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A dual temperature-responsive triblock polymer (poly(N-isopropyl acrylamide)-block-poly(N,N-dimethyl acrylamide)-block-poly(acrylamide-co-acrylonitrile)) (P(AM-co-AN)-b-PDMA-b-PNIPAM) (NDAA) was obtained by sequential reversible addition–fragmentation chain transfer (RAFT) polymerization,with the uncharged UCST temperature-sensitive block P(AM-co-AN) and the classic LCST-type temperature-sensitive block PNIPAM. This well-defined thermo-responsive copolymer with tunable compositions exhibits a dual thermal response behavior in water. Properly designing the length of the block can make the block copolymer undergo a phase transition within the envisaged temperature range. When the concentration is 5 wt%, the UCST of the NDAA polymer is around 20 °C, and the LCST is around 31 °C. All three blocks of these polymers are soluble in water within 20–31 °C. At high temperature, PNIPAM hydrophobically aggregates into a core, and NDAA self-assembles into a core1 (PNIPAM)–shell (PDMA)–corona1 (P(AM-co-AN)) structure. In contrast, at low temperatures, P(AM-co-AN) forms hydrogen bonds and is insoluble in water, and NDAA self-assembles into a core2–shell–corona2 structure. In this way, it is possible to prepare spontaneously reversible micellar aggregates in water. After the concentration reaches the lowest critical concentration, the NDAA polymer can undergo a reversible gel behavior, that is, a phase transition occurs near the UCST and LCST. This change in the polarity of the micelle core opens up the possibility of dissolving different compounds in water just by changing the temperature. [ABSTRACT FROM AUTHOR]

A brand new pH and thermo-responsive amphiphilic ABC triblock copolymer of poly(acrylic acid)-block-poly(N,N-dimethyl acrylamide)-block-poly(acrylamide-co-acrylonitrile) (PAA-b-PDMA-b-P(AM-co-AN)) was synthesized via sequential reversible addition–fragmentation chain transfer (RAFT) polymerization. Due to the pH-responsive blocks of PAA and thermo-responsive blocks of P(AM-co-AN), the properties of the copolymer solution were controlled by varying parameters such as temperature and pH. Specifically, it formed different nanostructures and showed gel behavior under different conditions. In detail, under high temperature alkaline conditions, ADAA was dissolved in an aqueous solution in the form of a molecular chain. Thereafter, when the temperature became lower or pH became acidic, the triblock copolymer self-assembled into different micelle structures, including shell–core, core–shell–core and tighter core–linking–core nanoparticles. In addition, the phase transition temperature of the copolymer was adjusted by pH and concentration. When the copolymer hydrogel was injected into a simulated human body device, it showed sustained drug release behavior and low transient drug concentrations. MTT experiments demonstrated the good biocompatibility of the ADAA hydrogels. This research provides inspiration to develop new polymers which are expected to be promising candidates as part of drug delivery platforms. Compared with traditional responsive hydrogels, its UCST can be easily controlled and is more stable through the feeding ratio, making it more advantageous in human drug delivery applications. In summary, we believe that this UCST and pH-responsive injectable ADAA hydrogel is researchable and applicable in the biomedical field. [ABSTRACT FROM AUTHOR]

Type II samples were obtained from the adjacent positions of the same crystal and annealed at different temperatures for 96 h. The nonlinear optical properties of these annealed samples, including nonlinear optical absorption (NLA) and nonlinear refraction (NLR), were measured at the third-harmonic-generation (THG) wavelength (355 nm) of a picosecond Nd:YAG laser by the Z-scan method. The NLA coefficient β and NLR index n were obtained by fitting the experimental data. According to the fitting result, the nonlinear absorption at 355 nm is identified as two-photon absorption and a nonlinear refraction index with a positive sign indicates the generation of a self-focusing effect. Our experiments showed that thermal annealing remarkably affected the nonlinear optical properties of 70% deuterated DKDP crystals. Both of the NLA coefficient β and NLR index n decrease with the increase of annealing temperature. At the optimum annealing temperature of 150 °C, the β and n of the type II THG sample were 3.5 × 10−2 cm GW−1 and 2.31 × 10−7 cm2 GW−1, which were only 25% and 45% that of the unannealed sample, respectively. The laser-induced damage threshold (LIDT) was measured at the THG wavelength (355 nm) of a nanosecond Nd:YAG laser by the R-on-1 method. The effect of annealing on the LIDT and on the nonlinear optical properties showed a similar trend, indicating that the process of crystal damage is related to NLA and NLR. [ABSTRACT FROM AUTHOR]

