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The cobalt-free high - nickel layered oxide possesses high capacity and controllable cost, positioning it as a prospective option for cathode materials in the future lithium-ion batteries (LIBs). However, the charge compensation effect and high nickel content usually cause serious cation mixing, resulting in poor capacity stability, and hindering its practical application. Here, three types of LiNi 0.9 Mn 0.1 O 2 microspheres with varying levels of cation mixing are constructed by simply adjusting the calcination temperatures, and the impacts of cation mixing on the electrochemical performance in LIBs are systematically investigated. By using XRD and cross-section STEM to characterize the levels of cation mixing, the resulting LiNi 0.9 Mn 0.1 O 2 after treated at 780 °C (denoted as NM91–780) shows a lower degree of cation mixing compared to other samples (NM91–720 and NM91–840). As a proof-of-concept application in LIBs, the NM91–780 exhibits remarkable cycling stability with 92.4% capacity retention after 100 cycles, along with excellent rate capability of 132.5 mAh g−1 at 10 C. In situ XRD analysis shows that the low cation mixing of NM91–780 inhibits harmful volumetric strain during the electrochemical process, providing structural and chemical stability for its long-term cycling. This investigation contributes to the advancement of commercializing cobalt-free high-nickel layered oxide LiNi 0.9 Mn 0.1 O 2 for use in LIBs. [Display omitted] • The relationship between temperature and cation mixing was investigated. • lower cation mixing promoted the consistency of the internal structure. • The electrochemical performance of NM91 was enhanced by reducing cation mixing. • The structure change caused by cation mixing in electrochemical process was explained. [ABSTRACT FROM AUTHOR]

Noble-metal hollow nanocrystals possess numerous unique advantages such as high surface-to-volume ratio and high utilization of noble metals, which make them a promising electrocatalyst for electro-oxidation of small molecules in fuel cells. Herein, we prepared bimetallic PdNi hollow nanocrystals (PdNi-HNCs) by taking advantage of the galvanic replacement reaction in an aqueous solution and developed a facile NiO-induced strategy for the controlled synthesis of PdNi-HNCs with dendritic or smooth outer shell architectures. A very short oxidation time of an amorphous Ni template is demonstrated to be the key factor to successful fabrication of the dendritic morphology. The results of electrochemical testing indicate that the electrocatalytic activities of PdNi-HNCs are highly dependent on their morphologies. The PdNi-HNCs with a rough and dendritic shell exhibit a mass activity of 1201.5 and 768.0 mA mg Pd −1 toward ethanol oxidation reaction (EOR) and formic acid oxidation reaction (FAOR), respectively, much greater than those of the commercial Pd black catalyst (502.6 and 266.3 mA mg Pd −1 , respectivlely). In particular, the 1500 cyclic voltammetry cycles in alkaline solution and the 30,000 s chronoamperometry tests in acid solution suggest an enhanced long-term durability of PdNi-HNCs with dendritic nanoarchitectures. We ascribe the better catalytic activity to the hollow feature, higher specific electrochemical surface area, more abundant active sites and more appropriate electronic structure of the PdNi-HNCs with a rough and dendritic shell. [ABSTRACT FROM AUTHOR]

Self-assembly of Keggin-type polyoxometalates (POMs) with diammonium ions containing oligo(ethylene oxide) units form parallelepiped or octahedral nanocrystals. These structures are tunable depending on the chemical structure of the ammonium ions and preparative conditions. The ether linkages in these ammonium ions exert conformational flexibility, which is essential to achieve long-range regular molecular alignments in the nanocrystals. [ABSTRACT FROM AUTHOR]

