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Halide perovskites have garnered significant attention for their unique optoelectronic properties in solar-to-fuel conversions. However, the efficiency of halide perovskites in the field of photocatalytic CO 2 reduction is largely limited by serious charge recombination and a lack of efficient active sites. In this work, a rubidium (Rb) doped Cs 2 AgBiBr 6 (Rb:CABB) hierarchical microsphere is developed for photocatalytic CO 2 reduction. Experimental and theoretical analysis discloses that partially substituting Rb + for Ag + can effectively modulate the electronic structure of CABB, favoring charge separation and making adjacent Bi atoms an electron-rich active site. Further investigations indicated that Rb doping also reduces the energy barriers of the rate-determining step in CO 2 reduction. As a result, Rb:CABB demonstrated an enhanced CO yield compared to its undoped counterpart. This work presents a promising approach to optimizing the electronic structures of photocatalysts and paving a new way for exploring halide perovskites for photocatalytic CO 2 reduction., (© 2024 Wiley‐VCH GmbH.)

In the field of photocatalytic CO 2 reduction, quantum dot (QD) assemblies have emerged as promising candidate photocatalysts due to their superior light absorption and better substrate adsorption. However, the poor contacts within QD assemblies lead to low interfacial charge transfer efficiency, making QD assemblies suffer from unsatisfactory photocatalytic performance. Herein, a novel approach is presented involving the construction of strongly interfacial fused CdS QD assemblies (CdS QD gel) for CO 2 reduction. The novel CdS QD gel demonstrates outstanding photocatalytic performance for CO 2 methanation, achieving a CH 4 generation rate of ≈296 µmol g -1 h -1 , with a selectivity surpassing 76% and an apparent quantum yield (AQY) of 1.4%. Further investigations reveal that the robust interfacial fusion in these CdS QDs not only boosts their ability to absorb visible light but also significantly promotes charge separation. The present work paves the way for utilizing QD gel photocatalysts in realizing efficient CO 2 reduction and highlights the critical role of interfacial engineering in photocatalysts., (© 2024 Wiley‐VCH GmbH.)

Selective producing ethanol from CO 2 electroreduction is highly demanded, yet the competing ethylene generation route is commonly more thermodynamically preferred. Herein, we reported an efficient CO 2 -to-ethanol conversion (53.5 % faradaic efficiency at -0.75 V versus reversible hydrogen electrode (vs. RHE)) over an oxide-derived nanocubic catalyst featured with abundant "embossment-like" structured grain-boundaries. The catalyst also attains a 23.2 % energy efficiency to ethanol within a flow cell reactor. In situ spectroscopy and electrochemical analysis identified that these dualphase Cu(I) and Cu(0) sites stabilized by grain-boundaries are very robust over the operating potential window, which maintains a high concentration of co-adsorbed *CO and hydroxyl (*OH) species. Theoretical calculations revealed that the presence of *OH ad not only promote the easier dimerization of *CO to form *OCCO (ΔG~0.20 eV) at low overpotentials but also preferentially favor the key *CHCOH intermediate hydrogenation to *CHCHOH (ethanol pathway) while suppressing its dehydration to *CCH (ethylene pathway), which is believed to determine the remarkable ethanol selectivity. Such imperative intermediates associated with the bifurcation pathway were directly distinguished by isotope labelling in situ infrared spectroscopy. Our work promotes the understanding of bifurcating mechanism of CO 2 ER-to-hydrocarbons more deeply, providing a feasible strategy for the design of efficient ethanol-targeted catalysts., (© 2024 Wiley-VCH GmbH.)

In recent years, halide perovskites have attracted considerable attention for photocatalytic CO 2 reduction. However, the presence of surface defects and the lack of specific catalytic sites for CO 2 reduction lead to low photocatalytic performance. In this study, we demonstrate a facile method that post-treats CsPbBr 3 with ZnBr 2 for photocatalytic CO 2 reduction. Our experimental and characterization results show that ZnBr 2 has a dual role: the Br - ions in ZnBr 2 passivate Br vacancies (V Br ) on the CsPbBr 3 surface, while Zn 2+ cations act as catalytic sites for CO 2 reduction. The ZnBr 2 -CsPbBr 3 achieves a photocatalytic CO evolution rate of 57 μmol g -1 h -1 , which is nearly three times higher than that of the pristine CsPbBr 3 . The enhanced performance over ZnBr 2 -CsPbBr 3 is mainly due to the decreased V Br and lower reaction energy barrier for CO 2 reduction. This work presents an effective method to simultaneously passivate surface defects and introduce catalytic sites, providing useful guidance for the regulation of perovskite photoelectric properties and the design of efficient photocatalysts.

In the field of photocatalysis, new heterojunction materials are increasingly explored to achieve efficient energy conversion and environmental catalysis under visible light and sunlight. This paper presents a study on two newly constructed two-dimensional van der Waals heterojunctions, Sc 2 CCl 2 /MoSe 2 and Sc 2 CCl 2 /PtSe 2 , using density-functional theory. The study includes a systematic investigation of their geometrical structure, electronic properties, and optical properties. The results indicate that both heterojunctions are thermodynamically, kinetically, and mechanically stable. Additionally, Bader charge analysis reveals that both heterojunctions exhibit typical type II band properties. However, the band gap of the Sc 2 CCl 2 /MoSe 2 heterojunction is only 1.18 eV, which is insufficient to completely cross the reduction and oxidation (REDOX) potential of 1.23 eV, whereas the band gap of Sc 2 CCl 2 /PtSe 2 heterojunction is 1.49 eV, which is theoretically capable for water decomposition. The subsequent calculation of the Sc 2 CCl 2 /PtSe 2 heterojunction demonstrate excellent hole carrier mobility and high efficiency light absorption in the visible light range, facilitating the separation of photogenerated electrons and holes. More importantly, Sc 2 CCl 2 /PtSe 2 vdW type II heterojunction can achieve full water decomposition from pH 1 to pH 4, and its thermodynamic feasibility is confirmed by Gibbs free energy results. The aim of this study is to develop materials and analyses that will result in optoelectronic devices that are more efficient, stable, and sustainable., (© 2024 Wiley-VCH GmbH.)

Structural features like 3D nano-size, ultrathin thickness and amorphous/crystalline interfaces play crucial roles in regulating charge separation and active sites of photocatalysts. However, their co-occurrence in a single catalyst and exploitation in photocatalytic CO 2 reduction (PCR) remains challenging. Herein, nano-sized bismuth oxychloride spheres (BiOCl-NS) confining three-layered nanoplates (∼2.2 nm ultrathin) and an amorphous/crystalline interface are exclusively developed via intrinsic engineering for an enhanced sacrificial-reagent-free PCR system. The results uncover a unique synergism wherein the three-layered nanoplates accelerate electron-hole separation, and the amorphous/crystalline interface exposes electron-localized active sites (Bi-O vac -Bi). Consequently, BiOCl-NS exhibit efficient CO 2 adsorption and activation with the lowering of rate-determining-step energy barriers, leading to remarkable CO production (102.72 μmol g -1 h -1 ) with high selectivity (>99%), stability (>30 h), and apparent quantum efficiency (0.51%), outperforming conventional counterparts. Our work provides a facile structural engineering approach for boosting PCR and offers distinct synergism for advancing diverse materials.

