Electrochemical hydrogen pumping using a platinum catalyst made in a fluidized bed via atomic layer deposition

Abstract

a b s t r a c t a r t i c l e i n f o Available online xxxx Keywords: Platinum Catalysts Hydrogen pumping Fluidized bed Fluidization Atomic layer depositionPlatinum nanoparticle catalysts for electrochemical hydrogen pumping were synthesized on a functionalized powder carbon substrate (XC72R) using atomic layer deposition (ALD) in a fluidized bed reactor (FBR). Trimethyl(methylcyclopentadienyl)platinum(IV) (MeCpPtMe 3 ) was used as the reagent for platinum delivery. Following deposition, MeCpPtMe 3 ligands were combusted or hydrogenated to yield platinum on the XC72R surface. Reactions throughout the ALD cycle were monitored using mass spectrometry and IR spectroscopy to clarify the deposition chemistry. The resultant platinum catalysts were compared to commercial products in hydrogen pumping tests. Hydrogenation made finer, more dispersed, platinum nanoparticles that performed similarly to their commercial equivalent when pumping hydrogen. Conversely, oxygenation made a coarser catalyst that underperformed its commercial equivalent. Thus, altering chemistries shows potential for improving ALD catalyst performance.

Synthesis of highly dispersed Pt nanoparticles into carbon supports by fluidized bed reactor atomic layer deposition to boost PEMFC performance

“…To fabricate powder coatings on a large scale, several modified ALD systems, such as static and rotary reactor methods, have been studied, and have synthesized diverse NP materials on porous materials [34][35][36] . Among them, to synthesize the Pt/carbon catalyst for commercialization of PEMFCs, a fluidized bed reactor (FBR) ALD is an excellent modified ALD system due to its excellent gas transfer, uniform NPs and large production quantity 37,38 . However, in light of a few reported FBR-ALD studies 21,38 , the synthesis of a FBR Pt catalyst through a process with increased efficiency and speed, and an improved fluidizing behavior is highly desired.…”

Electrochemical Compression Technologies for High-Pressure Hydrogen: Current Status, Challenges and Perspective

“…However, additional research has significantly lowered this loading to 0.2-0.8 mg cm −2 [18,107,147]. To further reduce Pt loading, researchers have synthesized Pt nanocatalysts using atomic layer deposition [148] or nanostructured thin membranes with a loading of 0.1 mg cm −2 [149]. As a result of these findings, research has shifted away from the thickness and cost of electrodes to the uniform distribution of catalyst particulates.…”

Proton Exchange Membrane Fuel Cell Flooding Caused by Residual Functional Groups after Platinum Atomic Layer Deposition

“…Efficacy of whole-cell evaluation and revelation of surface-compromised catalysts can be further exploited when considering alternative cell reactions. The catalysts inspected in this investigation were also utilized in a previous report focused on hydrogen pumping [37], with the same MEA composition.…”

“…With the same catalyst layer and MEA construction, the catalyst produced on the functionalized carbon was less effective for the ORR on the cathode in this report. Fuel cell cathodes are more sensitive to catalyst layer morphology because of water production, which was influenced by the functionalization process producing a lower surface area carbon [37]. Combined with a more hydrophilic interface, the catalyst layer constructed using the functionalized carbon is less fit for the PEMFC cathode.…”