It is feasible and profitable to figure out multidiscipline environmental issues synergistically. Coal fly ash based adsorbent materials are widely used in the emission control of volatile organic compounds. A solvent-free method which was more environmental-friendly for ZSM-5 zeolites synthesis from coal fly ash was proposed to eliminate toluene. The results indicated that ZSM-5 zeolites were successfully synthesized from the precursor gel of coal fly ash with 30–60 wt% moisture contents. The SiO 2 /Al 2 O 3 mole ratio of gel was up to 99 after the pretreatment of alkali roasting and acid precipitation. During the synthesis process, the appropriate Na 2 CO 3 -to-SiO 2 ratio was 0.3, and the mesoporous formation would be facilitated along with the moisture content of gel. On the tendency of adsorption testing, the microporous structure was prone to the toluene adsorption, and the desorption was dependent on the mesoporous structure. The maximum adsorption capacity of 75.1 mg·g−1 was observed on S-40 sample, and the minimum desorption activation energy of 39.97 kJ·mol−1 was found on S-60 sample. The humid condition can reduce the toluene adsorption performance, and the maximum adsorption capacity was down to 63.7 mg·g−1. Additionally, the synthetic ZSM-5 zeolites still have some superiority in economics and ecology when compared with commercial zeolites. The novel synthesis method, preparing controllable ZSM-5 zeolites from coal fly ash with the advantages of low cost and environmental friendliness, exhibited the tremendous application potential in environmental field. [Display omitted] • Coal fly ash was roasted with Na 2 CO 3 at 800 °C for 2 h to enrich silicon materials. • Bulk gel with 30–60 wt% moisture content was suitable for ZSM-5 zeolite synthesis. • Mesoporous structure was accelerated to grow with moisture content increasing. • Dry condition transition into wet condition can reduce the adsorption capacity. • Microporous was prone to toluene adsorption but mesoporous for desorption. [ABSTRACT FROM AUTHOR]

In this study, multi-morphological g-C 3 N 4 / Fe 2 O 3 were prepared via hydrothermal supramolecular preorganization for the removal of formaldehyde in simulated indoor environments. We synthesized bulk, spherical and tubular g-C 3 N 4 under hydrothermal conditions and subsequently attached Fe 2 O 3 nanoparticles by impregnation method. Tubular g-C 3 N 4 /Fe 2 O 3 (27.46 m2/g) and spherical g-C 3 N 4 /Fe 2 O 3 (33.50 m2/g) synthesized through hydrothermal supramolecular preorganization method possessed the higher specific surface area than bulk g-C 3 N 4 /Fe 2 O 3 (11.05 m2/g). Among three morphologies of g-C 3 N 4 /Fe 2 O 3 , tubular g-C 3 N 4 /Fe 2 O 3 exhibited the best performance (65%) than bulk (41%) and spherical (59%) and possessed favorable stability. In addition, we explored and optimized the effects of different indoor simulation conditions (formaldehyde concentration, relative humidity, light source power) on the photocatalytic removal of formaldehyde. The mechanism was proposed that g-C 3 N 4 /Fe 2 O 3 formed Z-type heterojunction to promote the separation of photo-generated electrons and holes, further generating hydroxyl radical and superoxide radical to oxidize formaldehyde. • Diverse shapes g-C 3 N 4 /Fe 2 O 3 were prepared by simple hydrothermal and impregnation method. • g-C 3 N 4 /Fe 2 O 3 exhibited excellent efficiency and favorable stability for HCHO degradation. • Z-type heterojunction was formed to enhance the photocatalytic degradation of HCHO. [ABSTRACT FROM AUTHOR]

The past five years have witnessed the significant breakthrough of perovskite solar cells (PSCs). High certificated power conversion efficiency (PCE) of 22.1% was achieved in a short time after the inorganic-organic perovskite was firstly used as the light absorber in the solar cells. It is believed that PSCs now become one of the most promising photovoltaic in the new-generation solar cells, which may rival silicon based solar cells. In this article, simplified planar perovskite solar cells without a hole-blocking layer were fabricated by a two-step spin-coating method, and the highest PCE of 15.1% was achieved with an average PCE of 13.6%. Moreover, it is found that the hysteresis effect is reduced in this kind of devices. The research on improved performance for the PSCs with simplified device architecture is very important both for understanding the working mechanism of cells, and for fabricating low-cost and high-performance PSCs to approach commercial applications. [ABSTRACT FROM AUTHOR]

