Ambient pressure X-ray photoelectron spectroscopy during electrochemical promotion of ethylene oxidation over a bimetallic Pt–Ag/YSZ catalyst

The rise of the electrochemical NAPXPS operated in the soft X-ray regime exemplified in the oxygen evolution reaction on IrOx electrocatalysts

Photoelectron spectroscopy offers detailed information about of the electronic structure and chemical composition of surfaces owing to the short distance that the photoelectrons can escape from a dense medium. Unfortunately,...

Identification of the surface species in electrochemical promotion: ethylene oxidation over a Pt/YSZ catalyst

The electrochemical promotion of the C₂H₄ + O₂ total oxidation reaction over a Pt catalyst, interfaced to yttrium stabilized zirconia (YSZ), has been studied at 0.25 mbar and T = 650 K using near ambient pressure X-ray photoelectron spectroscopy (NAP-XPS) as an in situ method. The electrochemical promoter effect is linked to the presence of a several layers thick graphitic overlayer that forms on the Pt surface in the presence of C₂H₄. Our NAP-XPS investigation reveals that electrochemical pumping of the Pt/YSZ catalyst, using a positive potential, leads to the spillover of oxygen surface species from the YSZ support onto the surface of the Pt electrode. Based on the XP spectra, the spillover species on Pt is identical to oxygen chemisorbed from the gas-phase.

Effect of reduction temperature on the structure and catalytic performance of mesoporous Ni–Fe–Al2O3 in oxidative dehydrogenation of ethane

The effects of reduction temperature on the structure and catalytic performance of mesoporous Ni–Fe–Al₂O₃ are investigated for the first time.

Recent progress on synchrotron-based in-situ soft X-ray spectroscopy for energy materials

Soft X-ray spectroscopy (SXS) techniques such as photoelectron spectroscopy, soft X-ray absorption spectroscopy and X-ray emission spectroscopy are efficient and direct tools to probe electronic structures of materials. Traditionally, these surface sensitive soft X-ray techniques that detect electrons or photons require high vacuum to operate. Many recent in situ instrument developments of these techniques have overcome this vacuum barrier. One can now study many materials and model devices under near ambient, semi-realistic, and operando conditions. Further developments of integrating the realistic sample environments with efficient and high resolution detection methods, particularly at the high brightness synchrotron light sources, are making SXS an important tool for the energy research community. In this progress report, we briefly describe the basic concept of several SXS techniques and discuss recent development of SXS instruments. We then present several recent studies, mostly in situ SXS experiments, on energy materials and devices. Using these studies, we would like to highlight that the integration of SXS and in situ environments can provide in-depth insight of material's functionality and help researchers in new energy material developments. The remaining challenges and critical research directions are discussed at the end.