Evidence for an active oxygen species on Au/TiO2(110) model catalysts during investigation with in situ X-ray photoelectron spectroscopy

Beam-Induced Effects on Platinum Oxidation during Ambient-Pressure X-ray Photoelectron Spectroscopy

Ambient-pressure X-ray photoelectron spectroscopy (APXPS) is commonly used to identify active phases of Pt-based catalysts. Unavoidable beam-induced chemistry under in situ conditions with high-flux X-rays is important yet has often been disregarded. To evaluate beam effects on Pt oxidation, we revisited surface species on Pt(111) and Pt(110) in O₂ environments using APXPS. The observed X-ray-induced phenomena strongly depended on pressure and surface orientation. Below 1 mbar of O₂, we found only chemisorbed oxygen species on both surfaces. No significant change in Pt(111) was observed with long-time illumination under ≤2 mbar of O₂. Under ∼5 mbar with similar oxygen exposure, beam-induced oxidation was apparent on Pt(111) with the formation of abundant surface oxide and chemisorbed oxygen. However, such beam-induced oxidation was strongly suppressed on Pt(110). Understanding these "pressure gap" and surface orientation-dependent beam-induced phenomena is essential for our interpretation of the in situ X-ray results, particularly for higher-pressure experiments with brighter synchrotron sources.

Present and new frontiers in materials research by ambient pressure x-ray photoelectron spectroscopy

In this topical review we catagorise all ambient pressure x-ray photoelectron spectroscopy publications that have appeared between the 1970s and the end of 2018 according to their scientific field. We find that catalysis, surface science and materials science are predominant, while, for example, electrocatalysis and thin film growth are emerging. All catalysis publications that we could identify are cited, and selected case stories with increasing complexity in terms of surface structure or chemical reaction are discussed. For thin film growth we discuss recent examples from chemical vapour deposition and atomic layer deposition. Finally, we also discuss current frontiers of ambient pressure x-ray photoelectron spectroscopy research, indicating some directions of future development of the field.

Oxidation modification of Ru-based catalyst for acetylene hydrochlorination

Oxidation modification enhances the interaction between the oxygenated functional groups and Ru species, strengthens the adsorption of reactants, and augments the amount of active species, enhancing the catalytic performance of the catalysts.

Non-mercury catalytic acetylene hydrochlorination over activated carbon-supported Au catalysts promoted by CeO2

Gold–cerium oxide catalysts were prepared to study the effects of cerium oxide additives on the catalytic performance of gold catalysts for acetylene hydrochlorination, using activated carbon as the support.

Effects of nitrogen-dopants on Ru-supported catalysts for acetylene hydrochlorination

A series of N-doped spherical active carbons were synthesizedviathe pyrolysis of melamine in activated carbon, and used as a support to prepare Ru-based catalysts for an acetylene hydrochlorination reaction.

Ru/N-AC catalyst to produce vinyl chloride from acetylene and 1,2-dichloroethane

N and Ru species in the Ru/N-AC catalyst can adsorb and activate EDC and acetylene, respectively, generating a synergistic effect.

Non-mercury catalytic acetylene hydrochlorination over bimetallic Au–Ba(ii)/AC catalysts

Ba(ii) additives well disperse and inhibit the reduction of Au, and strengthen the reactants adsorption, improving the catalysts' catalytic performance.

Activated carbon supported ternary gold–cesium(i)–indium(iii) catalyst for the hydrochlorination of acetylene

Promoting the effect of indium(iii) on activated carbon supported gold–cesium(i) catalyst in acetylene hydrochlorination.