Organic-inorganic hybrid perovskite formamidinium lead triiodide NH 2 CHNH 2 PbI 3 (FAPbI 3 ), methylammonium lead triiodide CH 3 NH 3 PbI 3 (MAPbI 3 ) and formamidinium methylammonium lead triiodide (NH 2 CHNH 2 ) 1-x (CH 3 NH 2 ) x PbI 3 (FA 1-x MA x PbI 3 ) thin films were synthesized and deposited on indium tin oxide glass substrates by spin coating process. Thin films of mixed FA 1-x MA x PbI 3 (x = 0-1) perovskites obtained by mixing FAPbI 3 and MAPbI 3 in different proportions. The morphological, structural and optical proprieties of all synthetized perovskites have been analyzed as a function of the MA/FA ratio. X-ray diffraction analyses indicated the formation a cubic perovskite phase with space group Pm-3m in the composition range 0 ≤ x ≤ 1. Mixed perovskites FAMAPbI 3 showed a high absorbance in the infrared region 780-900 nm. The band gap energy estimated from absorbance spectral measurements for FAMAPbI 3 thin films ranges from 1.50 eV for FAPbI 3 to 1.56 eV for MAPbI 3 , respectively. The overall PL emissions of mixed FA/MA perovskite thin films are located in intermediate values between 773 nm and 810 nm. [ABSTRACT FROM AUTHOR]

Integrating thermo-responsive polymer switching materials (TRPS) into lithium-ion batteries (LIBs) has been recognized as one of the most effective strategies to prevent thermal runaway under various abuse scenarios. However, the current methods to obtain TRPS cannot satisfy different practical applications. Herein, we develop a versatile strategy for the preparation of various metal carbides (e.g. , tungsten carbide, molybdenum carbide) with controllable hierarchical structure that is featured with surface protrusion structure, which is critical for high conductivity and rapid thermal response. Systematic studies of the phase and morphology evolutions by advanced characterizations illustrate that the reducing agent and reduction rate are critical for developing the specific morphology. By using the above-mentioned carbides as the conductive fillers of TRPS, the resulting TRPS with a specially controlled shape exhibits over 5 order of conductivity improvement compared with common carbides with particulate morphology, in addition to reversible shutdown performance and effective thermal abuse protections toward safe LIB operation. [Display omitted] • A universal synthetic route to obtain metallic carbides with any desired hierarchically structured was developed. • Spherical-spiky tungsten carbides and hollow sphere molybdenum carbides were synthesized successfully. • Separated reduction-carbonization process and uniform carbon coating layer benefit the maintenance of the architecture. • Thermo-responsive polymer switching materials were fabricated to provide thermal abuse protection to NCMǁGr full cells. • 5 orders of magnitudes improvement on conductivity of thermo-responsive polymer switching materials is achieved. [ABSTRACT FROM AUTHOR]

Modulation of perovskite oxide toward controlled active facets and defects has attracted much attention. However, the influence of facets and defects on the photocatalytic activity are still ambiguous, especially for the alkaline-earth stannates. In this work, a high-efficiency CaSnO 3 semiconductor photocatalyst was prepared by a facile one-step molten salt method without adding a capping agent. By simply varying the solutes, three kinds of CaSnO 3 with different morphology were successfully synthesized, including sphere, cube, and cuboctahedron. Meanwhile, both the facet exposure and formation of defects affected the photocatalytic performance of CaSnO 3 samples. The formation mechanism for various CaSnO 3 morphology and their facet-dependent photocatalytic performances were explored in detail, which indicated that the formation of {100} facets was beneficial for the photocatalytic performance rather than {111}. Although these samples showed similar absorption edges, the varying amount of oxygen vacancy was one of the reasons for the diverse photocatalytic activity. The distortion of crystal structure of CaSnO 3 was due to the formation of reduced Sn, which could influence the bond and angle of Sn–O–Sn and subsequently the photocatalytic activity. Different scavengers were also used to identify the role of active species in the photo-degradation process. The relationships between surface electronic structure, oxygen vacancy, and oxidation state of B site with the photocatalytic activity of tin stannate were clearly revealed. [Display omitted] • Shape-controlled CaSnO 3 with Sn enrichment surface was successfully synthesized by one-step molten salt method. • The solutes were crucial to modulate the morphology and facets of CaSnO 3 crystals. • CaSnO 3 sphere with predominant {100} exposed facets showed highest photodegradation of methylene blue. • The effects of defects, exposed facets and reduced Sn on the photodegradation activity were studied. [ABSTRACT FROM AUTHOR]

