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Carbon neutral becomes one of the most important environmental goals due to the excessive emission of CO2. The reduction of CO2 into valuable chemicals or fuels is one of the important strategies to solve the carbon cycle and achieve carbon neutral. Atomic site catalysts show high activity and selectivity in CO2 reduction reactions. However, due to the complexity of the multistep CO2 reduction reaction, it is difficult for an isolated atomic site to achieve multi-functional requirements. Bimetallic atomic site catalysts can take advantage of the high activity and selectivity of atomic sites, and the synergies between bimetallic atomic sites can fully optimize the CO2 reduction reactions. In this review, firstly, we summarize the design considerations of catalysts for CO2 reduction reactions. Secondly, the preparation and characterization of bimetallic atomic site catalysts are reviewed. Thirdly, the role of bimetallic atomic sites in CO2 reduction reactions was analyzed in detail.

Copyright © 2022 The Authors. Microstructural evolution and mechanical properties of H13 steel fabricated by selective laser melting (SLM) with subsequent tempering treatment were systematically examined. It was found that the microstructure of the as-SLMed H13 samples consisted of cellular structures, lath martensite and high-volume fraction of retained austenite. After tempering at 600 °C for 1 h, the nanoscale Cr23C6 particles were detected at the boundaries of the partially dissolved cellular structures. The fine grains, the retained cellular structures, and the formation of Cr23C6 carbides significantly improved the mechanical properties of the H13 steel. A superior mechanical properties, including the yield strength (YS) of 1647 ± 29 MPa, ultimate tensile strength (UTS) of 2013 ± 35 MPa and elongation (El) of 4.1 ± 0.3% have been achieved in the SLMed H13 steel after tempering at 600 °C for 1 h. With the increase of tempering temperature to 700 °C, the cellular structures were completely dissolved and the high number density of coarse Cr23C6 carbides were formed, which led to the decrease of UTS at 1083 ± 21 MPa, while the elongation was significantly improved to 12.3 ± 1.2% due to the recovery of dislocation density and the decomposition of martensite in the H13 steel. National Key Research and Development Program of China (Grant No. 2020YFB0311300ZL), National Natural Science Foundation of China (Grant No. 52071343).

In this work, effect of Mo content on the microstructure, thermal conductivity, and corrosion resistance of the die steels was investigated by optical microscopy, scanning electron microscopy, x-ray diffraction, laser thermal conductivity meter, electrochemical experiments, and pitting tests. The microstructure of the die steels is mainly composed of lath-shaped tempered martensite. At all the tested temperatures, the thermal conductivity of the die steels is decreased with the increase in Mo content from 1.2 to 5.0 wt.%. However, electrochemical experiments indicate that increase in Mo content in the die steels can reduce the corrosion current density and increase the charge transfer resistance in 0.5 mol·L−1 HCl solution. Furthermore, it was found that Mo in the die steels is beneficial to decrease weight loss and pitting corrosion rate, which improves the pitting corrosion resistance of the die steels.

Electrochemical production of hydrogen peroxide (H2 O2 ) through two-electron (2 e- ) oxygen reduction reaction (ORR) is an on-site and clean route. Oxygen-doped carbon materials with high ORR activity and H2 O2 selectivity have been considered as the promising catalysts, however, there is still a lack of direct experimental evidence to identify true active sites at the complex carbon surface. Herein, we propose a chemical titration strategy to decipher the oxygen-doped carbon nanosheet (OCNS900 ) catalyst for 2 e- ORR. The OCNS900 exhibits outstanding 2 e- ORR performances with onset potential of 0.825 V (vs. RHE), mass activity of 14.5 A g-1 at 0.75 V (vs. RHE) and H2 O2 production rate of 770 mmol g-1 h-1 in flow cell, surpassing most reported carbon catalysts. Through selective chemical titration of C=O, C-OH, and COOH groups, we found that C=O species contributed to the most electrocatalytic activity and were the most active sites for 2 e- ORR, which were corroborated by theoretical calculations.

