Thoi V Sara, Usiskin Robert E, Haile Sossina M
Departments of Materials Science and Chemical Engineering , California Institute of Technology , 1200 California Blvd , Pasadena , CA 91125 , USA . Email:
Chem Sci. 2015 Feb 1;6(2):1570-1577. doi: 10.1039/c4sc03003f. Epub 2014 Dec 22.
Pt-decorated carbon nanotubes (Pt-CNTs) were used to enhance proton reduction and hydrogen evolution in solid acid electrochemical cells based on the proton-conducting electrolyte CsHPO. The carbon nanotubes served as interconnects to the current collector and as a platform for interaction between the Pt and CsHPO, ensuring minimal catalyst isolation and a large number density of active sites. Particle size matching was achieved by using electrospray deposition to form sub-micron to nanometric CsHPO. A porous composite electrode was fabricated from electrospray deposition of a solution of Pt-CNTs and CsHPO. Using AC impedance spectroscopy and cyclic voltammetry, the total electrode overpotential corresponding to proton reduction and hydrogen oxidation of the most active electrodes containing just 0.014 mg cm of Pt was found to be 0.1 V (or 0.05 V per electrode) at a current density of 42 mA cm for a measurement temperature of 240 °C and a hydrogen-steam atmosphere. The zero bias electrode impedance was 1.2 Ω cm, corresponding to a Pt utilization of 61 S mg, a 3-fold improvement over state-of-the-art electrodes with a 50× decrease in Pt loading.
铂修饰的碳纳米管（Pt-CNTs）被用于增强基于质子传导电解质CsHPO的固体酸电化学电池中的质子还原和析氢反应。碳纳米管作为与集电器的互连材料，并作为Pt与CsHPO之间相互作用的平台，确保了催化剂的最小隔离以及大量的活性位点密度。通过电喷雾沉积形成亚微米到纳米级的CsHPO实现了粒径匹配。由Pt-CNTs和CsHPO溶液的电喷雾沉积制备了多孔复合电极。使用交流阻抗谱和循环伏安法，发现在240°C的测量温度和氢-蒸汽气氛下，对于仅含有0.014 mg cm² Pt的最活性电极，在电流密度为42 mA cm²时，对应于质子还原和氢氧化的总电极过电位为0.1 V（或每个电极0.05 V）。零偏置电极阻抗为1.2 Ω cm²，对应于61 S mg的Pt利用率，比现有技术电极提高了3倍，同时Pt负载量降低了50倍。
