RESUMEN
Two-component catalysts have garnered significant attention in the field of catalysis due to their ability to inhibit Ni sintering. In the present work, honeycomb-structured Al2O3-supported Ni and B were prepared to enhance coke tolerance during dry reforming of methane (DRM). Transmission electron microscopy (TEM) revealed that the average particle sizes on Ni/Al2O3 and Ni-0.16B/Al2O3 were 7.6 nm and 4.2 nm, respectively, indicating that B can effectively inhibit Ni sintering. After a 100-hour reaction, the conversion of CH4 and CO2 on Ni/Al2O3 decreased by approximately 5%, whereas on Ni-0.16B/Al2O3, there was no significant decrease in CH4 and CO2 conversion, with values of approximately 81.6% and 87.2%, respectively. In situ DRIFT spectra demonstrated that Ni-0.16B/Al2O3 enhanced the activation of CO2, thus improving the catalyst's stability. A Langmuir-Hinshelwood-Hougen-Watson (LHHW) model was developed for intrinsic kinetics, and the resulting kinetic expressions were well fit to the experimental data, with R2 values exceeding 0.9. The activation energies were also calculated. The outstanding stability of Ni-0.16B/Al2O3 can be attributed to its stable honeycomb structure and B's ability to significantly inhibit Ni sintering, reduce catalyst particle size, and enhance coke tolerance.
RESUMEN
The photocatalytic CO2 reduction strategy driven by visible light is a practical way to solve the energy crisis. However, limited by the fast recombination of photogenerated electrons and holes in photocatalysts, photocatalytic efficiency is still low. Herein, a WO3/BiOBr S-scheme heterojunction was formed by combining WO3 with BiOBr, which facilitated the transfer and separation of photoinduced electrons and holes and enhanced the photocatalytic CO2 reaction. The optimized WO3/BiOBr heterostructures exhibited best activity for photocatalytic CO2 reduction without any sacrificial reagents, and the CO yield reached 17.14 µmol g-1 after reaction for 4 h, which was 1.56 times greater than that of BiOBr. The photocatalytic stability of WO3/BiOBr was also improved.
RESUMEN
Photocatalytic CO2 reduction is a tactic for solving the environmental pollution caused by greenhouse gases. Herein, NH4H2PO4 was added as a phosphorus source in the process of the hydrothermal treatment of melamine for the first time, and phosphorus-doped hollow tubular g-C3N4 (x-P-HCN) was fabricated and used for photocatalytic CO2 reduction. Here, 1.0-P-HCN exhibited the largest CO production rate of 9.00 µmol·g-1·h-1, which was 10.22 times higher than that of bulk g-C3N4. After doping with phosphorus, the light absorption range, the CO2 adsorption capacity, and the specific surface area of the 1.0-P-HCN sample were greatly improved. In addition, the separation of photogenerated electron-hole pairs was enhanced. Furthermore, the phosphorus-doped g-C3N4 effectively activated the CO2 adsorbed on the surface of phosphorus-doped g-C3N4 photocatalysts, which greatly enhanced the CO production rate of photocatalytic CO2 reduction over that of g-C3N4.
RESUMEN
One-step fabrication of graphene-polyaniline (graphene-PANI) hybrid film was facilely achieved by cyclic voltammetric electrolysis of a bath containing both graphene oxide (GO) and aniline, where graphene is obtained by electrochemical reduction of GO and PANI is simultaneously obtained by aniline electropolymerization. As there is no strong attraction between aniline and GO under the electrodeposition conditions, the independent depositions of PANI and reduced GO nanosheets at their greatly differed potentials led to alternate layered graphene-PANI films, with the topmost layer being PANI particles or graphene sheets just by changing the initial scan directions. The two kinds of graphene-PANI hybrid films present excellent but different electrical and electrochemical behaviors.
