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[Display omitted] • Surface nitriding strategies were designed. • The degree of surface nitridation of the catalyst was regulated by controlling the calcination time. • The introduction of N atoms altered the electron transfer capacity of the catalyst and facilitated the generation of the key intermediate *OCH. • N-CuBi 2 O 4 exhibits excellent methanol production performance in CO 2 RR. Developing a high-performance electrocatalyst for converting CO 2 into methanol is of utmost importance. However, poor selectivity, and unavoidable competitive hydrogenolysis reaction (HER) are still challenges to be solved. In this study, a surface nitrided strategy was designed to synthesize a series N-copper-bismuth bimetallic oxide electrocatalysts (NCBO-t, t = 1, 2, 4 h) for CO 2 RR. The electrocatalyst NCBO-2 demonstrated a selectivity for methanol reaching 86.43 %, along with an impressive long-term stability lasting for 11 h, all achieved at a relatively low potential of −0.9 V. Experimental results and density functional theory (DFT) calculations indicated the introduction of nitrogen facilitates methanol production by optimizing binding of the reaction intermediate *OCH while promotes Faradaic efficiency of methanol products by suppressing the competitive HER, resulting in high Faradaic efficiency, current density, and stability of CO 2 RR at low overpotentials. This study offers a feasible idea for synthesis of high-performance CO 2 methanol by electroreduction. [ABSTRACT FROM AUTHOR]

