Graphite carbon nitride (g-C N ) is a promising candidate for photocatalytic hydrogen production, but only shows moderate activity owing to sluggish photocarrier transfer and insufficient light absorption. Herein, carbon quantum dots (CQDs) implanted in the surface plane of g-C N nanotubes were synthesized by thermal polymerization of freeze-dried urea and CQDs precursor. The CQD-implanted g-C N nanotubes (CCTs) could simultaneously facilitate photoelectron transport and suppress charge recombination through their specially coupled heterogeneous interface. The electronic structure and morphology were optimized in the CCTs, contributing to greater visible light absorption and a weakened barrier of the photocarrier transfer. As a result, the CCTs exhibited efficient photocatalytic performance under light irradiation with a high H production rate of 3538.3 μmol g h and a notable quantum yield of 10.94 % at 420 nm.

Purpose This study aims to explore the factors influencing the post-pandemic intentions of Chinese residents to participate in outbound travel. The mechanism by which residents' perception of the coronavirus disease (COVID-19) influenced their outbound travel intentions are studied. Design/methodology/approach This study developed an extended theory of planned behavior (TPB) model and used structural equations to analyze data received from 432 questionnaires. Responses were obtained through a combination of online surveys and a traditional paper-based distribution of questionnaires. Findings Results showed that attitude, subjective norms, perceived behavioral control and past outbound travel behavior have significant positive effects on post-pandemic outbound travel intentions. Although the perception of COVID-19 directly and negatively influences outbound travel intentions, it also has an indirect influence on outbound travel intentions through the mediating effect of non-pharmaceutical interventions. The authors also found that risk tolerance has a negative moderating effect on the direct impact of residents' perception of COVID-19 on their travel intentions. Practical implications The findings can serve as a reference for formulating appropriate tourism development policies by government agencies, tourism management departments and tourism enterprises in destination countries. Originality/value This study developed an extended TPB model by adding more constructs into the TPB model. Compared with the original TPB model, the extended TPB model has better explanatory power of post-pandemic travel intentions. The study also provides evidence for the applicability of the TPB model in studying travel intentions within the context of major public health emergencies and has expanded the application scope of the TPB model.

The increase of reaction temperature of electrocatalysts is regarded as an efficient method to improve the oxygen evolution reaction (OER) activity. Herein, it is reported that the electrocatalytic performance of dual functional (i.e., electrocatalytic and photothermal functions) Co3O4 can be dramatically improved via its photothermal effect. The operating temperature of the Co3O4 electrode is elevated in situ under near infrared (NIR) light irradiation, resulting in enhanced oxygen evolution activity due to its accelerated electrical conductivity, reaction kinetics, and desorption rate of O2 bubbles from the electrode. In addition, photothermal effect can also enhance the electrocatalytic reaction rates of metal‐doped Co3O4 electrodes, indicating that it is able to significantly improve the OER activities of electrodes together with other modification strategies. With the assistance of the photothermal effect, the obtained Ni‐doped Co3O4 catalyst requires an extremely low overpotential of 208 mV to achieve a benchmark of 10 mA cm−2 with a small Tafel slope, superior to most reported Co‐based catalysts. Significantly, the electrocatalytic performance of other electrodes with photothermal effect, such as CoN, CoP, and CoS, are also boosted under NIR light irradiation, indicating opportunities for implementing photothermal enhancement in electrocatalytic water splitting.

The utilization of sunlight to drive energy conversion via photocatalysis is a promising approach to pursue a sustainable future. In the past decade, the research of photocatalysts has been shifted from inorganic to abundant organic polymeric catalysts. Polymeric carbon nitride (PCN) has emerged as a promising photocatalyst for solar energy conversion on account of its superior physicochemical properties. However, its practical applications are still hindered by several limitations, including high-charge recombination probability and weak visible-light absorption, etc. As a result of facile structure modifications at the nano-and molecular levels, the structure engineering of PCN has been proven as an efficient solution. This review highlights a panorama of the latest research advancements regarding the structure engineering of PCN at the nano-and molecular scales. A perspective about the challenges and future trends in the structure engineering and applications of PCN is provided at the end of the review.

A granular clock is observed in a vertically vibrated compartmentalized granular gas composed of two types of grains with the same size. The dynamics of the clock is studied in terms of an unstable evaporation or condensation model for the granular gas. In this model, the temperatures of the two types of grains are considered to be different, and they are functions of the composition of the gas. Oscillations in the system are driven by the asymmetric collisions properties between the two types of grains. Both our experiments and model show that the transition of the system from a homogeneous state to an oscillatory state is via a Hopf bifurcation.