RESUMEN
A facile strategy is developed to fabricate 3 nm RuIrOx nanocrystals anchored onto N-doped hollow carbon for highly efficient and pH-universal overall water splitting and alkaline seawater electrolysis. The designed catalyst exhibits much lower overpotential and superior stability than most previously reported Ru- and Ir-based electrocatalysts for hydrogen/oxygen evolution reactions. It also manifests excellent overall water splitting activities and maintains ≈100% Faradic efficiency with a cell voltage of 1.53, 1.51, and 1.54 V at 10 mA cm-2 for 140, 255, and 200 h in acid, alkaline, and alkaline seawater electrolytes, respectively. The excellent electrocatalytic performance can be attributed to solid bonding between RuIrOx and the hollow carbon skeleton, and effective electronic coupling between Ru and Ir, thus inducing its remarkable electrocatalytic activities and long-lasting stability.
RESUMEN
MAX phase combines both ceramic and metallic properties, which exhibits widespread application prospects. 2D MAX nanosheets have more abundant surface-active sites, being anticipated to improve the performance of surface-related applications. Herein, for the first time, 2D Nb2AlC nanosheets (NSs) as novel supports anchored with Ru catalysts for overall water splitting are developed. The optimized catalyst of Ru@Nb2AlC NSs exhibit Pt-comparable kinetics and superior catalytic activity toward hydrogen evolution reaction (HER) (low overpotentials of 61 and 169 mV at 10 and 100 mA cm-2, respectively) with excellent durability (5000 cycles or 80 h) in alkaline media. In particular, Ru@Nb2AlC NSs achieve a mass activity of ≈4.8 times larger than the commercial Pt/C (20 wt.%) catalyst. The post-oxidation resultant catalyst of RuO2@Nb2AlC NSs also exhibit boosting HER and oxygen evolution reaction activities and ≈100% Faraday efficiency for overall water splitting with a cell voltage of 1.61 V to achieve 10 mA cm-2. Therefore, the novel category of 2D MAX supports anchored with Ru nanocrystals offers a novel strategy for designing a wide range of MAX-supported metal catalysts for the renewable energy field.
RESUMEN
Hypertension and its risk factors have been thoroughly investigated in multiple population studies, but little is known about Chinese minorities. In this study, we examined the association of hypertension prevalence with its risk factors in Han and non-Han minorities from Xinjiang Province, China, who have distinct lifestyles. A total of 9551 Han and non-Han Chinese (Han 83.9%, non-Han 16.1%) 17-81-years old participated in this clinical survey and anthropometric screening. Physical examination was performed on each participant, including measurement of systolic and diastolic blood pressure and body mass index (BMI). The prevalence of hypertension in non-Hans was found to be significantly greater than in Hans, in both men (39.92% vs. 28.55%, P<0.001) and women (19.49% vs. 10.29%, P<0.001) among the 36-55-year old age group. BMI was also found to be significantly higher in non-Hans than Hans in men (BMI: 26.54+/-3.23 vs. 24.82+/-2.77 kgm(-2), P<0.001) and women (BMI: 26.92+/-3.20 vs. 24.19+/-3.16 kgm(-2), P<0.001) in the same age group, but not in those <36-years old. Although Han women had normal weights or were slightly overweight (age >36, BMI=22.25-24.19 kgm(-2)), non-Han women from the same age group were found to be severely overweight (ages 36-55, BMI=24.94 kgm(-2), ages >56, BMI=26.92 kgm(-2)). A strong association between increased BMI and hypertension was shown in all ethnic and gender groups. The prevalence of hypertension in overweight (BMI> or =24 kgm(-2)) and obese (BMI> or =28 kgm(-2)), aged (36-81), male, and non-Han participants was significantly greater than in lean (BMI <24 kgm(-2)), young (17-35), female Hans, after adjustment for these variables in a multivariate logistic regression analysis (P<0.001). A high prevalence of hypertension in overweight and obese elderly non-Han men suggests that BMI, age, sex and race are important risk factors for hypertension in this Chinese population.