[Display omitted] • Silicon nanopillar arrays(Si-NPAs) with high light absorption are used as substrates for photodetectors to improve light utilization. • Large-area coating deposition of layer less MoS 2 on the surface of three-dimensional silicon nanopillar arrays. • Combining MoS 2 with silicon to form a heterojunction reduces the silicon surface compound, boosting the photocurrent and reducing the dark current. • The use of reticulated, high-transmittance conductive thin Ag nanowires as the upper electrode provides multiple paths for electron transport without affecting light absorption and enhances the photodetector response speed. Two-dimensional MoS 2 has shown great potential in the photoelectric field because of its excellent optical and electrical properties. However, the performance of MoS 2 -based planar photodetector is constrained by the short transmission path and limited light absorption capacity of the planar thin layer of MoS 2. In this paper, highly sensitive MoS 2 /silicon nanopillar arrays(Si-NPAs) photodetector by coating the surface of silicon nanotrap light array with MoS 2. The interaction between light waves and silicon nanopillars and MoS 2 is significantly enhanced by the Fabry-Pérot-enhanced Mie resonance between pillars as well as the multiple reflection. In the meantime, a Van der Waals heterojunction is constructed between the MoS 2 and Si-NPAs coated across a large area. This is beneficial to address the poor performance of traditional two-dimensional photodetectors in light absorption and prevent the surface recombination of silicon-based photodetectors. According to the research results,the detector has 4.15 × 102 excellent rectification characteristics and 1.93 × 103 high switch ratio, and the photovoltaic effect is significant. The average external quantum efficiency of MoS 2 /Si-NPAs photodetector is 61.2% in the visible and near infrared bands, which is twice that of MoS 2 /planar silicon photodetector. At 850 nm, the responsiveness of the MoS 2 /Si NPAs photodetector is 0.48 A/W. the detection rate reaches 1.058 × 1012cm·Hz 1/2 W−1, which is 10.7 times higher than that of MoS 2 /planar silicon photodetector. To sum up, this study contributes a fresh idea to the design and application of high-performance devices. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • A recrystallization-annealing strategy was developed to fabricate alkalinized g-C 3 N 4 and TiO 2 composite. • The C N bond was dissociated while C OH was formed. • Synergetic effect of adsorption and photocatalysis enhanced the degradation of methylene blue. Abstract This work reports the fabrication of alkalinized g-C 3 N 4 and its composite with TiO 2 via recrystallization-annealing strategy. The increased surface basicity boosted the fast adsorptive removal of methylene blue (MB) while the cooperated TiO 2 enhanced the degradation of adsorbed MB via photocatalysis. The synthesized materials were characterized by XPS, SEM, TEM, PXRD, BET surface area, FT-IR, EDX and TG analyses. TiO 2 nanoparticles were uniformly distributed in the framework of alkalinized g-C 3 N 4 which increased the surface area of g-C 3 N 4. Na was incorporated into g-C 3 N 4 via thermal treatment, and the bond between C and N was dissociated while that between C OH was formed. The alkaline and negatively charged surface of g-C 3 N 4 upon Na addition established a strong electrostatic interaction adsorption scenario with MB leading to higher adsorption efficiency of TiO 2 /Na-g-C 3 N 4 (90%) than pristine g-C 3 N 4 (80%). MB removal efficiency was further intensified (from 90% to 100% within 120 min) upon the sequential operation of adsorption followed by photocatalytic degradation over TiO 2 /Na-g-C 3 N 4 under visible light irradiation. This study can be deemed of potential applications for the removal of MB and similar dyes on industrial level using the newly synthesized TiO 2 /Na-g-C 3 N 4 and synergistic adsorption-photocatalytic oxidation approach. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • A novel synthesis route for porous metal oxide at three length scales is proposed. • The UV/visible photocatalytic activity of porous TiO 2 is 2.1/6.3 times of P25. • It shows high capacity of 100 mA h/g at 5 C, far better than commercial TiO 2. Abstract A feasible route with a dual-templating method including both ice and SiO 2 hard templates to fabricate hierarchical porous TiO 2 with micro-, meso-, and macro-pores from inorganic/organic metal oxo cluster precursors is proposed. As-prepared TiO 2 shows high photocatalytic activity and excellent electrochemical performances. The current strategy can be applied to fabrication of a broad range of metal oxide materials for catalysis and energy related applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • Hierarchical Ti-doped Co 3 O 4 miscrospheres with abundant oxygen defects was prepared. • Ti-doped Co 3 O 4 miscrospheres with more oxygen vacancies had a response of 64.9 to 50 ppm xylene. • Ti-doped Co 3 O 4 miscrospheres with more defect oxygen ions had a response of 57.2 to 50 ppm toluene. • The Ti-doped Co 3 O 4 miscrospheres showed excellent selectivity, repeatability, and stability. Vast efforts have been made to develop high-performance gas sensing materials for the detection of harmful volatile organic compounds (VOCs) like toluene and xylene. However, it is challenging to selectively detect toluene and xylene simultaneously. Herein, the hierarchical Ti-doped cobalt layered hydroxides miscrospheres were synthesized first and sintered at high temperature consequently to prepare hierarchical Ti-doped Co 3 O 4 miscrospheres. The incorporation of Ti into the lattice of Co 3 O 4 decreased the crystal sizes and crystallinity, resulting in higher specific surface area and more oxygen defects. Interestingly, the 3 at.% Ti-doped Co 3 O 4 miscrospheres sintered at 450 °C exhibited the highest response of 64.9 to 50 ppm of xylene at 210 °C, while the 1 at.% Ti-doped Co 3 O 4 miscrospheres calcined at 500 °C displayed the highest response of 57.2 to 50 ppm of toluene at 240 °C, which were about 11.8 and 7.8 times higher in comparison with pristine Co 3 O 4. The different selectivity of Ti-doped Co 3 O 4 to toluene and xylene arises from the different amounts of oxygen vacancies and defect oxygen ions. The obtained Ti-doped Co 3 O 4 microspheres also showed the merits of good selectivity, repeatability and long-term stability, indicating the promising applications of Ti-doped Co 3 O 4 miscrospheres in the detection of toluene and xylene. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel microcapsule system was constructed for sensitive detection of H 2 O 2 at high temperature. • The microcapsules were based on PCM core, electroactive layer, and surface-immobilized catalase. • The microcapsules show a high latent heat capacity for thermal regulation of H 2 O 2 biosensor. • The biosensor exhibits an enhanced ability for H 2 O 2 determination due to in-situ thermal management. • The biosensor finds great potential for detecting the H 2 O 2 level over a broad working temperature range. To address the deterioration in electrochemical biosensing detection of hydrogen peroxide (H 2 O 2) caused by enzymatic inactivation in high-temperature environments, we have developed a novel type of catalase-immobilized electroactive phase-change microcapsules based on a phase change material (PCM) core, an SiO 2 shell, and a poly(3,4 -ethylenedioxythiophene)/Au nanocomposite layer with the surface-immobilized catalase. The microcapsules not only show a well-defined core–shell microstructure with the desired chemical compositions, but also present a high latent heat capacity of over 130 J/g for thermal regulation. An electrochemical biosensor was established using the microcapsule-modified working electrode to obtain a high electrochemical response to H 2 O 2 through combining the highly electroactive layer with covalently bonded catalase. The developed biosensor achieved an enhanced electrochemical biosensing response to H 2 O 2 through regulating the microenvironmental temperature surrounding the working electrode by the latent heat release of its PCM core to prevent enzymatic inactivation at high temperature. Compared to conventional H 2 O 2 biosensors without thermal management by PCMs, the developed biosensor exhibits a higher sensitivity of 42.85 µA·mM−1·cm−2 and a lower detection limit of 3.56 µM at a high working temperature of 50 °C. The developed biosensor has found practical applications for sensitive detection and accurate determination of H 2 O 2 level in real food and biological samples over a wide temperature range. [ABSTRACT FROM AUTHOR]

