Quantifying the CO2 sink intensity of large and small saline lakes on the Tibetan Plateau.

This study quantitatively evaluates the carbon dioxide (CO2) sink intensity of a large saline lake (area > 2000 km2) and a small saline lake (area 1.4 km2) on the Tibetan Plateau (TP), alongside an alpine meadow, by analysing their net ecosystem exchange (NEE) figures obtained by eddy covariance (EC) measurements. Specifically, the "large lake" exhibits an NEE value of -122.51 g C m-2 yr-1, whereas the small lake has an NEE value of -47.17 g C m-2 yr-1. The alpine meadow, in contrast, demonstrates an NEE value of -128.18 g C m-2 yr-1. Through standardization of the eddy flux data processing and accounting for site-specific conditions with a wind direction filter and footprint analysis, the study provides robust estimates of CO2 sink intensity. The "large lake" was found to absorb CO2 primarily during non-icing cold periods with minimal exchange occurring during ice-covered season, whereas the "small lake" showed no significant CO2 exchange throughout the year. On the other hand, alpine meadows engaged in CO2 uptake during the vegetative growth season but showed weak CO2 release in winter. CO2 uptake in lakes is mainly controlled by ice barrier and chemical processes, while biological processes dominate the alpine meadow. The carbon sink intensity of the TP's saline lakes is estimated to be 1.87-3.01 Tg C yr-1, smaller than the previous reported estimations. By evaluating the CO2 sink intensity of different lakes, the study highlights the importance of saline lakes in regional carbon balance assessments. It specifically points out the differential roles lakes of various sizes play in the carbon cycle, thereby enriching our understanding of carbon dynamics in high-altitude lacustrine ecosystems.

Highly Active and Stable Alkaline Hydrogen Evolution Electrocatalyst Based on Ir-Incorporated Partially Oxidized Ru Aerogel under Industrial-Level Current Density.

The realization of large-scale industrial application of alkaline water electrolysis for hydrogen generation is severely hampered by the cost of electricity. Therefore, it is currently necessary to synthesize highly efficient electrocatalysts with excellent stability and low overpotential under an industrial-level current density. Herein, Ir-incorporated in partially oxidized Ru aerogel has been designed and synthesized via a simple in situ reduction strategy and subsequent oxidation process. The electrochemical measurements demonstrate that the optimized Ru98 Ir2 -350 electrocatalyst exhibits outstanding hydrogen evolution reaction (HER) performance in an alkaline environment (1 M KOH). Especially, at the large current density of 1000 mA cm-2 , the overpotential is as low as 121 mV, far exceeding the benchmark Pt/C catalyst. Moreover, the Ru98 Ir2 -350 catalyst also displays excellent stability over 1500 h at 1000 mA cm-2 , denoting its industrial applicability. This work provides an efficient route for developing highly active and ultra-stable electrocatalysts for hydrogen generation under industrial-level current density.

Rationally Construction of Mn-Doped RuO2 Nanofibers for High-Activity and Stable Alkaline Ampere-Level Current Density Overall Water Splitting.

Nowadays, highly active and stable alkaline bifunctional electrocatalysts toward water electrolysis that can work at high current density (≥1000 mA cm-2) are urgently needed. Herein, Mn-doped RuO2 (MnxRu1-xO2) nanofibers (NFs) are constructed to achieve this object, presenting wonderful hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) performances with the overpotentials of only 269 and 461 mV at 1 A cm-2 in 1 m KOH solution, and remarkably stability under industrial demand with 1 A cm-2, significantly better than the benchmark Pt/C and commercial RuO2 electrocatalysts, respectively. More importantly, the assembled Mn0.05Ru0.95O2 NFs||Mn0.05Ru0.95O2 NFs electrolyzer toward overall water splitting reaches the current density of 10 mA cm-2 with a cell voltage of 1.52 V and also delivers an outstanding stability over 150 h of continuous operation, far surpassing commercial Pt/C||commercial RuO2, RuO2 NFs||RuO2 NFs and most previously reported exceptional electrolyzers. Theoretical calculations indicate that Mn-doping into RuO2 can significantly optimize the electronic structure and weaken the strength of O─H bond to achieve the near-zero hydrogen adsorption free energy (ΔGH*) value for HER, and can also effectively weaken the adsorption strength of intermediate O* at the relevant sites, achieving the higher OER catalytic activity, since the overlapping center of p-d orbitals is closer to the Fermi level.

