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Electroreduction is a promising approach to transform CO2, a greenhouse gas, into valuable hydrocarbons and could help mitigate the global warming effect. However, the high overpotential associated...

The chemical and structural properties of atomically precise nanoclusters are of great interest in numerous applications, but predicting the stable structures of clusters can be computationally expensive. In this work, we present a procedure for rapidly predicting low-energy structures of nanoclusters by combining a genetic algorithm with interatomic potentials actively learned on-the-fly. Applying this approach to aluminum clusters with 21 to 55 atoms, we have identified structures with lower energy than any reported in the literature for 25 out of the 35 sizes. Our benchmarks indicate that the active learning procedure accelerated the average search speed by about an order of magnitude relative to genetic algorithm searches using only density functional calculations. This work demonstrates a feasible way to systematically discover stable structures for large nanoclusters and provides insights into the transferability of machine-learned interatomic potentials for nanoclusters.

Solid–liquid interface, which is the location that electrochemical reaction occurs, is essential for CO2 reduction. However, different theoretical calculations often use different models of solid–liquid interface and predict conflicting mechanisms, e.g. for the formation of HCOOH. To address this issue, we adopt different structures of solid–liquid interface to mimic the reaction circumstance using density functional theory calculations. We find that the reaction barriers and energies are sensitive to the reaction circumstance, such as the state of water molecules, the number of water molecules, and the available surface sites, whereas the selectivity of CO2 reduction can be hardly changed once a water bilayer network on Cu surface is used. In particular, a solid–liquid interface built from 4-6-4 water rings (5H2O/1H) can present an appropriate description of the solvent, predicting the formation pathways of HCOOH in reasonable agreement with the experiments. These results confirm the role of water bilayer networks in describing solid–liquid interface in the electrocatalysis, which serves as an important basis for the future studies.

CO2 reduction has been pursued for decades as an effective way to produce useful fuels and to mitigate global warming at the same time. Methanol synthesis from CO2 hydrogenation over Cu-based catalysts plays an important role in the chemical and energy industries. However, fundamental questions regarding the reaction mechanism and key reaction intermediates of this process are still unclear. To address these issues, we studied the CO2 hydrogenation process using density functional theory (DFT) combined with van der Waals (vdW) force corrections, finding that the most effective pathway proceeds along the reaction series CO* → CHO* → CH2O* → CH2OH* → CH3OH* with the reactive intermediate CH2O*, which is consistent with experimental findings. Additionally, we find that water molecules play an inhibiting role in the reaction, while H bonds and vdW forces have an essential effect on the reaction mechanisms. These findings shed light on the reaction mechanism of CH3OH formation from CO2 hydrogenation and reveal the essence of H2O in this reaction, providing a useful basis for preceding studies.

It is crucial to understand the electrochemical HClO 4 /Pt(111) interface in the field of electrochemistry, which is unfortunately still disputed. To reveal the fundamental properties of this interface, we have studied co-adsorption of possible species at the HClO 4 /Pt(111) interface using density functional theory (DFT). Our calculations demonstrate that HClO 4 * is most likely to dissociate into ClO 4 * on Pt(111) surface, leading to an adlayer of ClO 4 * co-adsorbed with H 3 O* and H 2 O* molecules. Interestingly, these co-adsorbed H 3 O* molecules exhibit the nature of hydronium ions with highly localized positive charge states. On the other hand, the stability of this ClO 4 * co-adsorbed adlayer is almost equal to that of a H 2 O* + H 3 O* bilayer. This competition would prohibit the formation of periodic ClO 4 * + H 2 O* + H 3 O* adlayer on Pt(111), yielding a weak adsorption of ClO 4 * in electrochemical condition as the experiments found. In addition, the electrostatic potential along the direction that is perpendicular to the substrate exhibits clearly distinguishable peaks for the different interfacial structures. These results provide deep insights into this fundamental electrochemical interface and offer promising clues for future experimental studies.

Cu demonstrates a unique capability towards CO2 electroreduction that can close the anthropogenic carbon cycle; however, its reaction mechanism remains elusive, owing to the obscurity of the solid-liquid interface on Cu surfaces where electrochemical reactions occur. Using a genetic algorithm method in addition to density functional theory, we explicitly identify the configuration of a water bilayer on Cu(2 1 1) and build electrochemical models. These enable us to reveal a mechanistic picture for CO2 electroreduction, finding the key intermediates CCO* for the C2 H4 pathway and CH* for the CH4 pathway, which rationalize a series of experimental observations. Furthermore, we find that the interplay between the Cu surfaces, carbon monomers, and water network (but not the binding of CO*) essentially determine the unique capability of Cu towards CO2 electroreduction, proposing a new and effective descriptor for exploiting optimal catalysts.

The effects of water molecules (promotion/prohibition) on CO oxidation remain debated. Herein, using density functional theory calculations, we demonstrate that water molecules can facilitate the CO + O/O2 oxidation process, but prohibit the CO + OH oxidation process, which is consistent with the experimental finding that water molecules have two distinct effects on CO oxidation. For the CO + O/O2 oxidation mechanisms, we find that the reactants were pushed towards each other due to the steric effect of the water molecules, which decreases the reaction barriers and promotes the CO + O/O2 oxidation process. For the CO + OH oxidation mechanisms, water molecules increase the stability of the COOH* intermeditae by H-bonds and van der Waals forces, which increase the barriers of the COOH* transformation process and the COOH*-tra dissociation process, and prohibit the CO + OH oxidation process. These results clarify the different effects of water molecules on CO oxidation and shed light on catalyst usage in the CO oxidation industry.

The impact property of a high-strength grade 42CrMoE alloy steel was investigated under varied insert lengths using reconstitution method. A new full-field strain measurement method was employed to explore the plastic deformation region of the steel. Meanwhile, in order to quantitatively examine the insert length influence, an instrumented impact method was proposed to analysis the impact property. The results have successfully demonstrated that inserts equal to or larger than 20 mm can be used to obtain valid data for 42CrMoE.

Cu demonstrates a unique capability towards CO

The method to improve the loading and unloading efficiency of container ships was elaborated in this paper. New structure of bridge support liftable quay container crane, dual-jacklift quay container crane, dual-lifting quay container crane, high support base quay container crane and elevator quay container crane was applied to promote the performance of quay container crane. The working principle and characteristic of those new quay container cranes were analyzed in details.