Step-scheme (S-scheme) heterojunctions have been extensively studied in photocatalytic carbon dioxide (CO

This paper describes a dynamic trajectory planning method for lane-changing maneuver of connected and automated vehicles (CAVs). The proposed dynamic lane-changing trajectory planning (DLTP) model adopts vehicle-to-vehicle (V2V) communication to generate an automated lane-changing maneuver with avoiding potential collisions and rollovers during the lane-changing process. The novelty of this method is that the DLTP model combines a detailed velocity planning strategy and considers more complete driving environment information. Besides, a lane-changing safety monitoring algorithm and a lane-changing starting-point determination algorithm are presented to guarantee the lane-changing safety, efficiency and stability of automated vehicles. Moreover, a trajectory-tracking controller based on model predictive control (MPC) is introduced to make the automated vehicle travel along the reference trajectory. The field traffic data from NGSIM are selected as the target dataset to simulate a real-world lane-changing driving environment. The simulations are performed in CarSim-Simulink platform and the experimental results show that the proposed method is effective for lane-changing maneuver.

The alkaline electrocatalytic hydrogen evolution reaction (HER) is a potential way to realize industrial hydrogen production. However, the sluggish process of H2O dissociation, as well as the accumulation of OH− around the active sites, seriously limit the alkaline HER performance. In this work, we developed a unique CoS2 needle array grown on a carbon cloth (NAs@C) electrode as an alkaline HER catalyst. Finite-element simulations revealed that CoS2 needle arrays (NAs) induce stronger local electric field (LEF) than CoS2 disordered needles (DNs). This LEF can greatly repel the local OH− around the active sites, and then promote the forward H2O dissociation process. The local pH changes of the electrode surface confirmed the lower OH− concentration and stronger local pseudo-acidic environment of NAs@C compared to those of DNs@C. As a result, the NAs@C catalyst exhibited a low HER overpotential of 121 mV at a current density of 10 mA cm−2 in 1 M KOH, with the Tafel slope of 59.87 mV dec−1. This work provides a new insight into nanoneedle arrays for the alkaline HER by electric field-promoted H2O dissociation.

Heteroatom-doping in metal-nitrogen-carbon single-atom catalysts (SACs) is considered a powerful strategy to promote the electrocatalytic CO

The effect of Ti addition on the microstructure and corrosion resistance of the as-cast Ti-stabilised Fe–17Cr ferritic stainless steels was investigated by optical microscopy, scanning electron mic...

Converting carbon dioxide (CO2) into value-added chemicals by CO2 reduction has been considered as a potential way to solve the current energy crisis and environmental problem. Among the methods of CO2 reduction, the electrochemical method has been widely used due to its mild reaction condition and high reaction efficiency. In the electrochemical reduction system, the CO2 electrocatalyst is the most important part. Although many CO2 electrocatalysts have been developed, efficient catalysts with high activity, selectivity and stability are still lacking. Copper sulfide compound, as a low-toxicity and emerging material, has broad prospects in the field of CO2 reduction due to its unique structural and electrochemical properties. Much progress has been achieved with copper sulfide nanocrystalline and the field is rapidly developing. This paper summarizes the preparation, recent progress in development, and factors affecting the electrocatalytic CO2 reduction performance with copper sulfide compound as a catalyst. Prospects for future development are also outlined, with the aim of using copper sulfide compound as a highly active and stable electrocatalyst for CO2 reduction.

With the fast development of society and industry, atmospheric levels of carbon dioxide (CO2) have increased seriously, becoming a threat to the world’s climate. Electrochemical transformation of CO2 into fuels and chemicals using copper (Cu)-based materials has attracted enormous attention. However, the competitive hydrogen evolution reaction (HER) heavily influences their efficiency. Thus, it is urgent to promote the CO2 reduction reaction (CO2RR) and suppress the competitive HER. In this work, enhanced CO2RR with suppressed HER was achieved on polytetrafluoroethylene (PTFE) coated Cu nanoneedles (CuNNs). The concentration of surface adsorbed CO2 could be enhanced via the field-induced reagent concentration (FIRC) effect through the CuNN structures. The hydrophobic PTFE can prevent the supply of protons to CuNNs and thus suppress the HER. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray absorption spectroscopy (XAS) revealed that the PTFE coated CuNNs maintained the nanoneedle structures and metallic Cu state during the catalytic reaction process. As a result, highly suppressed HER coupled with high C2 selectivity can be achieved on these PTFE coated CuNNs with a Faraday efficiency (FE) of 47% toward C2 products and an ultralow FE of 5.9% toward H2 at −1.49 V vs. RHE (without IR correction). This work provides an effective strategy to promote the CO2RR and suppress the competitive HER.