Transition metal phosphides (TMPs) have been one of the ideal candidates as low-cost and high-efficiency catalysts for hydrogen evolution reactions (HERs). We report herein a novel TMP architecture, Fe2P nanoparticles/reduced graphene oxide (rGO) nanosheets/Fe2P nanoparticles (Fe2P@rGO) sandwich-structured (Fe2P@rGO) nanowall arrays on a Ti plate. This nanostructure was easily prepared via one-step electrodeposition followed by a low-temperature phosphidation reaction. The Fe2P@rGO nanowall array film is featured with maximally exposed catalytic sites, fast electron and mass transport, and robust structure stability, and therefore it behaves as an excellent HER electrocatalyst. The Fe2P@rGO shows a low overpotential of 101 mV at a current density of 10 mA cm−2 and a small Tafel slope of 55.2 mV dec−1 with a large exchange current density of 0.146 mA cm−2. Furthermore, the catalyst exhibits superior durability evidenced by about 87% catalytic activity retention against about 55% for the commercial Pt/C catalyst after a 12 h test. The study presents a new nanoengineering strategy for high-performance TMP-based HER catalysts. [ABSTRACT FROM AUTHOR]

In this work, we for the first time synthesized nitrogen, boron co-doped curved graphene nanoribbons (NBCGNs) by a facile hydrothermal process using oxidized curved graphene nanoribbons (O-CGNs), urea and boric acid as the carbon precursor and heteroatom sources. The influence of N and B co-doping on the morphology, structure, composition and related electrochemical performance of the NBCGNs was systematically investigated, and the results show that urea and boric acid coexisting in the hydrothermal system not only act as the N and B doping sources but also act as the catalysts to boost the synergistical doping of N and B. It is the synergistical effect of N and B co-doping that endows the NBCGNs with enlarged specific surface area as well as pore volume, improved conductivity, promoted sulfur dispersibility and strengthened adsorbability for polysulfides caused by the notably increased doped N and B contents and higher percentage of the N–B structure when compared with the counterparts. As a result, the as-prepared NBCGN/S cathode presented synergistically enhanced cyclability and rate capability. Therefore, our results not only provide a superior carbon host for Li–S batteries but also offer a common approach to the preparation of heteroatom doped carbon nanomaterials with an optimized structure and composition. [ABSTRACT FROM AUTHOR]

Nitrogen-rich carbon material derived from carbon self-repairing g-C3N4 is self-assembled with graphene oxide (GO) to form a porous structure. Different from the pristine g-C3N4, which has scarcely been employed in supercapacitors because of its low charge mobility, the carbon self-repairing g-C3N4 (C-C3N4) shows an improved electrochemical activity. After carbon-repairing, a delocalized big π-bond can be formed by the homogeneous C-substitution for N atoms or the formation of new interstitial C–N bond. The extending π-conjugation planar layer of C-C3N4 possesses a closer contact with GO to form a three-dimensional (3D) pore structure, which ensures good mobility for electrons and quick access for electrolytes. Under the optimum C-repairing content of 5.99 at%, the C-C3N4@rGO exhibited high specific capacity of 379.7 F g−1 and energy density of 52.7 W h kg−1 at a current density of 0.25 A g−1. Moreover, the electrode kept 85% capacity retention after 10 000 cycles at a high constant current density of 10 A g−1. The active sites of pseudocapacitance can be confirmed in the oxygen-containing groups and the carbon atoms close to the nitrogen by the XPS results. [ABSTRACT FROM AUTHOR]

In this work, V2O5 with an interesting “L”-shape is successfully prepared by a simple hydrothermal method without using any surfactant or template. The formation mechanism of “L”-shaped V2O5 has been proposed. We have also investigated the effect of fluoride on the morphology, crystal structure and adsorption ability of the samples. The samples are characterized by scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM) with select area electron diffraction (SAED), X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, UV-vis diffuse reflectance spectroscopy (UV-DRS), photoluminescence (PL) spectroscopy and N2 sorption isotherms. It is found that the addition of fluoride can restrain the formation of “L”-shaped V2O5, resulting in the high-energy {010} facets being exposed and an increased number of oxygen vacancies. Density functional theory (DFT) calculations and PL spectra further confirm the results above. As a result, F-doped V2O5 shows a significantly improved adsorption capacity for methylene blue (MB) compared to the undoped one. The adsorption kinetics follows well a pseudo-second-order model, with correlation coefficients (R) higher than 0.99. [ABSTRACT FROM AUTHOR]

