Mesozoic-Cenozoic Topographic Evolution of the South Tianshan (NW China): Insights from Detrital Apatite Geo-Thermochronological and Geochemical Analyses

The present-day topography of Tianshan is the product of repeated phases of Meso-Cenozoic intracontinental deformation and reactivation, whereas the long-term Mesozoic topographic evolution and the timing of the onset of Cenozoic deformation remain debated. New insights into the Meso-Cenozoic geodynamic evolution and related basin-range interactions in the Tianshan were obtained based on new detrital single-grain apatite U-Pb, fission-track, and trace-element provenance data from Mesozoic sedimentary sequences on the northern margin of the Tarim Basin. Detrital apatite U-Pb age data from Early-Middle Triassic clastic rocks show two prominent age populations at 500–390 Ma and 330–260 Ma, with a paucity of ages between 390 and 330 Ma, suggesting that sediment source is predominantly from the northern Tarim and South Tianshan. From the Late Triassic to Early Jurassic, the first appearance of populations in the 390–330 Ma and 260–220 age ranges indicates that the Central Tianshan-Yili Block and Western Kunlun Orogen were source regions for the northern margin of Tarim Basin. In the Cretaceous strata, south-directed paleocurrents combined with the decrease in the 390–330 Ma age population from the Central Tianshan-Yili Block imply that South Tianshan was uplifted and again became the main source region to the Baicheng-Kuqa depression during the Cretaceous. Our new apatite fission-track data from the southern Chinese Tianshan suggest that rapid cooling commenced at c. 30 Ma along the southern margin, and the Early Mesozoic strata exposed on the southern flank of the Tianshan underwent c. 4–5 km of late Cenozoic exhumation during this period. This age is approximately synchronous with the onset of exhumation/deformation not only in the whole Tianshan but also in the interior of the Tibetan Plateau and its margins. It suggests that far-field, N-directed shortening resulting from the India-Asia collision was transmitted to the Tianshan at that time

Cationic Copper Species Stabilized by Zinc during the Electrocatalytic Reduction of CO2 Revealed by In Situ X‐Ray Spectroscopy

Advanced in situ X-ray absorption spectroscopy characterization of electrochemically co-electrodeposited bi-element copper alloy electrodes shows that zinc yields the formation of a stable cationic Cu species during the electroreduction of CO2 at high cathodic polarization. In contrast, the formation/stabilization of cationic Cu species in copper oxides, or doping Cu with another element, like Ni, is not possible. It is found that the pure and mixed Cu:Zn electrodes behave similarly in term of electrocatalytic selectivity to multi-carbon products. At higher Zn concentrations the electrode behaves like the pure Zn catalyst, which indicates that the Cu cationic species do not have a significant influence on the selectivity to multi-carbon products. It is found that in the non-monotonically distribution of products is dominated in term of surface energy in which copper prefers the surface. Otherwise, this work highlights the importance of in situ characterization to uncover the mechanisms mediating the catalytic reactions in contrast to ex situ or post mortem analysis, which can be a source of misinterpretation

Assessment of the Degradation Mechanisms of Cu Electrodes during the CO

Catalyst degradation and product selectivity changes are two of the key challenges in the electrochemical reduction of CO on copper electrodes. Yet, these aspects are often overlooked. Here, we combine X-ray spectroscopy, electron microscopy, and characterization techniques to follow the long-term evolution of the catalyst morphology, electronic structure, surface composition, activity, and product selectivity of Cu nanosized crystals during the CO reduction reaction. We found no changes in the electronic structure of the electrode under cathodic potentiostatic control over time, nor was there any build-up of contaminants. In contrast, the electrode morphology is modified by prolonged CO electroreduction, which transforms the initially faceted Cu particles into a rough/rounded structure. In conjunction with these morphological changes, the current increases and the selectivity changes from value-added hydrocarbons to less valuable side reaction products, , hydrogen and CO. Hence, our results suggest that the stabilization of a faceted Cu morphology is pivotal for ensuring optimal long-term performance in the selective reduction of CO into hydrocarbons and oxygenated products

Selective CO2 electroreduction over an oxidederived gallium catalyst

The electrochemical CO2 reduction reaction (CO2RR) powered by renewable electricity has emerged as a promising approach to alleviate global warming and energy depletion simultaneously. Notably, efficient catalysts containing Earth-abundant elements to achieve high CO2RR performance are in great demand for future applications. Herein, carbon-supported gallia gel nanoparticles were synthesized by precipitating gallium nitrate on carbon black in an ethanolic ammonia solution. Nano-sized gallia nanoparticles uniformly dispersed on the carbon support achieved a maximum CO faradaic efficiency of 77.0% at -0.71 V vs. the reversible hydrogen electrode (RHE) in CO2-saturated 0.1 M KHCO3 solution, showing a dramatic improvement compared to a bulk Ga electrode with only 24.2% CO faradaic efficiency at -0.80 V vs. RHE. X-ray photoelectron spectroscopy measurements revealed that surface Ga3+ species were reduced to metallic Ga when subjected to a negative potential during the CO2RR, indicative of the formation of oxide-derived active gallium sites. Control experiments further highlighted the necessity of close coalescence between the nano-sized gallia particles and the conductive carbon support. The present study underscores the feasibility of improving the CO2RR performance of Ga-related materials through nanostructuring of oxide-derived gallium catalysts

