Device testing of polymer electrolyte membrane fuel cell catalysts is essential for electrocatalyst development, yet most reported catalysts fabricated with nanoceramic coatings via atomic layer deposition (ALD) have not been thoroughly examined in this fashion. Platinum nanoparticle catalysts supported on functionalized XC72 carbon black that had been modified with sub-monolayer WN films and subjected to various thermal treatments were incorporated into membrane electrode assemblies and tested for oxygen reduction reaction activity in a fuel cell. The mass activities of the catalysts calculated at low current densities had comparable trends to those previously recorded in aqueous half-cell testing; however, significant deviations in catalyst performance became apparent at high current densities in the mass transport region of the polarization curves. The poor performance of the ALD-modified catalysts was attributed to water flooding induced by the low hydrophobicity of these catalyst layers, as determined by contact angle measurements on the cathode surfaces. It was seen that hydrophobicity was increased by thermal treatment and removal of surface groups known to be prone to hydrogen bonding, thereby improving the catalyst performance in the mass transport region. A heat-treated WN-coated ALD catalyst was found to have superior performance to commercial Pt/C. The field of research on fuel cell catalyst design via ALD is rapidly expanding, and this work demonstrates the importance of understanding the impact of ALD-deposited nanostructures on materials properties beyond the pure electrocatalytic activity.

聚合物电解质膜燃料电池催化剂的设备测试对于电催化剂的开发至关重要，但是尚未通过这种方式对通过原子层沉积（ALD）纳米陶瓷涂层制造的大多数报道的催化剂进行彻底检查。将负载在功能化XC72炭黑上的铂纳米颗粒催化剂（已用亚单层WN膜改性）并进行了各种热处理，然后将其掺入膜电极组件中，并测试燃料电池中的氧还原反应活性。在低电流密度下计算出的催化剂的质量活度具有与先前在含水半电池测试中记录的趋势相当的趋势。然而，在极化曲线的质量传递区域中的高电流密度下，催化剂性能的明显偏差变得明显。ALD改性催化剂的不良性能归因于由这些催化剂层的低疏水性引起的水驱，如通过在阴极表面上的接触角测量所确定的。可以看出，通过热处理和去除了易于形成氢键的表面基团，疏水性得到了提高，从而改善了在传质区域中的催化剂性能。发现热处理的WN涂覆的ALD催化剂具有优于商业Pt / C的性能。通过ALD设计燃料电池催化剂的研究领域正在迅速扩展，