The Effect of Surface Site Ensembles on the Activity and Selectivity of Ethanol Electrooxidation by Octahedral PtNiRh Nanoparticles

Abstract

Direct ethanol fuel cells are attractive power sources based on ab iorenewable,h igh energy-density fuel. Their efficiency is limited by the lackofactive anode materials which catalyze the breaking of the CÀCb ond coupled to the 12electron oxidation to CO 2 .W ereport shape-controlled PtNiRh octahedral ethanol oxidation electrocatalysts with excellent activity and previously unachieved low onset potentials as low as 0.1 Vv s. RHE, while being highly selective to complete oxidation to CO 2 .Our comprehensive characterization and in situ electrochemical ATRstudies suggest that the formation of at ernary surface site ensemble around the octahedral Pt 3 Ni 1 Rh x nanoparticles playsacrucial mechanistic role for this behavior.

Well‐Defined Platinum Surfaces for the Ethanol Oxidation Reaction

“…Whereas only the synthesis of monometallic high‐index facets NPs has been reported by using electrochemical methods, by the use of chemical methods have been reported also the synthesis of not only high‐index but also low‐index monometallic, bimetallic and trimetallic NPs, such as cubic, octahedral and rhombic dodecahedral NPs with predominantly {100}, {111} and {110} facets, respectively …”

“…Whereas only the synthesis of monometallic high-index facets NPs has been reported by using electrochemical methods, by the use of chemical methods have been reported also the synthesis of not only high-index but also low-index monometallic, bimetallic and trimetallic NPs, such as cubic, octahedral and rhombic dodecahedral NPs with predominantly {100}, {111} and {110} facets, respectively. [49][50][51][52][53][54][55][56][57][58][59] Regarding monometallic catalysts, Feliu and coworkers studied the ethanol oxidation in acid media on different shapecontrolled platinum nanoparticles: (100) and (111) predominantly oriented Pt nanoparticles with a preferential cubic and octahedron shape, respectively. [50] FTIRS and DEMS studies demonstrated that the CÀ C bond breaking was more favored on cubic Pt NPs (2B in Scheme 1), in agreement with the aforementioned results with Pt single crystals.…”

Porous Trimetallic PtRhCu Cubic Nanoboxes for Ethanol Electrooxidation

“…However, expensive price and weak ability of splitting CC bond seriously hamper its commercial applications. [17,22,23] Considering that CC bond cleavage and CO poisoning, trimetallic Pt-based electrocatalysts have been designed to simultaneously improve their CC bond cleavage capability and antipoisoning capability. [18][19][20][21] For example, the addition of Ru and Rh elements can obviously promote the CC bond cleavage, which is beneficial to the C 1 reaction pathway of the EOR.…”

“…[10,17] Recently, alloying Pt with other metal is generally considered as an efficient strategy for decreasing the cost of electrocatalyst and simultaneously improving electrocatalytic activity for the EOR. For example, PtPdRh [24] and PtRhNi [22] alloys nanoparticles displayed the excellent electrocatalytic activity for the EOR.Apart from chemical composition, the morphology of nanostructures also strongly affects their electrocatalytic performance. The introduction of highly oxophilic metals (such as Ni and Cu) can decrease the CO poisoning of electrocatalyst due to the bifunctional mechanism.…”

Fast Cryomediated Dynamic Equilibrium Hydrolysates towards Grain Boundary-Enriched Platinum Scaffolds for Efficient Methanol Oxidation

“…Thus, it is inevitable to develop high active precious metal electrocatalysts like platinum (Pt) to reduce the energy barriers of MOR [9][10][11]. From the perspective of Pt atomic efficiency [12], the precisely controlled synthesis of Pt nanocrystals such as Pt irregular nanoparticles [13,14], nanowires [15][16][17][18], and nanorods [19] is highly desirable since they have inherent anisotropic morphologies with abundant low-coordinated surface atoms [20,21], enabling to slow down the ripening process and increase the electrocatalytic activities for methanol oxidation.…”