CAJ | 학술논문

通过循环伏安法研究了三种商业催化剂--40%Pt/C, 20%Pt-10%Ru/C(Johnson Matthey)和 20%PtRu/C, Pt:Ru =1:1(E-TEK)在酸性介质中对二甲醚电氧化的催化性能,比较了不同商业催化剂的催化活性.实验发现,在Pt担载量为0.1 mg/cm2和25 ℃时,JM-两种催化剂的催化活性都高于E-TEK的,且JM-PtRu/C二元催化剂对二甲醚电氧化的活性又比JM-Pt/C高.这一结果表明了Ru的加入能一定程度上提高催化剂的活性和抗中毒能力.当温度由25 ℃升高到70 ℃,JM-PtRu/C对二甲醚电氧化的起始氧化和氧化峰电位分别负移160 mV和200 mV、氧化峰电流密度提高了0.63倍;而JM-Pt/C的分别仅负移80 mV和96 mV、氧化峰电流密度却提高了2.77倍.这表明了Ru 的加入提高了催化剂的抗中毒能力、催化活性和以二甲醚为燃料的电池输出电压.同时升高温度使得Pt对CO的吸附能力下降,可提高其电池的输出电流.进一步实验还表明了二甲醚的吸附是一个弱吸附,其吸附步骤是氧化的限制过程,而且Ru的加入一定程度上也抑制了二甲醚的吸附,即Pt和Ru的比应有一个优化值.实验还发现了这三种催化剂在50 ℃下电催化氧化二甲醚后,电极的电化学表面积均有增大的现象.本文的研究结果将为进一步探索新的直接二甲醚燃料电池阳极催化剂提供了一定的指导意义和基础数据.
통과순배복안법연구료삼충상업최화제--40%Pt/C, 20%Pt-10%Ru/C(Johnson Matthey)화 20%PtRu/C, Pt:Ru =1:1(E-TEK)재산성개질중대이갑미전양화적최화성능,비교료불동상업최화제적최화활성.실험발현,재Pt담재량위0.1 mg/cm2화25 ℃시,JM-량충최화제적최화활성도고우E-TEK적,차JM-PtRu/C이원최화제대이갑미전양화적활성우비JM-Pt/C고.저일결과표명료Ru적가입능일정정도상제고최화제적활성화항중독능력.당온도유25 ℃승고도70 ℃,JM-PtRu/C대이갑미전양화적기시양화화양화봉전위분별부이160 mV화200 mV、양화봉전류밀도제고료0.63배;이JM-Pt/C적분별부부이80 mV화96 mV、양화봉전류밀도각제고료2.77배.저표명료Ru 적가입제고료최화제적항중독능력、최화활성화이이갑미위연료적전지수출전압.동시승고온도사득Pt대CO적흡부능력하강,가제고기전지적수출전류.진일보실험환표명료이갑미적흡부시일개약흡부,기흡부보취시양화적한제과정,이차Ru적가입일정정도상야억제료이갑미적흡부,즉Pt화Ru적비응유일개우화치.실험환발현료저삼충최화제재50 ℃하전최화양화이갑미후,전겁적전화학표면적균유증대적현상.본문적연구결과장위진일보탐색신적직접이갑미연료전지양겁최화제제공료일정적지도의의화기출수거.
The electrooxidation of dimethyl ether (DME) on commercialised Pt/C and PtRu/C catalysts from Johnson Matthey (JM) and E-TEK in acid solution were investigated by the traditional electrochemistry method. The experimental results showed that catalysts from JM had better electrocatalytic activity and higher tolerance to the poisonous species for electrooxidation of DME at a loading of 0.1mg/cm2 and 25 ℃, and the JM's PtRu/C had the best performance and that showed that the addition of a second metal Ru enhanced the tolerance of Pt to the poisonous species of CO. When the reaction temperature was raised from 25 ℃ to 70 ℃, the onset and peak potentials of the DME electrooxidation shifted negatively 160 mV and 200 mV, respectively, the peak current density increased more than 0.63 times, while those values from JM's Pt/C only had negative shifts of 80 mV and 96 mV, respectively, but the current density increased more than 2.77 times. The above results showed that the introduction of Ru not only gave the best catalytic activity and lowest adsorption to CO species, but also would give better output of the cell potential. Raising the reaction temperatures will make ions move fast and weak the adsorption of CO to Pt and could increase the output of the cell current density. The E-TEK's PtRu/C showed the lowest electrocatalytic activity to DME oxidation. The experimental results also indicated that the adsorption of DME is likely to be rate determined step in the DME oxidation process and was suppressed with the addition of second metal Ru. So it is essential to optimize the atomic ratio of Pt and Ru. The results will be very helpful to find out new catalysts for DME oxidation and DME fuel cells.