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The first synthesized porous Pd59W8Rh19Bi14 metallene combines OH adsorption effects, electronic effects and C–C bond cleavage site strategies to improve EOR performance. The metallene stable structure further accelerates the mass transfer rate.

As ammonia is an important chemical raw material, a lot of efforts have been made in the field of electrochemical nitrogen reduction (NRR) to promote artificial nitrogen fixation. At present, research on NRR is widely focused on improving the catalyst's adsorption and activation of N2. However, it has not yet been studied how to promote the desorption of NH3 by the catalyst to obtain continuous and stable catalytic activity. Herein, we synthesized Pd octahedrons and icosahedrons with similar sizes and studied the role of twins in NRR for the first time. At −0.2 V vs. RHE, the Pd icosahedron achieved a high NH3 yield and FE, which were 17.56 μg h−1 cm−2 (43.9 μg h−1 mgcat.−1) and 31.98%, respectively. After 200 h of electrolysis, the NH3 yield of Pd icosahedrons did not significantly decrease, which maintained excellent catalytic stability. Its performance is better than other catalysts that have been reported. In situ FTIR measurements and DFT calculation proved that due to the existence of the twin structure, the energy required for the potential-determining step and the NH3 desorption step of the Pd catalyst is greatly reduced. Accelerating the desorption of NH3 improves the utilization of active sites due to which the Pd icosahedron maintains continuous excellent catalytic activity. This provides a new direction for the design of catalysts to improve their NRR performance.

H2O2 has a wide range of uses as an oxidant and is also utilized as a high density and environmentally friendly fuel. In this study, crystalline g-C3N4 was modified with K+, Ni and N-doped carbon by thermal-polymerization of Ni2+-anchored and polyvinyl pyrrolidone-encapsulated melamine-cyanuric acid supramolecules, followed by re-calcination in a KCl–LiCl mixture. The obtained strip-like g-C3N4 nanocrystals exhibited high charge separation efficiency and good light absorption capability. Density-functional theory calculations confirmed that the orbital hybridization of Ni–N atoms enabled the formation of charge-transfer channels, which can capture electrons, achieve enhanced oxygen adsorption and reduction via a two-electron pathway. Under the synergistic effects of K+, Ni and N-doped carbon dopants and crystallinity, the obtained sample exhibited high photocatalytic H2O2 yields of 79.6 μM in O2-saturated pure water, which was 10-fold higher than the yield using pristine g-C3N4. This work provides a novel design for production of highly efficient photocatalysts for H2O2 production.

In this work, holey graphitic carbon nitride(HCN) was prepared by one-step thermal polymerization of hydrothermal product of melamine and then loaded with Ni/MoO2(NiMo) cocatalyst obtained by NaBH4 reduction process. The obtained material was used for photocatalytic production of H2 from water reduction and H2O2 production from O2 reduction. The best photocatalyst(l% NiMo/HCN) exhibited a H2 evolution rate of 8.08 Omol/h while no H2 was detected over 1% NiMo-modifed bulk g-C3N4(BCN) under visible light illumination. Moreover, this rate is 1.7 times higher than that of 1% Pt-modified HCN. The 1% NiMo/HCN catalyst also exhibited the highest H2O2 production activity with a value of 6.13 μmol/h. Such enhancement was ascribed to the efficient charge carrier separation and migration, which were promoted by the large specific surface area and pore volume of HCN and the synergy between MoO2 and Ni. The proposed method to obtain HCN is expected to open up new ways in development of highly-active HCN-based photocatalysts for photocatalytic reduction reactions.

Solar-driven photocatalytic water-splitting for H2 production holds great promise to alleviate the growing energy and environmental crisis. Nevertheless, it is still challenging up to now to develop noble-metal-free photocatalysts which are efficient for the H2 evolution reaction (HER). In this work, based on the ion-exchange and alloying reactions between Zn and Cd ions in liquids, a template-assisted ion-exchange strategy combined with subsequent electrostatic assembly process was employed to prepare uniform ZnS@CdS@Cd0.5Zn0.5S-MoS2 hollow nanospheres for the first time. Under visible-light irradiation (λ > 420 nm), the ZnS@CdS@Cd0.5Zn0.5S-MoS2 hybrid exhibits an optimal HER activity of 50.65 mmol h−1 g−1, which is 20 times more than that of its Pt-decorated ZnS@CdS@Cd0.5Zn0.5S counterpart and superior to that of most CdS-based photocatalysts ever reported. Moreover, the ZnS@CdS@Cd0.5Zn0.5S-MoS2 hybrid exhibits good stability for the long-term HER. The outstanding HER capability of ZnS@CdS@Cd0.5Zn0.5S-MoS2 could be attributed to the dramatically facilitated separation of charge carriers, abundant active sites from the defect-rich 1T/2H MoS2 few-layered nanosheets, and enhanced light-harvesting of the hollow nanostructure. The findings indicated here could benefit the exploitation of high-performance photocatalysts for promising solar-to-fuel applications.

