Structure and reactivity of the Ru(0001) electrode towards fuel cell electrocatalysis

Dodecahedral W@WC Composite as Efficient Catalyst for Hydrogen Evolution and Nitrobenzene Reduction Reactions

Core-shell composites with strong phase-phase contact could provide an incentive for catalytic activity. A simple, yet efficient, H₂O-mediated method has been developed to synthesize a mesoscopic core-shell W@WC architecture with a dodecahedral microstructure, via a one-pot reaction. The H₂O plays an important role in the resistance of carbon diffusion, resulting in the formation of the W core and W-terminated WC shell. Density functional theory (DFT) calculations reveal that adding W as core reduced the oxygen adsorption energy and provided the W-terminated WC surface. The W@WC exhibits significant electrocatalytic activities toward hydrogen evolution and nitrobenzene electroreduction reactions, which are comparable to those found for commercial Pt/C, and substantially higher than those found for meso- and nano-WC materials. The experimental results were explained by DFT calculations based on the energy profiles in the hydrogen evolution reactions over WC, W@WC, and Pt model surfaces. The W@WC also shows a high thermal stability and thus may serve as a promising more economical alternative to Pt catalysts in these important energy conversion and environmental protection applications. The current approach can also be extended or adapted to various metals and carbides, allowing for the design and fabrication of a wide range of catalytic and other multifunctional composites.

An insight into methanol oxidation mechanisms on RuO2(100) under an aqueous environment by DFT calculations

In this work, we have studied methanol oxidation mechanisms on RuO₂(100) by using density functional theory (DFT) calculations and ab initio molecular dynamics (MD) simulations with some explicit interfacial water molecules. The overall mechanisms are identified as: CH₃OH* → CH₃O* → HCHO* → HCH(OH)₂* → HCHOOH* → HCOOH* → mono-HCOO* → CO₂*, without CO formation. This study provides a theoretical insight into C1 molecule oxidation mechanisms at atomic levels on metal oxide surfaces under an aqueous environment.

Methanol electro-oxidation at Ptx Ru(1–x)Oy electrodes — An in situ FTIR study

In this work we investigated the nature of the intermediates adsorbed during the electrooxidation of methanol on PtxRu(1–x)Oy electrodes, where 0.5 < x < 0.9, prepared by the decomposition of polymeric precursors. Thin layer electrodes with different compositions were prepared directly on a gold substrate by thermal decomposition of ethylene glycol – citric acid solutions containing the precursor salts at 400 °C. In situ IR reflectance spectra were obtained using the SPAIRS (single potential alteration infrared reflectance spectroscopy) and SNIFTIRS (subtractively normalized interfacial Fourier transform IR reflectance spectroscopy) techniques. For all the investigated compositions, the SNIFTIRS and SPAIRS spectra displayed three main bands, which were attributed to CO species in the linear (COL) and bridged (COB) forms adsorbed over Pt and linearly adsorbed over Ru. Formation of CO2 carbonyl species was also detected. The spectra features were analyzed in terms of the applied potential and they were compared with those reported for Pt–Ru electrodes prepared by other methods.Key words: methanol, electrocatalytic oxidation, in situ infrared reflectance spectroscopy, PtxRu(1–x)Oy, adsorption