Oxygen-rich PdSnCu nanocrystals with particle connection features as enhanced catalysts for ethanol oxidation reaction

High-efficient electrooxidation of ethylene glycol and ethanol on PdSn alloy loaded by versatile poly(3,4-ethylenedioxythiophene)

Developing a novel catalyst with lower noble-metal loading and higher catalytic efficiency is significant for promoting the widespread application of direct alcohol fuel cells (DAFCs). In this work, poly(3,4-ethylenedioxythiophene) (PEDOT) supported the PdSn alloy (PdSn/PEDOT) were simply synthesized and their electrocatalytic performance toward the oxidation of ethylene glycol and ethanol (EGOR and EOR) were investigated in alkaline media, respectively. In comparison with other control catalysts, the optimized Pd4Sn6/PEDOT catalyst exhibits the highest mass activity (7125/4166 mA mgPd-1) and specific activity (26/15 mA cm-2) towards EGOR/EOR. The mass activity of Pd4Sn6/PEDOT for EGOR and EOR are 11.9 and 10.9 times higher than commercial Pd/C, respectively. Moreover, chronoamperometry (CA) and successive cyclic voltammetry (CV) tests show that the CO resistance ability and durability of the Pd4Sn6/PEDOT catalyst were superior to Pd4Sn6, Pd/PEDOT and commercial Pd/C catalysts, which can be attributed to the d-band center of Pd can be effectively downshifted and the interface strain effect between electrons caused by the conjugated structure between PEDOT groups. This work provides an effective strategy for the development of highly efficient anode catalysts of DAFCs.

Sn-doped PdCu alloy nanosheet assemblies as an efficient electrocatalyst for formic acid oxidation

A ternary alloy catalyst has been confirmed to be an effective catalyst for anode catalysis in direct formic acid fuel cells, which can improve the electrocatalytic performance of the fuel cell by introducing commonly used metal elements to change the Pd electronic structure and can reduce the use of precious metals and the cost of catalyst production. In this study, PdCuSn Ns/C with a special 3D structure was synthesized by a simple two-step wet chemical method. The PdCuSn Ns/C catalyst prepared exhibits excellent catalytic activity and stability for the formic acid oxidation reaction (FAOR). The mass activity of 2420.1 mA mg-1Pd is 3.94 times that of the Pd/C catalyst. The improvement in the electrocatalytic performance stems from the introduction of Cu and Sn atoms and the unique 3D nanosheet structure, which changes the electronic structure of Pd to increase the reactive active site and accelerates the reaction mass transfer rate, and also reduces the content of precious metals, while improving the electrocatalytic performance. Therefore, the PdCuSn Ns/C catalyst has a promising future in the field of electrocatalysis.

Heterogeneous Pd-PdO mesoporous film for ammonia electrosynthesis

Exploring cost-effective and highly active electrocatalysts is of great significance for sustainable electrochemical NH₃synthesis. Palladium (Pd)-based catalysts have been unanimously considered as one of the most efficient catalysts for the nitrogen reduction reaction (NRR). Herein, self-supported mesoporous Pd film with partial oxidation on Ni foam (mPd-PdO/NF) was synthesized through the micelle-assisted chemical replacement method coupled with air oxidation under 260 °C, and the mPd-PdO/NF electrocatalyst exhibited superior NRR performance with the maximum values ofr_NH3(24.8 mg h^-1mg_cat.^-1) and FE (16.64%) were obtained at -0.1 V, relative to the single counterparts (mPd/NF and mPdO/NF). It is proposed that both metallic Pd and its oxide domains when co-existing with a phase boundary between them can facilitate nitrogen activation and hydrogenation, resulting in an enhanced NRR performance. This work provides an inspiring strategy for the rational design of highly active and durable metal-metal-oxide nanoarchitectonics for ammonia electrosynthesis.

Porous PdWM (M = Nb, Mo and Ta) Trimetallene for High C1 Selectivity in Alkaline Ethanol Oxidation Reaction

Direct ethanol fuel cells are among the most efficient and environmentally friendly energy-conversion devices and have been widely focused. The ethanol oxidation reaction (EOR) is a multielectron process with slow kinetics. The large amount of by-product generated by incomplete oxidation greatly reduces the efficiency of energy conversion through the EOR. In this study, a novel type of trimetallene called porous PdWM (M = Nb, Mo and Ta) is synthesized by a facile method. The mass activity (15.6 A mg_Pd ^-1 ) and C1 selectivity (55.5%) of Pd₅₀ W₂₇ Nb₂₃ /C trimetallene, obtained after optimizing the compositions and proportions of porous PdWM, outperform those of commercial Pt/C (1.3 A mg_Pt ^-1 , 5.9%), Pd/C (5.0 A mg_Pd ^-1 , 7.2%), and Pd₉₇ W₃ /C bimetallene (9.5 A mg_Pd ^-1 , 14.1%). The mechanism by which Pd₅₀ W₂₇ Nb₂₃ /C enhances the EOR performance is evaluated by in situ Fourier transform infrared spectroscopy and density functional theory calculations. It is found that W and Nb enhance the adsorption of CH₃ CH₂ OH and oxophilic high-valence Nb accelerates the subsequent oxidation of CO and CH_x species. Moreover, Nb promotes the cleavage of CC bonds and increases the C1 selectivity. Pd₆₀ W₂₈ Mo₁₂ /C and Pd₆₄ W₂₇ Ta₉ /C trimetallene synthesized by the same method also exhibit excellent EOR performance.