Highly Efficient Electrocatalytic Hydrogen Production over Carbon Nanotubes Loaded with Platinum Nanoparticles Using Solution Processing

Abstract

Abstract Proton exchange membrane (PEM) electrolyzers are used for hydrogen (H2) production by water electrolysis. The commercial cathodic electrocatalyst for this process is typically mechanically mixed platinum on carbon (Pt/C). However, aggregation of the platinum (Pt) makes high loading of the catalyst difficult. Therefore, a method for the homogeneous combination of Pt and carbon materials is required. Herein, the first example of a highly efficient single‐walled carbon nanotube (SWCNT) cathodic H2‐production electrocatalyst that is loaded with platinum nanoparticles (PtNPs) using a newly developed suspension method is reported. Combining SWCNTs lapped with a water‐soluble, thiol‐functionalized polymer with PtNPs in water yields a PtNP‐conjugated SWCNT suspension. The electrocatalyst exhibits a low overpotential of 47 mV at a current density of 10 mA cm−2 toward H2 evolution in 0.5 m sulfuric acid. A PEM electrolyzer fabricated using the optimally prepared electrocatalyst with the low loading of 15 µgPt cm−2 shows a high mass activity of 27 200 A gPt−1, which is 80 times that of Pt/C with a loading amount of 2.8 mgPt cm−2 (324 A gPt−1). In addition, the PEM electrolyzer produces H2 at a Faradaic efficiency of 97% and operates stably for 150 h at 100 mA cm−2.

Keywords

• carbon nanotubes
• hydrogen production
• noncovalent functionalization
• proton exchange membrane electrolyzer
• water electrolysis