The α-FeOOH nanorods with superb adsorption properties have been synthesised by a facile and scaled-up method. In this approach, KOH solution concentration plays a crucial role in controlling the morphology of α-FeOOH nanaocrystals. It has been demonstrated that the synthesised α-FeOOH nanorods are about 10 nm in diameter and 100 nm in length. The α-FeOOH nanorods have a high specific surface area (333 m2 g− 1), and exhibited super adsorption properties, with maximum adsorption capacity of 104.2 mg g− 1 for Congo red (CR). The as-prepared nanorods show a larger specific surface area than the nanoparticles do, which enhance their adsorption capacity and increase their potential for application in wastewater treatment. The adsorption process of CR on α-FeOOH nanorods was systematically investigated, which was found to obey the pseudo-second-order rate equation and Langmuir adsorption model. [ABSTRACT FROM AUTHOR]

Summary Solvothermal synthesis has advanced significantly over the past decades and became a versatile approach to achieve the morphology control of well-defined metal nanostructures. This review covers the most recent progress on the solvothermal syntheses and applications of metal nanocrystals. Key synthetic factors are summarized, including temperature, reaction time, solvent effects, ligand effects, facet-specific capping agent effects, and reductant effects. The synthetic strategies, growth mechanism, and enhanced properties of metallic nanocrystals and multimetallic nanocrystals are introduced. The perspectives in the solvothermal syntheses and applications of metal nanocrystals are discussed. [ABSTRACT FROM AUTHOR]

Photocatalysis is a green technology and has received increasing attention owing to its potential in solving environmental problems in a sustainable manner. Among the candidates of semiconductor photocatalysts, graphitic carbon nitride (g-C 3 N 4) stands out for environmental purification because of its elemental abundances, structure robustness, and high performances. In this paper, we present a mini review of sustainable photocatalytic remediation of micropollutants over morphology-engineered g-C 3 N 4. The methods for advanced morphology control of g-C 3 N 4 are discussed and insights into morphology-dependent photocatalysis over g-C 3 N 4 are unveiled. The review also provides perspectives of challenges and solutions to sustainable water purification over the metal-free polymer materials. [Display omitted] • Photocatalytic remediation over morphology-engineered g-C 3 N 4 are reviewed. • The methods for advanced morphology control of g-C 3 N 4 are discussed. • The morphology-dependent photocatalysis over g-C 3 N 4 are unveiled. • Future challenges and solutions to sustainable water purification using polymer materials are provided. [ABSTRACT FROM AUTHOR]

This paper reports the use of the hydrothermal method in the fabrication of pure BiFeO 3 (BFO) films with various morphologies [microparticle (BFO MP), microplate (BFO MPL), and microsheet (BFO MS)] on fluorine-doped tin oxide substrates and their applications in piezophotodegradation and piezophotoelectrochemical water splitting. These samples exhibited p-type characteristics, band gaps of approximately 2.1 eV, and favorable crystal. Piezoresponse force microscopy revealed that the piezoelectric coefficients of BFO MP , BFO MPL , and BFO MS were 13.0, 18.6, and 15.3 pm V−1, respectively. The associated piezotronic and piezophototronic characteristics of the samples were verified through facile current–voltage measurement, which revealed that BFO MPL outperformed BFO MP and BFO MS. Electrochemical and photoluminescence (PL) analyses demonstrated that BFO MPL possessed the highest electrochemical surface area per-unit mass (22.6 mF cm−2 mg−1) and the weakest PL emission. The combination of these characteristics and the favorable energy band positions under stress of BFO MPL contributed to its excellent piezophotocatalytic performance, with a piezophotodegradation rate constant of approximately 19.8 × 10–3 min−1 for methylene blue solutions, a piezophotoelectrochemical current density of approximately − 0.83 mA·cm−2 at −0.6 V (vs. Ag/AgCl) and a maximum piezo-induced applied bias photon-to-current conversion efficiency of 0.54% at −0.51 V. Based on the enhanced piezoelectricity, which can effectively enhance the separation of photogenerated electron-hole pairs, thus improving photocatalyst performance. BFO MPL also exhibited good reusability and versatility toward degrading different organic pollutants. The results indicate that our samples are promising for application in environmental sustainability. [Display omitted] • Hydrothermal fabrication of pure p-BiFeO 3 films with various morphologies [microparticle (BFO MP), microplate (BFO MPL), and microsheet (BFO MS)] on FTO substrates. • Piezotronic and piezophototronic measurement: BFO MPL outperforming BFO MP and BFO MS. • Electrochemical and PL analyses: BFO MPL possessing the highest electrochemical surface area per unit mass (22.6 mF cm−2 mg−1) and the weakest PL emission. • BFO MPL exhibiting excellent piezophotodegradation performance (19.8 × 10–3 min−1), a piezophotoelectrochemical current density [− 0.83 mA cm−2 at −0.6 V (vs. Ag/AgCl)], and a maximum piezo-induced applied bias photon-to-current conversion efficiency (0.54% at −0.51 V) • Our samples: promising for application in piezoelectricity-related fields [ABSTRACT FROM AUTHOR]

