Electrochemical top-down synthesis of C-supported Pt nano-particles with controllable shape and size: Mechanistic insights and application

Abstract

In this work, we demonstrate the power of a simple top-down electrochemical erosion approach to obtain Pt nanoparticle with controlled shapes and sizes (in the range from ∼ 2 to ∼ 10 nm). Carbon supported nanoparticles with narrow size distributions have been synthesized by applying an alternating voltage to macroscopic bulk platinum structures, such as disks or wires. Without using any surfactants, the size and shape of the particles can be changed by adjusting simple parameters such as the applied potential, frequency and electrolyte composition. For instance, application of a sinusoidal AC voltage with lower frequencies results in cubic nanoparticles; whereas higher frequencies lead to predominantly spherical nanoparticles. On the other hand, the amplitude of the sinusoidal signal was found to affect the particle size; the lower the amplitude of the applied AC signal, the smaller the resulting particle size. Pt/C catalysts prepared by this approach showed 0.76 A/mg mass activity towards the oxygen reduction reaction which is ∼ 2 times higher than the state-of-the-art commercial Pt/C catalyst (0.42 A/mg) from Tanaka. In addition to this, we discussed the mechanistic insights about the nanoparticle formation pathways.

Platinum Nanoparticles in Biomedicine: Preparation, Anti-Cancer Activity, and Drug Delivery Vehicles

“…The top-down method starts with the bulk material, which is progressively degraded, leading to the generation of fine NPs. For mass manufacture of NPs, a variety of physical techniques are used, including photolithography, milling techniques, anodization, and electron beam lithography ( Fichtner et al, 2020 ; Garlyyev et al, 2020 ; Kuriganova et al, 2020 ).…”

A fundamental comprehension and recent progress in advanced Pt‐based ORR nanocatalysts

“…25,[121][122][123] Apart from the above-discussed strategies, another method for minimizing the Pt element without compromising the catalytic ORR performance is to reduce the dimension down to clusters and even separately distributed metal atoms, which can greatly increase the atom utilization efficiency, potentially to 100 percentage. [124][125][126] Atomic site catalysts, including single-atomic site catalysts and diatomic site catalysis, are being pursued as economical alternatives to boosting their commercial applications in PEMFCs due to lower Pt usage and high performance triggered by nearby highly stable coordination atoms. Liu's group documented a strategy of fabricating highly active and stable ORR electrocatalyst with ultralow-loading Pt usage by carbonization of Co-containing Zn-based zeolitic imidazolate frameworks ( Figure 10G,H).…”

Avoiding Pyrolysis and Calcination: Advances in the Benign Routes Leading to MOF‐Derived Electrocatalysts

“…The electro‐reduction of oxygen is of high importance for various energy conversion systems such as fuel cells and metal‐air batteries [78] . So far, only Pt‐based catalysts have shown sufficient catalytic activity and stability [79] . Recently, there has been much attention on developing MOF‐based electrocatalysts towards ORR, owing to their easily tuneable structure and composition [80] .…”

“…[78] So far, only Pt-based catalysts have shown sufficient catalytic activity and stability. [79] Recently, there has been much attention on developing MOF-based electrocatalysts towards ORR, owing to their easily tuneable structure and composition. [80] First of all, it should be noted that there are several fundamental requirements for an efficient ORR catalyst.…”