[Display omitted] • Titania oxide with a shrubby morphology was prepared on carbon cloth to trigger SERS "hotspots" with a high-density. • The structure-dependent SERS and photocatalysis performance were investigated for as-prepared CC/TiO 2 /Ag hybrid substrates. • An actual detection of quercetin in teas was achieved by the self-cleaning SERS substrate. Constructing of plasmonic substrate with the capability of detecting nutritional food quality will soon be emerged as the frontier research directions with broad prospects in surface-enhanced Raman scattering (SERS) technology ascribed to an improvement of living standards. Herein, a novel TiO 2 framework with a shrubby morphology was successfully constructed on carbon cloth (CC) matrix to trigger significantly enhanced electromagnetic "hotspots" after dense Ag network with numerous sharp corners and edges was formed by a photo-induced reduction. Particularly, the structure-dependent optical performance was investigated for these as-prepared CC/TiO 2 /Ag hybrid substrates, screening out an optimal one with an enhancement factor of 6.38 × 107. Regarding a prominent photocatalytic efficiency ascribed to the high electron-hole separation efficiency assisted by the CC matrix and Ag decoration, a recyclable SERS-based monitoring of quercetin (QR) was achieved in teas, demonstrating recovery values distributed from 88.9 % to 106.4 %. The strategy proposed here opened a new way to create high-density "hotspots" for multifunctional SERS substrates, which might play a crucial role in food quality monitoring applications. [ABSTRACT FROM AUTHOR]

A composite of polyaniline nanofiber/large mesoporous carbon (PANI-F/LMC) hybrid was prepared by an in situ chemical oxidative polymerization of aniline monomer with nano-CaCO 3 templated LMC as host matrix for supercapacitors. The morphology, composition and electronic structure of the composites (PANI-F/LMC) together with pure PANI nanofibers and the LMC were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), FT-IR, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). It is found that the PANI nanofibers were incorporated into the large mesochannels of LMC with interpenetrating framework formed. Such unique structure endows the PANI-F/LMC composite with a high capacitance of 473 F g −1 at a current load of 0.1 A g −1 with good rate performance and cycling stability, suggesting its potential application in the electrode material for supercapacitors. [ABSTRACT FROM AUTHOR]

