甲醇氧化PtSnCo/C阳极催化剂

PtSnCo/C Anode Catalyst for Methanol Oxidation

通过乙二醇液相分步还原法制备了金属质量分数为20%的PtSn/C二元及PtSnCo/C三元催化剂.采用X射线衍射(XRD)光谱法、能量散射谱(EDS)对催化剂进行了表征;通过阳极线性伏安扫描法(LSV)、连续循环伏安法(CV)、预吸附单层CO溶出法研究了其电化学性质.结果表明,PtSnCo/C三元催化剂较商业化JM-PtRu/C催化剂具有更好的氧化甲醇催化活性.循环伏安扫描100圈后发现,PtSn/C二元催化剂的甲醇氧化峰电流快速衰减到其初始氧化峰电流的11%左右,而PtSnCo/C三元催化剂仅衰减到其初始值的50%左右,这表明PtSnCo/C三元催化剂具有更好的化学稳定性.在PtSnCo/C催化剂上,甲醇氧化起始电位比直接吸附CO后的CO阳极溶出电位负,意味着甲醇在PtSnCo/C催化剂上氧化的中间产物不是CO,而是比CO更为活泼且易于氧化的中间物种.

A binary metallic catalyst （PtSn/C） and a ternary metallic catalyst （PtSnCo/C） with a metal mass fraction of 20% were prepared by borohydride reduction and subsequent hydrothermal treatment in a glycol liquid phase. The structure and composition of the as-prepared electrocatalysts were characterized by X-ray diffraction （XRD） and energy-dispersive spectrometry （EDS）. Their activity and stability for the catalysis of methanol oxidation were evaluated by anodic linear sweep voltammetry （LSV）, cyclic voltammetry （CV）, and the anodic stripping of a pre-adsorbed CO monolayer. We found that the PtSnCo/C catalyst gave the best catalytic activity for the methanol oxidation of all the catalysts including the commercial JM-PtRu/C catalyst. After 100 cycles, the peak current of methanol oxidation for the PtSn/C catalyst rapidly decreased to 11% of its initial peak current but PtSnCo/C decreased to only 50%. This result suggests that the PtSnCo/C catalyst has better chemical stability for the catalysis of methanol oxidation compared to the PtSn/C catalyst. The more negative onset potential of methanol oxidation for the PtSnCo/C catalyst relative to pre-adsorbed CO oxidation implies that the intermediates of methanol oxidation on the PtSnCo/C catalyst may be ones, which can be more easily oxidized than CO, instead of CO.