Arantxa Davó-Quiñonero

Polymer brushes are widely used to control the surface chemistry of substrates and selectively block or allow metal deposition on samples. Polymer brushes have advantages such as the possibility of conformal coatings and chemical binding to surfaces, thus improving stability. Despite progress in the application of polymer brushes such as poly­(methyl methacrylate) (PMMA) and polystyrene (PS) for area-selective deposition (ASD), brush removal and activation have not been widely investigated. Herein, we present a method to fabricate a stacked brush APTS-PS or APTS-PMMA composite and investigate brush removal with UV ozone (UVO) treatment and oxygen plasma ashing. We believe this work will lead to improved processing of brushes and allow for the advancement of the ASD field.

The CO₂ methanation process in the presence of CO is a catalytic challenge toward the abatement of CO₂ emissions from industrial exhaust gases with the goal of producing CH₄ as a clean fuel. Herein, the CO _x methanation mechanisms of a NiO-CeO₂ (Np) catalyst constituted by nickel oxide-cerium oxide nanoparticles with efficient operation under CO₂ and CO + CO₂ gas mixtures were addressed. In situ diffuse reflectance infrared Fourier-transform spectroscopy (DRIFTS) analyses and ¹³C¹⁸O₂ (49) pulse isotopic experiments reveal that solo CO₂ methanation and comethanation (CO + CO₂) present a common mechanism in which CO₂ is transformed into *CO, from where the reaction proceeds. According to our outputs, inlet CO interferes with the CO₂ methanation activity, delaying the reaction onset without selectivity impacts. Conversely, in the absence of CO₂, the solo CO methanation performance is remarkably limited with poor CH₄ selectivity. As demonstrated, the solo CO methanation mechanism is based on formates as key intermediates at low temperatures (2 production takes place onward. Near-ambient pressure X-ray photoelectron spectroscopy (NAP-XPS) analyses conducted in synchrotron revealed a higher degree of reduction in the catalyst when CO and H₂ are fed either alone or in combination with CO₂, attributed to the CO oxygen abstraction capacity from the CeO₂ phase. In the comethanation mixture, CO₂ and CO are balanced in oxidation–reduction processes, yielding the maximum CO _x conversion, while in the solo CO methanation, reductive processes prevail, limiting the CH₄ formation.