Monocular depth estimation is a foundation task of three-dimensional (3D) reconstruction which is used to improve the accuracy of environment perception. Because of the simpler hardware requirement, it is more suitable than other multi-view methods. In this study, a new monocular depth estimation algorithm based on graph convolution network (GCN) is proposed. The pixel-wise depth relationship is introduced into conventional convolution neural network (CNN) to make up the disadvantage of processing non-Euclidian data. And the remaining depth topological graph information on the spatial latent variables are extracted based on a multi-scale reconstruction strategy. The final results on NYU-v2 depth dataset and KITTI depth dataset demonstrate that our algorithm improves the quality of monocular depth estimation, especially there are several little objects coexisting in the scenes.

Electrochemical CO

Ruthenium (Ru)-based catalysts, with considerable performance and desirable cost, are becoming highly interesting candidates to replace platinum (Pt) in the alkaline hydrogen evolution reaction (HER). The hydrogen binding at Ru sites (Ru-H) is an important factor limiting the HER activity. Herein, density functional theory (DFT) simulations show that the essence of Ru-H binding energy is the strong interaction between the 4 d z 2 orbital of Ru and the 1s orbital of H. The charge transfer between Ru sites and substrates (Co and Ni) causes the appropriate downward shift of the 4 d z 2 -band center of Ru, which results in a Gibbs free energy of 0.022 eV for H* in the RuCo system, much lower than the 0.133 eV in the pure Ru system. This theoretical prediction has been experimentally confirmed using RuCo alloy-nanosheets (RuCo ANSs). They were prepared via a fast co-precipitation method followed with a mild electrochemical reduction. Structure characterizations reveal that the Ru atoms are embedded into the Co substrate as isolated active sites with a planar symmetric and Z-direction asymmetric coordination structure, obtaining an optimal 4 d z 2 modulated electronic structure. Hydrogen sensor and temperature program desorption (TPD) tests demonstrate the enhanced Ru-H interactions in RuCo ANSs compared to those in pure Ru nanoparticles. As a result, the RuCo ANSs reach an ultra-low overpotential of 10 mV at 10 mA cm-2 and a Tafel slope of 20.6 mV dec-1 in 1 M KOH, outperforming that of the commercial Pt/C. This holistic work provides a new insight to promote alkaline HER by optimizing the metal-H binding energy of active sites.

Converting CO

The alkaline electrocatalytic hydrogen evolution reaction (HER) is a potential way to realize industrial hydrogen production. However, the sluggish process of H

Two-dimensional (2D) materials have been utilized for the photoelectrochemical (PEC) production of hydrogen by water splitting, however the reaction performance of which is limited by thermodynamic protons adsorptions, the specific materials solar absorption spectrum, materials carrier mobility and lifetime. Here, we report a facile solution processed method for the synthesis of 2D In2Se x S3−x alloy films, in which the obvious crystalline to amorphous transition was observed as the annealing temperature decreased from 400 °C to 80 °C. Different porous nanostructures of the films have been created by the temperature controls, showing over 200% absorption in the near-infrared range for the sample that annealed at 400 °C than the other samples. The transient absorption measurements of crystalline samples are clearly shown the carrier lifetime is dramatically improved than the amorphous samples, which are critical to the hydrogen evolution performance. Finally, the PEC water splitting performances have been measured to discuss the structure-properties relations, showing the overpotentials reduction of over 100 mV for enhanced near-infrared absorption samples. This work clearly gives out the optical structure and crystal structure design strategy for improving the PEC performance.

Electrocatalytic hydrogen evolution reaction (HER) in alkaline media is a promising electrochemical energy conversion strategy. Ruthenium (Ru) is an efficient catalyst with a desirable cost for HER, however, the sluggish H2O dissociation process, due to the low H2O adsorption on its surface, currently hampers the performances of this catalyst in alkaline HER. Herein, we demonstrate that the H2O adsorption improves significantly by the construction of Ru–O–Mo sites. We prepared Ru/MoO2 catalysts with Ru–O–Mo sites through a facile thermal treatment process and assessed the creation of Ru–O–Mo interfaces by transmission electron microscope (TEM) and extended X-ray absorption fine structure (EXAFS). By using Fourier-transform infrared spectroscopy (FTIR) and H2O adsorption tests, we proved Ru–O–Mo sites have tenfold stronger H2O adsorption ability than that of Ru catalyst. The catalysts with Ru–O–Mo sites exhibited a state-of-the-art overpotential of 16 mV at 10 mA cm–2 in 1 M KOH electrolyte, demonstrating a threefold reduction than the previous bests of Ru (59 mV) and commercial Pt (31 mV) catalysts. We proved the stability of these performances over 40 h without decline. These results could open a new path for designing efficient and stable catalysts.