A series of Pt/CeO 2 catalysts with different Pt contents were prepared using an incipient wetness impregnation method and tested for CO oxidation. Kinetic study on the catalysts indicated that the reaction rate was independent of the partial pressures of CO and O 2 ( r = k app [CO] 0 [O 2 ] 0 ). The derived reaction pathways involved chemisorption of CO on surface Pt atoms and reacting with lattice oxygen provided by the CeO 2 support at the Pt–CeO 2 interface, suggesting a Mars van-Krevelen type reaction on these catalysts and the interfacial Pt–O–Ce ensembles being the active sites. Also, turnover frequencies (TOFs) calculated based on Pt dispersion and periphery Pt atoms were found to be proportional to the Pt particle size, with the large Pt particles possessing higher TOF than the small ones. Such a trend was interpreted by the important role of the oxygen vacancies via the formation of Pt–Ce–O solid solution, which could accelerate the mobility of lattice oxygen and consequently the activity. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ultra-high quality O/N co-doped graphene with high surface area is derived from biomass. • Intrinsic Ca-containing species in biomass transfers into CaO during pyrolysis process. • The imbedded CaO functions as template and catalyst to generate hierarchical porous graphene. • KOH effectively facilitated the graphene formation and enhanced the porosity. • Biomass-based graphene exhibits excellent supercapacitive performance. Ultrahigh-quality graphene with structural hierarchy has been successfully fabricated through a novel and effective bioinspired in situ self-catalyzing strategy with camphor leaves as a renewable carbon source. The intrinsic Ca-containing species in biomass transfers into CaO via the intermediate of CaCO 3 during the pyrolysis process, and the finally imbedded CaO functions as in situ hard template and catalyst to generate hierarchical structure and construct the graphitic structure. The utilization of KOH effectively facilitated the graphene formation and enhanced the porosity of the carbon materials. The resultant graphene possesses many advantages for supercapacitor application, including large surface area, hierarchical porosity (crosslinked micro/meso/macroporous vacancies), well-organized graphene layers and favorable dually co-doping of O/N, thereby contributing to rapid charge transportation on the electrode/electrolyte interface, fast diffusion of electrolyte ions and high conductivity. When directly used as supercapacitor electrode (without the mixture of any conductive agent), as-produced graphene exhibited a specific capacitance of 397F/g at a current density of 1.0 A/g with a high rate retention of 74% from 1 to 20 A/g in a three-electrode system with 6 M KOH aqueous electrolyte. The high-quality graphene prepared from biomass via a readily scalable method opened up new vision towards high performance applications in energy storage and conversion. [ABSTRACT FROM AUTHOR]

[Display omitted] • We fabricated a type of phase-change microcapsules with surface-constructed Ni(OH) 2 nanoflowers. • The resultant microcapsules show a well-defined layer-by-layer core-shell microstructure. • The microcapsules achieve a significant enhancement in heat transfer and thermal response. • The microcapsules exhibit a satisfactory latent-heat capacity and stable thermal energy-storage process. • This study offers a new design of phase-change microcapsules with fast thermal response. A phase-change microcapsule system based on an n -docosane core and SiO 2 /nanostructural Ni(OH) 2 layer-by-layer shell was designed with the aim to enhance the heat transfer and thermal response capability of phase-change microcapsules. This system was fabricated through emulsion-templated interfacial polycondensation to form a SiO 2 / n -docosane microcapsule system, followed by anchoring Ni(OH) 2 nanoflowers on the surface of the SiO 2 shell via structure-directed interfacial precipitation. The resultant microcapsule system achieved a satisfactory latent heat-storage capacity of around 130 J/g with high energy-storage efficiency over 99%. Compared to conventional SiO 2 / n -docosane phase-change microcapsules, this microcapsule system not only presents high thermal conductivity, rapid heat transfer rate, good leakage prevention capability, high heat charging-discharging stability, but also exhibits a good phase-change reversibility and resilience ability to perform repetitious solid-liquid phase transformations. The combination of traditional phase-change microcapsules with a nanostructural Ni(OH) 2 outer layer results in a significant enhancement in heat transfer, which makes the system a fast thermal response ability to satisfy a variety of applications where fast and stable thermal energy storage/release is required. Through constructing the Ni(OH) 2 nanoflowers on the surface of conventional phase-change microcapsules, this study offers a promising strategy for the design and fabrication of high-performance phase-change microcapsules with fast thermal response. [ABSTRACT FROM AUTHOR]

