Rhodium–Cobalt Alloy Nanotubes Toward Methanol Oxidation Reaction

Abstract

The sluggish reaction kinetics of the anodic methanol oxidation reaction (MOR) seriously hinders the commercial development of direct methanol fuel cells. Considering the vital role of catalysts, this work focuses on the synthesis of rhodium–cobalt alloy nanotubes (RhCo‐NTs) through a simple one‐pot reduction approach using hydrazine hydrate as a reducing agent. RhCo‐NTs with different Rh/Co atomic ratios can be handily achieved by simply controlling RhIII/CoII feeding proportions. The hollow and tubular architecture of RhCo‐NTs gains abundant boundary/defect atoms, improves the atomic utilization of Rh, and enlarges the valid connection between active sites and reactants. Compared with commercial Rh nanocrystals, RhCo‐NTs with optimized Rh/Co atomic ratio show sharply enhanced MOR electroactivity and long‐term stability because of the particular tubular morphology, big electrochemical active area, suitable Co introduction, excellent self‐stability, and eminent anti‐poison capability.

A rhodium–cobalt alloy bimetallene towards liquid C1 molecule electrooxidation in alkaline media

“…This shift derives from the partial charge transfer from Co to Rh due to the different electronegativity between Rh and Co (Rh: 2.28 vs. Co: 1.88), which increases the density of the electron cloud around Rh and further confirms the formation of Rh–Co alloy. 15…”

“…This shi derives from the partial charge transfer from Co to Rh due to the different electronegativity between Rh and Co (Rh: 2.28 vs. Co: 1.88), which increases the density of the electron cloud around Rh and further conrms the formation of Rh-Co alloy. 15 The scanning electron microscopy (SEM) pattern shows that Rh-Co ABM has three-dimensionally (3D) hierarchical owerlike morphology, accompanied by an abundance of channels (Fig. 2a).…”

“…13 Given the high price and scarcity of Rh metal, structural and component engineering are generally applied to elevate the atom utilization efficiency and boost the electrocatalytic activity. [14][15][16][17][18][19][20] Recently, metallene, a class of two-dimensional (2D) graphene-like metallic nanosheets, have emerged as the star electrocatalysts because of their abundant unsaturated atoms with high activity and ultrahigh surface area. [21][22][23][24][25][26] For example, Wang and his co-workers successfully synthesized Pd metallene with 1 nm thickness using a one-pot wet-chemical method, which exhibited excellent electroactivity for the oxygen reduction reaction, owing to optimized oxygen binding ability and the active site-rich feature.…”

Bio-assisted Synthesis of Au/Rh Nanostructure Electrocatalysts for Hydrogen Evolution and Methanol Oxidation Reactions: Composition Matters!

“…However, the widespread use of Pt-based catalysts is always a problem as they are expensive and easily poisoned by CO molecules. , Rh-based bimetallic nanostructures are well documented for efficient methanol oxidation reactions. Most recently, Ding et al synthesized a hollow and tubular architecture of RhCo alloy nanotubes for enhanced MOR electroactivity with long-term stability and anti-poison capability . Chen’s research group designed ultrathin rhodium nanosheet–gold nanowire nanocomposites that were employed for methanol oxidation reaction.…”

CO2 and Formate Pathway of Methanol Electrooxidation at Rhodium Electrodes in Alkaline Media: An In Situ Electrochemical Attenuated Total Refection Surface-Enhanced Infrared Absorption Spectroscopy and Infrared Reflection Absorption Spectroscopy Investigation

“…In terms of MOR, although Pt- and Pd-based materials have been the most widely explored and approved in the past, − Chen et al recently discovered that Rh has unexpectedly high activity for MOR in alkaline media. They also designed and invented some new Rh-based catalytic materials, such as RhCo alloy, , RhCu, Rh nanosheet-reduced graphene oxide hybrids, and hierarchical porous Rh nanosheets, all of which show considerably higher MOR activity and longer durability in alkaline media than Pd catalysts. On the other hand, Rh was also doped as a co-catalyst to obtained more advanced MOR electrocatalysts in alkaline media.…”