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"Liu, Di"
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Jie neng jian zhu = Sustainable & green building
Ben shu jiang shu le jie neng jian zhu zai ban gong shang ye jie de ti xian he yun yong, Bing li ju ma de li ke kou ke le gong si zong bu, Ha xi xin qu fa zhan da sha, Rui shi lian bang shui zi yuan yan jiu zhong xin ban gong da lou, Du lin qu di fang fa yuan deng jian zhu shi li jin xing fen xi.
Book
Highly efficient nonprecious metal catalyst prepared with metal–organic framework in a continuous carbon nanofibrous network
Fuel cell vehicles, the only all-electric technology with a demonstrated >300 miles per fill travel range, use Pt as the electrode catalyst. The high price of Pt creates a major cost barrier for large-scale implementation of polymer electrolyte membrane fuel cells. Nonprecious metal catalysts (NPMCs) represent attractive low-cost alternatives. However, a significantly lower turnover frequency at the individual catalytic site renders the traditional carbon-supported NPMCs inadequate in reaching the desired performance afforded by Pt. Unconventional catalyst design aiming at maximizing the active site density at much improved mass and charge transports is essential for the next-generation NPMC. We report here a method of preparing highly efficient, nanofibrous NPMC for cathodic oxygen reduction reaction by electrospinning a polymer solution containing ferrous organometallics and zeolitic imidazolate framework followed by thermal activation. The catalyst offers a carbon nanonetwork architecture made of microporous nanofibers decorated by uniformly distributed high-density active sites. In a single-cell test, the membrane electrode containing such a catalyst delivered unprecedented volumetric activities of 3.3 A·cm⁻³ at 0.9 V or 450 A·cm⁻³ extrapolated at 0.8 V, representing the highest reported value in the literature. Improved fuel cell durability was also observed.
Journal Article
Ultralow-loading platinum-cobalt fuel cell catalysts derived from imidazolate frameworks
Platinum (Pt)–group metals, which are scarce and expensive, are used for the demanding oxygen reduction reaction (ORR) in hydrogen fuel cells. One competing approach for reducing their use is to create nanoparticles with earth-abundant metals to increase their activity and surface area; another is to replace them with metals such as cobalt (Co) in carbide or nitride sites. Chong et al. thermally activated a Co metal-organic framework compound to create ORR-active Co sites and then grew PtCo alloy nanoparticles on this substrate. The resulting catalyst had high activity and durability, despite its relatively low Pt content. Science , this issue p. 1276 Active cobalt sites and platinum-cobalt nanoparticles are combined in a highly active and durable oxygen reduction catalyst. Achieving high catalytic performance with the lowest possible amount of platinum is critical for fuel cell cost reduction. Here we describe a method of preparing highly active yet stable electrocatalysts containing ultralow-loading platinum content by using cobalt or bimetallic cobalt and zinc zeolitic imidazolate frameworks as precursors. Synergistic catalysis between strained platinum-cobalt core-shell nanoparticles over a platinum-group metal (PGM)–free catalytic substrate led to excellent fuel cell performance under 1 atmosphere of O 2 or air at both high-voltage and high-current domains. Two catalysts achieved oxygen reduction reaction (ORR) mass activities of 1.08 amperes per milligram of platinum (A mg Pt −1 ) and 1.77 A mg Pt −1 and retained 64% and 15% of initial values after 30,000 voltage cycles in a fuel cell. Computational modeling reveals that the interaction between platinum-cobalt nanoparticles and PGM-free sites improves ORR activity and durability.
Journal Article
Highly selective electrocatalytic CO2 reduction to ethanol by metallic clusters dynamically formed from atomically dispersed copper
Direct electrochemical conversion of CO
2
to ethanol offers a promising strategy to lower CO
2
emissions while storing energy from renewable electricity. However, current electrocatalysts offer only limited selectivity toward ethanol. Here we report a carbon-supported copper (Cu) catalyst, synthesized by an amalgamated Cu–Li method, that achieves a single-product Faradaic efficiency (FE) of 91% at −0.7 V (versus the reversible hydrogen electrode) and onset potential as low as −0.4 V (reversible hydrogen electrode) for electrocatalytic CO
2
-to-ethanol conversion. The catalyst operated stably over 16 h. The FE of ethanol was highly sensitive to the initial dispersion of Cu atoms and decreased significantly when CuO and large Cu clusters become predominant species. Operando X-ray absorption spectroscopy identified a reversible transformation from atomically dispersed Cu atoms to Cu
n
clusters (
n
= 3 and 4) on application of electrochemical conditions. First-principles calculations further elucidate the possible catalytic mechanism of CO
2
reduction over Cu
n
.
