Cheng Qingqing, Hu Chuangang, Wang Guoliang, Zou Zhiqing, Yang Hui, Dai Liming
Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201210, China.
Center of Advanced Science and Engineering for Carbon (Case4Carbon), Department of Macromolecular Sciences and Engineering, Case Western Reserve University, Cleveland, Ohio 44106, United States.
J Am Chem Soc. 2020 Mar 25;142(12):5594-5601. doi: 10.1021/jacs.9b11524. Epub 2020 Mar 13.
Pt atomic clusters (Pt-ACs) display outstanding electrocatalytic performance because of their unique electronic structure with a large number of highly exposed surface atoms. However, the small size and large specific surface area intrinsically associated with ACs pose challenges in the synthesis and stabilization of Pt-ACs without agglomeration. Herein, we report a novel one-step carbon-defect-driven electroless deposition method to produce ultrasmall but well-defined and stable Pt-ACs supported by defective graphene (Pt-AC/DG) structures. A theoretical simulation clearly revealed that the defective regions with a lower work function and hence a higher reducing capacity compared to those of normal hexagonal sites triggered the reduction of Pt ions preferentially at the defect sites. Moreover, the strong binding energy between Pt and carbon defects effectively restricted the migration of spontaneously reduced Pt atoms to immobilize/stabilize the resultant Pt-ACs. Electrochemical analyses demonstrated the high performance of Pt-ACs in catalyzing the hydrogen evolution reaction, showing a greatly enhanced mass activity, a high Pt utilization efficiency, and excellent stability compared with commercial Pt/C catalysts. The integration of proton exchange membrane water electrolysis with Pt-AC/DG as a cathode exhibited an excellent hydrogen generation activity and extraordinary stability (during 200 h of electrolysis) with a greatly reduced Pt usage compared with commercial Pt/C catalysts.
铂原子簇（Pt-ACs）由于其独特的电子结构和大量高度暴露的表面原子而表现出出色的电催化性能。然而，与原子簇本质相关的小尺寸和大比表面积给Pt-ACs的合成及在不团聚情况下的稳定带来了挑战。在此，我们报道了一种新颖的一步碳缺陷驱动的化学沉积方法，以制备由缺陷石墨烯（Pt-AC/DG）结构支撑的超小但明确且稳定的Pt-ACs。理论模拟清楚地表明，与正常六边形位点相比，具有较低功函数从而具有较高还原能力的缺陷区域优先触发了Pt离子在缺陷位点的还原。此外，Pt与碳缺陷之间的强结合能有效地限制了自发还原的Pt原子的迁移，从而固定/稳定了所得的Pt-ACs。电化学分析表明Pt-ACs在催化析氢反应方面具有高性能，与商业Pt/C催化剂相比，表现出大大增强的质量活性、高Pt利用效率和出色的稳定性。以Pt-AC/DG作为阴极的质子交换膜水电解集成系统表现出优异的产氢活性和非凡的稳定性（在200小时的电解过程中），与商业Pt/C催化剂相比，Pt用量大大减少。