The unremitting pursuit of high-performance and multifunctional materials has consistently propelled modern industries forward, stimulating research and motivating progress in related fields. In such materials, polybenzoxazine (PBz) aerogel, which combines the virtues of PBz and aerogel, has attracted salient attention recently, emerging as a novel research focus in the realm of advanced materials. In this review, the preparation scheme, microscopic morphology, and fundamental characteristics of PBz aerogels are comprehensively summarized and discussed in anticipation of providing a clear understanding of the correlation between preparation process, structure, and properties. The effective strategies for enhancing the performance of PBz aerogels including composite fabrication and hybridization are highlighted. Moreover, the applications of PBz-based aerogels in various domains such as adsorption (including wastewater treatment, CO 2 capture, and microwave adsorption), thermal insulation, energy storage as well as sensors are covered in detail. Furthermore, several obstacles and potential directions for subsequent research are delineated with a view to surmounting the prevailing constraints and achieving a realization of the shift from experimental exploration to practical applications., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier B.V.)

Perovskite nanocrystals (PNCs) bear a huge potential for widespread applications, such as color conversion, X-ray scintillators, and active laser media. However, the poor intrinsic stability and high susceptibility to environmental stimuli including moisture and oxygen have become bottlenecks of PNC materials for commercialization. Appropriate barrier material design can efficiently improve the stability of the PNCs. Particularly, the strategy for packaging PNCs in organosilicon matrixes can integrate the advantages of inorganic-oxide-based and polymer-based encapsulation routes. However, the inert long-carbon-chain ligands (e.g., oleic acid, oleylamine) used in the current ligand systems for silicon-based encapsulation are detrimental to the cross-linking of the organosilicon matrix, resulting in performance deficiencies in the nanocrystal films, such as low transparency and large surface roughness. Herein, we propose a dual-organosilicon ligand system consisting of (3-aminopropyl)triethoxysilane (APTES) and (3-aminopropyl)triethoxysilane with pentanedioic anhydride (APTES-PA), to replace the inert long-carbon-chain ligands for improving the performance of organosilicon-coated PNC films. As a result, strongly fluorescent PNC films prepared by a facile solution-casting method demonstrate high transparency and reduced surface roughness while maintaining high stability in various harsh environments. The optimized PNC films were eventually applied in an X-ray imaging system as scintillators, showing a high spatial resolution above 20 lp/mm. By designing this promising dual organosilicon ligand system for PNC films, our work highlights the crucial influence of the molecular structure of the capping ligands on the optical performance of the PNC film.

Converting CO 2 into high-value-added chemicals has been recognized as a promising way to tackle the fossil fuel crisis. Quantum dots (QDs) have been extensively studied for photocatalytic CO 2 reduction due to their excellent optoelectronic properties. However, most of the photogenerated charge carriers recombine before they participate in the photocatalytic reaction. It is crucial to regulate the charge carriers to minimize undesired charge recombination, thus, promoting surface photocatalysis. Herein, we report a copper-doped CdS (Cu:CdS) QD photocatalyst for CO 2 reduction. Density functional theory simulations and experimental results demonstrate that Cu dopants create intermediate energy levels in CdS QDs that can extend the lifetime of exciton charge carriers. Furthermore, the long-lived charge carriers can be harnessed for the photocatalytic reaction on Cu:CdS QDs. The resultant Cu:CdS QDs exhibited a significantly enhanced photocatalytic activity toward CO 2 reduction compared to the pristine CdS QDs. This work highlights the importance of charge regulation in photocatalysts and opens new pathways for the exploration of efficient QD photocatalysts.

Halide perovskites exhibit outstanding optoelectronic properties, which make them an ideal choice for photocatalytic CO 2 reduction and benzyl alcohol (BA) oxidation. Nevertheless, the simultaneous realization of the above redox coupling reactions on halide perovskites remains a great challenge, as it requires distinct catalytic sites for different target reactions. Herein, the catalytic sites of Cs 2 AgBiCl 6 (CABC) are regulated by doping Fe for efficient coupling of photocatalytic CO 2 reduction and BA oxidation. The Fe-doped CABC (Fe: CABC) exhibits an enhanced visible-light response and effective charge separation. Experimental results and theoretical calculations reveal a synergistic interplay between Bi and Fe sites, where the Bi and Fe sites have lower activation energies toward CO 2 reduction and BA oxidation. Further investigations demonstrate that electrons and holes prefer to accumulate at the Bi site and Fe site under light irradiation, respectively, which creates favorable conditions for facilitating CO 2 reduction and BA oxidation. The resultant Fe: CABC achieves a high photocatalytic performance toward CO (18.5 µmol g -1  h -1 ) and BD (1.1 mmol g -1  h -1 ) generation, which surpasses most of the state-of-the-art halide photocatalysts. This work demonstrates a facile strategy for regulating the catalytic site for redox coupling reactions, which will pave a new way for designing halide perovskites for photocatalysis., (© 2023 Wiley-VCH GmbH.)

Fabricating a cost-effective yet highly active photocatalyst to reduce CO 2 to CO and oxidize benzyl alcohol to benzaldehyde simultaneously, is challenging. Herein, we construct an S-scheme 0D/2D CsPbBr 3 /TiO 2 heterostructure for bifunctional photocatalysis. An in-situ synthetic route is used, which enables the precise integration between CsPbBr 3 nanocrystals and ultrathin TiO 2 nanosheets exposed with (001) facets (termed as TiO 2 -001), resulting in a tightly coupled heterointerface and desirable band offsets. The as-prepared CsPbBr 3 /TiO 2 -001heterojunctions exhibit boosted charge carrier kinetics, particularly, quick carrier separation/transfer and efficient utilization. Experimental results and theoretical calculations validate the S-scheme route in CsPbBr 3 /TiO 2 -001, which allows the enrichment of strongly conserved electrons-holes at conduction and valence bands of CsPbBr 3 and TiO 2 -001, respectively. Consequently, compared to its counterparts, an excellent bifunctional activity (with 24 h reusability) is realized over CsPbBr 3 /TiO 2 -001, where the production rate of CO and benzaldehyde reach up to 78.06 μmol g -1 h -1 and 1.77 mmol g -1 h -1 respectively, without employing any sacrificial agents. This work highlights the development of perovskite-based heterostructures and describes the efficient harnessing of redox potentials and charge carriers towards combined photocatalytic systems., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Inc. All rights reserved.)

A combined experimental and density functional theory (DFT) study on the UV-Vis spectra of o -methoxyaniline-terminated mono azo dyes was conducted. By applying time-dependent-DFT calculations, details of excitation processes were determined and visualization by hole-electron analysis was undertaken. Fragment-divided analysis revealed the contributions of different parts of the structures for the UV-Vis spectra, that richer/poorer electron density on aromatic rings lead to greater/less maximum absorption wavelengths ( λ max ) and larger/smaller half peak width ( W 1/2 ). Combining theoretical prediction with experimental verification, we answered the question of how the electronegativities of substituents affected the electron densities and how it affected the spectra. In addition, a linear model connecting the λ max and W 1/2 to the chemical shifts obtained by NMR spectroscopy was constructed, which laid the foundation for construction of a spectral library., Competing Interests: There are no conflicts of interest to declare., (This journal is © The Royal Society of Chemistry.)