Electrocatalytically reducing CO
2
to ethanol can provide renewably generated fuel, but catalysts are often poorly selective for this conversion. Here the authors use a Cu catalyst to produce ethanol with high selectivity. Cu dispersion is key to the performance and operando studies indicate that it changes under reaction conditions.
Journal Article
Short-chain fatty acids in diseases
Short-chain fatty acids (SCFAs) are the main metabolites produced by bacterial fermentation of dietary fibre in the gastrointestinal tract. The absorption of SCFAs is mediated by substrate transporters, such as monocarboxylate transporter 1 and sodium-coupled monocarboxylate transporter 1, which promote cellular metabolism. An increasing number of studies have implicated metabolites produced by microorganisms as crucial executors of diet-based microbial influence on the host. SCFAs are important fuels for intestinal epithelial cells (IECs) and represent a major carbon flux from the diet, that is decomposed by the gut microbiota. SCFAs play a vital role in multiple molecular biological processes, such as promoting the secretion of glucagon-like peptide-1 by IECs to inhibit the elevation of blood glucose, increasing the expression of G protein-coupled receptors such as GPR41 and GPR43, and inhibiting histone deacetylases, which participate in the regulation of the proliferation, differentiation, and function of IECs. SCFAs affect intestinal motility, barrier function, and host metabolism. Furthermore, SCFAs play important regulatory roles in local, intermediate, and peripheral metabolisms. Acetate, propionate, and butyrate are the major SCFAs, they are involved in the regulation of immunity, apoptosis, inflammation, and lipid metabolism. Herein, we review the diverse functional roles of this major class of bacterial metabolites and reflect on their ability to affect intestine, metabolic, and other diseases.
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Journal Article
Thermoelectric Generators: Alternative Power Supply for Wearable Electrocardiographic Systems
Research interest in the development of real‐time monitoring of personal health indicators using wearable electrocardiographic systems has intensified in recent years. New advanced thermoelectrics are potentially a key enabling technology that can be used to transform human body heat into power for use in wearable electrographic monitoring devices. This work provides a systematic review of the potential application of thermoelectric generators for use as power sources in wearable electrocardiographic monitoring systems. New strategies on miniaturized rigid thermoelectric modules combined with batteries or supercapacitors can provide adequate power supply for wearable electrocardiographic systems. Flexible thermoelectric generators can also support wearable electrocardiographic systems directly when a heat sink is incorporated into the design in order to enlarge and stabilize the temperature gradient. Recent advances in enhancing the performance of novel fiber/fabric based flexible thermoelectrics has opened up an exciting direction for the development of wearable electrocardiographic systems. This work overviews that both rigid and flexible thermoelectric power generators, with the advantages of eco‐friendliness and maintenance‐free, are suitable for harvesting electricity from the human body to power up wearable electrocardiographic systems. Moreover, advances in flexible thermoelectric materials will further boost the large‐scale application in electrocardiographic systems.
Journal Article
Interfacial water engineering boosts neutral water reduction
Hydrogen evolution reaction (HER) in neutral media is of great practical importance for sustainable hydrogen production, but generally suffers from low activities, the cause of which has been a puzzle yet to be solved. Herein, by investigating the synergy between Ru single atoms (RuNC) and RuSe
x
cluster compounds (RuSe
x
) for HER using ab initio molecular dynamics, operando X-ray absorption spectroscopy, and operando surface-enhanced infrared absorption spectroscopy, we establish that the interfacial water governs neutral HER. The rigid interfacial water layer in neutral media would inhibit the transport of H
2
O*/OH* at the electrode/electrolyte interface of RuNC, but the RuSe
x
can promote H
2
O*/OH* transport to increase the number of available H
2
O* on RuNC by disordering the interfacial water network. With the synergy of RuSe
x
and RuNC, the resulting neutral HER performance in terms of mass-specific activity is 6.7 times higher than that of 20 wt.% Pt/C at overpotential of 100 mV.
