Zhang Junming, Qu Ximing, Shen Linfan, Li Guang, Zhang Tianen, Zheng Jinhong, Ji Lifei, Yan Wei, Han Yu, Cheng Xiaoyang, Jiang Yanxia, Sun Shigang
State Key Laboratory of Physical Chemistry of Solid Surfaces, Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, P. R. China.
School of Chemical and Material Science, Shanxi Normal University, Linfen, 041004, P. R. China.
Small. 2021 Feb;17(6):e2006698. doi: 10.1002/smll.202006698. Epub 2021 Jan 20.
Tailoring the near-surface composition of Pt-based alloy can optimize the surface chemical properties of a nanocatalyst and further improve the sluggish H electrooxidation performance in an alkaline electrolyte. However, the construction of alloy nanomaterials with a precise near-surface composition and smaller particle size still needs to overcome huge obstacles. Herein, ultra-small PtRu binary nanoparticles (<2 nm) evenly distributed on porous carbon (PtRu /PC), with different near-surface atomic compositions (Pt-increased and Ru-increased), are successfully synthesized. XPS characterizations and electrochemical test confirm the transformation of a near-surface atomic composition after annealing PtRu /PC-300 alloy; when annealing in CO atmosphere, forming the Pt-increased near-surface structure (500 °C), while the Ru-increased near-surface structure appears in an Ar heat treatment process (700 °C). Furthermore, three PtRu /PC nanocatalysts all weaken the hydrogen binding strength relative to the Pt/PC. Remarkably, the Ru-increased nanocatalyst exhibits up to 38.8-fold and 9.2-fold HOR improvement in mass activity and exchange current density, compared with the Pt/PC counterpart, respectively. CO-stripping voltammetry tests demonstrate the anti-CO poisoning ability of nanocatalysts, in the sequence of Ru-increased ≥ PtRu /PC-300 > Pt-increased > Pt/PC. From the perspective of engineering a near-surface structure, this study may open up a new route for the development of high-efficiency electrocatalysts with a strong electronic effect and oxophilic effect.
调整铂基合金的近表面组成可以优化纳米催化剂的表面化学性质，并进一步改善其在碱性电解质中缓慢的氢电氧化性能。然而，构建具有精确近表面组成和更小粒径的合金纳米材料仍需克服巨大障碍。在此，成功合成了均匀分布在多孔碳上的超小铂钌二元纳米颗粒（<2纳米），其具有不同的近表面原子组成（铂增加和钌增加）。X射线光电子能谱表征和电化学测试证实了对PtRu /PC-300合金进行退火后近表面原子组成的转变；在CO气氛中退火时，形成了铂增加的近表面结构（500°C），而在Ar热处理过程（700°C）中出现了钌增加的近表面结构。此外，相对于Pt/PC，三种PtRu /PC纳米催化剂均削弱了氢结合强度。值得注意的是，与Pt/PC相比，钌增加的纳米催化剂在质量活性和交换电流密度方面的氢氧化反应性能分别提高了38.8倍和9.2倍。CO溶出伏安法测试证明了纳米催化剂的抗CO中毒能力，顺序为钌增加≥PtRu /PC-300>铂增加>Pt/PC。从工程近表面结构的角度来看，这项研究可能为开发具有强电子效应和氧亲合效应的高效电催化剂开辟一条新途径。
