Electrocatalysts and photocatalysts are key to a sustainable future, generating clean fuels, reducing the impact of global warming, and providing solutions to environmental pollution. Improved ...processes for catalyst design and a better understanding of electro/photocatalytic processes are essential for improving catalyst effectiveness. Recent advances in data science and artificial intelligence have great potential to accelerate electrocatalysis and photocatalysis research, particularly the rapid exploration of large materials chemistry spaces through machine learning. Here a comprehensive introduction to, and critical review of, machine learning techniques used in electrocatalysis and photocatalysis research are provided. Sources of electro/photocatalyst data and current approaches to representing these materials by mathematical features are described, the most commonly used machine learning methods summarized, and the quality and utility of electro/photocatalyst models evaluated. Illustrations of how machine learning models are applied to novel electro/photocatalyst discovery and used to elucidate electrocatalytic or photocatalytic reaction mechanisms are provided. The review offers a guide for materials scientists on the selection of machine learning methods for electrocatalysis and photocatalysis research. The application of machine learning to catalysis science represents a paradigm shift in the way advanced, next-generation catalysts will be designed and synthesized.
Submicrometer‐sized (830 ± 40 nm) mesoporous TiO2 beads are used to form a scattering layer on top of a transparent, 6‐µm‐thick, nanocrystalline TiO2 film. According to the Mie theory, the large ...beads scatter light in the region of 600–800 nm. In addition, the mesoporous structure offers a high surface area, 89.1 m2 g−1, which allows high dye loading. The dual functions of light scattering and electrode participation make the mesoporous TiO2 beads superior candidates for the scattering layer in dye‐sensitized solar cells. A high efficiency of 8.84% was achieved with the mesoporous beads as a scattering layer, compared with an efficiency of 7.87% for the electrode with the scattering layer of 400‐nm TiO2 of similar thickness.
Mesoporous anatase TiO2 beads (∼830 nm) with a high surface area of 89.1 m2/g have improved the incident‐photon‐to‐current efficiency (IPCE) when used as a scattering layer on top of a 6‐µm transparent TiO2 film. Dye‐sensitized solar cells with a scattering layer composed of the mesoporous beads gave a photo‐to‐electrical conversion efficiency of 8.84% under AM 1.5 sunlight, much higher than that of the 6‐µm transparent TiO2 film (6.19%) due to the beads' dual functions of light scattering and electrode participation.
Due to the excellent characteristics of Synthetic Aperture Radar (SAR), it has become an important technical means for land and sea target detection applications worldwide. However, the SAR image ...imaging process is often accompanied by speckle noise, which affects the accuracy of target detection. For this problem, this paper proposes an SAR image reconstruction model based on image denoising and feature extraction. Given a noisy SAR image, at each pixel of the image, the value of the singularity index of a metric defined by the signal gradient norm density is calculated. Then through a hierarchical decomposition of these singular indices, a set of pixels containing the most informative feature set of the image is extracted, and a denoised image is reconstructed using the extracted features. In comparison to traditional filtering and denoising techniques such as non‐local filtering, this algorithm achieves remarkable local filtering and denoising effects while preserving the image's texture information. The denoising performance of the proposed method is evaluated through a series of quantitative indicators and visual comparisons. The results demonstrate that this method effectively reduces background clutter, resulting in a higher contrast between the target and the background.
This paper proposes an SAR image reconstruction model that addresses speckle noise through image denoising and feature extraction. The model calculates singularity indices and extracts informative features to reconstruct a denoised image, achieving excellent filtering effects while preserving texture information. Evaluation results demonstrate its effectiveness in reducing background clutter and enhancing target‐background contrast.
Device scale‐up and long‐term stability constitute two major hurdles that the emerging perovskite solar technology will have to overcome before commercialization. Here, a comparative study was ...performed between ZnO and TiO2 electron‐selective layers, two materials that allow the low‐temperature processing of perovskite solar cells on polymer substrates. Although the use of TiO2 is well established on glass substrates, ZnO was chosen because it can be readily printed at low temperature and offers the potential for the large‐scale roll‐to‐roll manufacturing of flexible photovoltaics at a low cost. However, a rapid degradation of CH3NH3PbI3 was observed if it was deposited on ZnO, therefore, the influence of the perovskite film preparation conditions on its morphology and degradation kinetics was investigated. This study showed that CH3NH3PbI3 could withstand a higher temperature on TiO2 than ZnO and that TiO2‐based perovskite devices were more stable than their ZnO analogues.
So solar: A comparison between CH3NH3PbI3/ZnO‐ and CH3NH3PbI3/TiO2‐based perovskite solar cells on polymer substrates demonstrates a higher thermal device stability if constructed on TiO2. Exacerbated degradation of CH3NH3PbI3 leads us to question the viability of ZnO as an effective electron‐selective layer in low‐temperature processed perovskite solar cells.
Abstract
This work investigates the synthesis, chemical composition, defect structures and associated dielectric properties of (Mg
2+
, Ta
5+
) co-doped rutile TiO
2
polycrystalline ceramics with ...nominal compositions of (Mg
2+
1/3
Ta
5+
2/3
)
x
Ti
1−
x
O
2
. Colossal permittivity (>7000) with a low dielectric loss (e.g. 0.002 at 1 kHz) across a broad frequency/temperature range can be achieved at
x
= 0.5% after careful optimization of process conditions. Both experimental and theoretical evidence indicates such a colossal permittivity and low dielectric loss intrinsically originate from the intragrain polarization that links to the electron-pinned
$${\bf{M}}{{\bf{g}}}_{{\bf{T}}{\bf{i}}}^{{\prime}{\prime} }+{{\bf{V}}}_{{\bf{O}}}^{\bullet \bullet }+{\bf{2}}{\bf{T}}{{\bf{a}}}_{{\bf{T}}{\bf{i}}}^{\bullet }+{\bf{2}}{\bf{T}}{{\bf{i}}}_{{\bf{T}}{\bf{i}}}^{\prime}$$
M
g
T
i
′
′
+
V
O
•
•
+
2
T
a
T
i
•
+
2
T
i
T
i
′
defect clusters with a specific configuration, different from the defect cluster form previously reported in tri-/pent-valent ion co-doped rutile TiO
2
. This work extends the research on colossal permittivity and defect formation to bi-/penta-valent ion co-doped rutile TiO
2
and elucidates a likely defect cluster model for this system. We therefore believe these results will benefit further development of colossal permittivity materials and advance the understanding of defect chemistry in solids.
