Enhanced oxygen reduction activity of platinum subnanocluster catalysts through charge redistribution

Abstract

Single-size platinum Pt6 subnanoclusters exhibit superior mass-specific and surface-specific activities for the oxygen reduction reaction.

Moving Mountains: Reshaping the Activity Volcano of Electrocatalysis with Fluxional Subnano Clusters

“…The carbon substrate is modeled by a graphite slab (see section Methods), which could represent the surface of glassy carbon electrode or any graphitic carbon substrate. 13 The ensemble-averaged cluster-support interaction energies in the absence of the applied potential are calculated to be -1.92 eV, -1.30 eV, -1.03 eV, and -0.64 eV for Pd, Pt, Ag, and Au, respectively. The strongest cluster-support binding for Pt 4 /C flips its isomer distribution at 300 K: from the butterfly structure being prevalent over the tetrahedral in the gas phase, to the tetrahedron being prevalent over the butterfly on the surface.…”

Platinum nanocluster catalysts supported on Marimo carbon via scalable dry deposition synthesis

“…Pt catalyst is robust against oxidation under ambient conditions, judging from X-ray photoelectron spectroscopy and X-ray absorption ne structure. 42 It should be noted that the sputtering conditions for Pt NC generation were optimized with another HiPIMS NC source, which was equipped with a quadrupole mass spectrometer (Extrel CMS LLC, MAX-16000), 38,39 and the same cell pressures under similar sputtering conditions were used.…”

“…Although NC/NP growth can be characterized by Pt atom aggregation either in the gas phase or liquid phase, aggregation in the gas phase may occur more uniformly than that in the liquid phase because the aggregation in the liquid is a rather inhomogeneous process through chemical reduction reactions. 42,43 Treatments involving no chemical reagents or solvents appear to yield a cleaner Pt catalyst in the dry process; dry-deposition Pt catalysts.…”

“…22,40 Furthermore, while a demanding task of FCs with lower Pt loading is more challenging (<0.1 mg Pt cm À2 per a membrane-electrode assembly (MEA)), overall FC performance will become susceptible to accessibility of protons and gases to Pt catalysts due to locally restricted transport, which results in the loss at high power region. 41 In this study, to develop an efficient PEFC with increasing the Pt utilization efficiency, smaller and more uniformly sized Pt NC catalysts are generated by a dry process in the gas phase, 38,39,42 and the Pt NC(d) catalysts are directly embedded on MC powder, forming dry-deposition Pt-NC(d)/MC. By measuring the output power density of the FC with a single cell by fabricating a MEA of size 25 cm 2 , the power density of the MEA formed by Pt-NC(d)/MC, at minimum Pt loading of 0.05 mg Pt cm À2 for both anode and cathode (0.1 mg Pt cm À2 in total), is observed to be better than that formed by Pt NP catalysts loaded on MC through a wet process (Pt-NP(w)/MC).…”

Simple and high-yield preparation of carbon-black-supported ∼1 nm platinum nanoclusters and their oxygen reduction reactivity

“…Previous studies on ~1-nm Pt NCs mainly used the following synthesis/preparation methods: 1) laser vaporization 11,12 or ion sputtering 7 of bulk Pt under vacuum (Figure S3a), 2) liquidphase synthesis using a special dendrimer as a template (Figure S3b), 5,6 3) liquid-phase synthesis using carbon monoxide (CO) as ligands (or as a part of ligands) (Figure S3c), 13 4) liquid-phase synthesis using a metal-organic framework (MOF) as a template (Figure S3d), 14 or 5) particle growth on a support via an impregnation method (Figure S3e). 15 However, method 1 requires expensive equipment and method 2 requires precise synthesis of special dendrimers and are thus not suitable for the mass production of Pt NCs.…”