Nonprecious metal (NPM) catalysts are considered as the most promising candidate to replace Pt‐based electrocatalysts for oxygen reduction reaction (ORR). However, in comparison with the commercial Pt catalyst, the development of high efficiency and low cost NPM catalysts for ORR still remains a big challenge. Here, a simple but efficient way to fabricate porous N‐doped graphene immobilized molybdenum nitride (MoN) nanoparticles is reported, and simultaneously, the introduction of H2O2 plays a key role in modulating the particle size of MoN and the microstructure of the composite to achieve different configuration. As results, it is shown that the as‐prepared material owns outstanding ORR activity and excellent stability in an alkaline medium. To the best knowledge, this catalyst possesses the best performance among the same class catalysts as reported. It is believed that the H2O2‐assisted strategy can provide new insights in synthesis of high efficient metal nitride/carbon hybrid materials toward advanced energy conversion and storage.

Yungang Grottoes in Shanxi, China, which represent outstanding example of Chinese outdoor immovable stone artifacts, are precious world cultural heritage. In the present study, the preparation and assessment of superhydrophobic hybrid coatings with photocatalytic activity on the sandstone substrate collected from Yungang were explored preliminarily. The protection efficiency of coating is investigated by measuring the water-stone contact angles, water vapor permeability, water absorption, and resistance to acid and salt corrosion. Results show that the superhydrophobic organic-inorganic hybrid coatings with photocatalytic and self-cleaning properties are highly suitable for the conservation of stone monuments.

No abstract

With the accelerating urbanization in developing countries, sustainable urban development has become a strategic goal for governments. To promote sustainable development of individual cities, it is necessary to break away from the limitations of administrative divisions and use the synergistic effect of urban clusters to solve the many difficulties facing sustainable development. The assessment of economic vitality is a critical way to evaluate the development potential of cities. This paper proposes a quantitative assessment method for urban economic vitality. Using 26 cities in the Yangtze River Delta region as the research object and local statistical yearbooks as the data source, we construct 18 urban economic vitality assessment indicators. First, we use the Principal Component Analysis (PCA) method to obtain the five major factors of city vitality assessment: manufacturing and people’s life factor, service industry and government management factor, industrial economic growth rate factor, urban development potential factor and primary and secondary industry efficiency factor. Then, we use spatial hotspot analysis to classify the urban economic vitality of the Yangtze River Delta region into three categories: low, medium and high. The research results have important implications for the coordinated and sustainable development of the regional economy and the formulation of economic development strategies for low-vitality regions.