Targeting mitochondria respiration is an effective therapeutic strategy in renal cell carcinoma (RCC). Atovaquone is a FDA‐approved antibiotic but is also known as a mitochondrial inhibitor. We found ...that atovaquone inhibited proliferation and induced apoptosis of RCC cells. Mechanistically, atovaquone inhibits mitochondrial respiration in a concentration‐dependent and time‐dependent manner, via targeting mitochondrial respiratory complex III. Although increased glycolysis was observed in atovaquone‐treated cells, atovaquone decreased ATP levels. As a consequence of mitochondrial respiration inhibition, reactive oxygen species levels were increased by atovaquone. The complete rescue of atovaquone's effects by an antioxidant suggests the important role of oxidative stress in the action of atovaquone in RCC. Importantly, atovaquone enhanced the in vitro and in vivo efficacy of 5‐fluorouracil (5‐FU) and interferon‐α (IFN‐α). Our preclinical findings suggest that atovaquone is a useful addition for RCC treatment. Our work also further demonstrates that RCC is more dependent on mitochondrial respiration than glycolysis.
We reported the electrochemical studies on mesoporous carbon spheres (MCS) enriched in nitrogen on frameworks serving as an electrode for electric double layer capacitor (EDLC) in an organic ...electrolyte. The preparation of the carbon spheres is involved in a facile polymerization-induced colloid aggregation method by using melamine-formaldehyde resin (MF) as the carbon precursor, and commercial fumed silica (Aerosil-200) as a hard template. After the carbonization of as-formed resin-template composites at 1000
°C under a nitrogen atmosphere, and the removal of silica template by HF treatment, monodisperse MCS with diameter size of ∼1.2
μm, high specific surface area (up to 1460
m
2/g) and uniform pore size as large as 31
nm can be obtained. The MCS product presents a high specific capacitance as 159
F/g at 0.5
A/g. The high specific capacitance of the MCS is believed to be associated with its suitable nitrogen content that can afford pseudocapacitance as well as the high specific surface area. Furthermore, the specific capacitance of MCS can remain 130
F/g at high current density of 20
A/g. Our results show that the moderate nitrogen content can enhance the surface wettability and reduce the resistance, the large pore size can accelerate the diffusion process for the ions solvated with big organic solvent molecules in the pores. In view of the facts that precursors used in this simple process are commercially available low-cost chemicals, researches on the synthesis of such MCS materials templated by silica nanoparticles may not only be theoretically important, but also provide more options for economical and large-scale productions of mesoporous carbon materials with desired nanostructures, which might find practical applications in the fields of EDLC with high power performance.
Surface reconstruction is a promising approach to obtain highly efficient electrocatalysts for oxygen evolution reaction (OER), which is vital for many renewable energy conversion and storage ...processes. Herein, we synthesized CoFe based difluoride by a simple solvothermal treatment process with the assistance of an ionic liquid (BmimBF4). The final sample originated from Co0.67Fe0.33F2 demonstrated the highest electrocatalytic activity, generating a current density of 10 mA/cm2 at an overpotential of 270 mV. The appropriate amount of iron dopant can increase the number of active sites. Besides, the in-situ leaching of fluorine accompanied with OER was found to generate metal oxyhydroxide layer with abundant oxygen vacancies, thus leading to the high performance of the electrocatalysts.
The stellarator has inherent advantages over the tokamak in achieving steady-state operation, especially due to its absence of disruptions and lack of need for current drive and the associated ...recirculating power. In recent years, there have been remarkable advances in the field of stellarator optimization, where precisely quasi-symmetric and precisely quasi-isodynamic magnetic configurations have been achieved with coils, allowing the neoclassical transport and energetic particle losses of stellarators to be reduced to levels comparable to those of tokamaks. At the same time, the development of high-temperature superconducting magnet technology will potentially double the magnetic field strength of stellarators. While these strong fields are expected to introduce new challenges, and while turbulent transport remains a common challenge for both stellarators and tokamaks, the combination of these physical and technological advances results in the expectation that stellarators will become a competitive approach to tokamaks for realizing steady-state fusion.
To investigate the mechanical properties of graphene (G) and calcium silicate hydrate (C-S-H) composites in different directions, molecular dynamics (MD) simulations and experiments were used, and ...the effects of temperature, loading rate, and graphene defects were also investigated. The experimental results show that the addition of graphene can improve the flexural, compressive, and tensile strength of the composite. The results of molecular dynamics simulation show that the addition of graphene in x and z directions can enhance the tensile strength of G/C-S-H in three directions, while the addition of graphene in y direction can reduce the tensile strength of G/C-S-H. At the same time, the tensile strength of G/C-S-H decreases with the increase in temperature and increases with the increase in loading rate. Meanwhile, the mechanical properties of G/C-S-H can be improved using a certain concentration of monatomic vacancy defects, diatomic vacancy defects, and S-W defects.
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