RESUMEN
Structural engineering, including electronic and geometric modulations, is a good approach to improve the activity of electrocatalysts. Herein, we employed FeOOH and the second metal center Ni to modulate the electronic structure of CoMoO4 and used a low temperature solvothermal route and a chemical etching method to prepare the special hollow hierarchical structure. Based on the prediction of multi-method calculations by density functional theory (DFT) and ab initial molecular dynamics (AIMD), a series of materials were fabricated. Among them, the optimal hollow FeOOH/(Ni1Co1)MoO4 by coating (NiCo)MoO4 nanosheets on FeOOH nanotubes showed excellent performances toward high current density oxygen evolution reaction (OER) in alkaline and simulated seawater solutions, hybrid supercapacitor (HSC), and aqueous battery due to the well-controlled electronic and geometric structures. The optimal FeOOH/(Ni1Co1)MoO4 required overpotentials of 225 and 546 mV to deliver 10 and 1000 mA cm-2 current densities toward alkaline OER, and maintained a good stability for 100 h at 200 mA cm-2 with negligible attenuation. The FeOOH/(Ni1Co1)MoO4//Pt/C electrolyzer exhibited a low cell voltage of 1.52 and 1.79 V to drive 10 and 200 mA cm-2 and retained a long-term durability nearly 100 h at 1.79 V. As the electrode of energy storage devices, it possessed a specific capacity of 342 mA h g-1 at 1 A g-1. HSC and SC-type battery devices were fabricated. The assembled HSC kept a capacitance retention of 94 % after 10,000 cycles. This work provided a way to fabricate effective and stable multifunctional materials for energy storage and conversion with the aid of multi-method calculations.
RESUMEN
The four-electron oxidation process of the oxygen evolution reaction (OER) highly influences the performance of many green energy storage and conversion devices due to its sluggish kinetics. The fabrication of cost-effective OER electrocatalysts via a facile and green method is, hence, highly desirable. This review summarizes and discusses the recent progress in creating carbon-based materials for alkaline OER. The contents mainly focus on the design, fabrication, and application of carbon-based materials for alkaline OER, including metal-free carbon materials, carbon-based supported composites, and carbon-based material core-shell hybrids. The work presents references and suggestions for the rational design of highly efficient carbon-based OER materials.
RESUMEN
Exploring efficient and low-cost oxygen evolution reaction (OER) electrocatalysts reaching the industrial level current density is crucial for hydrogen production via water electrolysis. In this feature article, we summarize the recent progress in hierarchical nanostructures for the industrial-level OER. The contents mainly concern (i) the design of a hierarchical structure; (ii) a Ni-based hierarchical structure for the industrial current density OER; and (iii) the surface reconstruction of the hierarchical structure during the OER process. The work provides valuable guidance and insights for the manufacture of hierarchical nanomaterials and devices for industrial applications.
RESUMEN
OBJECTIVE: To evaluate the role of high risk factors in octogenarians and nonagenarians with hip trauma, which may lead to excessive mortality and morbi- dity postoperatively. METHODS: Fifty-four octogenarians and nonagenarians patients were enrolled in the study, receiving surgical repair of hip fracture in our hospital from January 2006 to January 2010. High risk factors were recorded preoperatively in detail. Complications and survival state were followed up by telephone for 2 years postoperatively. All the data were analyzed by Chi-square test with SPSS 13.0. RESULTS: Twenty-six males (48.1%), aged from 80 to 94 years with a mean age of 84.2 years, and twenty-eight females (51.9%), aged from 80 to 95 years with a mean age of 83.4 years, were presented in the cohort study. The hip traumas were caused by daily slight injuries (52 cases) and car accidents (2 cases), respectively. Twenty-eight patients (51.9%) with femoral neck fracture while 26 patients (48.1%) with intertrochanteric fracture were diagnosed through an anterior-posterior pelvic radiophotograph. In this series, 39 patients (72.2%) suffered from one or more comorbidities preoperatively. The morbidity was 48.1% and the major cause was urinary tract infection, while a significant difference was noted between females and males. The mortality was 20.4% with a predominant cause of acute renal failure. CONCLUSIONS: The gender should be considered as a critical high risk factor in octogenarians and nonagenarians with hip trauma postoperatively. Females are more likely to suffer complications postoperatively, which is especially obvious in senile patients over 80 years (P less than 0.05). Urinary tract infection is the most frequent complication after hip surgery, followed by low limb embolism and malnutrition. The mortality is dramatically greater in patients over 80 years old than those below, and major causes are acute renal failure, multiple organ dysfunction syndrome and mental deterioration. Multidisciplinary consultations and mental assessment are encouraged in patients over 80 years old after hip trauma and surgery. Hip fractures in octogenarians and nonagenarians deserve special attention because of their advanced age and comorbidities.