Perovskite nanocrystals (PNCs) are promising candidates for solar-to-fuel conversions yet exhibit low photocatalytic activities mainly due to serious recombination of photogenerated charge carriers. Constructing heterojunction is regarded as an effective method to promote the separation of charge carriers in PNCs. However, the low interfacial quality and non-directional charge transfer in heterojunction lead to low charge transfer efficiency. Herein, a CsPbBr 3 -CdZnS heterojunction is designed and prepared via an in situ hot-injection method for photocatalytic CO 2 reduction. It is found that the high-quality interface in heterojunction and anisotropic charge transfer of CdZnS nanorods (NRs) enable efficient spatial separation of charge carriers in CsPbBr 3 -CdZnS heterojunction. The CsPbBr 3 -CdZnS heterojunction achieves a higher CO yield (55.8 µmol g -1  h -1 ) than that of the pristine CsPbBr 3 NCs (13.9 µmol g -1  h -1 ). Furthermore, spectroscopic experiments and density functional theory (DFT) simulations further confirm that the suppressed recombination of charge carriers and lowered energy barrier for CO 2 reduction contribute to the improved photocatalytic activity of the CsPbBr 3 -CdZnS heterojunction. This work demonstrates a valid method to construct high-quality heterojunction with directional charge transfer for photocatalytic CO 2 reduction. This study is expected to pave a new avenue to design perovskite-chalcogenide heterojunction., (© 2023 Wiley-VCH GmbH.)

Electrochemical CO 2 reduction reaction (CO 2 RR) provides a promising approach for sustainable chemical fuel production of carbon neutrality. Neutral and alkaline electrolytes are predominantly employed in the current electrolysis system, but with striking drawbacks of (bi)carbonate (CO 3 2- /HCO 3 - ) formation and crossover due to the rapid and thermodynamically favourable reaction between hydroxide (OH - ) with CO 2 , resulting in low carbon utilization efficiency and short-lived catalysis. Very recently, CO 2 RR in acidic media can effectively address the (bi)carbonate issue; however, the competing hydrogen evolution reaction (HER) is more kinetically favourable in acidic electrolytes, which dramatically reduces CO 2 conversion efficiency. Thus, it is a big challenge to effectively suppress HER and accelerate acidic CO 2 RR. In this review, we begin by summarizing the recent progress of acidic CO 2 electrolysis, discussing the key factors limiting the application of acidic electrolytes. We then systematically discuss addressing strategies for acidic CO 2 electrolysis, including electrolyte microenvironment modulation, alkali cations adjusting, surface/interface functionalization, nanoconfinement structural design, and novel electrolyzer exploitation. Finally, the new challenges and perspectives of acidic CO 2 electrolysis are suggested. We believe this timely review can arouse researchers' attention to CO 2 crossover, inspire new insights to solve the "alkalinity problem" and enable CO 2 RR as a more sustainable technology., (© 2023 Wiley-VCH Verlag GmbH.)

Aerogels, especially MXene aerogels, are an ideal multifunctional platform for developing efficient photocatalysts for CO 2 reduction because they are featured by abundant catalytic sites, high electrical conductivity, high gas absorption ability and self-supported structure. However, the pristine MXene aerogel has almost no ability to utilize light, which requires additional photosensitizers to assist it in achieving efficient light harvesting. Herein, we immobilized colloidal CsPbBr 3 nanocrystals (NCs) onto the self-supported Ti 3 C 2 T x (where T x represents surface terminations such as fluorine, oxygen, and hydroxyl groups) MXene aerogels for photocatalytic CO 2 reduction. The resultant CsPbBr 3 /Ti 3 C 2 T x MXene aerogels exhibit a remarkable photocatalytic activity toward CO 2 reduction with total electron consumption rate of 112.6 μmol g -1 h - 1 , which is 6.6-fold higher than that of the pristine CsPbBr 3 NC powders. The improvement of the photocatalytic performance is presumably attributed to the strong light absorption, effective charge separation and CO 2 adsorption in the CsPbBr 3 /Ti 3 C 2 T x MXene aerogels. This work presents an effective perovskite-based photocatalyst in aerogel form and opens a new avenue for their solar-to-fuel conversions., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Inc. All rights reserved.)

With the increasing demand for tooth bleaching in esthetic dentistry, its safety has been the focus of a comprehensive body of literature. In this context, the aim of the present study was to evaluate the application effects of pentalysine β-carbonylphthalocyanine zinc (ZnPc(Lys) 5 )-mediated photodynamic therapy in dentin bleaching and its effects on dentin collagen. We first established a new and reproducible tooth staining model using dentin blocks stained by Orange II and then bleached with ZnPc(Lys) 5 (25 μM) and hydrogen peroxide (10% or 30%). Data were analyzed with one- and two-way ANOVA and a significance level of p < 0.05. ZnPc(Lys) 5 effectively bleached the dentin samples to an extent comparable to hydrogen peroxide at either 10% or 30% concentrations. Further studies on the dentin morphology, chemical element distribution, and protein constituents, using an electron microscope, energy dispersive spectroscopy, X-ray photoelectron spectroscopy, and SDS-PAGE, demonstrated that treatment with the photosensitizer preserved the dentin structure and, at the same time, the major organic component, collagen type I. For comparison, hydrogen peroxide (10% or 30%) treatment significantly degraded the collagen protein. This work indicated that the photosensitizer exerts potent bleaching effects on dentin staining; importantly, does not damage dentin and its collagen content; and opens up a new strategy to further explore various photosensitizers for the bleaching of both tooth enamel and dentin.

In vehicular edge computing (VEC), some tasks can be processed either locally or on the mobile edge computing (MEC) server at a base station (BS) or a nearby vehicle. In fact, tasks are offloaded or not, based on the status of vehicle-to-infrastructure (V2I) and vehicle-to-vehicle (V2V) communication. In this paper, device-to-device (D2D)-based V2V communication and multiple-input multiple-output and nonorthogonal multiple access (MIMO-NOMA)-based V2I communication are considered. In actual communication scenarios, the channel conditions for MIMO-NOMA-based V2I communication are uncertain, and the task arrival is random, leading to a highly complex environment for VEC systems. To solve this problem, we propose a power allocation scheme based on decentralized deep reinforcement learning (DRL). Since the action space is continuous, we employ the deep deterministic policy gradient (DDPG) algorithm to obtain the optimal policy. Extensive experiments demonstrate that our proposed approach with DRL and DDPG outperforms existing greedy strategies in terms of power consumption and reward.

All-inorganic lead-free halide double perovskites have emerged as rising star photocatalysts to substitute the toxic lead-based hailed perovskites (LHPs) owing to their unique photophysical properties. Nevertheless, their photocatalytic activities toward CO 2 reduction are still far from comparable with the LHPs, associated with severe charge recombination and sluggish surface catalytic reaction. Herein, a delicate 0D/2D heterojunction of Cs 2 AgBiBr 6 /Bi 2 WO 6 (CABB/BWO) was assembled by in-situ growing cubic CABB nanocrystals on the flat surface of BWO nanosheets via a facile hot-injection method. Density functional theory (DFT) calculations disclose that the work function and Fermi level difference between CABB and BWO give rise to charge redistribution at the interface upon the formation of the heterojunction, creating an internal electric field (IEF). Upon light irradiation, the IEF enables the photogenerated electron transfer from BWO to CABB via direct Z-scheme electron transfer mode with striking spatial charge separation as verified by in-situ X-ray photoelectron (XPS) and electron spin resonance (ESR) spectra. Consequently, the CABB/BWO heterojunction realizes 7-fold higher photocatalytic activity than pristine CABB with significant electron consumption rate of 87.66 µmol g -1 h -1 under simulated solar light (AM 1.5G)., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Inc. All rights reserved.)