It is still a big challenge to facilely tune the energy bands of a semiconductor. Herein, we have mainly investigated energy bands and photochemical properties of Bi6S2O15 and Bi2O(OH)2SO4, which have very similar layered structures. It is found that the hydroxyls have down shifted the conduction band (CB, 0.21 eV) and valence band (VB, 4.39 eV) of Bi2O(OH)2SO4, compared with those (CB = 0 eV; VB = 3.36 eV) of Bi6S2O15. Moreover, the main oxidative species of Bi6S2O5 and Bi2O(OH)2SO4 are holes (h+) and hydroxyl radicals (ṖOH) for the degradation of rhodamine B (RhB) dye, respectively. This obvious difference has been mainly attributed to the hydroxyls, which have changed the energy band structure and the band gap. In addition, we have also investigated the morphology-dependent properties of Bi2O(OH)2SO4. Under ultraviolet light irradiation (λ≤ 420 nm), Bi2O(OH)2SO4 microspheres show an activity 1.3 times and 2.2 times higher than the long flakes and straw sheaves for the degradation of (RhB), respectively. This study provides us a new idea that we can facilely tune the energy band of a semiconductor by introducing or removing hydroxyl or other anions. [ABSTRACT FROM AUTHOR]

In this study, a potential ilmenite cathode material Ni0.9TiO3 is designed for efficient CO2 electrolysis in an oxide-ion-conducting solid-oxide electrolyzer. Spatially confined catalysis has been successfully achieved to substantially improve cathode activity by in situ growth of catalytically active nickel nanoparticles on a ceramic skeleton. The combined analysis of XRD, SEM, EDS, XPS, TGA and Raman results together confirm that the growth of nickel catalyst is completely reversible in redox cycles. The n-type electrical properties of cathodes are systematically investigated and correlated to electrochemical performance. Efficient CO2 electrolysis with a Faraday efficiency above 90% has been demonstrated with Ni0.9TiO3 in contrast to 60% for a TiO2 cathode at 800 °C. [ABSTRACT FROM AUTHOR]

A composite cathode based on lanthanum chromate has uncovered tremendous potential for direct high temperature electrolysis. Unfortunately, a major setback of insufficient electrocatalytic activity limits the efficient carbon dioxide electrolysis. In this paper, catalytically active Ti is doped to partially replace Cr at the B-site in perovskite La0.75Sr0.25Cr0.5−xFe0.5TixO3−δ (LSCrFT, x = 0, 0.1, 0.2, 0.3, 0.4 and 0.5) to improve the polarization and electrocatalytic property of the cathode materials of the solid oxide electrolyzer. The transition of the dominant mechanism from p-type conduction to n-type conduction is observed for the LSCrFT cathode with the Ti doping level at x = 0.3. The doping of Ti in LSCrFT largely improves the electrode activity and therefore reduces electrode polarization resistance. A high-temperature CO2 electrolysis test demonstrates that the Faraday efficiencies of LSCrFT (x = 0.1) cathodes are enhanced by approximately 30% in contrast to bare LSCrF cathodes at 800 °C. [ABSTRACT FROM AUTHOR]

A composite cathode based on redox-stable La0.2Sr0.8TiO3+δ (LSTO) can perform direct carbon dioxide electrolysis; however, the insufficient electro-catalytic activity limits the electrode performances and current efficiencies. In this work, catalytically active scandium is doped into LSTO to enhance the electro-catalytic activity for CO2 electrolysis. The structures, electronic conductivities and ionic conductivities of La0.2Sr0.8Ti1−xScxO (LSTSxO) (x = 0, 0.05, 0.1, 0.15 and 0.2) are systematically studied and further correlated with electrode performances. The ionic conductivities of single-phase LSTSxO (x = 0, 0.05, 0.1 and 0.15) remarkably improve versus the scandium doping contents though the electrical conductivities gradually change in an adverse trend. Electrochemical measurements demonstrate promising electrode polarisation of LSTSxO electrodes and increasing scandium doping contents accordingly improve electrode performances. The Faradic efficiencies of carbon dioxide electrolysis are enhanced by 20% with LSTS0.15O in contrast to bare LSTO electrodes in a solid oxide electrolyser at 800 °C. [ABSTRACT FROM AUTHOR]

It is still a big challenge to facilely tune the energy bands of a semiconductor. Herein, we have mainly investigated energy bands and photochemical properties of Bi6S2O15 and Bi2O(OH)2SO4, which have very similar layered structures. It is found that the hydroxyls have down shifted the conduction band (CB, 0.21 eV) and valence band (VB, 4.39 eV) of Bi2O(OH)2SO4, compared with those (CB = 0 eV; VB = 3.36 eV) of Bi6S2O15. Moreover, the main oxidative species of Bi6S2O5 and Bi2O(OH)2SO4 are holes (h+) and hydroxyl radicals (ṖOH) for the degradation of rhodamine B (RhB) dye, respectively. This obvious difference has been mainly attributed to the hydroxyls, which have changed the energy band structure and the band gap. In addition, we have also investigated the morphology-dependent properties of Bi2O(OH)2SO4. Under ultraviolet light irradiation (λ≤ 420 nm), Bi2O(OH)2SO4 microspheres show an activity 1.3 times and 2.2 times higher than the long flakes and straw sheaves for the degradation of (RhB), respectively. This study provides us a new idea that we can facilely tune the energy band of a semiconductor by introducing or removing hydroxyl or other anions. [ABSTRACT FROM AUTHOR]