Asunto(s)
Compuestos de Anilina/química , Grafito/química , Técnicas Electroquímicas , Electrodos , Galvanoplastia , Concentración de Iones de Hidrógeno , Nanoestructuras/química , Óxidos/químicaRESUMEN
Constructing an efficient photoelectron transfer channel to promote the charge carrier separation is a great challenge for enhancing photocatalytic hydrogen evolution from water. In this work, an ultrathin 2D/2D Ti3 C2 Tx /ZnIn2 S4 heterostructure is rationally designed by coupling the ultrathin ZnIn2 S4 with few-layered Ti3 C2 Tx via the electrostatic self-assembly strategy. The 2D/2D Ti3 C2 Tx /ZnIn2 S4 heterostructure possesses larger contact area and strong electronic interaction to promote the charge carrier transfer at the interface, and the sulfur vacancy on the ZnIn2 S4 acting as the electron trap further enhances the separation of the photoinduced electrons and holes. As a consequence, the optimal 2D/2D Ti3 C2 Tx /ZnIn2 S4 composite exhibits a high photocatalytic hydrogen evolution rate of 148.4 µmol h-1 , which is 3.6 times and 9.2 times higher than that of ZnIn2 S4 nanosheet and flower-like ZnIn2 S4 , respectively. Moreover, the stability of the ZnIn2 S4 is significantly improved after coupling with the few-layered Ti3 C2 Tx . The characterizations and density functional theory calculation demonstrate that the synergistic effect of the sulfur vacancy and Ti3 C2 Tx cocatalyst can greatly promote the electrons transfer from ZnIn2 S4 to Ti3 C2 Tx and the separation of photogenerated charge carriers, thus enhancing the photocatalytic hydrogen evolution from water.
RESUMEN
BACKGROUND: Da Vinci surgery is used extensively, but the high costs of the surgical instrument are a serious clinical and management problem. OBJECTIVE: To reduce the cost of the Da Vinci robotic surgical instrument supply chain. METHODS: Patients were selected from the First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China. Control group patients underwent Da Vinci robot-assisted surgery between January 2019 and June 2019 (control group). Patients who were operated with the same robot from July 2019 to December 2019 were selected as the experimental group (SCM group). The cost analysis and comparison were carried out to integrate instrument sets, working hours, workforce expenditure, and direct and indirect expenses. RESULTS: Compared with the control group, the number of instrument packages was lower (4.5 ± 1.4 vs. 11.5 ± 1.6, P< 0.001) and the personnel's awareness of the instruments was higher (92.3 ± 4.2 vs. 83.4 ± 3.7, P< 0.001) in the SCM group. The SCM group showed lower processing time per device (8.1 ± 1.6 vs. 44.2 ± 5.6 min, P< 0.001) and lower costs per surgical instrument (RMB 11.5 ± 2.3 vs. 60.3 ± 10.2, P< 0.001). CONCLUSION: The application of the supply chain management can reduce the costs of robotic surgery, improve work efficiency and decrease the failure rate of instruments.
Asunto(s)
Procedimientos Quirúrgicos Robotizados , Robótica , Costos y Análisis de Costo , Humanos , Estudios Retrospectivos , Instrumentos QuirúrgicosRESUMEN
BACKGROUND: Multimodal intraoperative neuromonitoring (IONM) has been proposed as an effective way to reduce permanent neurologic injury during spinal deformity surgery. However, few studies have reported evoked potential changes at different surgical stages of thoracic posterior vertebral column resection (PVCR). METHODS: A total of 82 cases with severe thoracic deformity (Yang's A type) treated by PVCR in a single institution between January 2010 and March 2015 were reviewed. Multimodal IONM including somatosensory evoked potential, motor evoked potential, and descending neurogenic evoked potential was performed for real-time assessment of spinal cord function during surgery. The risk factors of neuromonitoring events at different surgical stages were documented and analyzed. RESULTS: Multimodal IONM was successfully performed in all 82 cases. Thirty-nine neuromonitoring events presented in 27 (32.9%) cases. Neurologic monitoring events were more likely to occur in patients with larger scoliosis and kyphosis, longer osteotomy closure distance, more Halo gravity traction, more screw insertion, and higher PVCR segments. The reasons for monitoring changes included 6 events during screw insertion, 20 during osteotomy, 9 during osteotomy gap closure, and 4 during deformity correction. New postoperative neurologic deficits were observed in 11 (13.4%) cases including 1 incomplete paraplegia, 8 transient cord deficits, and 2 nerve root injuries. CONCLUSIONS: Multimodal IONM can effectively identify neurologic deficits throughout surgery. Osteotomy and osteotomy gap closure are the surgical stages with the highest neurologic risks during PVCR procedures. It is imperative to improve dexterity since the majority of neuromonitoring events are caused by surgical techniques.