The electrochemical N2 reduction reaction (NRR) under ambient conditions is highly attractive. However, it is still a challenge to achieve a high NH3 yield rate at low overpotential. Herein, we report RuO2 nanoparticles with different degrees of surface selenation, which show excellent NRR performance at low overpotential. The NH3 yield rate and FE of RuO2–Se0.18/C reach 12.97 μg h−1 cm−2 and 26.01% at −0.1 V vs. RHE, respectively, which is the highest NH3 yield rate reported at low overpotential. The RuO2–Se0.18/C catalyst also shows excellent stability. The related NH3 yield rate stays pretty constant after 50 h of electrolysis. The density functional theory (DFT) calculations show multiple promoted-synergism of surface selenation on the RuO2 catalyst. First, optimized surface selenization could drive the adsorption of N2 on RuO2 sites. Second, surface hydrogenation promoted by surface selenization can suppress the hydrogen evolution reaction (HER, competitive reaction), enabling high NRR performance at low potential. Third, optimizing the surface selenization on RuO2 can promote N2 activation (*N2 → *NNH). Fourth, surface selenization can promote NH3 desorption (the rate-limiting step).

Both an excess and shortage of iron(III), away from normal permissible limits, can induce serious disorders, therefore its detection is significant, but still remains a challenge. Luminescent metal–organic frameworks (LMOFs) are a class of attractive materials for the detection of Fe3+ ions. However, improvement in their hydrolytic stability, speed, sensitivity, and selectivity of function is the key to the advanced application of LMOFs in an aqueous environment. Herein, two hydrostable LMOFs, Zn-DTA and Cd-DTA, based on the π-conjugated aromatic ligand 2,5-di(1H-imidazol-1-yl)terephthalic acid (H2DTA), were selected as highly efficient sensors for the rapid, sensitive and selective detection of Fe3+ in aqueous solutions. On the basis of the rigid structure and multiple coordination sites of the H2DTA ligand, Zn-DTA and Cd-DTA possess brilliant stability and excellent fluorescence emission. Both of them exhibit high selectivity (Ksv = 8400 and 6420 M−1) and high sensitivity (0.82 and 1.07 μM) for the rapid detection (less than 30 s) of small quantities of Fe3+ (0.2 mg mL−1) in water. It is worth noting that the compounds not only remain stable in the water for a long time but also maintain structural integrity at high temperatures. To the best of our knowledge, Zn-DTA and Cd-DTA, as two exceptionally stable MOF chemosensors used for the selective detection of Fe3+, show very rare behavior compared to the reported Zn/Cd-MOFs. The quenching mechanism for such a high selectivity can be mainly explained by the competition between the absorption of Fe3+ and the excitation of the compounds. Moreover, the introduced carboxyl O atoms of Zn-DTA additionally donate their lone-pair electrons to the Fe3+ ions, leading to enhanced detection ability. Our work reveals the enormous potential of LMOFs as an appealing platform upon which to construct sensing materials.

A K, P, N-co-doped hollow carbon polyhedron (KPN-HCP) was prepared by two-step calcination of triphenylphosphine@ZIF-8, which was then used to modify CdSe quantum dots (QDs). The effect of the dopants on the photocatalytic activity of CdSe QDs for H2/H2O2 production and tetracycline degradation was investigated. Through post-calcination in KCl-LiCl, the hollow polyhedron morphology was retained in KPN-HCP, and the graphitization degree increased. The introduction of P atoms followed by K+ doping could significantly enhance light harvesting, and accelerate electrons transfer from CdSe QDs to HCP. The H2 evolution rate and apparent rate constant of TC degradation for CdSe/KPN-HCP were 39.9- and 7.5-fold larger than those for CdSe QDs, respectively. The yield of H2O2 for CdSe/KPN-HCP in water was 900.0 μmol g−1 after 60 min. This work provides new insights for design of QD-based photocatalysts with high photocatalytic H2/H2O2 evolution, and tetracycline degradation activity.

