Significant progress has been made in the development of non-precious metal electrocatalysts （NPMEs） during the past decade. Correspondingly, there is an urgent demand for an appropriate measurement method to be est...Significant progress has been made in the development of non-precious metal electrocatalysts （NPMEs） during the past decade. Correspondingly, there is an urgent demand for an appropriate measurement method to be established for the reliable evaluation of NPMEs. In this study, platinum and graphite counter electrodes were used to investigate the impact of counter electrode material on the accelerated durability testing （ADT） of NPMEs in acidic medium. Platinum used as the coun- ter electrode in a traditional three-electrode electrochemical cell was found to dissolve in acidic medium and re-deposit on NPME coated on the working electrode during ADT. Such re-deposition causes the oxygen reduction reaction （ORR） performance of NPMEs to remarkably improve, and thus will seriously mislead our judgment of NPMEs if we are unaware of it. The phenomenon can be avoided using a graphite counter electrode.展开更多
The development of a non-precious metal electrocatalyst （NPME） with a performance superior to commercial Pt/C for the oxygen reduction reaction （ORR） is important for the commercialization of fuel cells. We report...The development of a non-precious metal electrocatalyst （NPME） with a performance superior to commercial Pt/C for the oxygen reduction reaction （ORR） is important for the commercialization of fuel cells. We report the synthesis of a NPME by heat-treating Co-based metal organic frameworks （ZIF-67） with a small average size of 44 nm. The electrocatalyst pyrolyzed at 600 ~C showed the best performance and the performance was enhanced when it was supported on BP 2000. The resulting electrocatalyst was composed of 10 nm Co nanoparticles coated by 3-12 layers of N doped graphite layers which as a whole was embedded in a carbon matrix. The ORR performance of the electrocatalyst was tested by rotating disk electrode tests in O2-saturated 0.1 mol/L KOH under ambient conditions. The electrocatalyst （1.0 mg/cm~] showed an onset potential of 1.017 V （[vs. RHE] and a half-wave potential of 0.857 V （vs. RHE], which showed it was as good as the commer- cial Pt/C （20 BgPt/cm2）. Furthermore, the electrocatalyst possessed much better stability and re- sistance to methanol crossover than Pt/C.展开更多
本文通过分步还原Ru、Pt前驱体,制备了以Ru为核、Pt Ru合金为壳的Ru@Pt_(0.24)Ru纳米花电催化剂,其平均直径为16.5±4.0 nm.利用高分辨电子显微镜、电感耦合等离子体原子发射光谱和X射线光电子能谱等表征了这种电催化剂的结构和组成...本文通过分步还原Ru、Pt前驱体,制备了以Ru为核、Pt Ru合金为壳的Ru@Pt_(0.24)Ru纳米花电催化剂,其平均直径为16.5±4.0 nm.利用高分辨电子显微镜、电感耦合等离子体原子发射光谱和X射线光电子能谱等表征了这种电催化剂的结构和组成.在1 mol·L^(-1)KOH水溶液中,核壳结构Ru@Pt_(0.24)Ru/C纳米花氢析出反应的过电位为22 mV(@10 m A·cm^(-2)),耐久性测试后过电位增加至30 m V(@10 m A·cm^(-2)),明显优于商业Pt/C电催化剂(初始值:60 m V@10 mA·cm^(-2),耐久性测试后:85 mV@10mA·cm^(-2)).显著提高的电化学活性可能源于核壳结构Ru@Pt_(0.24)Ru纳米花的电子效应和几何效应,耐久性的改善可能源于核壳结构Ru@Pt0.24Ru纳米花结构的稳定性.展开更多
基金supported by the Fundamental Research Funds for the Central Universities(DUT15RC(3)001,DUT15ZD225)the Program for Liao-ning Excellent Talents in University(LR2015014)+1 种基金the Liaoning BaiQianWan Talents Program(201519)Dalian Excellent Young Scientific and Technological Talents(2015R006)
文摘Significant progress has been made in the development of non-precious metal electrocatalysts （NPMEs） during the past decade. Correspondingly, there is an urgent demand for an appropriate measurement method to be established for the reliable evaluation of NPMEs. In this study, platinum and graphite counter electrodes were used to investigate the impact of counter electrode material on the accelerated durability testing （ADT） of NPMEs in acidic medium. Platinum used as the coun- ter electrode in a traditional three-electrode electrochemical cell was found to dissolve in acidic medium and re-deposit on NPME coated on the working electrode during ADT. Such re-deposition causes the oxygen reduction reaction （ORR） performance of NPMEs to remarkably improve, and thus will seriously mislead our judgment of NPMEs if we are unaware of it. The phenomenon can be avoided using a graphite counter electrode.
基金supported by the National Basic Research Program of China(973 Program,2015CB932304)the National Natural Science Founda-tion of China(21436003)
文摘The development of a non-precious metal electrocatalyst （NPME） with a performance superior to commercial Pt/C for the oxygen reduction reaction （ORR） is important for the commercialization of fuel cells. We report the synthesis of a NPME by heat-treating Co-based metal organic frameworks （ZIF-67） with a small average size of 44 nm. The electrocatalyst pyrolyzed at 600 ~C showed the best performance and the performance was enhanced when it was supported on BP 2000. The resulting electrocatalyst was composed of 10 nm Co nanoparticles coated by 3-12 layers of N doped graphite layers which as a whole was embedded in a carbon matrix. The ORR performance of the electrocatalyst was tested by rotating disk electrode tests in O2-saturated 0.1 mol/L KOH under ambient conditions. The electrocatalyst （1.0 mg/cm~] showed an onset potential of 1.017 V （[vs. RHE] and a half-wave potential of 0.857 V （vs. RHE], which showed it was as good as the commer- cial Pt/C （20 BgPt/cm2）. Furthermore, the electrocatalyst possessed much better stability and re- sistance to methanol crossover than Pt/C.
基金supported by National Key Research & Development Program of China (Gran No.2016YFB0101307)National Natural Science Fund of China (Grant Nos.21003114,21103163,21306188,21373211,and 21306187)+1 种基金Liaoning BaiQianWan Talents Program (Grant No.201519)Program fo
文摘本文通过分步还原Ru、Pt前驱体,制备了以Ru为核、Pt Ru合金为壳的Ru@Pt_(0.24)Ru纳米花电催化剂,其平均直径为16.5±4.0 nm.利用高分辨电子显微镜、电感耦合等离子体原子发射光谱和X射线光电子能谱等表征了这种电催化剂的结构和组成.在1 mol·L^(-1)KOH水溶液中,核壳结构Ru@Pt_(0.24)Ru/C纳米花氢析出反应的过电位为22 mV(@10 m A·cm^(-2)),耐久性测试后过电位增加至30 m V(@10 m A·cm^(-2)),明显优于商业Pt/C电催化剂(初始值:60 m V@10 mA·cm^(-2),耐久性测试后:85 mV@10mA·cm^(-2)).显著提高的电化学活性可能源于核壳结构Ru@Pt_(0.24)Ru纳米花的电子效应和几何效应,耐久性的改善可能源于核壳结构Ru@Pt0.24Ru纳米花结构的稳定性.
