Supplementary information files for High CO-tolerant Ru-based catalysts by constructing an oxide blocking layer

Supplementary files for article High CO-tolerant Ru-based catalysts by constructing an oxide blocking layer.
 CO poisoning of Pt-group metal catalysts is a long-standing problem, particularly for hydrogen oxidation reaction in proton exchange membrane fuel cells. Here, we report a catalyst of Ru oxide-coated Ru supported on TiO₂ (Ru@RuO₂/TiO₂), which can tolerate 1–3% CO, enhanced by about 2 orders of magnitude over the classic PtRu/C catalyst, for hydrogen electrooxidation in a rotating disk electrode test. This catalyst can work stably in 1% CO/H₂ for 50 h. About 20% of active sites can survive even in a pure CO environment. The high CO tolerance is not via a traditional bifunctional mechanism, i.e., oxide promoting CO oxidation, but rather via hydrous metal oxide shell blocking CO adsorption. An ab initio molecular dynamics (AIMD) simulation indicates that water confined in grain boundaries of the Ru oxide layer and Ru surface can suppress the diffusion and adsorption of CO. This oxide blocking layer approach opens a promising avenue for the design of high CO-tolerant electrocatalysts for fuel cells.

《通过构建氧化物阻挡层制备高抗CO中毒钌基催化剂》论文补充材料。铂族金属催化剂的CO中毒问题长期存在，尤其针对质子交换膜燃料电池（proton exchange membrane fuel cell, PEMFC）中的氢氧化反应（hydrogen oxidation reaction, HOR）而言尤为突出。本文报道了一种负载于二氧化钛（TiO₂）上的氧化钌包覆钌催化剂（Ru@RuO₂/TiO₂），在旋转圆盘电极（rotating disk electrode, RDE）测试中用于氢电氧化反应时，可耐受1%~3%的CO，其抗CO中毒性能较经典PtRu/C催化剂提升约两个数量级。该催化剂可在含1% CO的氢气氛围中稳定运行50小时，即便在纯CO环境中仍有约20%的活性位点得以保留。其优异的抗CO中毒性能并非通过传统双功能机制——即氧化物促进CO氧化——实现，而是通过含水金属氧化物壳层阻挡CO吸附达成。从头算分子动力学（ab initio molecular dynamics, AIMD）模拟显示，局限于氧化钌层晶界及钌表面的水可抑制CO的扩散与吸附。该氧化物阻挡层策略为燃料电池用高抗CO中毒电催化剂的设计开辟了极具前景的新途径。