Improved CO₂ Electroreduction Performance on Plasma-Activated Cu Catalysts via Electrolyte Design: Halide Effect

As a sustainable pathway for energy storage and to close the carbon cycle, CO₂ electroreduction has recently gained significant interest. We report here the role of the electrolyte, in particular of halide ions, on CO₂ electroreduction over plasma-oxidized polycrystalline Cu foils. It was observed that halide ions such as I^– can induce significant nanostructuring of the oxidized Cu surface, even at open circuit potential, including the formation of Cu crystals with well-defined shapes. Furthermore, the presence of Cl^–, Br^–, and I^– was found to lower the overpotential and to increase the CO₂ electroreduction rate on plasma-activated preoxidized Cu catalyst in the order Cl^– < Br^– < I^–, without sacrificing their intrinsically high C₂–C₃ product selectivity (∼65% total Faradaic efficiency at −1.0 V vs RHE). This enhancement in catalytic performance is mainly attributed to the specific adsorption of halides with a higher coverage on our oxidized Cu surface during the reaction, which have been previously reported to facilitate the formation and stabilization of the carboxyl (*COOH) intermediate by partial charge donation from the halide ions to CO₂

Dynamic Changes In The Structure, Chemical State And Catalytic Selectivity Of Cu Nanocubes During Co2 Electroreduction: Size And Support Effects

In situ and operando spectroscopic and microscopic methods were used to gain insight into the correlation between the structure, chemical state, and reactivity of size- and shape-controlled ligand-free Cu nanocubes during CO2 electroreduction (CO2RR). Dynamic changes in the morphology and composition of Cu cubes supported on carbon were monitored under potential control through electrochemical atomic force microscopy, X-ray absorption fine-structure spectroscopy and X-ray photoelectron spectroscopy. Under reaction conditions, the roughening of the nanocube surface, disappearance of the (100) facets, formation of pores, loss of Cu and reduction of CuOx species observed were found to lead to a suppression of the selectivity for multi-carbon products (i.e. C2H4 and ethanol) versus CH4. A comparison with Cu cubes supported on Cu foils revealed an enhanced morphological stability and persistence of CuI species under CO2RR in the former samples. Both factors are held responsible for the higher C2/C1 product ratio observed for the Cu cubes/Cu as compared to Cu cubes/C. Our findings highlight the importance of the structure of the active nanocatalyst but also its interaction with the underlying substrate in CO2RR selectivity

The functions of SET domain bifurcated histone lysine methyltransferase 1 (SETDB1) in biological process and disease

Abstract Histone methyltransferase SETDB1 (SET domain bifurcated histone lysine methyltransferase 1, also known as ESET or KMT1E) is known to be involved in the deposition of the di- and tri-methyl marks on H3K9 (H3K9me2 and H3K9me3), which are associated with transcription repression. SETDB1 exerts an essential role in the silencing of endogenous retroviruses (ERVs) in embryonic stem cells (mESCs) by tri-methylating H3K9 (H3K9me3) and interacting with DNA methyltransferases (DNMTs). Additionally, SETDB1 is engaged in regulating multiple biological processes and diseases, such as ageing, tumors, and inflammatory bowel disease (IBD), by methylating both histones and non-histone proteins. In this review, we provide an overview of the complex biology of SETDB1, review the upstream regulatory mechanisms of SETDB1 and its partners, discuss the functions and molecular mechanisms of SETDB1 in cell fate determination and stem cell, as well as in tumors and other diseases. Finally, we discuss the current challenges and prospects of targeting SETDB1 for the treatment of different diseases, and we also suggest some future research directions in the field of SETDB1 research

High-density iron nanoparticles encapsulated within nitrogen-doped carbon nanoshell as efficient oxygen electrocatalyst for zinc-air battery

Exploring highly efficient electrocatalysts toward oxygen reduction and evolution reactions are critical for the development of rechargeable zinc air batteries. As a novel class of electrocatalyst, transition metal nanoparticles encapsulated within nitrogen-doped carbon have been regarded as competitive alternative to replace noble metal electrocatalysts. Herein, we report successful synthesis of high-density iron nanoparticles encapsulated within nitrogen-doped carbon nanoshell (Fe@N-C) by solid-phase precursor's pyrolysis of dicyandiamide and ammonium ferric citrate. The resulting Fe@N-C material shows excellent bifunctionality for ORR and OER in alkaline medium compared to state-of-the-art commercial Pt/C and IrO2, which demonstrates high performance and cycling durability in zinc air battery as efficient oxygen electrocatalyst. (C) 2015 Published by Elsevier Ltd

Electrocatalytic reduction of carbon dioxide over reduced nanoporous zinc oxide

Nanoporous zinc oxide (ZnO) is prepared by a hydrothermal method followed by thermal decomposition for electrocatalytic reduction of CO2. In situ X-ray absorption spectroscopy results indicate that ZnO is reduced to Zn under the electrolysis conditions for catalyzing CO2 electroreduction. The reduced nanoporous ZnO exhibits obviously higher CO Faradaic efficiency and current density than commercial Zn foil with a maximum CO Faradaic efficiency of 92.0%, suggesting that the nanoporous structure facilitates electrocatalytic reduction of CO2 over reduced nanoporous ZnO, probably due to increased surface area and more coordination unsaturated surface atoms. (C) 2016 Elsevier B.V. All rights reserved