• NiCo 2 O 4 nano-flakes with different dopant concentrations of Ruthenium (NiCo 2-x Ru x O 4) are synthesized. • Ru dopant changes the valance state of Co, and adjust the ratio of Co2+/Co3+. • The free energy of the potential-determining step is reduced. • The optimized Ru-doped NiCo 2 O 4 exhibits excellent OER activities and smaller charge transfer resistance. Spinel oxide has a unique open structure, the existence of numerous empty interstitial sites is conducive to cation migration, so the valence of transition metal in spinel oxide is modifiable. Optimizing the valence state on the spinel surface has always been the focus of research because it is key for realizing efficient oxygen evolution reaction. In this paper, we introduced metal Ru into spinel oxide NiCo 2 O 4 to adjust the valence state of the cations on the spinel surface, achieving a suitable ion ratio of Co2+/Co3+. The catalytic performance is the best when the doping concentration of Ru is 5.7% (NiCo 1.7 Ru 0.3 O 4). In 1.0 M KOH, NiCo 1.7 Ru 0.3 O 4 required only 280 mV overpotential to drive the current of 10 mA·cm−2. The incorporation of Ru induces more Co2+ on the octahedral site and changes the valence state of Co, optimizing the adsorption of the oxygen intermediate. In addition, the coordinated charge transfer between Ru, Co, and Ni will also accelerate the reaction. These results confirm that the Ru doping process can not only change the electrochemical performance of spinel oxides but also provide new insights into the design of OER (Oxygen evolution reaction) catalysts. [ABSTRACT FROM AUTHOR]

• The low-electron-density defect is detected by positron annihilation spectra. • A quantitative correlation between defects and performance is demonstrated. • The correlation is pervasive in various materials and photochemical processes. • Decreasing the defect concentration would promote electron transfer rate. • The sample with lower defect concentration shows higher photochemical activity. Establishing definite correlations between specific defects and physicochemical processes is the prerequisite for applying defect-engineering to optimize material properties. However, systematic investigations are required to fulfill this task. In this work, for the first time, a kind of defect with low electron density is quantitatively demonstrated to be correlative with photocatalysis efficiency by using perovskite oxide Na 0.5 Bi 2.5 Ta 2 O 9 nanosheets as the model material, in which the defect was systematically introduced and engineered. More importantly, the correlation is found to be not only valid for photocatalysis in Na 0.5 Bi 2.5 Ta 2 O 9 , but also is pervasive in various materials and different photochemical processes, though it has been overlooked in previous reports. The defect with low electron density acts as the recombination center for photogenerated carriers, therefore it is detrimental to the photo(electro)chemical performance, and the elimination of this kind of defect will be critical for improving photochemical efficiency. [ABSTRACT FROM AUTHOR]

In this study, carbon-coated α-Fe 2 O 3 @Fe 3 O 4 heterostructures were designed and synthesized by a simple ball-milling and an auxiliary rheological phase method combined with carbothermal reduction. Due to the synergistic effect between α-Fe 2 O 3 and Fe 3 O 4 , the carbon-coated α-Fe 2 O 3 @Fe 3 O 4 heterostructures have an excellent electrochemical performance. In order to elucidate the reaction process, the types of gases produced during the pyrolysis of citric acid are preliminarily examined, and the possible chemical reactions are deduced from the experimental results. The Mössbauer spectrum is used to determine the relative ratio of α-Fe 2 O 3 to Fe 3 O 4. As an anode material for lithium ion batteries, a carbon-coated Fe 2 O 3 @Fe 3 O 4 electrode exhibits a high initial discharge/charge capacity of 1462.2/968.2 mAh g−1 and a good reversible capacity (971.5 mAh g−1) at a current density of 0.1 A g−1. Moreover, even after 200 cycles, a reversible capacity of 711.0 mAh g−1 can be maintained at a current density of 0.5 A g−1. • Preparation of carbon-coated Fe 2 O 3 @Fe 3 O 4 heterostructured electrode uses a simple and low-cost method. • The types of reducing gases in the pyrolysis of citric acid were determined and the chemical reaction was inferred. • The possible chemical reaction is deduced from the experiment. • The carbon-coated Fe 2 O 3 @Fe 3 O 4 heterostructured has achieved good rate performance and cycle stability. [ABSTRACT FROM AUTHOR]

