开发纳米级或原子级的Pt基电催化剂用于氢析出反应（HER），这对于缓解Pt储量低的问题非常重要。这里，提出了一种方法来构建分级的Pt-MXene-单壁碳纳米管（SWCNTs）异质结构用于HER催化。在该异质结构中，高活性的纳米/原子级金属Pt固定在Ti3C2Tx MXene薄片（MXene @ Pt）上，它与导电的SWCNT框架相连接。利用MXene的亲水性和可还原性等优势，MXene @ Pt胶体悬浮液可通过自发将Pt阳离子还原成金属Pt制备而得，无需额外的还原剂或后处理。如此制备的分级HER催化剂（以膜的形式存在），在800 h工作期间显示出高的稳定性，在-50 mV vs. RHE时，体积电流密度高达230 mA cm−3。该溶液处理的策略提供了一种简单，高效但可扩展的方法来构建稳定高效的HER催化剂。考虑到Pt-MXene-SWCNT分级结构的性质和结构-活性关系，其他MXene可能在HER电催化中有着更大的应用前景。
 
Figure 1. （a）制备Ti3C2Tx胶体悬浮液和（b）MXene@Pt/SWCNTs纳米催化剂的示意图。                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  
 
Figure 2.形貌及元素分析。（a）几层Ti3C2Tx纳米薄片的TEM图，（b）Ti3C2Tx@5Pt 的TEM图，（c-d）MXene@5Pt的HAADF-STEM图和相应的元素分布图，（e）原子级HAADF-STEM图，（f）Pt颗粒尺寸分布情况，（g）观察到单个Pt原子，（h）尖端探头超声处理后SWCNT的TEM图，（i）SWCNT薄膜的SEM图。
 

Figure 3. 催化剂的HER性能表征。（a-b）极化曲线（分别用面积电流和体积电流呈现），（c）Tafel斜率，（d）S-M-5Pt催化剂的LSV曲线，（e）5片S-M-5Pt的长时间稳定性测试。
 

Figure 4. 动力学研究。（a，b，d，e）不同电极在-50 mV电位下的EIS图，（c）赝电容行为和（f）HER行为的等效电路图。
 
     该研究工作由中国科学院金属研究所王晓辉课题组于2020年发表在Adv. Funct. Mater.期刊上。原文：Ultrastable MXene@Pt/SWCNTs' Nanocatalysts for Hydrogen Evolution Reaction