As naturally derived material, cellulose aerogels have excellent thermal insulation properties due to their unique high porosity and three-dimensional mesoporous structure. However, its hydrophilic properties limit its application in the field of building insulation. Here, we propose a method to prepare high hydrophobicity by adopting the sol-gel method and chemical vapor reaction strategy using cellulose acetate type II as raw material and 2,4-toluene diisocyanate as the cross-linking agent. Thermal properties of cellulose acetate aerogels (CAAs) were measured, where pyridine was the catalyst, acetone was the solvent, and perfluorodecyltriethoxysilane (PFDS), hexamethyldisilazane (HMDS), and methyltriethoxysilane (MTES) were used as hydrophobic agents (by process hydrophobic test). Compared with MTES-modified cellulose acetate aerogels (M-CAAs) and HMDS (H-CAAs)-modified cellulose acetate aerogels, PFDS-modified (P-CAAs) cellulose acetate aerogels are the most hydrophobic. By implementing hydrophobic modification of PFDS both inside and outside the structure of cellulose acetate aerogels, the water contact angle can reach up to 136°, strongly demonstrating the potential of PFDS as a hydrophobic agent. The results show that the thermal conductivity and compressive strength of cellulose acetate aerogel with the best hydrophobic properties are 0.035 W m -1 K -1 at normal pressure and 0.39 MPa at 3% strain, respectively. This work shows that the highly hydrophobic cellulose acetate aerogel has potential as a waterproof material in the field of building thermal-insulation materials.

An in-depth theoretical study on the Pt(ii)/Pt(iv)-bisphenylpyridinylmethane complexes was carried out, which focused on the geometric/electronic structures, excitation procedures, on-off phosphorescence mechanisms, and structure-optical performance relationships. The key roles of the linkages (LK) connected in the middle of phenylpyridines were carefully investigated using multiple wavefunction analysis methods, such as non-covalent interaction (NCI) visualizations and natural bond orbital (NBO) studies. The phosphorescence-off phenomenon was considered by hole-electron analysis and visualizations, spin-orbit coupling (SOC) studies, and NBO analysis. Through these investigations, the relationship of the substituents in LK and the optical performances were revealed, as well as the fundamental principles of the phosphorescence-quenching mechanism in Pt(iv) complexes, which pave the way for further performance/structural renovation works. In addition, an intuitive visualization method was developed using a heatmap to quantitatively express the SOC matrix elementary (SOCME), which is helpful for big data simplification for phosphorescence analysis., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Strain engineering can endow versatile functions, such as refining d-band center and inducing lattice mismatch, on catalysts for a specific reaction. To this end, effective strain engineering for introducing strain on the catalyst is highly sought in various catalytic applications. Herein, a facile laser ablation in liquid (LAL) strategy is adopted to synthesize gold nanoparticles (Au NPs) with rich compressive strain (Au-LAL) for electrochemical CO 2 reduction. It is demonstrated that the rich compressive strain can greatly promote the electrochemical CO 2 reduction performance of Au, achieving a CO partial current density of 24.9 mA cm -2 and a maximum CO faradaic efficiency of 97% at -0.9 V for Au-LAL, while it is only 2.77 mA cm -2 and 16.2% for regular Au nanoparticles (Au-A). As revealed by the in situ Raman characterization and density functional theory calculations, the presence of compressive strain can induce a unique electronic structure change in Au NPs, significantly up-shifting the d-band center of Au. Such a phenomenon can greatly enhance the adsorption strength of Au NPs toward the key intermediate of CO 2 reduction ( i.e. , *COOH). More interestingly, we demonstrate that, an important industrial chemical feedstock, syngas, can be obtained by simply mixing Au-LAL with Au-A in a suitable ratio. This work provides a promising method for introducing strain in metal NPs and demonstrates the important role of strain in tuning the performance and selectivity of catalysts.

Developing near-infrared responsive (NIR) photocatalysts is very important for the development of solar-driven photocatalytic systems. Metal sulfide semiconductors have been extensively used as visible-light responsive photocatalysts for photocatalytic applications owing to their high chemical variety, narrow bandgap and suitable redox potentials, particularly the benchmark ZnIn 2 S 4 . However, their potential as NIR-responsive photocatalysts is yet to be reported. Herein, for the first time demonstrated that upconversion nanoparticles can be delicately coupled with hierarchical ZnIn 2 S 4 nanorods (UCNPs/ZIS) to assemble a NIR-responsive composite photocatalyst, and as such composite is verified by ultraviolet-visible diffuse reflectance spectra and upconversion luminescence spectra. As a result, remarkable photocatalytic CO and CH 4 production rates of 1500 and 220 nmol g - 1 h -1 , respectively, were detected for the UCNPs/ZIS composite under NIR-light irradiation (λ ≥ 800 nm), which is rarely reported in the literature. The remarkable photocatalytic activity of the UCNPs/ZIS composite can be understood not only because the heterojunction between UCNPs and ZIS can promote the charge separation efficiency, but also the intimate interaction of UCNPs with hierarchical ZIS nanorods can enhance the energy transfer. This finding may open a new avenue to develop more NIR-responsive photocatalysts for various solar energy conversion applications., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Inc. All rights reserved.)

A combined crystallography and DFT study of cucurbit[ n ]urils ( n = 5-8, 10) was carried out, and PBE0 was certified to be the most rational density functional method for optimization task. Steric hindrance and electronic effect of the hindered lone pair electrons in cucurbit[ n ]urils were qualitatively measured by bond order analysis, lone pair electron (LP) visualization and electrostatic potential (ESP) study. Together with energy decomposition analysis of some selected host-guest systems, we quantitatively verified the effect of size/cavity and noncovalent interaction in host-guest recognition. This solid study revealed that lone pairs electrons affect not only on host-guest identification mode but also on geometry stability, which pave the avenue for further sophisticated applications., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Utilizing sunlight to convert CO 2 into chemical fuels could simultaneously address the greenhouse effect and fossil fuel crisis. ZnSe nanocrystals are promising candidates for photocatalysis because of their low toxicity and excellent photoelectric properties. However, pristine ZnSe generally has low catalytic activities due to serious charge recombination and the lack of efficient catalytic sites for CO 2 reduction. Herein, a ZnSe nanorods-CsSnCl 3 perovskite (ZnSe-CsSnCl 3 ) type II heterojunction composite is designed and prepared for photocatalytic CO 2 reduction. The ZnSe-CsSnCl 3 type II heterojunction composite exhibits enhanced photocatalytic activity for CO 2 reduction with respect to pristine ZnSe nanorods. The experimental characterizations and theoretical calculations reveal that the efficient charge separation and lowered free energy of CO 2 reduction facilitate the CO 2 conversion on the ZnSe-CsSnCl 3 heterojunction composite. This work presents a type II heterojunction composite photocatalyst based on ecofriendly metal chalcogenides and metal halide perovskites. Our study has also promoted the understanding of the CO 2 reduction mechanisms on perovskite nanocrystals, which could be valuable for the development of metal halide perovskite photocatalysts.