A series of stable glycine/palygorskite (GLY/PAL) nanohybrid absorbents were prepared by incorporating GLY molecules into PAL via a simple high-pressure homogenization. The structural characterization demonstrated that 3.15% of GLY molecules were incorporated into the GLY/PAL hybrid adsorbent and formed H-bonding interactions with siloxane and inner channels of PAL, which caused slight distortion of the crystalline framework. Compared with conventional surface modification, high-pressure homogenization and heat treatment enabled GLY to insert into PAL channels well to form hybrid nanostructure. Among all hybrid absorbents, the 60GLY/PAL showed the highest adsorption capacities of 147 mg/g for methyl violet (MV) and 80 mg/g for Cs(I) as well as the removal ratios of 98% for MV and 80% for Cs(I) from 150 mg/L of MV and 100 mg/L of Cs(I) solutions, respectively. In contrast, raw PAL (without modification) could adsorb only 112 mg/g of MV and 45 mg/g of Cs(I). This work has demonstrated that utilizing a simple high-pressure homogenization process improved stability of GLY/PAL nanohybrid absorbents by increasing the incorporation of guest (GLY) molecules into the tunnels/channels of hosts (PAL), leading to a novel enhanced adsorbent for Cs(I) and MV. This finding has provided a new way to fabricate nanohybrid adsorbents.

Two novel inorganic–organic hybrid zinc phosphites, namely, [Zn(1,2-bimb)0.5(HPO3)]n (1) and [Zn(1,4-bmimb)0.5(HPO3)]n (2), (1,2-bimb = 1,2-bis(imidazol-1ylmethyl)benzene; 1,4-bmimb = 1,4-bis((2-methyl-1H-imidazol-1yl)methyl)benzene) were synthesized for the first time by hydrothermal reaction. Compound 1 generates a three-dimensional (3D) pillared-layer structure with a 2-nodal 3,4-connected 3,4T15 topology. While compound 2 exhibits a 2D hybrid zinc phosphite sheet with a 3,4-connected 3,4L83 topology network. Utilizing compound 1 and compound 2 as templates and Na2S as an etching agent, a series of highly efficient ZnO/ZnS photocatalysts were obtained. The optimized 1-160 sample demonstrates the highest evolution rate of 22.6 mmol g−1 h−1, exceeding the rate of commercial ZnS samples by more than 14.5 times. The remarkable photocatalytic activity should be attributed to the unique heterojunction structure which shortens the free path of charge carriers and enhances the charge separation efficiency. This work provides a facile strategy for preparing photocatalysts with efficient photocatalytic hydrogen production derived from inorganic–organic hybrid material.

Correction for ‘Designed synthesis of unique ZnS@CdS@Cd0.5Zn0.5S-MoS2 hollow nanospheres for efficient visible-light-driven H2 evolution’ by Bowen Sun et al., CrystEngComm, 2020, 22, 2743–2755, DOI: 10.1039/D0CE00064G.

Magnetically superhydrophobic oil sorbent was prepared by directly immobilization of Fe 3 O 4 nanoparticles on the surface of kapok fiber and subsequent hydrophobic modification. The results show that the as-prepared fibers demonstrated excellent superhydrophobicity and magnetic responsivity. They also exhibited high separation efficiency for oil/water mixtures and can quickly absorb floating oils on water surface via magnetic driving. Compared with raw fiber, the oil sorption capacity of as-prepared fiber for n -hexane, toluene, chloroform, paraffin oil, gasoline, and diesel can increase by 70.8%, 58.5%, 96.1%, 23%, 37.3%, and 30.5%, respectively. Furthermore, the fibers can be used to continuously separate a large quantity of oil contaminants from water surface by means of a vacuum pump. Importantly, the water contact angel still can reach above 143° after being repeatedly used several times and immersed in various oils and harsh water environments for long time period, implying excellent recyclability and chemical durability in the oil sorption. The findings suggest that the magnetically superhydrophobic kapok fiber has the prospect of potential applications in the removal and recovery of spilled oil contaminants.

In this work, the rational design of phosphidated MoS2 (P-MoS2) nanosheets decorated on CdS nanoparticles (NPs) is reported. First, the P-MoS2 nanosheets were obtained by the phosphidation of MoS2 at 300 °C and using NaH2PO2 as P source. Then, the coupling of P-MoS2 nanosheets with CdS NPs was completed by a hydrothermal treatment. The photocatalytic performance of resulted composite was evaluated by evolution of H2 from water splitting. The experimental results revealed that the P-MoS2/CdS composite containing 20% P-MoS2 exhibited an optimum H2 evolution rate as high as 58.9 µmol h−1, which was 2.9 and 2.3 times higher than that of the pristine CdS (20.5 µmol h−1) and 0.2MoS2/CdS (26.1 µmol h−1), respectively. The improved activity of P-MoS2/CdS composite compared to MoS2/CdS can be ascribed to (i) its enhanced visible-light absorption, (ii) its efficient electron-hole separation resulting from the enhanced conductivity of P-MoS2, the positive conduction band potential of P-MoS2 in comparison with that of MoS2, and (iii) the more exposed active sites on P-MoS2 resulting from the enlarged interlayer spacing. This work may open up a new avenue to explore other hybrid co-catalysts to enhance the charge separation and thus the photocatalytic H2-evolution performance of semiconductors.