Understanding the slow kinetics of hydrogen evolution reaction in neutral media is of fundamental importance for the rational design of high-performance electrocatalysts for hydrogen energy. Here, by studying Ru single atom and RuSe
x
cluster, the authors report how the rate of hydrogen evolution reaction activity in neutral media is governed by interfacial water.
Journal Article
Centralized scheduling, decentralized scheduling or demand scheduling? How to more effectively allocate and recycle shared takeout lunch boxes
Efficient scheduling of shared takeaway containers plays a significant role in the sharing economy system. An effective scheduling system ensures the maximization of container reuse, reducing resource waste and environmental pollution. To explore the applicability of different scheduling models for shared takeaway containers, this paper constructs differential game models for three modes: centralized scheduling, decentralized scheduling, and demand-based scheduling. The equilibrium outcomes are compared and analyzed. The research findings indicate that when the revenue from scheduling takeaway containers is low, decentralized scheduling can yield the maximum benefit for takeaway platforms; conversely, when the revenue is high, centralized scheduling offers the greatest benefit. For restaurant enterprises, when the revenue from scheduling is low, if the cost of scheduling is also low, demand-based scheduling can provide the maximum benefit; however, if the cost is high, decentralized scheduling is more advantageous; otherwise, centralized scheduling can maximize the benefits for restaurant enterprises.
Journal Article
Selection rules of triboelectric materials for direct-current triboelectric nanogenerator
The rapid development of Internet of Things and artificial intelligence brings increasing attention on the harvesting of distributed energy by using triboelectric nanogenerator (TENG), especially the direct current TENG (DC-TENG). It is essential to select appropriate triboelectric materials for obtaining a high performance TENG. In this work, we provide a set of rules for selecting the triboelectric materials for DC-TENG based on several basic parameters, including surface charge density, friction coefficient, polarization, utilization rate of charges, and stability. On the basis of the selection rules, polyvinyl chloride, used widely in industry rather than in TENG, is selected as the triboelectric layer. Its effective charge density can reach up to ~8.80 mC m
−2
in a microstructure-designed DC-TENG, which is a new record for all kinds of TENGs. This work can offer a basic guideline for the triboelectric materials selection and promote the practical applications of DC-TENG.
Appropriate triboelectric material selection is vital to for high performance direct current triboelectric nanogenerator (DC-TENG). The authors here provide effective selection rules as guideline to select triboelectric materials for DC-TENG to reduce the trial-and-error cost for DC-TENG’s research.
Journal Article
High performance platinum single atom electrocatalyst for oxygen reduction reaction
For the large-scale sustainable implementation of polymer electrolyte membrane fuel cells in vehicles, high-performance electrocatalysts with low platinum consumption are desirable for use as cathode material during the oxygen reduction reaction in fuel cells. Here we report a carbon black-supported cost-effective, efficient and durable platinum single-atom electrocatalyst with carbon monoxide/methanol tolerance for the cathodic oxygen reduction reaction. The acidic single-cell with such a catalyst as cathode delivers high performance, with power density up to 680 mW cm
−2
at 80 °C with a low platinum loading of 0.09 mg
Pt
cm
−2
, corresponding to a platinum utilization of 0.13 g
Pt
kW
−1
in the fuel cell. Good fuel cell durability is also observed. Theoretical calculations reveal that the main effective sites on such platinum single-atom electrocatalysts are single-pyridinic-nitrogen-atom-anchored single-platinum-atom centres, which are tolerant to carbon monoxide/methanol, but highly active for the oxygen reduction reaction.
High-performance electrocatalysts for the oxygen reduction reaction (ORR) typically use platinum (Pt), however its high cost is a hindrance to commercial scale up. Here, the authors report a cost-effective, efficient and durable Pt single-atom electrocatalyst for ORR with a Pt utilization of 0.13 g
Pt
kW
−1
in a fuel cell.
Journal Article