Chitosan (CTS) aerogel is a new type of functional material that could be possibly applied in the thermal insulation field, especially in energy-saving buildings. However, the inhibition method for the very big shrinkage of CTS aerogels from the final gel to the aerogel is challenging, causing great difficulty in achieving a near-net shape of CTS aerogels. Here, this study explored a facile strategy for restraining CTS-based aerogels' inherent shrinkage depending on the chemical crosslinking and the interpenetrated supramolecular interaction by introducing nanofibrillar cellulose (NFC) and polyvinyl alcohol (PVA) chains. The effects of different aspect ratios of NFC on the CTS-based aerogels were systematically analyzed. The results showed that the optimal aspect ratio for NFC introduction was 37.5 from the comprehensive property perspective. CTS/PVA/NFC hybrid aerogels with the aspect ratio of 37.5 for NFC gained a superior thermal conductivity of 0.0224 W/m K at ambient atmosphere (the cold surface temperature was only 33.46 °C, despite contacting the hot surface of 80.46 °C), a low density of 0.09 g/cm 3 , and a relatively high compressive stress of 0.51 MPa at 10% strain.

Metal halide perovskite (MHP) nanocrystals (NCs) have shown promising application in photocatalytic CO 2 reduction, but their activities are still largely restrained by severe charge recombination and narrow solar spectrum response. Assembly of heterojunctions can be beneficial to the charge separation in MHPs while the assembly process usually brings native interfacial defects, impeding efficient charge separation between two materials. Herein, an in-situ generation strategy was developed to prepare CsPbBr 3 /WO 3 heterojunction, using WO 3 nanosheets (NSs) as growing substrate for the growth of CsPbBr 3 NCs. The developed CsPbBr 3 /WO 3 heterojunction exhibited a high-quality interface, greatly facilitating charge transfer between two semiconductors. The hybrid photocatalyst displayed an excellent activity toward CO 2 reduction, which was about 7-fold higher than pristine CsPbBr 3 NCs and 3.5-fold higher than their assembled counterparts. The experimental results and theoretical simulations revealed that a Z-scheme mechanism with a favorable internal electric field was responsible for the good performance of CsPbBr 3 /WO 3 heterojunction. By using O-defective WO 3 NSs as a near-infrared (NIR) light absorber, the CsPbBr 3 /WO 3 heterojunction could harvest NIR light and showed an impressive activity toward CO 2 reduction. This work demonstrates a new strategy to design MHP-based heterojunctions by synergistically considering the interface quality, charge transfer mode, interfacial electric field, and light response range between two semiconductors., (© 2021 Wiley-VCH GmbH.)

Dye-sensitized system holds great potential for the development of visible-light-responsive photocatalysts not only because it can enhance the light absorption and charge separation efficiency of the systems but also because it can tune the band structure of catalysts. Herein, two-dimensional (2D) Fe-MOF nanosheets (Fe-MNS) with a LUMO potential of 0.11 V (vs. RHE) was prepared. Interestingly, it has been found that when the 2D Fe-MNS catalyst was functionalized with visible-light-responsive [Ru(bpy)] 3 2+ as a dye-sensitizer, the electrons from the [Ru(bpy)] 3 2+ can effectively inject into the 2D Fe-MNS, which resulted in a negative shift of the LUMO potential of the 2D Fe-MNS to -0.15 V (vs. RHE). Consequently, the [Ru(bpy)] 3 2+ /Fe-MNS catalytic system exhibits a sound photocatalytic CO 2 -to-CO activity of 1120 μmol g -1 h -1 under visible-light-irradiation. The photocatalytic CO production was further ameliorated by regulating the electronic structure of the 2D Fe-MNS by doping Co ions, achieving a remarkable photocatalytic activity of 1637 μmol g -1 h -1 . This work further supports that the dye-sensitized system is an auspicious strategy worth exploring with different catalysts for the development of visible-light-responsive photocatalytic systems., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Objectives: The current tooth bleaching materials are associated with adverse effect. Photodynamic method based on a novel photosensitizer alone, without combining with peroxides, is evaluated for tooth bleaching application., Materials and Methods: Teeth samples were randomly divided into 3 groups with different treatment schemes, including negative control group (group A, physiological saline), experimental group (group B, ZnPc(Lys) 5 ), and the positive control group (group C, hydrogen peroxide). Tooth color, surface microhardness, and roughness were determined at baseline, right after the first and second phase of bleaching, as well as 1 week and 1 month post-bleaching. Four samples in each group was randomly selected to evaluate the changes in surface morphology using the scanning electron microscope., Results: The color change values (ΔE) in group B (7.10 ± 1.03) and C (12.22 ± 2.35) were significantly higher than that in group A (0.93 ± 0.30, P < 0.05). Additionally, surface microhardness and roughness were significantly affected in group C, but not in the group A and B. Furthermore, the scanning electron microscope images showed no adverse effect of enamel in the group A and B while the group C demonstrated corrosive changes., Conclusions: ZnPc(Lys) 5 had a satisfactory bleaching effect and is promising to be a new type of tooth bleaching agent., Clinical Relevance: The current tooth bleaching materials give a satisfactory clinical outcome and long-term stability, but associated with some adverse reactions. Photosenstizer ZnPc(Lys) 5 eliminated the main side effects observed in hydrogen peroxide-based agents on the enamel, and also had a satisfactory bleaching effect and provide a novel selective bleaching scheme for clinical use., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Cellulose and its derivative aerogels have attracted much attention due to their renewable and biodegradable properties. However, the significant shrinkage in the supercritical drying process causes the relatively high thermal conductivity and low mechanical property of cellulose and its derivatives aerogels. Considering the pearl-necklace-like skeleton network of silica aerogels, which can improve thermal insulation property and mechanical property. Herein, we propose a new strategy for fabricating cellulose diacetate aerogels (CDAAs) with pearl-necklace-like skeletons by using tert-butanol (TBA) as exchange solvent after experiencing the freezing-drying course. CDAAs obtained have the low density of 0.09 g cm -3 , the nanopore size in the range of 10-40 nm, the low thermal conductivity of 0.024 W m -1 K -1 at ambient conditions, and the excellent mechanical properties (0.18 MPa at 3% strain, 0.38 MPa at 5% strain). Ultimately, CDAAs with moderate mechanical property paralleled to cellulose-derived aerogels obtained from supercritical drying process are produced, only simultaneously owning the radial shrinkage of 6.2%. The facile method for fabricating CDAAs could provide a new reference for constructing cellulose/cellulose-derived aerogels and other biomass aerogels.

Biomass aerogels have received extensive attention due to their unique natural characteristics. However, biomass-based chitosan aerogels are often confronted with the traditional issue concerning a weak skeleton structure, namely, the corresponding huge shrinkage for chitosan aerogels in the stage from the final gel to the aerogel. Herein, we put forward a new approach to enhance chitosan aerogels by introducing natural biomaterial cellulose nanocrystal (CNC). CNC is applied to connect/cross-link chitosan chains to form its networking construction through supramolecular interaction/physical entanglement, eventually realizing the enhancement of the chitosan aerogel network structure. Chitosan aerogels modified with CNC exhibit a high specific surface area of 578.43 cm 2 g -1 , and the pore size distribution is in the range of 20-60 nm, which is smaller than the mean free path of gas molecules (69 nm), triggering a "no convection" effect. Hence, the gaseous heat transfer of chitosan aerogel is effectively suppressed. Chitosan aerogels with the addition of CNC show an excellent thermal insulation property (0.0272 W m -1 K -1 at ambient condition) and an enhanced compressive strength (0.13 MPa at a strain of 3%). This improvement method of chitosan aerogel in enhancing the skeleton structure aspect provides a new kind of idea for strengthening the nanoscale morphology structure of biomass aerogels.

