Xin Zhao

Saliency prediction has been extensively studied for natural images. In the area of video coding and video quality assessment, researchers attempt to integrate a saliency model to individual frames of a video sequence. In selecting best-performing saliency models for these applications, the evaluation only considers the average model performance over all frames of a video. This may mask the defects of a saliency model and consequently hinder further improvement of the model. In this paper, we present the identification of pitfalls in the evaluation of saliency models for videos. We demonstrate the importance of considering the video content classification and temporal effect. Building on the findings, we make recommendations for saliency model evaluation and selection for videos.

The effect of metal surface nanomorphology on the output performance of a TENG

Plastics are now indispensable in daily lives. However, the pollution from plastics is also increasingly becoming a serious environmental issue. Recent years have seen more sustainable approaches and technologies, commonly known as upcycling, to transform plastics into value‐added materials and chemical feedstocks. In this review, the latest research on upcycling is presented, with a greater focus on the use of renewable energy as well as the more selective methods to repurpose synthetic polymers. First, thermal upcycling approaches are briefly introduced, including the redeployment of plastics for construction uses, 3D printing precursors, and lightweight materials. Then, some of the latest novel strategies to deconstruct condensation polymers to monomers for repolymerization or introduce vulnerable linkers to make the plastics more degradable are discussed. Subsequently, the review will explore the breakthroughs in plastics upcycling by heterogeneous and homogeneous photocatalysis, as well as electrocatalysis, which transform plastics into more versatile fine chemicals and materials while simultaneously mitigating global climate change. In addition, some of the biotechnological advances in the discovery and engineering of microbes that can decompose plastics are also presented. Finally, the current challenges and outlook for future plastics upcycling are discussed to stimulate global cooperation in this field.

Forming a Bi₂O₄/BiVO₄ heterojunction can effectively improve the activity and stability of BiVO₄ for water splitting reactions.

Efficient clean energy harvesting, conversion, and storage technologies are of immense importance for the sustainable development of human society. To this end, scientists have made significant advances in recent years regarding new materials and devices for improving the energy conversion efficiency for photovoltaics, thermoelectric generation, photoelectrochemical/electrolytic hydrogen generation, and rechargeable metal ion batteries. The aim of this Special Issue is to provide a platform for research scientists and engineers in these areas to demonstrate and exchange their latest research findings. This thematic topic undoubtedly represents an extremely important technological direction, covering materials processing, characterization, simulation, and performance evaluation of thin films used in energy harvesting, conversion, and storage.

Ni₅P₄ has received considerable attention recently as a potentially viable substitute for Pt as the cathode material for catalytic water splitting. The current investigation focuses on theoretical understandings of the characteristics of active sites toward water splitting using first-principle calculations. The results indicate that the activity of bridge NiNi sites is highly related on the bond number with neighbors. If the total bond number of NiNi is higher than 14, the sites will exhibit excellent HER performance. For the top P sites, the activity is greatly affected by the position of coplanar atoms besides the bond number. Data of bond length with neighbors can be used to predict the activity of P sites as reviewed by machine learning. Partial density of state (PDOS) analysis of different P sites illustrates that the activity of P sites should form the appropriate bond to localize some 3p orbits of the P atoms. Bond number and position of neighbors are two key parameters for the prediction of the HER activity. Based on the current work, most of the low-energy surfaces of Ni₅P₄ are active, indicating a good potential of this materials for hydrogen evolution reactions.

This review presents the latest processes for designing anode materials to improve the efficiency of water photolysis. Based on different contributions towards the solar-to-hydrogen efficiency, we mainly review the strategies to enhance the light absorption, facilitate the charge separation, and enhance the surface charge injection. Although great achievements have been obtained, the challenges faced in the development of anode materials for solar energy to make water splitting remain significant. In this review, the major challenges to improve the conversion efficiency of photoelectrochemical water splitting reactions are presented. We hope that this review helps researchers in or coming to the field to better appreciate the state-of-the-art, and to make a better choice when they embark on new research in photocatalytic water splitting.

The effect of oxygen vacancies (V_O) on α-Fe₂O₃ (110) facet on the performance of photoelectrochemical (PEC) water splitting is researched by both experiments and density functional theory (DFT) calculations. The experimental results manifest that the enhancement in photocurrent density by the presence of V_O is related with increased charge separation and charge-transfer efficiencies. The electrochemical analysis reveals that the sample with V_O demonstrates an enhanced carrier density and reduced charge-transfer resistance. The results of DFT calculation indicate that the better charge separation is also contributed by the decrease of potential on the V_O surface, which improves the hole transport from the bulk to the surface. The reduced charge-transfer resistance is owing to the greatly increased number of active sites. The current study provides important insight into the roles of V_O on α-Fe₂O₃ photoanode, especially on its surface catalysis. The generated lesson is also helpful for the improvement of other PEC photoanode materials.