Interstitial Hydrogen Atom Modified PdPt Nanosheets for Efficient Ethanol Electro-oxidation with High C–C Bond Cleavage Selectivity

Abstract

Direct ethanol fuel cells (DEFCs) are a type of promising portable power source with low environmental pollution and high energy density. However, the further commercialization of DEFCs is hindered by the incomplete oxidation of ethanol on the electrocatalysts. Herein, we report a successful synthesis of ultrathin PdPtH nanosheets (NSs) for the first time by the in situ formation of interstitial hydrogen atoms accompanied by wet-chemical coreduction of Pd and Pt precursors. The PdPtH NSs possess selectivity of 15.1% related to C–C bond splitting for ethanol complete oxidation to CO2 through the C1 pathway at a low potential, while the contrast selectivity is 4.8% for Pt black, 9.2% for commercial Pd black, and 11.7 for PdH NSs, respectively. Accordingly, the PdPtH NSs exhibited enhanced catalytic activity in comparison to the counterparts. The mass activity toward ethanol oxidation reaction (EOR) of the PdPtH NSs is 5.2 times and 87 times higher than that of commercial Pd and commercial Pt, respectively. The structure stability and growth mechanism of the PdPtH NSs were also investigated. The results of in situ Fourier transform infrared spectra revealed a stronger C–C bond cleavage ability and CO stripping shows the better antipoisoning properties of the PdPtH NSs arising from the cooperation of the PdPt alloy with interstitial H atoms.

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

“…In ethanol oxidation, with the increase of voltage, the intensity of consumption of ethanol and OH – is more obvious, and more acetate is produced (Figure a). The band at 1348 cm –1 is the stretching vibration of the methyl group in acetate, while the bands at 1413 and 1550 cm –1 belong to the symmetric and antisymmetric stretching of the C–O bond in the acetate. − The peak intensity at 1413 cm –1 is stronger than that at 1550 cm –1 , which is due to the superposition with carbonate at approximately 1390 cm –1 , and carbon dioxide (CO 2 ) can be detected at 2345 cm –1 at 1.1 V, indicating that the C–C bond in ethanol is broken (Figure d) (CH 3 CH 2 OH – 12e – + 16OH – → 2CO 3 2– + 11 H 2 O). − In EGOR, PdPtBiTe/C detects signals from low potential at 0.4 V, which is consistent with the fast dynamics in Figure b. The bands at 1076, 1238, 1326, and 1575 cm –1 are attributed to glycolate.…”

Recent advances of H-intercalated Pd-based nanocatalysts for electrocatalytic reactions

“…4). 59 The PdPtH nanosheets show a high selectivity of 15.1% related to C–C bond splitting for the EOR to CO 2 through the C1 pathway at a low potential.…”

“…[48][49][50][51] In recent years, modifying the electronic structure of Pd has paved another pathway for substantially enhancing their electrocatalytic performance. [52][53][54][55][56][57][58][59][60] Incorporating H atoms into Pd lattice can tailor the d-band center of Pd and accelerate the reaction kinetics by weakening the bond between the catalyst and reaction intermediate. 61,62 Kabiraz and coworkers have demonstrated that β-PdH cubes and octahedra could deliver enhanced catalytic activity and stability for MOR, due to the ligand effect originating from the interstitial alloying of β-PdH.…”

Facile electrolysis-solvothermal synthesis of NiOx/graphene for enhanced ethanol oxidation to acetate

“…4 It is now generally accepted that electrochemical ethanol oxidation reaction (EOR) might follow a dual-pathway mechanism, including the C 1 reaction pathway with complete ethanol oxidation and the C 2 route with the preservation of the C-C bond. [5][6][7] The C 1 pathway involves a 12-electron transfer per molecular unit, which is preferred in improving the energy density of direct ethanol fuel cells (DEFCs). [8][9][10] However, the commercialization of DEFCs still faces some challenges: (1) the cleavage of the C-C bond requires noble metal catalysts such as Rh and Pt/Rh/SnO 2 , 11,12 Rh can even dissociate the C-C bond at open circuit potential in an alkaline solution.…”