Photoreduction of CO 2 to valuable fuels with semiconductor photocatalysts is a good solution to the problems of global warming and energy crisis. Creation of hybrid nanomaterials with hierarchical and/or heterojunction structures is beneficial to develop efficient photocatalysts for CO 2 reduction. Herein we present a convenient method to obtain a hybrid photocatalyst consisting of MnS and In 2 S 3 nanosheets with assembled hierarchical structures through using Mn 2+ -loaded MIL-68(In) submicro-rods as templates. Owing to the dispersive Mn 2+ and In 3+ ions in templates, numerous small p-n heterojunctions of MnS/In 2 S 3 could be simultaneously produced in each hierarchical particle. The p-type MnS and n-type In 2 S 3 with an original type II band alignment can create a stronger built-in electric field after the formation of p-n heterojunctions, which is favorable for charge separation and migration to catalyst surface. The prepared MnS/In 2 S 3 heterojunctions show an 4-fold higher photocatalytic activity toward CO 2 reduction than pristine MnS and In 2 S 3 . The MnS/In 2 S 3 hierarchical structures were well characterized and their working mechanism was explored. This work demonstrates a facile strategy to create efficient hybrid photocatalysts with both hierarchical structures and p-n heterojunctions for photocatalytic applications., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Developing suitable catalysts capable of receiving injected electrons and possessing active sites for hydrogen evolution reaction (HER) is the key to building an efficient dye-sensitized system for hydrogen production. Fe 3 S 4 is generally regarded as an inferior HER catalyst among the metal sulfide family, mainly due to its weak surface adsorption toward H atoms. In this work, we demonstrate a facile metal-organic framework-derived method to synthesize uniform Fe 3 S 4 nanorods and active them for HER by Ni doping. Our experimental results and theoretical calculations reveal that Ni doping can greatly modify the electronic structure of Fe 3 S 4 nanorods, improving their electron conductivity and optimizing their surface adsorption energy toward H atoms. Sensitized by a commercial organic dye (eosin-Y), 1%Ni-doped Fe 3 S 4 nanorods display a high H 2 production rate of 3240 μmol g cat -1 h -1 with an apparent quantum yield of 12% under 500 nm wavelength, which is significantly higher than that of pristine Fe 3 S 4 and even higher than that of 1% Pt-deposited Fe 3 S 4 . The working mechanism of this dye-sensitized system is explored, and the effect of Ni-doping concentration has been studied. This work presents a facile strategy to synthesize metal-doped sulfide nanocatalysts with greatly enhanced activity toward photocatalytic H 2 production.

Photocatalytic reduction of CO 2 into value-added chemical fuels is an appealing approach to address energy crisis and global warming. CsPbBr 3 quantum dots (QDs) are good candidates for CO 2 reduction because of their excellent photoelectric properties, including high molar extinction coefficient, low exciton binding energy, and defect tolerance. However, the pristine CsPbBr 3 QDs generally have low photocatalytic performance mainly due to dominant charge recombination and lack of efficient catalytic sites for CO 2 adsorption/activation. Herein, we report a new photocatalytic system, in which CsPbBr 3 QDs are coupled with covalent triazine frameworks (CTFs) for visible-light-driven CO 2 reduction. In this hybrid photocatalytic system, the robust triazine rings and periodical pore structures of CTFs promote the charge separation in CsPbBr 3 and endow them with strong CO 2 adsorption/activation capacity. The resulting photocatalytic system exhibits excellent photocatalytic activity towards CO 2 reduction. This work presents a new photocatalytic system based on CTFs and perovskite QDs for visible-light-driven CO 2 reduction, which highlights the potential of perovskite-based photocatalysts for solar fuel applications., (© 2021 Wiley-VCH GmbH.)

Background: Brain metastases (BM) are severe incidents among patients with non-small cell lung cancer (NSCLC) and have been associated with significant morbidity and decreased survival; thus, new methods are required to improve clinical management. Magnetic resonance spectroscopy (MRS) allows noninvasive measurements of biochemical information from tumor tissue, providing clinically useful imaging biomarkers. The primary aim of this study was to explore the application of MRS in the assessment of tumor prognosis after stereotactic radiotherapy in NSCLC patients with BM., Patients and Methods: MRS was performed on NSCLC patients attending Qingdao Center Hospital with suspected BM, and 68 patients were included in the survival analysis. The qualitative and quantitative parameters of MRS metabolites, such as choline (Cho), creatine (Cr), and N-acetyl-aspartate (NAA), were recorded. To select a cutoff for MRS metabolite parameters in the tumor and to distinguish patients who had recurrence, we performed an ROC curve analysis. Univariate and multivariate Cox regression analyses were used to assess the association between MRS metabolite parameters and clinical cancer prognosis., Results: The average age was 56 years. A total of 68 NSCLC patients underwent metabolic evaluation with single voxel proton MRS and were selected for retrospective analysis. According to the area under the curve (AUC) to predict recurrence, the MRS metabolite parameters were determined as Cho (AUC=0.550), Cr (AUC=0.415), NAA (AUC=0.524), NAA/Cr (AUC=0.600), Cho/Cr (AUC=0.723), and Cho/NAA (AUC=0.543). Cho and Cr predicted poor survival while Cho/Cr and NAA/Cr predicted improved survival ( P <0.05). In the multivariate model with adjustment to establish the potential role of MRS metabolite parameters, Cho/Cr showed a significant association with OS ( P =0.009) and PFS ( P =0.006) after stereotactic radiotherapy., Conclusion: The positive results of this study indicate the predictive value of metabolic characteristics of BM detected with MRS for the outcome after stereotactic radiotherapy., Competing Interests: The authors report no conflicts of interest in this work., (© 2020 Jia et al.)

Inorganic halide perovskite quantum dots (IHP QDs) have been widely studied in optoelectronic devices because of their size-dependent tunable bandgaps, long electron-hole diffusion lengths and excellent absorption properties. Herein, a novel floating-gate organic field-effect transistor memory (FGOFETM) is demonstrated, comprising a floating-gate of IHP QDs embedded in a polystyrene matrix. Notably, the FGOFETM exhibits photoinduced-reset characteristic that allows data removal by photo irradiation. This feature makes low energy-consuming memory and innovative devices possible. The nonvolatile devices also show a large memory window (≈90 V), ultrahigh memory on/off ratio (over 10 7 ) and therefore excellent multilevel information storage, in which 4 recognizable non-volatile states and long retention time (up to 10 years) are obtained. This work not only offers an effective guideline of high-performance FGOFETMs, but also shows great potential to realize multilevel data storage under electrical programming and photoinduced-reset processes., Competing Interests: The authors declare no competing financial interest., (This journal is © The Royal Society of Chemistry.)