Rational design of bimetal phosphide embedded in carbon nanofibers for boosting oxygen evolution.

The development of non-precious metal electrocatalysts for oxygen evolution reaction (OER) is crucial for generating large-scale hydrogen through water electrolysis. In this work, bimetal phosphides embedded in electrospun carbon nanofibers (P-FeNi/CNFs) were fabricated through a reliable electrospinning-carbonization-phosphidation strategy. The incorporation of P-FeNi nanoparticles within CNFs prevented them from forming aggregation and further improved their electron transfer property. The bimetal phosphides helped to weaken the adsorption of O intermediate, promoting the OER activity, which was confirmed by the theoretical results. The as-prepared optimized P-Fe1Ni2/CNFs catalyst exhibited very high OER electrocatalytic performance, which required very low overpotentials of just 239 and 303 mV to reach 10 and 1000 mA cm-2, respectively. It is superior to the commercial RuO2 and many other related OER electrocatalysts reported so far. In addition, the constructed alkaline electrolyzer based on the P-Fe1Ni2/CNFs catalyst and Pt/C delivered a cell voltage of 1.52 V at 10 mA cm-2, surpassing the commercial RuO2||Pt/C (1.61 V) electrolyzer. It also offered excellent alkaline OER performance in simulated seawater electrolyte. This demonstrated its potential for practical applications across a broad range of environmental conditions. Our work provides new ideas for the ration design of highly efficient non-precious metal-based OER catalysts for water electrolysis.

Wet chemical synthesis of rhodium nanoparticles anchored on cobalt/nitrogen-doped carbon nanofibers for high-performance alkaline and acidic hydrogen evolution.

Constructing high-activity electrocatalysts towards hydrogen evolution reaction (HER) is an essential way to achieve efficient, green and sustainable energy from water electrolysis. In this work, rhodium (Rh) nanoparticles anchored on cobalt (Co)/nitrogen (N)-doped carbon nanofibers (NCNFs) catalyst is prepared by the electrospinning-pyrolysis-reduction method. The synergy effect between Co-NCNFs and Rh nanoparticles contributes to the superior HER activity and favorable durability. The optimized 0.15Co-NCNFs-5Rh sample exhibits ultralow overpotentials of 13 and 18 mV to reach 10 mA cm-2 in an alkaline and acidic electrolyte, surpassing many Rh-based or Co-based electrocatalysts reported in the literature. Additionally, the Co-NCNFs-Rh sample shows a better HER activity than benchmark Pt/C catalyst in an alkaline medium at all current densities and in an acidic condition at higher current densities, offering its promising practical applications. Thus, this work provides an efficient methodology to construct high-performance HER electrocatalysts.

Interface Engineering of Heterogeneous CeO2-CoO Nanofibers with Rich Oxygen Vacancies for Enhanced Electrocatalytic Oxygen Evolution Performance.

The development of highly efficient and cheap electrocatalysts for the oxygen evolution reaction (OER) is highly desirable in typical water-splitting electrolyzers to achieve renewable energy production, yet it still remains a huge challenge. Herein, we have presented a simple procedure to construct a new nanofibrous hybrid structure with the interface connecting the surface of CeO2 and CoO as a high-performance electrocatalyst toward the OER through an electrospinning-calcination-reduction process. The resultant CeO2-CoO nanofibers exhibit excellent electrocatalytic properties with a small overpotential of 296 mV at 10 mA cm-2 for the OER, which is superior to many previously reported nonprecious metal-based and commercial RuO2 catalysts. Furthermore, the prepared CeO2-CoO nanofibers display remarkable long-term stability, which can be maintained for 130 h with nearly no attenuation of OER activity in an alkaline electrolyte. A combined experimental and theoretical investigation reveals that the excellent OER properties of CeO2-CoO nanofibers are due to the unique interfacial architecture between CeO2 and CoO, where abundant oxygen vacancies can be generated due to the incomplete matching of atomic positions of two parts, leading to the formation of many low-coordinated Co sites with high OER catalytic activity. This research provides a practical and promising opportunity for the application of heterostructured nonprecious metal oxide catalysts for high-efficiency electrochemical water oxidation.

General fabrication of metal-organic frameworks on electrospun modified carbon nanofibers for high-performance asymmetric supercapacitors.

