Deep insight into regulation mechanism of band distribution in phase junction CdS for enhanced photocatalytic H2 production.

An in-depth understanding of structure-activity relationship between the phase constitution and solar-to-hydrogen (STH) conversion efficiency is conducive to guiding the optimization route of targeted photocatalyst candidates, further establishing advanced photocatalytic systems. Herein, based on the concept of phase engineering, we encompassed the crystalline phase of CdS and achieved precise regulation of phase proportion as well as phase boundary width in the phase junction for the first time. The above cooperative effect not only modifies energy band distribution for sufficient redox potentials, but also guarantees the reverse migration orientation of photogenerated carriers in phase junction, thereby endowing photocarriers with a prolonged lifetime. Compared to pure cubic or hexagonal phase (72.6 or 101.1 µmol h-1 g-1), this CdS system with optimized phase junction demonstrates an improved photocatalytic hydrogen evolution activity of 1.04 mmol h-1 g-1 and favorable stability without cocatalyst assistance, which mainly stems from an efficient protons reduction process interacting with long-lived photogenerated electrons. This research explores the mechanism behind phase regulation and its relationship with junction capability, providing a powerful strategy to manipulate crystal phase distribution and paving a feasible avenue for other phase-dependent photocatalysts towards rational design of heterostructures based on different phases in solar energy conversion field.

Enhancing Electrocatalytic Kinetics via Synergy of Co Nanoparticles and Co/Ni-N4-C- and N-Doped Porous Carbon.

Transition-metal species embedded in carbon have sparked intense interest in the fields of oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). However, improvement of the electrocatalytic kinetics remains a challenge caused by the synergistic assembly. Here, we propose a biochemical strategy to fabricate the Co nanoparticles (NPs) and Co/Ni-N4-C co-embedded N-doped porous carbon (CoNPs&Co/Ni-N4-C@NC) catalysts via constructing the zeolitic imidazolate framework (ZIF)@yeast precursor. The rich amino groups provide the possibility for the anchorage of Co2+/Ni2+ ions as well as the construction of Co/Ni-ZIF@yeast through the yeast cell biomineralization effect. The functional design induces the formation of CoNPs and Co/Ni-N4-C sites in N-doped carbon as well as regulates the porosity for exposing such sites. Synergy of CoNPs, Co/Ni-N4-C, and porous N-doped carbon delivered excellent electrocatalytic kinetics (the ORR Tafel slope of 76.3 mV dec-1 and the OER Tafel slope of 80.4 mV dec-1) and a high voltage of 1.15 V at 10 mA cm-2 for the discharge process in zinc air batteries. It provides an effective strategy to fabricate high-performance catalysts.

Twin Zn1- x Cdx S Solid Solution: Highly Efficient Photocatalyst for Water Splitting.

Twins in crystal defect, one of the significant factors affecting the physicochemical properties of semiconductor materials, are applied in catalytic conversion. Among the catalysts serving for photocatalytic water splitting, Zn1- x Cdx S has become a hot-point due to its adjustable energy band structure. Via limiting mass transport to control the release rate of anions/cations, twin Zn1- x Cdx S solid solution is prepared successfully, which lays a foundation for the construction of other twin crystals in the future. On twin Zn1- x Cdx S, water tends to be dissociated after being adsorbed by Zn2+ /Cd2+ at twin boundary, then the fast-moving electrons at twin boundary quickly combine with the protons already attached to S2- to form hydrogen. According to the theoretical calculation, not only the intracrystalline electron mobility, but also the extracrystalline capacity of water-adsorption/dissociation and proton-adsorption on the twin boundary are superior to those of the counterpart plane in defect-free phase. The synthetic twin Zn1- x Cdx S apparent quantum efficiency of photocatalysis water splitting for hydrogen reached 82.5% (λ = 420 nm). This research opens up an avenue to introduce twins in crystals and it hopes to shed some light on photocatalysis.

Design of Boron Carbonitrides-Polyaniline (BCN-PANI) assembled supercapacitor with high voltage window.

Boron carbonitrides (BCN) have been widely concerned in the field of energy storage and conversion. However, the energy storage mechanism of electrical double-layer behavior and their stacked-layer structure severely limit the improvement of capacitance, thereby hindering their further development in energy storage. Therefore, an ultrasonic-ball milling method was first chosen to obtain BCN nanosheets, together with a feasible way of polyaniline (PANI) modification performed to boost the capacitive reaction of BCN nanosheets. For the first time, a BCN-PANI-based symmetric supercapacitor device can reach a high voltage window of 3.0 V when 1 M Et4N·BF4 was chosen as the electrolyte. The working voltage of 3.0 V is three times that of a device with pure PANI with the ultrahigh energy density of 67.1 W h kg-1, superior to most of the reported PANI-based devices. The eminent electrochemical performance provides a promising strategy to pave the way for configuring carbon-based multiple composite electrodes for other energy storage devices.

In situ configuration of dual S-scheme BP/(Ti3C2Tx@TiO2) heterojunction for broadband spectrum solar-driven photocatalytic H2 evolution in pure water.

Artificial photocatalysis with high-efficiency is a promising route for storing sustainable energy from water splitting. Whereas it is challenging to broaden the solar-spectrum responsive window for harvesting high level of conversion. Herein, based on the band-matching engineering theory, a design of dual S-Scheme heterojunction system is proposed and established in a BP/(Ti3C2Tx@TiO2) composite photocatalyst. The complementary light response region between TiO2 and BP realizes the extension of solar energy utilization over a broad absorption window. Furthermore, this specific band-matching configuration endows spatially long-lived charge carriers with greater accumulation on the divided sub-systems, thereby maintaining the sufficient potential energy capacity associated with excellent photocatalytic properties (H2 evolution rate of 564.8 µmol h-1 g-1 and AQE of 2.7% at 380 nm in pure water). This work describes a promising protocol of designing advanced broadband light-activated photocatalytic systems for solar-chemical energy conversion applications.