In order to maximize energy efficiency in heterogeneous networks (HetNets), a turbo Q-Learning (TQL) combined with multistage decision process and tabular Q-Learning is proposed to optimize the resource configuration. For the large dimensions of action space, the problem of energy efficiency optimization is designed as a multistage decision process in this paper, according to the resource allocation of optimization objectives, the initial problem is divided into several subproblems which are solved by tabular Q-Learning, and the traditional exponential increasing size of action space is decomposed into linear increase. By iterating the solutions of subproblems, the initial problem is solved. The simple stability analysis of the algorithm is given in this paper. As to the large dimension of state space, we use a deep neural network (DNN) to classify states where the optimization policy of novel Q-Learning is set to label samples. Thus far, the dimensions of action and state space have been solved. The simulation results show that our approach is convergent, improves the convergence speed by 60% while maintaining almost the same energy efficiency and having the characteristics of system adjustment.

Photocatalytic CO 2 reduction is an appealing approach to convert solar energy into high value-added chemicals. All-inorganic CsPbBr 3 quantum dots (QDs) have emerged as a promising photocatalyst for reducing CO 2 . However, pristine CsPbBr 3 has a low catalytic performance, mainly due to severe charge recombination. Herein, a 0D/2D heterojunction of CsPbBr 3 QDs/Bi 2 WO 6 nanosheet (CPB/BWO) photocatalysts is fabricated for photocatalytic CO 2 reduction. The CPB/BWO photocatalyst achieves excellent photocatalytic performance: the total yield of CH 4 /CO is 503 μmol g -1 , nearly 9.5 times higher than the pristine CsPbBr 3 . The CPB/BWO heterojunction also exhibits much-improved stability during photocatalytic reactions. On the basis of various characterization techniques, our investigations verified a direct Z-scheme charge migration mechanism between CsPbBr 3 QDs and Bi 2 WO 6 nanosheets. The improved photocatalytic performance is originated from the high spatial separation of photoexcited charge carriers in CPB/BWO, which can also preserve strong individual redox abilities of two components. This work reports an efficient direct Z-scheme heterojunction photocatalytic system based on metal halide perovskites. The novel strategy we proposed may bring up new opportunities for the development of metal halide perovskite photocatalysts with greatly enhanced activities.

Photocatalytic CO2 reduction is a promising technology to mitigate global warming and enrich energy supply. Metal-organic frameworks (MOFs) are prospective photocatalysts for CO2 reduction, but severe charge recombination and limited visible light response largely restrain their applications. As carbon dots (CDs) can act as both electron receptors and photosensitizers, here we propose to develop CD-hybridized MOF photocatalysts for improving their activity for CO2 reduction. In particular, because of the small size of CDs, we have managed to encapsulate CDs inside MOF particles and found that these CD@MOFs exhibit hugely improved photocatalytic activity compared with CD-decorated MOFs or pristine MOFs. Our investigations suggest that placing small CD cocatalysts near the internal metal-oxo clusters of MOFs can help efficient charge transfer and separation in the hybrid photocatalysts, due to the formation of many small heterojunctions among MOFs. The developed CD-hybridized MOF catalysts are characterized in detail and their working mechanism is explored. This work may demonstrate a novel strategy to develop MOF-based hybrid photocatalysts with enhanced photocatalytic activity.

Harvesting solar energy to convert carbon dioxide (CO 2 ) into fossil fuels shows great promise to solve the current global problems of energy crisis and climate change. To achieve this goal, it is desirable to develop efficient catalysts with visible light response to cater for the solar spectrum. CdTe QDs are ideal candidates for absorbing visible light, but it is difficult to directly perform CO 2 reduction due to the lack of effective catalytic sites. Herein, we report a strategy for the activation of mercaptopropionic acid (MPA)-capped CdTe QDs for visible-light-driven CO 2 reduction, in which iron ions (Fe 2+ ) are immobilized onto CdTe QDs using l-cysteine as a bridging ligand (CdTe-b-Fe). This ligand bridging strategy can immobilize Fe 2+ ions on the surface of CdTe QDs as catalytic sites, and these catalytic sites can be conveniently adjusted by directly adding different types or numbers of metal ions. In addition to effectively immobilizing catalytic sites, the bridging ligands can also provide a pathway for electron transport between CdTe QDs and the catalytic sites. The CdTe-b-Fe QD system based on the ligand bridging strategy exhibits excellent catalytic properties: the yield of CH 4 /CO (two products together) is 126 μmol g -1 h -1 , and the selectivity for carbon-based products approaches 98%. This work presents a facile strategy for immobilizing catalytic sites on QDs and provides a platform for designing efficient visible-light driven catalysts for CO 2 reduction.

