水热合成二硫化钨/石墨烯复合材料及其氧还原性能

Hydrothermal Synthesis and ORR Performance of Tungsten Disulfide/Reduced Graphene Oxide Composite

以六氯化钨、硫代乙酰胺、氧化石墨烯为原料,采用一步水热法合成了二维的二硫化钨/石墨烯(WS_2/RGO)复合材料。水热合成的WS_2/RGO具有薄层的二维结构,且由于石墨烯的存在,WS_2以较少的层数形成薄片状生长在石墨烯的表面。尝试将这种非Pt类材料用于电催化氧化原反应,测试结果表明,WS_2在碱性条件下氧还原活性非常低,但是复合RGO形成WS_2/RGO复合材料后,电催化氧化原性能有了极大的提高,其起始电位为-0.17 V(vs SCE),转移电子数为3.7,极限电流密度为2.5 m A·cm-2,同时其具有较好的抗甲醇性能和循环稳定性。这是因为WS_2/RGO复合材料的二维结构具有更高的电子传输速率,同时硫化钨和石墨烯可以发挥协同催化作用。这种新型的二硫化钨/石墨烯(WS_2/RGO)复合材料作为非贵金属催化剂表现出良好的氧还原性能,在燃料电池上具有较好的应用前景。

Two-dimensional tungsten disulfide/reduced graphene oxide（WS2/RGO） composite was synthesized by one-step hydrothermal method using tungsten hexachlorid, thioacetamide and graphene oxide（GO） as precursors.Due to the presence of graphene, WS2 with few layers is uniformly grown on the surface of RGO. We attempted to employ this non-Pt material as an electrocatalyst for oxygen reduction reaction（ORR）. Test results indicate that the ORR activity of WS2 in alkaline electrolyte is actually very low. However, after the formation of WS2/RGO composite, the electrocatalytic performance has been greatly improved. The composite shows an initial potential of-0.17 V（vs SCE） and the limiting current density is 2.5 mA·cm^-2. Besides, the number of transfer electrons in ORR is 3.7, which is nearly comparable to that of commercial Pt/C（20%）. Moreover, it shows remarkable durability and better resistance toward methanol crossover in ORR. It is thought that WS2/RGO has better electronic conductivity and WS2 can play a synergistic catalytic effect with RGO. As a result, the novel WS2/RGO material as a non noble metal catalyst in fuel cells is considerably promising.