Theory-guided enhancement of CO2 reduction to ethanol on Ag-Cu tandem catalysts via particle-size effects

In the CO2 reduction reaction, the design of electrocatalysts that selectively promote alcohols over hydrocarbons (e.g., ethanol over ethylene) hinges on the understanding of the pathways and specific sites that forms alcohols. Herein, theoretical considerations guide state-of-the-art synthesis of well-defined catalysts to show that higher selectivity toward ethanol is achieved on Cu(110) edge sites compared to Cu(100) terraces. Specifically, we study the catalytic behavior of Cu nano-cubes (Cucub) of different sizes in the framework of tandem catalysis with CO-producing Ag nanospheres. We predict and experimentally find that the smaller Cucub possess higher selectivity for ethanol in view of their larger edge-to-faces ratio and of the fact that ethylene is produced at terraces while ethanol is selectively produced at step edges. These results call for synthetic developments toward Cu nanostructures exposing only edge sites, such as hollow cubic nanocages, to further increase ethanol selectivity. More generally, this study encourages the application of well-defined nano catalysts as a bridge between theory and experiments in electrocatalysis.This work was financially supported by Gaznat S.A. J.R.P. acknowledges the H2020 Marie Curie Individual Fellowship grant SURFCAT with Agreement No. 837378. This publication was created as part of NCCR Catalysis, a National Centre of Competence in Research funded by the Swiss National Science Foundation. The theoretical effort was supported by Spanish MICIUN’s RTI2018-095460–B-I00, Ramón y Cajal RYC-2015-18996, and María de Maeztu MDM-2017-0767 Grants, and partly by Generalitat de Catalunya via 2017SGR13. M.J.K. and F.C.V. are thankful to Red Española de Supercomputación (RES) for supercomputing time at SCAYLE (Projects QS-2019-3-0018, QS-2019-2-0023, and QCM-2019-1-0034). The use of supercomputing facilities at SURFsara was sponsored by NWO Physical Sciences

Assembly and photocarrier dynamics of heterostructured nanocomposite photoanodes from multicomponent colloidal nanocrystals

Multicomponent oxides and their heterostructures are rapidly emerging as promising light absorbers to drive oxidative chem. To fully exploit their functionality, precise tuning of their compn. and structure is crucial. Here, we report a novel soln.-based route to nanostructured bismuth vanadate (BiVO4) that facilitates the assembly of BiVO4/metal oxide (TiO2, WO3, and Al2O3) nanocomposites in which the morphol. of the metal oxide building blocks is finely tailored. The combination of transient absorption spectroscopy-spanning from picoseconds to second time scales-and photoelectrochem. measurements reveals that the achieved structural tunability is key to understanding and directing charge sepn., transport, and efficiency in these complex oxide heterostructured films

Clinical usefulness of microsatellite instability for the prediction of gastric adenoma or adenocarcinoma in patients with chronic gastritis

To assess a role of microsatellite instability (MSI) in the development of gastric adenocarcinoma or adenoma from chronic gastritis, we analysed mutations of five microsatellite loci in gastritis, adenoma and adenocarcinoma retrospectively. Gastric mucosa was biopsied from the same area in each patient at different periods and examined for MSI. Only one of 55 patients with chronic gastritis revealed MSI-H phenotype and the other 54 patients showed microsatellite stable (MSS) phenotypes. In six of 17 patients with gastric adenoma or well-differentiated adenocarcinoma, MSI-positive phenotypes were demonstrated. Interestingly, all of six patients showing MSI, including three high-level MSI (MSI-H) cases and three low-level (MSH-L) cases, had already revealed MSI at the stage of chronic gastritis. In two of three MSI-H cases, the identical MSI patterns had been observed at the stage of gastritis 1.5–7 years before the final diagnosis of adenocarcinoma. The adjacent gastritis mucosa within 10 mm from the carcinoma demonstrated MSI as well. MSI was not found in any of 35 patients with Helicobacter pylori infection, but found in one of 30 patients without infection. Moreover, two of three cases of gastric adenoma or well-differentiated adenocarcinoma with MSI-H at the stage of chronic gastritis showed no evidence of Helicobacter pylori infection throughout the observation periods. These results indicate that MSI in biopsy specimens at the stage of chronic gastritis may predict the risk of the progression to adenoma and well-differentiated adenocarcinoma, and that Helicobacter pylori infection itself may not induce MSI directly in the gastric mucosa. © 2000 Cancer Research Campaig

Synthesis and Photocatalytic Activity of Anatase TiO2 Nanoparticles-coated Carbon Nanotubes

A simple and straightforward approach to prepare TiO2-coated carbon nanotubes (CNTs) is presented. Anatase TiO2 nanoparticles (NPs) with the average size ~8 nm were coated on CNTs from peroxo titanic acid (PTA) precursor even at low temperature of 100 °C. We demonstrate the effects of CNTs/TiO2 molar ratio on the adsorption capability and photocatalytic efficiency under UV–visible irradiation. The samples showed not only good optical absorption in visible range, but also great adsorption capacity for methyl orange (MO) dye molecules. These properties facilitated the great enhancement of photocatalytic activity of TiO2 NPs-coated CNTs photocatalysts. The TiO2 NPs-coated CNTs exhibited 2.45 times higher photocatalytic activity for MO degradation than that of pure TiO2

2022 roadmap on low temperature electrochemical CO2 reduction

Electrochemical CO2 reduction (CO2R) is an attractive option for storing renewable electricity and for the sustainable production of valuable chemicals and fuels. In this roadmap, we review recent progress in fundamental understanding, catalyst development, and in engineering and scale-up. We discuss the outstanding challenges towards commercialization of electrochemical CO2R technology: energy efficiencies, selectivities, low current densities, and stability. We highlight the opportunities in establishing rigorous standards for benchmarking performance, advances in in operando characterization, the discovery of new materials towards high value products, the investigation of phenomena across multiple-length scales and the application of data science towards doing so. We hope that this collective perspective sparks new research activities that ultimately bring us a step closer towards establishing a low- or zero-emission carbon cycle.Catalysis and Surface Chemistr