[Display omitted] • A two-dimensional composite semiconductor was developed by in-situ growing reticular ZIF-67 film upon black phosphorus (BP) nanosheets. • An attractive synergistic chemical enhancement was triggered attributed to the efficient continued charge transfer process in the BP/ZIF-67 system. • A selective SERS enhancement of food additive molecules with different orbital structures was achieved. Semiconductor-based surface-enhanced Raman scattering (SERS) dependent on chemical mechanism has shown favorable selective enhancement and recognition capabilities. However, the limited Raman enhancement capability of conventional semiconductor-based still remains a great challenge in the effective monitoring of trace molecules in a practical complex environment. In this context, a novel two-dimensional composite semiconductor substrate was developed by in-situ growing reticular ZIF-67 mesoporous film upon black phosphorus (BP) nanosheets. An attractive synergistic chemical enhancement was triggered attributed to the efficient continued charge transfer process in the BP/ZIF-67 system. Particularly, a selective SERS enhancement of food additive molecules with different orbital structures was found owing to the coupling degree of intrinsic molecular resonance and photo-induced charge transfer. A sensitive detection of lycopene in beverage samples with a high recovery rate was finally realized by the BP/ZIF-67 composite substrate, which exhibited great potential in practical molecular selective recognition. [ABSTRACT FROM AUTHOR]

[Display omitted] • A RuSe 2 /MoSe 2 heterostructure was prepared for HER in alkaline media. • RuSe 2 nanoparticles was uniformly dispersed onto MoSe 2 rods. • The charge redistribution over interface of RuSe 2 /MoSe 2 facilitated charge transfer. • The RuSe 2 /MoSe 2 heterostructure exhibited good performance for HER in alkaline media. • DFT was performed to investigate the mechanism behind performance improvement. Despite being regarded as a favorable substitute for platinum-based catalysts in hydrogen evolution reaction (HER), molybdenum diselenide (MoSe 2) exhibits inferior electrocatalytic performance due to its inadequate conductivity and limited active sites. However, employing molecular engineering for modification holds great potential in significantly enhancing its performance, yet it still poses significant challenges. Herein, an interface engineering strategy was adopted to obtain RuSe 2 modified MoSe 2 composite catalysts (RuSe 2 /MoSe 2). In alkaline media, RuSe 2 /MoSe 2 exhibited a reduced overpotential of 147.8 mV at 10 mA cm−2 comparing with pristine MoSe 2 (351.8 mV). Experimental findings and density functional theory (DFT) calculations indicated that increased conductivity, enhanced hydrophily and optimized adsorption free energies of hydrogen contribute to its enhanced HER activity. This work opens up an interface engineering strategy for designing more efficient selenide-based electrocatalysts. [ABSTRACT FROM AUTHOR]

A novel surface ion-imprinted composite membrane was fabricated using layer-by-layer technology for selective adsorption separation of copper ion. The ion-imprinted multilayer was introduced on modified polyethersulfone substrates by electrostatic interaction. Photocrosslinking was initiated by adding 4,4′-diazostilbene-2,2′-disulfonic acid disodium salt and template ions were eluted by HAc solution. Effects of preparation and adsorption conditions, such as cationic polyelectrolyte species, crosslinking agent concentration, assembly layer number, pH and initial Cu(II) concentration, on adsorption behaviors were investigated. Fourier transform infrared spectroscopy, scanning electron microscopy, atomic force microscope and X-ray photoelectric spectroscopy were used for the characterization of the copper ion-imprinted membrane (Cu-IIM). Batch adsorption experiments for studies of adsorption kinetics, adsorption selectivity and stability were conducted. The maximum adsorption capacity reached up to 48.0 mg·g −1 when 3.5 bilayers were deposited on the surface of membrane under specific experimental conditions (C 0  = 200 mg·L −1 , pH 6.0, 400 mL, 25 °C). The Cu-IIM exhibited a higher selectivity for copper ions when competitive ions were present. In addition, the Cu-IIM showed good stability. Moreover, according to the observation of the surface color change of the Cu-IIM during the adsorption process, the membrane could be used for qualitative concentration detection of copper ions in aqueous solution. [ABSTRACT FROM AUTHOR]

