伏安法 (CV) 研究电催化性能，其中催化活性与 Pd 负载成比例增加，达到 400 和 450 次循环的最高值，而 ALD 循环次数的进一步增加 (N _ALD) 没有显示出甲醇氧化电流密度的任何额外改进。用 400、450 和 600 Pd ALD 循环装饰的 TNT 层显示出无特征的曲线，表明完全的抗中毒能力或可能证明从 CH ₃ OH 直接转化为 CO ₂（没有任何中间副产物）。在阳极扫描期间没有氧化峰，因此在阴极扫描期间没有还原峰，这证实了 Pd NPs（由 TiO ₂稳定）有效地利用了 OH_广告和化学吸附的 CH ₃OH 以某种方式抑制其 CO 中毒。因此，调谐的高表面积 TNT 层作为 Pd NPs 的支撑材料表现出优异的性能，可防止电化学毒物的形成。最后，假设了 TNT 层与 Pd NPs 相互作用的机制，这导致推动甲醇氧化反应而不会在循环过程中损失性能。