Boosting Hydrogen Production by Selective Anodic Electrooxidation of Ethanol over Trimetallic PdSbBi Nanoparticles: Composition Matters

Bifunctional PdMoPt trimetallene boosts alcohol-water electrolysis

Substituting oxygen evolution with alcohol oxidation is crucial for enhancing the cathodic hydrogen evolution reaction (HER) at low voltages. However, the development of high-performance bifunctional catalysts remains a challenge. In this study, an ultrathin and porous PdMoPt trimetallene is developed using a wet-chemical strategy. The synergetic effect between alloying metals regulates the adsorption energy of reaction intermediates, resulting in exceptional activity and stability for the electrooxidation of various alcohols. Specifically, the mass activity of PdMoPt trimetallene toward the electrooxidation of methanol, ethylene glycol, and glycerol reaches 6.13, 5.5, and 4.37 A mgPd+Pt -1, respectively. Moreover, the catalyst demonstrates outstanding HER activity, requiring only a 39 mV overpotential to achieve 10 mA cm-2. By employing PdMoPt trimetallene as both the anode and cathode catalyst, we established an alcohol-water hybrid electrolysis system, significantly reducing the voltage requirements for hydrogen production. This work presents a promising avenue for the development of bifunctional catalysts for energy-efficient hydrogen production.

Strain and Shell Thickness Engineering in Pd3 Pb@Pt Bifunctional Electrocatalyst for Ethanol Upgrading Coupled with Hydrogen Production

The ethanol oxidation reaction (EOR) is an attractive alternative to the sluggish oxygen evolution reaction in electrochemical hydrogen evolution cells. However, the development of high-performance bifunctional electrocatalysts for both EOR and hydrogen evolution reaction (HER) is a major challenge. Herein, the synthesis of Pd3 Pb@Pt core-shell nanocubes with controlled shell thickness by Pt-seeded epitaxial growth on intermetallic Pd3 Pb cores is reported. The lattice mismatch between the Pd3 Pb core and the Pt shell leads to the expansion of the Pt lattice. The synergistic effects between the tensile strain and the core-shell structures result in excellent electrocatalytic performance of Pd3 Pb@Pt catalysts for both EOR and HER. In particular, Pd3 Pb@Pt with three Pt atomic layers shows a mass activity of 8.60 A mg-1 Pd+Pt for ethanol upgrading to acetic acid and close to 100% of Faradic efficiency for HER. An EOR/HER electrolysis system is assembled using Pd3 Pb@Pt for both the anode and cathode, and it is shown that low cell voltage of 0.75 V is required to reach a current density of 10 mA cm-2 . The present work offers a promising strategy for the development of bifunctional catalysts for hybrid electrocatalytic reactions and beyond.

Length-tunable Pd2Sn@Pt core-shell nanorods for enhanced ethanol electrooxidation with concurrent hydrogen production

The electrooxidation of ethanol as an alternative to the oxygen evolution reaction presents a promising approach for low-cost hydrogen production. However, the design and synthesis of efficient ethanol oxidation electrocatalysts remain key challenges. Here, a colloidal procedure is developed to prepare Pd2Sn@Pt core-shell nanorods with an expanded Pt lattice and tunable length. The obtained Pd2Sn@Pt catalysts exhibit superior activity and stability for ethanol electrooxidation compared to Pd2Sn and commercial Pt/C catalysts. By tuning the length of the Pd2Sn@Pt nanorods, remarkable mass activity of up to 4.75 A mgPd+Pt-1 and specific activity of 20.14 mA cm-2 are achieved for the short nanorods owing to their large specific surface area. A hybrid electrolysis system for ethanol oxidation and hydrogen evolution is constructed using Pd2Sn@Pt as the anodic catalyst and Pt mesh as the cathode. The system requires a low cell voltage of 0.59 V for the simultaneous production of acetic acid and hydrogen at a current density of 10 mA cm-2. Density functional theory calculations further reveal that the strained Pt shell reduces energy barriers in the ethanol electrooxidation pathway, facilitating the conversion of ethanol to acetic acid. This work provides valuable guidance for developing highly efficient ethanol electrooxidation catalysts for integrated hydrogen production systems.

Abundant Exterior/Interior Active Sites Enable Three-Dimensional PdPtBiTe Dumbbells C-C Cleavage Electrocatalysts for Actual Alcohol Fuel Cells

Developing high-activity electrocatalysts is of great significance for the commercialization of direct alcohol fuel cells (DAFCs), but it still faces challenges. Herein, three-dimensional (3D) porous PdPtBiTe dumbbells (DBs) were successfully fabricated via the visible photoassisted method. The alloying effect, defect-rich surface/interface and nanoscale cavity, and open pores make the 3D PdPtBiTe DBs a comprehensive and remarkable electrocatalyst for the C1-C3 alcohol (ethanol, ethylene glycol, glycerol, and methanol) oxidation reaction (EOR, EGOR, GOR, and MOR, respectively) in an alkaline electrolyte, and the results of in situ Fourier transform infrared spectra revealed a superior C-C bond cleavage ability. The 3D PdPtBiTe DBs exhibit ultrahigh EOR, EGOR, GOR, and MOR mass activities of 25.4, 23.2, 16.8, and 18.3 A mgPd + Pt-1, respectively, considerably surpassing those of the commercial Pt/C and Pd/C. Moreover, the mass peak power densities of 3D PdPtBiTe DBs in actual ethanol, ethylene glycol, glycerol, or methanol fuel cells increase to 409.5, 501.5, 558.0, or 601.3 mW mgPd + Pt-1 in O2, respectively. This study provides a new class of multimetallic nanomaterials as state-of-the-art multifunctional anode electrocatalysts for actual DAFCs.