The paper reports a study on a near-UV blue photoluminescence (PL) in graphene oxide (GO) films prepared by Langmuir–Blodgett (LB)-based method. GO films was reduced into reduced-graphene oxide (rGO) through thermal process at 800 °C. The surface morphology of both GO and rGO is characterized by atomic force microscope (AFM) and scanning electron microscope (SEM). X-ray photoelectron spectroscopy (XPS) analysis shows the largely restoration of graphitic domains in GO after reduction. The photoluminescence (PL) of rGO shows the near-UV blue emission, which is blueshifted along with luminescent decreased as compared to GO. This blueshift and decrease in PL is mainly due to the newly formed sp 2 clusters in rGO, which established percolation pathways between the sp 2 clusters already present. [ABSTRACT FROM AUTHOR]

The paper reports an effective LB-based process to produce graphene oxide (GO). Uniform and controlled graphene oxide (GO) films were deposited on substrates by a simple and high-efficient Langmuir–Blodgett (LB)-based method. The influence of thermal reduction on GO films was systematically characterized and the annealing temperature of 800 °C was considered the most effective for reduction of GO. The optical and electrical properties were investigated for different reduced GO films to obtain the excellent sheet resistances of 440–620 Ω/sq with 60–70% range of light transparencies. A tunable surface wettability of GO films was found after heat treatment. [ABSTRACT FROM AUTHOR]

Highlights: [•] Al substitution in LaMnO3 structure promoted redox property of the catalyst. [•] Al substitution in LaMnO3 structure enhanced surface acidity of the catalyst. [•] Activity was determined by synergy of reducibility and surface acidity of catalyst. [•] Intrinsic activity was related to the presence of high valent Mn4+ species. [ABSTRACT FROM AUTHOR]

Highlights: [•] Palladium nanoparticles with diameters of 3–10nm were prepared by in situ method that ethanol was reduction agent. [•] Electrospinning technology was applied to obtain heterogeneous PVP-supported Pd NPs composite nanofibers films catalyst. [•] This catalyst is high-activity, stabilized; reusable, catalytic activity remains unchanged after recycling three times. [Copyright &y& Elsevier]

Abstract: Using ascorbic acid as the reducing agent, AgNO3 as the source of Ag, the ultrafine silver powder was prepared by liquid-phase reduction method. The optimal conditions to prepare the ultrafine silver powder were obtained by studying the effects of following factors, such as the selection of dispersant, the doses of dispersant and pH, on the dispersibility of silver powder under other constant conditions. The pure ultrafine silver powder with quasi-spherical shape and mean size of 1.15μm was synthesized under the optimal conditions of polyvinyl alcohol (PVA) as disperser, PVA/AgNO3 mass ratio of 4:100 and pH 7 while maintaining other conditions exactly in the same circumstances, such as AgNO3 concentration of 0.20molL−1, ascorbic acid concentration of 0.15molL−1 and reaction temperature of 40°C. The ultrafine silver powder was characterized by SEM and XRD. And a PVA dispersive mechanism for preparing highly dispersive ultrafine silver powder, proved by the ultraviolet spectra, is that PVA absorbed on the surface of silver particles by coordination bond preventing the silver particles from diffusion and aggregation. In addition, the steric effect may help to reduce aggregation. [Copyright &y& Elsevier]