Summary: The ability to prepare inorganic nanocrystals with well-defined morphologies and sharp faces should facilitate the examination of their facet-dependent surface, catalytic, electrical, and other properties. In this review we cover different synthetic methods for the growth of Cu2O nanocrystals with morphological control. Cu2O nanocrystals with cubic, cuboctahedral, truncated octahedral, octahedral, and multipod structures have been prepared mainly by wet chemical, electrodeposition, and solvothermal synthesis methods. Methods used for the formation of hollow Cu2O nanocubes, octahedra, and truncated rhombic dodecahedra are also presented. Morphology of Cu2O nanocrystals can be expanded with the use of gold nanocrystal cores to guide the overgrowth of Cu2O shells. Surface properties of Cu2O nano- and microcrystals with sharp faces have been examined in a few studies. The {111} faces were found to interact well with negatively charged molecules, while the {100} faces are less sensitive to molecular charges. Preferential adsorption of sodium dodecyl sulfate molecules on the {111} faces of Cu2O crystals has been demonstrated via plane-selective deposition of gold nanoparticles on only the {100} faces. It is expected that the development of improved synthetic methods for Cu2O nanocrystals and more knowledge of their facet-dependent properties should lead to their applications in photoactivated energy conversion and catalysis. [Copyright &y& Elsevier]

Long-range exciton diffusion on picosecond time scale, which serves to efficient charge separation at the donor/acceptor (D/A) interfaces, has been regarded as a key step for the working mechanisms of organic photovoltaics. Rationally understanding and manipulating this vital process over a wide temporal scale remains some challenges, especially in ternary organic solar cells (OSCs). Herein, we reveal how exciton migration behaviors are reasonably improved and maintained relying on the simultaneously enhanced efficiency and thermal stability in the PM6:IT4F:PC 71 BM and PM6:BTP-4Cl:PC 71 BM ternary devices. Two separate factors can be responsible for these benefits: (1) the coexistence of dual Förster-type energy transfer (FRET) can contribute to the directed exciton diffusion and rapidly quench the highly excited states to stabilize the "energy donors". (2) The more favorable multi-length scale morphologies optimized by the addition of guest PC 71 BM yield the plentiful interfacial region to shorten the real distance of diffusion process and boost the stability of microstructure. In particular, the diffusion lengths > 10 nm of IT4F singlet excitons induced by dual FRET effects were obtained by employing the exciton-exciton annihilation strategy. These experimental results open a novel horizon for further strengthening efficiency and stability of ternary OSCs from the perspective of improving exciton diffusion. The improved exciton diffusion behaviors across a wide temporal scale have been obtained relying on the simultaneously enhanced efficiency and thermal stability in the PM6:IT4F:PC 71 BM and PM6:BTP-4Cl:PC 71 BM ternary organic solar cells. Two dominant separate working mechanisms are responsible for these benefits: (1) the coexistence of dual Förster resonance energy transfer (FRET) effects, and (2) the more favorable multi-length scale morphologies. ga1 • Effective exciton diffusion behaviors are obtained and well maintained across a wide temporal scale. • Dual FRET effects contribute to the directed exciton diffusion in ternary blends. • The diffusion lengths > 10 nm of IT4F singlet excitons are induced by dual FRET mechanisms. • The optimized multi-length scale morphologies shorten the real distance of exciton reaching the interface region. [ABSTRACT FROM AUTHOR]

PbWO4 particles with different morphologies were synthesised by controlling processing conditions, using lead nitrate and sodium tungstate as starting materials. Processing conditions were found to have close relation with morphologies of the final products, such as the kind of surfactant and reaction rate. The products were characterised by powder X-ray diffraction pattern, field emission SEM and TEM. The possible formation mechanism of PbWO4 particles was proposed. When excited at 245 nm, PbWO4 particles exhibit emission spectrum comprising different luminescent bands. [ABSTRACT FROM AUTHOR]