Atomically dispersed transition metal sites have been extensively studied for CO

Effect of crystallographic orientations on the corrosion resistance of the Fe-17Cr ferritic stainless steel sheets was investigated by electron backscatter diffraction and electrochemical measurements. Nearly homogeneous {111}〈112〉 γ-fiber recrystallization texture is produced in the Fe-17Cr ferritic stainless steel sheets. Comparison between the inverse pole figure orientation map and scanning electron microscopy microstructures etched by aqua regia reveals that the severest corrosion occurs on the sheet rolling surface where {111} crystal plane dominates. Electrochemical measurements demonstrate that the plane perpendicular to transverse direction displays the lowest corrosion current density. This indicates that this plane, where {110} plane dominates, exhibits the best corrosion resistance.

The appropriate interfacial contact of heterojunction photocatalysts plays a critical role in transfer/separation of interfacial charge carriers. Design of two-dimensional (2D)/2D surface-to-surface heterojunction is an effective method for improving photocatalytic activity since greater contact area can enhance interfacial charge transfer rate. Herein, ultrathin 2D/2D WO3/g-C3N4 step-like composite heterojunction photocatalysts were fabricated by electrostatic self-assembly of ultrathin tungsten trioxide (WO3) and graphitic carbon nitride (g-C3N4) nanosheets. The ultrathin WO3 and g-C3N4 nanosheets were obtained by electrostatic-assisted ultrasonic exfoliation of bulk WO3 and a two-step thermal-etching of bulk g-C3N4, respectively. The thickness of ultrathin WO3 and g-C3N4 nanosheets are 2.5–3.5 nm, which is equivalent to 5–8 atomic or molecular layer thickness. This ultrathin layered heterojunction structure can enhance surface photocatalytic rate because photogenerated electrons and holes at heterogeneous interface more easily transfer to surface of photocatalysts. Therefore, the obtained ultrathin 2D/2D WO3/g-C3N4 step-scheme (S-scheme) heterojunction photocatalysts exhibited better H2-production activity than pure g-C3N4 and WO3 with the same loading amount of Pt as cocatalyst. The mechanism and driving force of charge transfer and separation in S-scheme heterojunction photocatalysts are investigated and discussed. This investigation will provide new insight about designing and constructing novel S-scheme heterojunction photocatalysts.

Microstructure and mechanical properties of the as-annealed Ti-stabilized Fe-17Cr ferritic stainless steel were investigated by scanning electron microscopy (SEM), electron backscatter diffraction (EBSD) and tensile tests. Experimental results show that the size of the ferrite grain in the Fe-17Cr stainless steel is about 40 µm after rolling and annealing. Orientation distribution function (ODF) by EBSD indicates that nearly homogeneous {111} annealing texture is produced in the annealed sheets. Pole figures (PF) by EBSD show that Kurdjumov–Sachs orientation relationship between the TiN particles and ferrite grains is established in the as-annealed microstructure. Tensile tests demonstrate that the yield strength (YS), ultimate tensile strength (UTS), and elongation (EL) of the as-annealed Ti-stabilized Fe-17Cr ferritic stainless steel are 319 MPa, 626 MPa, and 36.5%, respectively. In the SEM micrograph of the fracture, deep dimples can be observed and TiN particles can be found in the core of the dimples, which indicates that the samples undergo large deformation before fracture.

Electrocatalytic CO2 reduction reaction (CO2RR) to obtain C2 products has drawn widespread attentions. Copper-based materials are the most reported catalysts for CO2 reduction to C2 products. Design of high-efficiency pseudo-copper catalysts according to the key characteristics of copper (Cu) is an important strategy to understand the reaction mechanism of C2 products. In this work, density function theory (DFT) calculations are used to predict nickel-zinc (NiZn) alloy catalysts with the criteria similar structure and intermediate adsorption property to Cu catalyst. The calculated tops of 3d states of NiZn3(001) catalysts are the same as Cu(100), which is the key parameter affecting the adsorption of intermediate products. As a result, NiZn3(001) exhibits similar adsorption properties with Cu(100) on the crucial intermediates *CO2, *CO and *H. Moreover, we further studied CO formation, CO hydrogenation and C-C coupling process on Ni-Zn alloys. The free energy profile of C2 products formation shows that the energy barrier of C2 products formation on NiZn3(001) is even lower than Cu(100). These results indicate that NiZn3 alloy as pseudo-copper catalyst can exhibit a higher catalytic activity and selectivity of C2 products during CO2RR. This work proposes a feasible pseudo-copper catalyst and provides guidance to design high-efficiency catalysts for CO2RR to C2 or multi-carbon products.