Stress analysis of the thoracolumbar junction in the process of backward fall: An experimental study and finite element analysis.

The aim of the present study was to evaluate the biomechanical mechanism of injuries of the thoracolumbar junction by the methods of a backward fall simulation experiment and finite element (FE) analysis (FEA). In the backward fall simulation experiment, one volunteer was selected to obtain the contact force data of the sacrococcygeal region during a fall. Utilizing the fall data, the FEA simulation of the backward fall process was given to the trunk FE model to obtain the stress status of local bone structures of the thoracolumbar junction during the fall process. In the fall simulation test, the sacrococcygeal region of the volunteer landed first; the total impact time was 1.14±0.58 sec, and the impact force was up to 4,056±263 N. The stress of thoracic (T)11 was as high as 42 MPa, that of the posterior margin and the junction of T11 was as high as 70.67 MPa, and that of the inferior articular process and the superior articular process was as high as 128 MPa. The average stress of T12 and the anterior margin of lumbar 1 was 25 MPa, and that of the endplate was as high as 21.7 MPa, which was mostly distributed in the back of the endplate and the surrounding cortex. According to the data obtained from the fall experiment as the loading condition of the FE model, the backward fall process can be simulated to improve the accuracy of FEA results. In the process of backward fall, the front edge of the vertebral body and the root of vertebral arch in the thoracolumbar junction are stress concentration areas, which have a greater risk of injury.

Boron carbonitride with tunable B/N Lewis acid/base sites for enhanced electrocatalytic overall water splitting.

In-depth research on energy storage and conversion is urgently needed; thus, water splitting has become a possible method to achieve sustainable energy utilization. However, traditional carbon material with high graphitization degree exhibits a relatively low electrocatalytic oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) activity as it is electrochemically inert. In this work, according to the Lewis theory of acids and bases and the density functional theory (DFT) results, which show that the enriched heteroatom of B/N in the boron carbonitride (BCN) system may introduce stronger adsorption strength of OH*/H2O, respectively, we have designed and synthesized self-supporting BCN materials with different enrichment degrees of B/N (B-BCN/N-BCN) using carbon paper as substrate. Furthermore, by adjusting the contents of B and N, the optimum electrocatalytic performance of overall water splitting was obtained in which the onset voltage of water splitting on B-BCN//N-BCN was lower than 1.60 V. Our strategy of synthesizing materials with different heteroatom enrichment to improve the electronic environment of materials has opened up new opportunities for developing efficient metal-free electrocatalysts.

Ultrasonic-Ball Milling: A Novel Strategy to Prepare Large-Size Ultrathin 2D Materials.

Large-size ultrathin 2D materials, with extensive applications in optics, medicine, biology, and semiconductor fields, can be prepared through an existing common physical and chemical process. However, the current exfoliation technologies still need to be improved upon with urgency. Herein, a novel and simple "ultrasonic-ball milling" strategy is reported to effectively obtain high quality and large size ultrathin 2D materials with complete lattice structure through the introduction of moderate sapphire (Al2 O3 ) abrasives in a liquid phase system. Ultimately numerous high-quality ultrathin h-BN, graphene, MoS2 , WS2 , and BCN nanosheets are obtained with large sizes ranging from 1-20 µm, small thickness of ≈1-3 nm and a high yield of over 20%. Utilizing shear and friction force synergistically, this strategy provides a new method and alternative for preparing and optimizing large size ultrathin 2D materials.

Three-Dimensional Printing-Assisted Cervical Anterior Bilateral Pedicle Screw Fixation of Artificial Vertebral Body for Cervical Tuberculosis.

BACKGROUND: Cervical tuberculosis accounts for only 4.2%-12% of the total incidence of spinal tuberculosis cases. Although antituberculosis drugs have been the mainstay treatment of cervical tuberculosis, they have been ineffective against the symptoms of existing spinal deformities and spinal cord compression, which often require surgical intervention. The conventional surgical methods have been anterior debridement and titanium mesh, cage bone graft fusion and internal fixation. However, all have certain deficiencies regarding the stability of fixation. CASE DESCRIPTION: We have presented the case of a 41-year-old Chinese man who had been experiencing neck pain and stiffness for 1 month. The symptoms had been accompanied by low-grade fever and repeated night sweats. The purified protein derivative test result was positive and the antituberculosis test result was negative. Imaging examination showed destruction of the C5 and C6 vertebral bodies and C5 andC6 intervertebral discs, with an intensive abscess at the C5-C6 vertebral level. After 3-dimensional printing-assisted anterior debridement and artificial vertebral body replacement, his preoperative symptoms of neck pain and stiffness had been alleviated. Also, his symptoms of numbness in both upper limbs had disappeared completely. At the last follow-up examination, he had recovered well and the tuberculosis focus had been completely cured. CONCLUSION: To the best of our knowledge, we have reported the first clinical application of 3-dimensional printing-assisted cervical anterior bilateral pedicle screw fixation of an artificial vertebral body. We accomplished ultrashort segment fixation, with excellent clinical outcomes obtained, which were maintained at the recent 2-year follow-up examination.