Synthesis of CO‐tolerant Ni‐Pt Rhombic Dodecahedra Bimetallic Electrocatalytic Nanoparticles

Abstract

Developing scalable synthetic routes for fabricating low-cost CO-tolerant and highly active electrocatalysts have significant relevance for fuel cell applications. Here, we report a novel and rapid single step synthesis of Ni enriched bimetallic core-shell (NiÀ Pt) rhombic dodecahedra nanoparticles (NPs) via the thermal decomposition of precursor in the presence of oleylamine. Electrochemical dealloying in acidic medium (0.1 M HClO 4 ) subjecting NPs to different potential cycles is employed to vary the chemical composition and morphologies of parent bimetallic core-shell NPs. As a result, rhombic dodecahedra NPs transform to different morphologies such as concave, nanocage (open structure), and squeezed nanocage. Our results reveal that concave rhombic dodecahedra shaped electrocatalysts show high resistance to CO poisoning compare to core-shell, nanocage, and squeezed nanocage morphologies as well as commercial Pt/C electrocatalysts. The improved CO tolerant of concave rhombic dodecahedra bimetallic NPs results from the presence of optimal content of Ni along with Pt content at the surface. We also demonstrate that CO tolerance of concave bimetallic NPs can be changed by electrochemical parameters such as the scan rate and CO adsorption potential. Overall, the present study presents a conceptual strategy for achieving improved CO tolerance by change in the composition and morphologies of bimetallic core-shell NPs.

Molybdenum‐based Nanocatalysts for CO Oxidation Reactions in Direct Alcohol Fuel Cells: A Critical Review

“…According to previous interpretations, CO ads stripping on Mo‐ECs displays two major peaks: a pre‐peak and a main peak (CO ads oxidation) [74] . The origin of pre‐peak at a lower potential (~0.05–0.35 V), consistent with a bifunctional mechanism, corresponds to the removal of weakly attached CO molecules from the Pt surface via strongly bonded immobilized water molecules at Mo sites that oxidize CO ads [74] .…”

“…[74] The origin of pre-peak at a lower potential (~0.05-0.35 V), consistent with a bifunctional mechanism, corresponds to the removal of weakly attached CO molecules from the Pt surface via strongly bonded immobilized water molecules at Mo sites that oxidize CO ads . [74] The main peak in the higher potential region (~0.45-0.80 V) corresponds to the oxidation of actual CO ads , and this reaction takes place on Pt sites between the CO ads and PtÀ OH. [56,75] The main CO ads oxidation peak potentials comprise onset and peak potential.…”

“…A lower onset potential compared to Pt/C indicates easier CO ads oxidation, while a higher onset potential (compared to Pt/C) implies more difficulty in oxidizing CO ads . [53,74] A common characteristic of PtMo alloy composition is the negative shift of onset potential to a lower value than Pt/C and PtRu/C. Figure 3(a) shows the CO ads stripping curve of PtSnMo catalyst displayed multiple Co ads oxidation peaks, and the lowest potential peak is referred to as onset potential around 0.3 V, highlighted in red line.…”

Advancing Photoelectrochemical Energy Conversion through Atomic Design of Catalysts

“…The above work shows that controlling the exposed facets of photoelectrocatalysts is an effective way to improve the performance. At present, the exposed facets of noble metal nanocatalysts can be realized by controlling the crystal morphology, such as icosahedron, [ 165 , 166 ] dodecahedra, [ 167 , 168 ] decahedron, [ 169 , 170 , 171 ] tetrahedron, [ 172 , 173 ] cube, [ 174 ] etc. However, the accurate regulation of the exposed facets on most non‐noble metal catalysts is still a big challenge.…”

Bimetallic Nanocrystals: Structure, Controllable Synthesis and Applications in Catalysis, Energy and Sensing

“…Zero-dimensional Tetrahedron PdPt [26], PdCu [27] Octahedron and truncated octahedron Pt@Pd [28], Pt 3 Ni [29] PtCo [30] Cube and truncated cube Au-Pd [31], Pt-Pd [32] Icosahedron Pt-Pd [32] Rhombic dodecahedron AuPd [33], NiPt [34] One-dimensional…”