Metal-organic framework (MOF)-based electrode materials have become a hot subject for supercapaitors. Herein, Ni-MOFs grown on Co nanoparticles modified carbon nanofibers (CNFs) (C-Co@MOF) are prepared via a facile process. Interestingly, the presence of Co nanoparticles in CNFs not only boosts the hybridization of CNF and MOFs, but also releases Co ions to participate in the growth of MOF, leading to a favorable electrochemical behavior. In detail, the specific capacitance of C-Co@MOF reaches 1201.6 F g-1 that exceeds those of C-M@MOFs (M = Ni, V, Mo, Mn, Fe, Cu and Zn) and CNF@MOF. More importantly, an asymmetric solid-state supercapacitor is assembled using C-Co@MOF and nitrogen-doped carbon nanotubes derived from polyaniline as positive and negative electrode materials, respectively, representing a high energy density of 37.0 Wh kg-1 and outstanding durability. This work highlights the superiority of electrospun CNFs modified by metal nanoparticles for the growth of MOF, showing great potential for electrochemical energy storage and conversion applications.

RuNi Nanoparticles Embedded in N-Doped Carbon Nanofibers as a Robust Bifunctional Catalyst for Efficient Overall Water Splitting.

Developing high-performance, low-cost, and robust bifunctional electrocatalysts for overall water splitting is extremely indispensable and challenging. It is a promising strategy to couple highly active precious metals with transition metals as efficient electrocatalysts, which can not only effectively reduce the cost of the preparation procedure, but also greatly improve the performance of catalysts through a synergistic effect. Herein, Ru and Ni nanoparticles embedded within nitrogen-doped carbon nanofibers (RuNi-NCNFs) are synthesized via a simple electrospinning technology with a subsequent carbonization process. The as-formed RuNi-NCNFs represent excellent Pt-like electrocatalytic activity for the hydrogen evolution reaction (HER) in both alkaline and acidic conditions. Furthermore, the RuNi-NCNFs also exhibit an outstanding oxygen evolution reaction (OER) activity with an overpotential of 290 mV to achieve a current density of 10 mA cm-2 in alkaline electrolyte. Strikingly, owing to both the HER and OER performance, an electrolyzer with RuNi-NCNFs as both the anode and cathode catalysts requires only a cell voltage of 1.564 V to drive a current density of 10 mA cm-2 in an alkaline medium, which is lower than the benchmark of Pt/C||RuO2 electrodes. This study opens a novel avenue toward the exploration of high efficient but low-cost electrocatalysts for overall water splitting.

Impact of the CYP3A5, CYP3A4, COMT, IL-10 and POR genetic polymorphisms on tacrolimus metabolism in Chinese renal transplant recipients.

Tacrolimus is a widely used immunosuppressive drug for preventing the rejection of solid organ transplants. The efficacy of tacrolimus shows considerable variability, which might be related to genetic variation among recipients. We conducted a retrospective study of 240 Chinese renal transplant recipients receiving tacrolimus as immunosuppressive drug. The retrospective data of all patients were collected for 40 days after transplantation. Seventeen SNPs of CYP3A5, CYP3A4, COMT, IL-10 and POR were identified by the SNaPshot assay. Tacrolimus blood concentrations were obtained on days 1-3, days 6-8 and days 12-14 after transplantation, as well as during the period of the predefined therapeutic concentration range. Kruskal-Wallis test was used to examine the effect of genetic variation on the tacrolimus concentration/dose ratio (C 0/D) at different time points. Chi-square test was used to compare the proportions of patients who achieved the target C 0 range in the different genotypic groups at weeks 1, 2, 3 and 4 after transplantation. After correction for multiple testing, there was a significant association of C 0/D with CYP3A5*3, CYP3A4*1G and CYP3A4 rs4646437 T>C at different time points after transplantation. The proportion of patients in the IL-10 rs1800871-TT group who achieved the target C 0 range was greater (p = 0.004) compared to the IL-10 rs1800871-CT and IL-10 rs1800871-CC groups at week 3 after transplantation. CYP3A5*3, CYP3A4 *1G, CYP3A4 rs4646437 T>C and IL-10 rs1800871 C>T might be potential polymorphisms affecting the interindividual variability in tacrolimus metabolism among Chinese renal transplant recipients.