Optimizing the Size of Platinum Nanoparticles for Enhanced Mass Activity in the Electrochemical Oxygen Reduction Reaction

Abstract

High oxygen reduction (ORR) activity has been for many years considered as the key to many energy applications. Herein, by combining theory and experiment we prepare Pt nanoparticles with optimal size for the efficient ORR in proton-exchange-membrane fuel cells.O ptimal nanoparticle sizes are predicted near 1, 2, and 3nmb yc omputational screening.T oc orroborate our computational results,w eh ave addressed the challenge of approximately 1nms ized Pt nanoparticle synthesis with am etal-organic framework (MOF) template approach. The electrocatalyst was characterized by HR-TEM, XPS,a nd its ORR activity was measured using ar otating disk electrode setup.T he observed mass activities (0.87 AE 0.14 Amg Pt À1)a re close to the computational prediction (0.99 Amg Pt À1 ). We report the highest to date mass activity among pure Pt catalysts for the ORR within similar sizerange.The specific and mass activities are twice as high as the Tanaka commercial Pt/C catalysis.

Revealing the nature of active sites in electrocatalysis

“…For instance, nearly spherical, unstrained Pt particles show theoretical maxima in mass activity for diameters around 1, 2 and 3 nm. 71,72 These maxima are constrained by a narrow size distribution (AE0.2 nm), which is difficult to transfer to real-life applications using conventional methods, although recent experimental results are rather encouraging. 72 Therefore, it is desirable to provide further possibilities for tailoring surface properties.…”

Size effects of platinum particles@CNT on HER and ORR performance

“…Yan et al [17] investigated the size effect of Pt nanoparticles supported on S-doped carbon material on HER, and found that~1.5 nm Pt clusters had better HER activity than Pt single atoms, indicating the electron transfer played an important role in HER. Garlyyev et al [18] studied the effect of different Pt particle sizes on ORR activity by using a metal-organic framework (MOF) to regulate the particle size, and pointed out that Pt particles with size of 1.1 nm exhibited better ORR activity. Though lots of efforts have been made to enhance the HER and/or ORR catalytic activities of Pt species by modulating the particle size, the debates of what sized Pt particle determining the main role during the electrochemical reaction still exist.…”

Prospects of Value‐Added Chemicals and Hydrogen via Electrolysis

“…In electrocatalytic reactions the overpotential is mainly governed by the electrocatalyst activity, which mainly depends on its surface structure and composition . Furthermore, in recent studies the rate of the reaction is shown to be largely influenced by the so‐called spectator species in the electrolyte .…”