A series of palygorskite samples modified with electrolytes including KCl, KBr, KI, KH 2 PO 4 , KHSO 4 , K 2 HPO 4 , K 2 SO 4 , and K 3 PO 4 were prepared with the aid of high pressure homogenization. The changes of electrokinetic and rheological properties, as well as suspension stability of obtained palygorskite, were investigated through measurement of the zeta potential, flow curve, and sedimentation volume. The influences of charge, concentration, and type of anions on surface charge density of palygorskite were compared. The correlation among the surface charge, the rheological behavior, and suspension stability of palygorskite was discussed. The homogenization process could favor the migration of anions onto palygorskite. It was found that the structure maker anions (H 2 PO 4 − , HSO 4 − , HPO 4 2 − , SO 4 2 − , and PO 4 3 − ) made the surface of palygorskite more negatively charged. The flow curve measurements demonstrated that the association capacity of rods depended on the surface potential of palygorskite. A stable suspension was obtained when palygorskite was dispersed in K 2 SO 4 solutions and homogenized at 30 MPa.

A three-layer Back-Propagation neural network has been developed to predict the limiting temperature of steel planar tubular truss under fire. The input parameters of the network model include the diameter ratio (β), the wall thickness ratio (τ), the diameter–thickness ratio (γ) and the load ratio. The output parameters include the limiting temperature. In this paper, the training and testing samples of the neural network were obtained by using the finite element software ABAQUS. 105 sets of data were used to train the Back-Propagation neural network; 15 sets of data were used to test and validate the BP network. In the process of training the Back-Propagation network, the Levenberg–Marquardt Back-Bropagation algorithm was adopted. The ‘tansig’ function was adopted in the hidden layer, and the ‘purelin’ function was adopted in the output layer. The results obtained by analyzing show that the prediction of the limiting temperature using the Back-Propagation network model is accurate and effective.

Attapulgite (APT) is a natural one-dimensional nanorod with higher mechanical strength and shows great potential as an effective reinforce filler for deriving nanocomposites. The dispersion degree and aspect ratio of APT are keys to decide the performance of nanocomposites. However, natural APT cannot develop its nanometer reinforce advantages because it usually appears as a crystal bundle or aggregate. In this work, we effectively disaggregate the crystal bundles of APT by a simple high-pressure homogenization technology at various pressures. The obtained nanometer APT as an ideal reinforce filler was introduced into chitosan (CS)/poly(vinyl alcohol) (PVA) matrix to derive a series of nanocomposites by the solution casting method. The CS/PVA/APT nanocomposites were characterized by field emission scanning electron microscopy (FESEM) and Fourier transform infrared spectroscopy (FTIR). Tests results indicated that the nanometer APT can enhance the mechanical properties and water resistance of nanocomposites more obvious than pristine APT. The nanocomposites also were shown to be highly transparent and the introduction of APT into CS/PVA matrix nearly not affected the optical property of the films.

A series of palygorskite samples modified with electrolytes containing LiCl, NaCl, KCl, CsCl, MgCl2, CaCl2, AlCl3, and FeCl3 were prepared with the aid of high-pressure homogenization and mechanica...

Three azobenzene acrylate monomers containing alkyl spacers of different length were synthesized. Thermodynamic and mesomorphic properties of the monomers were measured by differential scanning calorimetry and polarizing optical microscopy. A crosslinker with the undecyl spacer was also synthesized to prepare crosslinked liquid-crystalline polymer films by photopolymerization. Polarized UV spectra and polarizing optical micrographs demonstrated that the mesogens are aligned homogeneously in the films. Low glass transition temperature of the films enabled them to bend near room temperature upon UV irradiation. Besides, the films generally bent away from the light source before they at last bent towards the light irradiation.

An acrylate monomer and diacrylate crosslinker containing a spacer of undecylene were synthesized and crosslinked liquid-crystalline polymer films with different crosslinking densities were prepared by photopolymerization of mixtures of the monomer and the crosslinker. Due to the relatively long spacer, distinct bending behavior was observed in the film with a low crosslinking density: when the temperature was lower than 90 °C, the film first bent away from the light source and then towards it upon the irradiation of UV light. As the temperature was raised above 90 °C, the film bent directly towards the light source. X-ray diffraction was used to probe the phase structures of the film at different temperatures and a plausible mechanism was presented to explain the distinct phenomenon. In addition, when the crosslinking density was increased, all the films bent directly towards the light source with faster speed, which is related to their modulus and order parameters.