The successful development of efficient and stable catalysts for 4-NP reduction reactions is beneficial to the environment and ecology. Fe 3 O 4 @Pt exhibits excellent catalytic performance for 4-NP reduction reaction due to the synergistic effect between Fe and Pt. But its structure and catalytic performance are extremely unstable. Here, we utilized the small-scale organic compound 2-hydroxyethylamine as surfactant to construct a stable composite nanomaterial. Then investigated the influence of monochromatic light (650 nm, 808 nm and 980 nm) and temperature on the kinetics of 4-NP reduction reaction by 2-hydroxyethylamine stabilized Fe 3 O 4 @Pt. The results indicate that both temperature and monochromatic light radiation can affect kinetic regulation. Increasing temperature can promote the catalytic rate, while monochromatic light radiation can induce agglomeration and inhibit the catalytic rate. This study opens up a new way for developing and regulating catalysts for heterogeneous catalysis reactions., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Reasonable design of bimetallic nanomaterials with support is beneficial to improve catalytic performance. This work reports a new kind of sodium sesquicarbonate-supporting Fe 2 O 3 @Pt via etching Fe 3 O 4 @Pt@SiO 2 , which exhibits highly efficient and stable catalytic reduction performance towards 4-NP. Sodium sesquicarbonate-supporting Fe 2 O 3 @Pt has an interconnected one-dimensional network structure that provides sufficient channels for mass transfer. At the same time, a large amount of Fe 2 O 3 @Pt is exposed on its surface, which hinders the aggregation of pt clusters and Fe 2 O 3 nanoparticles, and facilitates the direct contact of Fe 2 O 3 @Pt reaction sites with reactant molecules, thus improving the catalytic rate of 4-NP reduction reaction. Moreover, the introduction of non-metallic Fe can not only reduce the consumption of precious metal Pt, but also improve the catalytic efficiency due to the synergistic effect. This study opens up a new avenue to develop robust catalysts for heterogeneous catalytic reactions., Competing Interests: There are no conflicts to declare, (This journal is © The Royal Society of Chemistry.)

It is still a big challenge to facilely tune the energy bands of a semiconductor. Herein, we have mainly investigated energy bands and photochemical properties of Bi6S2O15 and Bi2O(OH)2SO4, which have very similar layered structures. It is found that the hydroxyls have down shifted the conduction band (CB, 0.21 eV) and valence band (VB, 4.39 eV) of Bi2O(OH)2SO4, compared with those (CB = 0 eV; VB = 3.36 eV) of Bi6S2O15. Moreover, the main oxidative species of Bi6S2O5 and Bi2O(OH)2SO4 are holes (h(+)) and hydroxyl radicals (˙OH) for the degradation of rhodamine B (RhB) dye, respectively. This obvious difference has been mainly attributed to the hydroxyls, which have changed the energy band structure and the band gap. In addition, we have also investigated the morphology-dependent properties of Bi2O(OH)2SO4. Under ultraviolet light irradiation (λ ≤ 420 nm), Bi2O(OH)2SO4 microspheres show an activity 1.3 times and 2.2 times higher than the long flakes and straw sheaves for the degradation of (RhB), respectively. This study provides us a new idea that we can facilely tune the energy band of a semiconductor by introducing or removing hydroxyl or other anions.

Composite cathodes based on Sr0.94Ti0.9Nb0.1O3 (STNO) can be utilized for direct steam electrolysis; however, the insufficient electrocatalytic activity limits electrode performance and current efficiency. In this work, redox-reversible (Sr0.94)0.9(Ti0.9Nb0.1)0.9Ni0.1O3 (STNNO) with A-site deficiency and B-site excess has been designed as a cathode material in an oxide-ion-conducting solid oxide electrolyzer for direct steam electrolysis. The XRD, TEM, SEM, EDS, TGA and XPS results together confirm that the exsolution or dissolution of Ni nanoparticles anchored on the STNO surface is completely reversible in the redox cycles. The electrical properties of STNO and STNNO are investigated and correlated to electrode performances. The current efficiency with an STNNO cathode is enhanced by about 20% compared to the values with a bare STNO cathode in 5% H2O/H2/Ar or 5% H2O/Ar at 800 °C. The synergetic effect of catalytically active nickel nanoparticles and the redox-stable STNO skeleton contributes to the improved performance and excellent stability of the cathode for steam electrolysis.