Glucose oxidase (GOx) can react with intracellular glucose and oxygen (O 2 ) to produce hydrogen peroxide (H 2 O 2 ) and gluconic acid, which can cut off the nutrition source of cancer cells and consequently inhibit their proliferation. Therefore, GOx is recognised as an ideal endogenous oxido-reductase for cancer starvation therapy. This process can further regulate the tumor microenvironment by increasing the hypoxia and the acidity. Thus, GOx offers new possibilities for the elaborate design of multifunctional nanocomposites for tumor therapy. However, natural GOx is expensive to prepare and purify and exhibits immunogenicity, short in vivo half-life, and systemic toxicity. Furthermore, GOx is highly prone to degrade after exposure to biological conditions. These intrinsic shortcomings will undoubtedly limit its biomedical applications. Accordingly, some nanocarriers can be used to protect GOx from the surrounding environment, thus controlling or preserving the activity. A variety of nanocarriers including hollow mesoporous silica nanoparticles, metal-organic frameworks, organic polymers, and magnetic nanoparticles are summarized for the construction of GOx-based nanocomposites for multimodal synergistic cancer therapy. In addition, current challenges and promising developments in this area are highlighted., (© 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Splitting water into hydrogen (H 2 ) with sunlight is an appealing approach towards alleviating the fossil fuel crisis. However, as one of the most promising light harvesters, colloidal quantum dots (QDs) generally exhibit low photocatalytic activity towards H 2 evolution because of the lack of catalytic sites on their surface. Many researchers have focused on activating QDs by anchoring metal complexes on their surface, in which the photoexcited electrons may transfer from the QDs to the metal centres via the organic ligands. These bulky organic ligands usually have poor electrical conductivity and chemical instability, thereby causing high charge recombination and low durability in these QDs/metal complex catalysts. To address these issues, we herein report the doping of cadmium telluride (CdTe) QDs with nickel ions (Ni 2+ ), achieving a remarkable H 2 generation rate without the use of co-catalysts. The formation rate of H 2 exceeded 27.3 mmol/g/h under visible light irradiation, which is approximately 110-fold higher than that of pristine CdTe QDs. This doping strategy provides a versatile route to reduce protons to H 2 with a turnover number of 13,650 in terms of Ni and confer superior durability on the CdTe QDs., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Photocatalytic degradation of environmental pollutants by using semiconductor-based photocatalysts offers great potential for remediation of toxic chemicals. For an economical and eco-friendly method to eliminate hexavalent chromium (Cr(VI)), favourable catalysts own high efficiency, stability and capability of harvesting light. Combination of metal with semiconductor is a promising route to improve the photocatalytic performance for Cr(VI) reduction. Herein, well-dispersed platinum (Pt) nanocubes (NCs) were synthesized by a facile one-step hydrothermal method with poly-l-lysine (PLL) as the growth-directing agent, followed by their uniform dispersion on graphitic carbon nitride (g-C 3 N 4 ). Their morphology, crystal structure, chemical composition, and formation mechanism were mainly characterized by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD). The hybrid nanocomposite was further explored for photocatalytic reduction of Cr(VI) to trivalent chromium (Cr(III)) under visible light at room temperature, by using formic acid (HCOOH) as a reducing agent, showing great improvement in photocatalytic activity and reusability, outperforming the referenced g-C 3 N 4 and home-made Pt black/g-C 3 N 4 catalysts. The effects of various experimental parameters and the proposed mechanism are discussed in detail., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Quantum dots (QDs), a class of promising candidates for harvesting visible light, generally exhibit low activity and selectivity towards photocatalytic CO 2 reduction. Functionalizing QDs with metal complexes (or metal cations through ligands) is a widely used strategy for improving their catalytic activity; however, the resulting systems still suffer from low selectivity and stability in CO 2 reduction. Herein, we report that doping CdS QDs with transition-metal sites can overcome these limitations and provide a system that enables highly selective photocatalytic reactions of CO 2 with H 2 O (100 % selectivity to CO and CH 4 ), with excellent durability over 60 h. Doping Ni sites into the CdS lattice leads to effective trapping of photoexcited electrons at surface catalytic sites and substantial suppression of H 2 evolution. The method reported here can be extended to various transition-metal sites, and offers new opportunities for exploring QD-based earth-abundant photocatalysts., (© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Platooning strategy is an important component of autonomous driving technology. Autonomous vehicles in platoons are often equipped with a variety of on-board sensors to detect the surrounding environment. The abundant data collected by autonomous vehicles in platoons can be transmitted to the infrastructure through vehicle-to-infrastructure (V2I) communications using the IEEE 802.11 distributed coordination function (DCF) mechanism and then uploaded to the cloud platform through the Internet. The cloud platform extracts useful information and then sends it back to the autonomous vehicles respectively. In this way, autonomous vehicles in platoons can detect emergency conditions and make a decision in time. The characteristics of platoons would cause a fair-access problem in the V2I communications, i.e., vehicles in the platoons moving on different lanes with different velocities would have different resident time within the infrastructure's coverage and thus successfully send different amounts of data to the infrastructure. In this case, the vehicles with different velocities will receive different amounts of useful information from the cloud. As a result, vehicles with a higher velocity are more likely to suffer from a traffic accident as compared to the vehicles with a lower velocity. Hence, this paper considers the fair-access problem and proposes a fair-access scheme to ensure that vehicles with different velocities successfully transmit the same amount of data by adaptively adjusting the minimum contention window of each vehicle according to its velocity. Moreover, the normalized throughput of the proposed scheme is derived. The validity of the fair-access scheme is demonstrated by simulation.

Multi-platooning is an important management strategy for autonomous driving technology. The backbone vehicles in a multi-platoon adopt the IEEE 802.11 distributed coordination function (DCF) mechanism to transmit vehicles' kinematics information through inter-platoon communications, and then forward the information to the member vehicles through intra-platoon communications. In this case, each vehicle in a multi-platoon can acquire the kinematics information of other vehicles. The parameters of DCF, the hidden terminal problem and the number of neighbors may incur a long and unbalanced one-hop delay of inter-platoon communications, which would further prolong end-to-end delay of inter-platoon communications. In this case, some vehicles within a multi-platoon cannot acquire the emergency changes of other vehicles' kinematics within a limited time duration and take prompt action accordingly to keep a multi-platoon formation. Unlike other related works, this paper proposes a swarming approach to optimize the one-hop delay of inter-platoon communications in a multi-platoon scenario. Specifically, the minimum contention window size of each backbone vehicle is adjusted to enable the one-hop delay of each backbone vehicle to get close to the minimum average one-hop delay. The simulation results indicate that, the one-hop delay of the proposed approach is reduced by 12% as compared to the DCF mechanism with the IEEE standard contention window size. Moreover, the end-to-end delay, one-hop throughput, end-to-end throughput and transmission probability have been significantly improved.

Converting CO 2 into high-valued chemicals with sunlight is regarded as a promising way to solve the impending energy and environmental crisis. Development of efficient photocatalysts with suitable energy band gap, high stability and favorable structure is thus of very importance. Herein, a novel hierarchical Bi 2 WO 6 photocatalyst assembled by Bi 2 WO 6 nanosheets with a hollow and rod-shaped appearance has been developed via a facile hydrothermal process. Interestingly, we found that the hydrolysis of Bi(NO 3 ) 3 in water can produce solid Bi 6 O 5 (OH) 3 (NO 3 ) 5 ·3H 2 O microrods which can be transformed to hollow-hierarchical Bi 2 WO 6 nanosheets by virtue of the Kirkendall effect. The developed Bi 2 WO 6 nanosheets exhibit a 58 times higher specific surface area than that of bulk Bi 2 WO 6 and a remarkable enhancement in electrochemical performance such as photocurrent and charge transfer. As a result, the hollow-hierarchical structured Bi 2 WO 6 photocatalysts achieve a high CH 4 yield of 2.6 μmol g -1  h -1 , 8 times higher than that of bulk Bi 2 WO 6 . Moreover, the developed photocatalysts exhibit a high stability during the recycling experiments. This work may present a new strategy to attain hierarchical structured photocatalysts with high activity and stability toward CO 2 reduction., (Copyright © 2018 Elsevier Inc. All rights reserved.)

The design and fabrication of rare earth upconversion nanoparticle (UCNP)-based nanomedical platforms have evoked increasing interest. However, their bio-safety is always the most worrisome problem. Most nanoparticles can accumulate in the internal organs, leading to acute toxicity, a long-term inflammatory response, or even fibrosis and cancer. In contrast, ultrasmall (sub-10 nm) nanoparticles have minimal safety risk because they can escape from macrophages, pass biological barriers, and be easily degraded or excreted from the body. In this review, we mainly introduce new progress in preparation strategies, imaging and drug delivery with regards to ultrasmall UCNPs, with an emphasis on rare earth fluorides, NaREF 4 . Finally, we discuss the future outlook and challenges relating to ultrasmall UCNPs.

This study investigates the superiority of cooperative broadcast transmission over traditional orthogonal schemes when applied in a downlink relaying broadcast channel (RBC). Two proposed cooperative broadcast transmission protocols, one with an amplify-and-forward (AF) relay, and the other with a repetition-based decode-and-forward (DF) relay, are investigated. By utilizing superposition coding (SupC), the source and the relay transmit the private user messages simultaneously instead of sequentially as in traditional orthogonal schemes, which means the channel resources are reused and an increased channel degree of freedom is available to each user, hence the half-duplex penalty of relaying is alleviated. To facilitate a performance evaluation, theoretical outage probability expressions of the two broadcast transmission schemes are developed, based on which, we investigate the minimum total power consumption of each scheme for a given traffic requirement by numerical simulation. The results provide details on the overall system performance and fruitful insights on the essential characteristics of cooperative broadcast transmission in RBCs. It is observed that better overall outage performances and considerable power gains can be obtained by utilizing cooperative broadcast transmissions compared to traditional orthogonal schemes.