银锡双金属催化剂的制备及其对氧还原的催化性能

在乙醇为溶剂和还原剂、碳粉为载体的体系中，采用水热法将Ag+或Ag+-Sn2+还原，形成纳米多孔网状结构的Ag或Ag-Sn双金属纳米颗粒，制备碳粉负载的Ag/C和Ag-Sn/C催化剂。 利用循环伏安和线性扫描技术，研究了碱性溶液中这些催化剂对氧还原反应(ORR)的电活性。 研究表明，Ag/C和Ag-Sn/C对ORR均表现出强的电催化活性，它们对ORR的起始电位约0.05 V（vs.Ag/AgCl）。 在Ag97Sn3/C催化剂上，ORR的电流密度为2.87×10-3 A/cm2(800 r/min),高于Ag/C。 Levich方程分析表明，在Ag-Sn/C催化剂上，ORR转移电子数明显大于Ag/C，说明在Ag-Sn/C催化剂上，氧气能够较为彻底被还原。 此外，在甲醇存在下，Ag/C和Ag-Sn/C对ORR的活性基本保持不变，表明它们对甲醇有较强的耐受力。

Synthesis and Electrocatalysis Activity of Silver-Tin Bimetallic Catalysts for Oxygen Reduction Reaction

Carbon-loaded Ag or Ag-Sn bimetallic nanoparticles were prepared by the hydrothermal process, in which Ag+ or Ag++Sn2+ dissolved in ethanol were reduced to Ag or binary Ag-Sn nanoparticles by ethanol as the reduction agent. The morphological features of the catalysts show a typical nanoporous structure. Cyclic voltammetry and steady state polarization measurements were used to investigate the electroactivity of the samples for oxygen reduction reaction(ORR). The results show that both Ag/C and Ag-Sn/C exhibits a high electrocatalysis activity, with the onset potential of ca. 0.05 V(vs.Ag/AgCl) and a high current density for the ORR. Levich analysis shows that the binary Ag-Sn/C possesses a much greater electron number for ORR than Ag/C. Among the prepared samples, the Ag97Sn3/C catalyst displays the highest current density for oxygen reduction reaction. In addition, the Ag/C and Ag-Sn/C catalysts exhibit strong tolerance towards methanol.