Designing efficient catalysts with high activity and selectivity is desirable and challenging for CO2 reduction reaction (CO2RR). Nickel phthalocyanine (NiPc) is a promising molecule catalyst for CO2RR. However, the pristine NiPc suffers from poor CO2 adsorption and activation due to its electron deficiency of Ni–N4 site, which leads to inferior activity and stability during CO2RR. Here, we develop a substituent-induced electronic localization strategy to improve CO2 adsorption and activation, and thus catalytic performance. Theoretic calculations and experimental results indicate that the electronic localization on the Ni site induced by electron-donating substituents (hydroxyl or amino) of NiPc greatly enhances the CO2 adsorption and activation, which is positively associated with the electron-donating abilities of substituents. Employing the optimal catalyst of amino-substituted NiPc to catalyze CO2 into CO in flow cell can achieve an ultrahigh activity and selectivity of 99.8% at the current densities up to 400 mA cm-2. This work offers a novel strategy to regulate the electronic structure of the active site by introducing substituents for highly efficient CO2RR.

Electrochemical CO2 reduction is a promising strategy for utilization of CO2 and intermittent excess electricity. Cu is the only single-metal catalyst that can electrochemically convert CO2 to multi-carbon products. However, Cu has an undesirable selectivity and activity for C2 products, due to its insufficient amount of CO* for C-C coupling. Considering the strong CO2 adsorption and ultra-fast reaction kinetics of CO* formation on Pd, an intimate CuPd(100) interface was designed to lower the intermediate reaction barriers and then improve the efficiency of C2 products. Density functional theory (DFT) calculations showed that the CuPd(100) interface has enhanced CO2 adsorption and decreased CO2* hydrogenation energy barrier, which are beneficial for C-C coupling. The potential-determining step (PDS) barrier of CO2 to C2 products on CuPd(100) interface is 0.61 eV, which is lower than that on Cu(100) (0.72 eV). Motivated by the DFT calculation, the CuPd(100) interface catalyst was prepared by a facile chemical solution method and demonstrated by transmission electron microscope (TEM). The CO2 temperature programmed desorption (CO2-TPD) and gas sensor experiments proved the enhancements of CO2 adsorption and CO2* hydrogenation abilities on CuPd(100) interface catalyst. As a result, the obtained CuPd(100) interface catalyst exhibits a C2 Faradaic efficiency of 50.3 (+/-) 1.2% at -1.4 VRHE in 0.1 M KHCO3, which is 2.1 times higher than 23.6(+/-) 1.5% of Cu catalyst. This work provides a rational design of Cu-based electrocatalyst for multi-carbon products by fine-tuning the intermediate reaction barriers.

Effect of Mn content on the microstructure and corrosion resistance of Al-Cu-Mg-Mn alloys was examined by optical microscope (OM), scanning electron microscope (SEM), tensile tests, pitting corrosion and electrochemical tests. It is shown that increase of Mn content can accelerate the aging process of the Al-Cu-Mg-Mn alloys, which is beneficial to shorten heat treatment time. Polarization curves indicate that the corrosion current density and corrosion rate of Al-4Cu-2Mg-1.2Mn alloy are the lowest compared with Al-4Cu-2Mg-0.6Mn and Al-4Cu-2Mg-0.9Mn alloys for both the as-cast and heat-treated conditions. Electrochemical impedance spectroscopy (EIS) tests also demonstrate that Al-4Cu-2Mg-1.2Mn alloy displays the highest resistance. The maximum pitting corrosion depth of the as-aged Al-4Cu-2Mg-1.2Mn and Al-4Cu-2Mg-0.6Mn alloys is about 65μm and 110μm, respectively. Therefore, Mn addition can improve the mechanical properties and corrosion resistance of the Al-Cu-Mg alloys.

