A Highly Ordered Hydrophilic–Hydrophobic Janus Bi‐Functional Layer with Ultralow Pt Loading and Fast Gas/Water Transport for Fuel Cells

Abstract

One of the critical challenges that limit broad commercialization of proton exchange membrane fuel cells (PEMFC) is to reduce the usage of Pt while maintaining high power output and sufficient durability. Herein, a novel bi‐functional layer consisting of vertically aligned carbon nanotubes (VACNTs) and nanoparticles of Pt‐Co catalysts (Pt‐Co/VACNTs) is reported for high‐performance PEMFCs. Readily prepared by a two‐step process, the Pt‐Co/VACNTs layer with a hydrophilic catalyst‐loaded side and a hydrophobic gas diffusion side enables a PTFE‐free electrode structure with fully exposed catalyst active sites and superior gas–water diffusion capability. When tested in a PEMFC, the bi‐functional Pt‐Co/VACNTs layer with ultralow Pt loading (~65 μgcathode cm−2) demonstrates a power density of 19.5 kW gPt cathode−1 at 0.6 V, more than seven times that of a cell with commercial Pt/C catalyst (2.7 kW gPt cathode−1 at 0.6 V) at a loading of 400 μgcathode cm−2 tested under similar conditions. This remarkable design of VACNTs‐based catalyst with dual functionalities enables much lower Pt loading, faster mass transport, and higher electrochemical performance and stability. Further, the preparation procedure can be easily scaled up for low‐cost fabrication and commercialization.

Ce‐Modified Ni(OH)2 Nanoflowers Supported on NiSe2 Octahedra Nanoparticles as High‐Efficient Oxygen Evolution Electrocatalyst

“…Figure S13 in the Supporting Information shows the EIS data with fitting curves according to the previous reported method. [44][45][46] The Ce-m-Ni(OH) 2 @NiSe 2 electrode shows smaller solution resistance (R s = 0.7 Ω) and charge transfer resistance (R ct = 1.4 Ω) relative to Ni(OH) 2 @NiSe 2 (R s = 0.8 Ω, R ct = 2.8 Ω) and Ce(OH) 3 @NiSe 2 (R s = 1.1 Ω, R ct = 3.1 Ω). This implies that the Ce-m-Ni(OH) 2 @NiSe 2 electrode can afford faster charge transfer kinetics, contributing to its superior catalytic activity.…”

Vertically Aligned Carbon Nanotube Membranes: Water Purification and Beyond

“…Murata et al developed cathode electrodes for PEMFCs coated with VACNT using a perfluorosulfonic acid polymer instead of Nafion [ 131 ]. Recently, various cathode electrodes for PEMFCs using VACNT have been studied [ 132 , 133 , 134 ].…”

Self‐catalyzed formation of strongly interconnected multiphase molybdenum‐based composites for efficient hydrogen evolution

“…Furthermore, as a new class of electrocatalysts, freestanding films fabricated by electrospinning require no binders and usually demonstrate excellent electrical conductivity, abundant electrochemical surface area, and fine mechanical stability, which show great promise for applications in advanced electrocatalysts 26–29 …”