Charge effect in S enhanced CO adsorption: A theoretical study of CO on Au, Ag, Cu, and Pd (111) surfaces coadsorbed with S, O, Cl, and Na

Quantitatively Determining Surface-Adsorbate Properties from Vibrational Spectroscopy with Interpretable Machine Learning

Learning microscopic properties of a material from its macroscopic measurables is a grand and challenging goal in physical science. Conventional wisdom is to first identify material structures exploiting characterization tools, such as spectroscopy, and then to infer properties of interest, often with assistance of theory and simulations. This indirect approach has limitations due to the accumulation of errors from retrieving structures from spectral signals and the lack of quantitative structure-property relationship. A new pathway directly from spectral signals to microscopic properties is highly desirable, as it would offer valuable guidance toward materials evaluation and design via spectroscopic measurements. Herein, we exploit machine-learned vibrational spectroscopy to establish quantitative spectrum-property relationships. Key interaction properties of substrate-adsorbate systems, including adsorption energy and charge transfer, are quantitatively determined directly from Infrared and Raman spectroscopic signals of the adsorbates. The machine-learned spectrum-property relationships are presented as mathematical formulas, which are physically interpretable and therefore transferrable to a series of metal/alloy surfaces. The demonstrated ability of quantitative determination of hard-to-measure microscopic properties using machine-learned spectroscopy will significantly broaden the applicability of conventional spectroscopic techniques for materials design and high throughput screening under operando conditions.

Octahedral gold-silver nanoframes with rich crystalline defects for efficient methanol oxidation manifesting a CO-promoting effect

Three-dimensional bimetallic nanoframes with high spatial diffusivity and surface heterogeneity possess remarkable catalytic activities owing to their highly exposed active surfaces and tunable electronic structure. Here we report a general one-pot strategy to prepare ultrathin octahedral Au₃Ag nanoframes, with the formation mechanism explicitly elucidated through well-monitored temporal nanostructure evolution. Rich crystalline defects lead to lowered atomic coordination and varied electronic states of the metal atoms as evidenced by extensive structural characterizations. When used for electrocatalytic methanol oxidation, the Au₃Ag nanoframes demonstrate superior performance with a high specific activity of 3.38 mA cm⁻², 3.9 times that of the commercial Pt/C. More intriguingly, the kinetics of methanol oxidation on the Au₃Ag nanoframes is counter-intuitively promoted by carbon monoxide. The enhancement is ascribed to the altered reaction pathway and enhanced OH⁻ co-adsorption on the defect-rich surfaces, which can be well understood from the d-band model and comprehensive density functional theory simulations.

Direct methanol fuel cells are promising for clean, sustainable energy, but catalysts should be optimized. Here the authors construct ultrathin nanoframes with rich crystalline defects to increase electrocatalytic activity of gold for methanol oxidation, which is surprisingly promoted by carbon monoxide.

Recent advances in the nanoengineering of electrocatalysts for CO2 reduction

Emissions of CO2 from fossil fuel combustion and industrial processes have been regarded as the dominant cause of global warming. Electrochemical CO2 reduction (ECR), ideally in aqueous media, could potentially solve this problem by the storage of energy from renewable sources in the form of chemical energy in fuels or value-added chemicals in a sustainable manner. However, because of the sluggish reaction kinetics of the ECR, efficient, selective, and durable electrocatalysts are required to increase the rate this reaction. Despite considerable progress in using bulk metallic electrodes for catalyzing the ECR, greater efforts are still needed to tackle this grand challenge. In this Review, we highlight recent progress in using nanoengineering strategies to promote the electrocatalysts for the ECR. Through these approaches, considerable improvements in catalytic performance have been achieved. An outlook of future developments in applying and optimizing these strategies is also proposed.

Electrode Build-Up of Reducible Metal Composites toward Achievable Electrochemical Conversion of Carbon Dioxide

At the beginning of the 21st century, our world is faced with a global-warming problem due to the continuous increase in carbon dioxide emission, and thus, the development of novel experimental techniques is needed. The electrochemical conversion of carbon dioxide into high-value organic compounds could be of vital importance to solve this issue. The biggest challenge has always been to develop an electrocatalyst that is chemically active and structurally stable. Herein, previous studies, recent approaches, and current points of view on the electrode structure of metal oxide composites for the advanced electrochemical conversion of carbon dioxide are reviewed.