Iron phthalocyanine (FePc) is a promising non-precious catalyst for the oxygen reduction reaction (ORR). Unfortunately, FePc with plane-symmetric FeN4 site usually exhibits an unsatisfactory ORR activity due to its poor O2 adsorption and activation. Here, we report an axial Fe–O coordination induced electronic localization strategy to improve its O2 adsorption, activation and thus the ORR performance. Theoretical calculations indicate that the Fe–O coordination evokes the electronic localization among the axial direction of O–FeN4 sites to enhance O2 adsorption and activation. To realize this speculation, FePc is coordinated with an oxidized carbon. Synchrotron X-ray absorption and Mössbauer spectra validate Fe–O coordination between FePc and carbon. The obtained catalyst exhibits fast kinetics for O2 adsorption and activation with an ultralow Tafel slope of 27.5 mV dec−1 and a remarkable half-wave potential of 0.90 V. This work offers a new strategy to regulate catalytic sites for better performance., Iron phthalocyanine with a 2D structure and symmetric electron distribution around Fe-N4 active sites is not optimal for O2 adsorption and activation. Here, the authors report an axial Fe–O coordination induced electronic localization strategy to enhance oxygen reduction reaction performance.

The effects of Nb addition on the microstructure and corrosion resistance of the as-rolled Ti-stabilized Fe-17Cr ferritic stainless steels were investigated by optical microscopy, scanning electron microscopy, X-ray diffraction, pitting tests, and electrochemical measurements. TiN precipitate tends to form in the microstructure of Ti-stabilized Fe-17Cr ferritic stainless steel. After 0.1 wt. % Nb addition, (Ti, Nb) (C, N) composite precipitates with MgO and Al2O3 core form in the microstructure. After adding 0.1 wt. % Nb, the corrosion rate of the Ti-stabilized Fe-17Cr ferritic stainless steel in FeCl3 solution is decreased significantly. The corrosion current densities decrease in HNO3, NaOH, and NaCl solutions, and the pitting corrosion potentials can be improved in NaCl solution for the Fe-17Cr ferritic stainless steel with 0.1 wt. % Nb addition.

Constructing direct Z-scheme heterojunction photocatalysts is a highly efficient pathway to completely utilize the high redox ability of photogenerated charge carriers. Herein, a direct Z-scheme porous g-C3N4 (Pg-C3N4)/BiOI heterojunction was constructed through the in-situ growth of BiOI on the surface of Pg-C3N4. First principle density functional theory calculations indicated that charge transfer would occur from Pg-C3N4 to BiOI due to the difference in their Fermi energies, resulting in a strong internal electric field (IEF) at the interface between Pg-C3N4 and BiOI. Under photoexcitation, the electrons in the conduction band (CB) of BiOI combine with the holes in the valance band (VB) of Pg-C3N4 with the help of IEF at the interface. A possible Z-scheme type charge transfer can be achieved. This special charge transfer mechanism greatly improved the separation efficiency of photogenerated charge carriers and maintained the high redox ability of photogenerated electrons in the CB of Pg-C3N4 and photogenerated holes in the VB of BiOI. Photocatalytic activities were estimated by the photodegradation of methylene blue under visible light. Results indicated that Pg-C3N4/BiOI exhibited higher photocatalytic performance than pure Pg-C3N4 and BiOI, which can be attributed to the Z-scheme type charge transfer between Pg-C3N4 and BiOI. This work provides new insights into the high photocatalytic activities of g C3N4 based heterojunction photocatalysts.

Graphene (GR) was used to blend with eugenol polysiloxane-polycarbonate (Si-PC) copolymer to prepare a Si-PC/GR nanocomposite via a solution blending method and the impact of graphene on the properties of Si-PC/GR nanocomposite was investigated. The morphology and structure of the Si-PC/GR nanocomposite were characterized. Combining morphology and property analysis, the result showed that when the graphene dispersed uniformly in the Si-PC matrix, the mechanical properties, thermostability and barrier property of Si-PC/GR nanocomposite were enhanced. Compared with Si-PC copolymer, the pyrolytic temperature of Si-PC/2.5%GR nanocomposite at 5% weight loss was 434.3 &deg, C, which was 20.6 &deg, C higher than Si-PC copolymer, and the oxygen barrier value of Si-PC/1.5%GR nanocomposite decreased to 160.2 cm3/m2 24 h 0.1 MPa, which was 53.2 less than pure Si-PC. The mechanical properties of Si-PC/GR nanocomposite were enhanced with an appropriate additive amount of graphene. The hydrophobicity also had been enhanced at the meantime.

