Double-atom catalysts for energy-related electrocatalysis applications: a theoretical perspective

Due to the excellent activity, selectivity, and stability, atomically dispersed metal catalysts with well-defined structures have attracted intensive research attention. As the extension of single-atom catalyst (SAC), double-atom catalyst (DAC) has recently emerged as a research focus. Compared with SAC, the higher metal loading, more complicated and flexible active site, easily tunable electronic structure, and the synergetic effect between two metal atoms could provide DACs with better catalytic performance for a wide range of catalytic reactions. This review aims to summarize the recent advance in theoretical research on DACs for diverse energy-related electrocatalytic reactions. It starts with a brief introduction to DACs. Then an overview of the main experimental synthesis strategies of DACs is provided. Emphatically, the catalytic performance together with the underlying mechanism of the different electrocatalytic reactions, including nitrogen reduction reaction, carbon dioxide reduction reaction, oxygen reduction reaction, and oxygen and hydrogen evolution reactions, are highlighted by discussing how the outstanding attributes mentioned above affect the reaction pathway, catalytic activity, and product selectivity. Finally, the opportunities and challenges for the development of DACs are prospected to shed fresh light on the rational design of more efficient catalysts at the atomic scale in the future.

Synergetic Effect of Physical Activity and Fruit-vegetable Intake on the Decreasing of Cognitive Decline in Older Taiwanese

Factors which are associated with cognitive decline among elders include physical activity and the intake of fruit and vegetable, however, long-term effects and the concurrence of physical activity and fruit-vegetable intake are unknown. The present study explores this potential synergy for the mitigation of cognitive decline among a cohort of older Taiwanese in a 16-year longitudinal study. Five population-based surveys from the Taiwan Longitudinal Survey on Aging (1995–2015) involving 4,440 respondents over 53 years old in 1999 were studied. Trends in decrease of cognitive decline were observed for 16 years. Cognitive function was assessed using the Short Portable Mental Status Questionnaire (SPMSQ). Adjustments made on regression analysis included demographic, socioeconomic, health behavioral, and disease status covariates. The risk of cognitive decline decreased 63% when high physical activity group and high intake of fruit-vegetable group were combined (OR :0.37, 95% CI: 0.23–0.59). More physical activity was combined with greater fruit-vegetable intake, cognitive decline among older Taiwanese was mitigated. This indicates that there may be a synergistic effect of physical activity and fruit-vegetable intake on mitigating cognitive decline. Synergistic personal behavior is a safe, effective, and economical approach to health in later life.

RURAL TERRITORIES AS A SYSTEM OF INTERACTION OF ECONOMIC AND SOCIAL PROCESSES

The article deals with the problems of interaction of economic and social processes in rural municipal areas, which is a determining factor in the quality of life of the rural population. The aim is to study on the basis of constructive simplification of the territorial system the allocation of its subsystems for separate study. The criterion for such allocation is to take into account the main links considered by the economic and social subsystems with the structure of the system as a whole. Rural territory can be represented in the form of interconnected spatial subsystems of the following: agricultural production, household, service, transport and information communications. At the same time, the potential for consumption of material and spiritual goods can be considered from the standpoint of three types of social accessibility: material, spiritual and spatial-temporal. It is revealed that the main disproportions in the modern development of rural areas are the disproportions between the potential of consumption, on the one hand, and the level of actual availability of material and spiritual goods, on the other. To eliminate these imbalances, it is advisable to use system analysis tools that allow you to obtain the necessary information about the interaction of social and economic factors. At the same time, the study of current trends in the interaction of economic and social processes that determine the standard of living of the rural population shows that the placement of capital investments within a rural municipal district should be based on a comprehensive cost-effectiveness analysis, since the evaluation of the effectiveness of investments for individual objects does not take into account the interrelationships, interaction and synergetic effect of socio-economic factors affecting the qual

Varying electrical and dielectric properties of Ni:SnO2 films by MWCNTs and GNPs coating

In this research, pure SnO2 and Ni-doped SnO2 (Ni:SnO2) nanocomposite films were produced by chemical bath deposition method and the latter were coated with multi-walled carbon nanotubes (Ni:SnO2/MWCNTs) or graphene nanoplatelets (Ni:SnO2/GNPs) by spin coating. All samples have tetragonal rutile SnO2 structure with the presence of carbon (002) peak in MWCNTs- or GNPs-coated films. Crystallite size of SnO2 films decreased remarkably with Ni doping followed by a slight decrease with MWCNTs coating and slight increase with GNPs coating. Scanning electron microscope images manifested a dispersed agglomerative nature of SnO2 nanoparticles which reduced especially with MWCNTs coating due to the porous surface provided by carbon nanotubes. From the photoluminescence measurements, oxygen defects-related peaks were spotted in the SnO2-based structures with different luminescence intensities. The most significant decrease in resistance was observed with the addition of GNPs into Ni-doped SnO2 nanocomposites compared to the other produced films mainly due to the synergetic effect that promotes excellent charge transfer between surfaces of Ni:SnO2 and graphene nanosheet. The huge increase in conductivity of GNPs-coated films led to a huge increase in dielectric losses and this followed by a drop down of dielectric constant of the GNPs-coated films.

Rapid Synthesis of Nickel Boride/Graphene by Microwave Thermal Shock and its Application in Hydrogen Evolution Reaction

The urgent demand for sustainable and clean energy has promoted the development of water splitting. Herein, metal borides assisted synthesis of graphene-based material (Ni-B/G) has been carried out by facile and fast microwave heating method and applied to hydrogen evolution reaction (HER) in alkaline solution. The Ni-B combining with 2D graphene give rise to highly efficient HER performance with low overpotential of 187 mV at current density of 10 mA cm−2. In addition, it exhibits good stability and retains 76% of current density after continuous oxygen release. The excellent performance is ascribed to the synergetic effect of Ni-B and graphene. The Ni-B not only acts as initiator to adsorb microwave energy but also works as active centre of catalyst. The high conductivity and large specific area of graphene offer accessible contact between electrolyte and intermediates. Therefore, Ni-B/G indicates a promising candidate for HER in alkaline media.

The synergetic effect of aqua ligand and metal site on performance of single-atom catalysts in H2O2 synthesis: a Density Functional Theory Study

To study the effect of coordination field on catalytic property is critical for rational design of outstanding electrocatalyst for H2O2 synthesis. Herein, via density functional theory calculations, we built an...