This study aims to understand the knowledge, attitudes and practices of COVID-19 in the Chinese context and to provide insights for developing targeted outbreak prevention and control measures among the general public. We conducted an online survey of urban and rural residents in Henan Province. A total of 517 valid questionnaires were collected via the online platform. The mean scores for knowledge and practice were 5.57/9 and 2.04/3, respectively. More than 90% of the participants believed COVID-19 was serious and preventable, were concerned about the disease process, and actively engaged in learning related knowledge. Our results showed that the COVID-19 knowledge level was significantly different among groups with different ages, genders, education levels and marital statuses; COVID-19 practice was significantly different among different regions. Multiple linear regression analysis showed that education level, female sex, unmarried status, and health care worker status had a significant impact on COVID-19 knowledge; urban area was associated with a higher practice score; COVID-19 knowledge was significantly associated with residents' attitude toward preventive measures that can prevent COVID-19 infection; urban area was significantly related to the willingness to go to a fever clinic to check for suspected infection. We found that Chinese urban and rural residents held a moderate level of COVID-19 knowledge and practice and showed a positive attitude toward the disease. It is necessary to develop relevant education programs targeting the general population in China to improve COVID-19-related knowledge, attitudes and practices, particularly for rural and undereducated residents.

Exploring efficient and economical electrocatalysts for hydrogen evolution reaction is of great significance for water splitting on an industrial scale. Tungsten oxide, WO, has been long expected to be a promising non-precious-metal electrocatalyst for hydrogen production. However, the poor intrinsic activity of this material hampers its development. Herein, we design a highly efficient hydrogen evolution electrocatalyst via introducing oxygen vacancies into WO nanosheets. Our first-principles calculations demonstrate that the gap states introduced by O vacancies make WO act as a degenerate semiconductor with high conductivity and desirable hydrogen adsorption free energy. Experimentally, we prepared WO nanosheets rich in oxygen vacancies via a liquid exfoliation, which indeed exhibits the typical character of a degenerate semiconductor. When evaluated by hydrogen evolution, the nanosheets display superior performance with a small overpotential of 38 mV at 10 mA cm and a low Tafel slope of 38 mV dec. This work opens an effective route to develop conductive tungsten oxide as a potential alternative to the state-of-the-art platinum for hydrogen evolution.

Ultra-high temperature ceramics (UHTCs) are generally referred to the carbides, nitrides, and borides of the transition metals, with the Group IVB compounds (Zr & Hf) and TaC as the main focus. The UHTCs are endowed with ultra-high melting points, excellent mechanical properties, and ablation resistance at elevated temperatures. These unique combinations of properties make them promising materials for extremely environmental structural applications in rocket and hypersonic vehicles, particularly nozzles, leading edges, and engine components, etc. In addition to bulk UHTCs, UHTC coatings and fiber reinforced UHTC composites are extensively developed and applied to avoid the intrinsic brittleness and poor thermal shock resistance of bulk ceramics. Recently, highentropy UHTCs are developed rapidly and attract a lot of attention as an emerging direction for ultra-high temperature materials. This review presents the state of the art of processing approaches, microstructure design and properties of UHTCs from bulk materials to composites and coatings, as well as the future directions.