Hierarchical Nanostructured Pd/Co₃N‐Ni₃N as an Efficient Catalyst for Ethanol Electrooxidation in Alkaline Media

Abstract

to synthesize multicomponent and/or nanocomposite catalysts. Alloying Pt or Pd with 3d transition metals provides a straightforward way to alter the electronic structure and optimize the binding energies of adsorbates on the catalyst surface. [15][16][17][18][19][20][21][22][23][24][25] Creating synergistic catalysts via a combination of noble metals with oxophilic metal oxides/hydroxides proved a promising approach for improving the durability. [26][27][28][29][30][31][32][33][34] In a rational catalyst design, the OH adspecies on the surface of oxides/ hydroxides will facilitate the oxidative removal of carbonaceous intermediates adsorbed on the nearby Pd or Pt sites.Recently, the search for synergistic phases was further extended to transition metal non-oxides, like phosphides, [35][36][37][38] sulfides, [39] carbides, [40,41] and nitrides. [42][43][44][45][46] In comparison with the corresponding oxides, metal non-oxides exhibit much more abundant physicochemical properties owing to the complex and tunable interactions between metals and non-oxygen elements. For instance, in contrast to the insulator nature of most oxides, transition metal non-oxides span a remarkable range of conductivity properties, from insulator to semiconductor and to metal. Evidently, a rich variety of metal non-oxides with diverse properties offers increased degrees of freedom in the design of synergestic catalysts for the EOR. Among the materials of choice, transition metal nitrides (TMNs) are highly appealing but less well explored candidates. Theoretical studies found that TMNs (like Ni 3 N) typically show moderate binding energies of OH species, implying a compromise between the activation of OH and poisoning of the surface with reaction intermediates. [47] This, together with their high electrical conductivity and good chemical stability, clearly suggests the potential of TMN as a component phase in the synergistic catalysis of EOR. [48,49] Herein, we report the synthesis of a carbon fiber clothsupported nanocomposite catalyst consisting of highly dispersed Pd nanoparticles on the porous Co 3 N-Ni 3 N nanowires using a hydrothermal method followed by ammonization treatment and electrochemical deposition. Our study found that incorporation of Co 3 N-Ni 3 N of metallic nature could effectively improve the poisoning tolerance, while preserving good electrical conductivity of the electrocatalyst. Furthermore, the resulting hierarchical nanostructure of Co 3 N-Ni 3 N from the applied synthesis methods ensures the exposure of abundant active sites and a favorable reactant/product mass transfer kinetics. As a consequence, the Pd/Co 3 N-Ni 3 N/CFC catalyst Creating synergistic active sites via combination of palladium (Pd) or platinum (Pt) with oxophilic metal compounds has been extensively investigated as a promising approach for developing active and robust electrocatalysts toward the ethanol oxidation reaction (EOR). Among the metal compounds of choice, transition metal nitrides are highly appealing but less well explored candidates. H...

Ir Single Atoms Doped Cuboctahedral Pd for Boosted Methanol Oxidation Reaction

“…Apparently, Ir‐SAs/Pd has the largest ECSA value among all the samples which means Ir‐SAs/Pd catalysts could provide more active sites. [ 23 ] For Ir‐SAs/Pd catalysts, the oxidation peak current density toward MOR normalized to the mass of Pd was 1717.3 mA mg Pd −1 , which is nearly 2.4 times higher than pure Pd catalysts (720.2 mA mg Pd −1 ) and 6.7 times higher than commercial Pd/C (257.1 mA mg Pd −1 ), respectively (Figure 4c). More importantly, Ir‐SAs/Pd catalysts show lower MOR onset potential which indicates that the initial oxidation of methanol is more likely to occur in Ir‐SAs/Pd than pure Pd and Pd/C (Figure S5, Supporting Information).…”

“…Apparently, Ir-SAs/Pd has the largest ECSA value among all the samples which means Ir-SAs/Pd catalysts could provide more active sites. [23] For Ir-SAs/Pd catalysts, the oxidation peak current density toward MOR normalized to the mass of Pd was 1717. ), respectively (Figure 4c).…”

Review and Development of Anode Electrocatalyst Carriers for Direct Methanol Fuel Cell

“…The OH functional groups on their surfaces facilitated in the oxidative removal of carbonaceous intermediates adsorbing on the active component Pt attachment and improved the toxin resistance of the catalyst (Figure 8b). [ 175 ] C fiber paper is a porous composite material composed of carbon fiber and carbon matrix, which has good porosity and good electrical conductivity, and is responsible for the dual role of mass transfer and electrical conductivity. Sawangphruk et al used a spray technique to coat hydrated graphene oxide nanosheets on flexible C fiber paper, followed by direct electrodeposition to encapsulate the superporous palladium catalyst.…”

“…Reproduced with permission. [175] Copyright 2020, Wiley-VCH. contact of the active components reduces the reaction's activation energy, and the kinetics of catalytic methanol oxidation is considerably increased.…”

Ternary Interface of Pt|Few‐Layered N‐rGO|TiN for the Boasting Electrocatalytic Activity in Ethylene Glycol Oxidation

“…[ 1–3 ] Due to the abundance, low toxicity, and high energy density (≈6000 Wh kg −1 for methanol and ≈8000 Wh kg −1 for ethanol), ethanol and methanol are the most commonly used fuels for DAFCs. [ 4,5 ] However, the industrialization of methanol and ethanol fuel cells is hindered by several constraints, such as high permeability across proton exchange membrane (PEM), difficulty in transportation due to their low boiling point and volatility, and so on. [ 6 ] In recent years, the electro‐oxidation of ethylene glycol (EG) has received significant attentions, since EG is provided with similar energy density (5270 Wh kg −1 ), lower permeability across PEM, and better transportability, compared with that of methanol and ethanol.…”