The formation mechanism of lathy ferrite in AISI 304 stainless steel during directional solidification was discussed in terms of the orientation relationship between ferrite and austenite. Experimental results show that most of the ferrite laths are arranged parallel and a few ferrite laths with perpendicular morphology can also be observed in the solidified microstructure. Selected-area diffraction patterns by transmission electron microscopy (TEM) and pole figures by electron backscatter diffraction (EBSD) show that Nishiyama–Wassermann orientation relationship between the lathy ferrite and austenite exists in the solidified microstructure. Based on the pole figures of the ferrite, it was found that (103) and [001] of the lathy ferrite are parallel to the sample surface and heat flow direction, respectively, during directional solidification. The elongated directions of the lathy ferrite are found to be [001], [011], and [123], which means that the lathy ferrite grows without preferential direction during directional solidification.

Photocatalytic reduction of CO2 into hydrocarbon fuels has been regarded as a promising approach to ease the greenhouse effect and the energy shortage. Herein, an electrostatic self-assembly method was exploited to prepare g-C3N4/ZnO composite microsphere. This method simply utilized the opposite surface charge of each component, achieving a hierarchical structure with intimate contact between them. A much improved photocatalytic CO2 reduction activity was attained. The CH3OH production rate was 1.32 μmol h−1 g−1, which was 2.1 and 4.1 times more than that of the pristine ZnO and g-C3N4, respectively. This facile design bestowed the g-C3N4/ZnO composite an extended light adsorption caused by multi-light scattering effect. It also guaranteed the uniform distribution of g-C3N4 nanosheets on the surface of ZnO microspheres, maximizing their advantage and synergistic effect. Most importantly, the preeminent performance was proposed and validated based on the direct Z-scheme. The recombination rate was considerably suppressed. This work features the meliority of constructing hierarchical direct Z-scheme structures in photocatalytic CO2 reduction reactions.

More and more serious energy crisis and greenhouse effect force people to find the appropriate solutions. Photocatalytic reduction of CO2 into hydrocarbon fuels is one of the most potential strategies. In this paper, novel one-dimensional (1D) carbon nanofibers@TiO2 core-shell nanocomposites have been prepared via electrospun synthesis of carbon nanofibers core followed by in situ growth of TiO2 shell, which exhibit a 2.3-fold higher photocatalytic activity than the pure TiO2. The increase of catalytic performance attributed to higher specific surface areas of carbon nanofibers@TiO2 core-shell nanocomposites for providing more surface-active sites. Moreover, the black carbon nanofibers promote light absorption, and the light energy can be converted into heat energy that can speed up the diffusion of reactants and products. Most importantly, the carbon nanofibers with good electrical conductivity can speed up the separation of the photo-induced electron and hole pairs in photocatalyst. This work provides a good synthesis of 1D core-shell heterostructure, and proves that the carbon nanofibers can be an ideal cocatalyst for enhancing photocatalytic CO2 reduction performance of TiO2.

The effect of Sc on the microstructure and mechanical properties of Al–Si–Mg–Cu–Ti alloy was investigated. Results obtained in this research indicate that, with increasing Sc content, the microstru...

Orientation relationships between the TiN precipitates and ferrite grains in the solidified microstructure of Fe-17Cr stainless steel were systematically investigated. Remelting experiments were carried out to obtain more TiN precipitates within an electron backscattered diffraction (EBSD) observed zone. Accumulation of TiN precipitates in the microstructure in the central section of the remelted samples is resulted from the redistribution of Ti and N during solidification. Pole figures by EBSD show that seven orientation relationships between the TiN precipitates and ferrite grains, including Kurdjumov–Sachs and other six ones, exist in the solidified samples after remelting. Based on the misfits and orientation relationships between the TiN precipitates and ferrite grains obtained EBSD, the preferential growth direction of ferrite grains is [111] along [001] and [110] in (001) of the TiN precipitates. The refinement mechanism of ferrite grains by the TiN precipitates in the steel was then discussed according to the experimental results and the orientation relationships between the TiN precipitates and ferrite grains.

Seeking for a suitable cocatalyst to realize highly efficient photocatalytic hydrogen (H2) production is a great challenge in the field of solar energy conversion. Herein, hollow cobalt sulfide (Co...