• O 2 molecule is very hard to dissociate spontaneously on Ga 2 O 3 nanosheet. • O 2 molecule physisorption enhance the non-radiative decay. • H 2 O molecule adsorption has weak effects on Ga 2 O 3 nanosheet. • Ga 2 O 3 nanosheet exhibits extremely high air-resistance. 2D Ga 2 O 3 nanosheet with ultra-high carrier mobility and wide bandgap has gained extensively interests due to its great potential in next generation of solar-bind photodetectors, high-power devices, and gas sensors. However, the study of the stability and air-resistance of Ga 2 O 3 nanosheet is scare up to now. Herein, we investigate the stability and electronic properties of Ga 2 O 3 in air through first-principles calculations. It is found that O 2 molecule can physisorb on Ga 2 O 3 nanosheet with the binding energy of −0.12 eV, while it is very hard to dissociate spontaneously due to an extremely high dissociation energy barrier of 4.78 eV. The O 2 molecule physisorption can introduce extra energy levels in the bandgap and affect the optical properties of Ga 2 O 3 nanosheet. While H 2 O molecule adsorption has weak effects on the structural and electronic properties of Ga 2 O 3 nanosheet. The high air-resistance of Ga 2 O 3 nanosheet is attributed to the strong charge transfer between the Ga and O ions, which avoids the surplus electrons induced by the dangling bonds to interact with foreign molecules. These theoretical results indicate Ga 2 O 3 nanosheet has extremely high stability to resist oxidation and humid environment, which is a very promising next-generation 2D material for high-power and ultraviolet applications. [ABSTRACT FROM AUTHOR]

• The 2H-MoTe 2 /β-Ga 2 O 3 (01) heterojunction has a type I band alignment, with valence and conduction band offsets of 0.16 eV and 3.56 eV, respectively. • The heterojunction diodes exhibit the rectifying ratio of 105 and on-current density of up to 1 mA/cm2. • Abnormal build-in potential in the heterojunction diode could be attributed to an interfacial layer of MoO X evidenced by TEM and XPS measurements. Beta phase gallium oxide (β-Ga 2 O 3) has attracted wide attention due to its unique material property; however, the lack of p-type doping hinders its practical application. Here, we report a 2H-MoTe 2 /β-Ga 2 O 3 (2 - 01) vertical p-n heterojunction diode via chemical vapor deposition, which exhibited excellent rectification characteristics with a rectifying ratio of 105, and an on-current density of up to 1 mA/cm2. The depletion comes from strain-free interface of the 2H-MoTe 2 and β-Ga 2 O 3 (2 - 01) by van der Waals force. The band offsets and the interface element distribution of the heterojunction were investigated by the X-ray photoelectron spectroscopy and transmission electron microscope. The valence and conduction band offsets between the 2H-MoTe 2 and β-Ga 2 O 3 were consequently determined to be 0.16 eV and 3.56 eV, with a nested gap (type I) band alignment. Moreover, an abnormal build-in potential was observed in the 2H-MoTe 2 /β-Ga 2 O 3 p-n heterojunction diode which could be attributed to the formation of an interfacial layer of MoO X. These observations in the 2H-MoTe 2 /β-Ga 2 O 3 heterojunction show the great potential in optoelectronic devices. [ABSTRACT FROM AUTHOR]

• P123@SrTiO 3 shows high efficiency of photocatalytic hydrogen reduction performance, which is 31 times of SrTiO 3. • The P123@SrTiO 3 heterojunction was synthesized by one-step solvothermal method. • The hydrophilic heterojunction greatly improves the surface conductivity and inhibits the recombination of photogenerated carriers. Surface modification is a key strategy for promoting the photocatalytic performance of nanoparticles. In this work, triblock copolymer P123 (PEO-PPO-PEO) has been used as a surfactant in the synthesis of SrTiO 3. Instead of removing P123 by annealing after the synthesis process, the photocatalytic performance of P123@SrTiO 3 heterostructures was evaluated. Compared with SrTiO 3 , the hydrophilicity of P123@SrTiO 3 has been greatly improved. Poly ethylene oxide and its copolymers have excellent affinity for carriers and contribute to carriers transfer. At the same time, the improvement of surface wettability is beneficial to reduce the adsorption energy of water molecules, which speeds up the frequency at which carriers react with water molecules. As a result, photocatalytic hydrogen production of P123@SrTiO 3 reaches as high as 402 μmol·g−1·h−1 in the absence of any cocatalyst, which is 31 times that of pure SrTiO 3. However, the specific surface area of P123@SrTiO 3 is only 5.2 times that of SrTiO 3. P123@SrTiO 3 retained high catalytic activity after a long reaction. The construction of surface hydrophilic heterojunction provides a new idea for the design of photocatalytic materials. [ABSTRACT FROM AUTHOR]