Strongly coupled Nafion molecules and ordered porous CdS networks are fabricated for visible‐light photoelectrochemical (PEC) hydrogen evolution. The Nafion layer coating shifts the band position of ...CdS upward and accelerates charge transfer in the photoelectrode/electrolyte interface. It is highly expected that the strong coupling effect between organic and inorganic materials will provide new routes to advance PEC water splitting.
Phase engineering of nanomaterials (PEN) offers a promising route to rationally tune the physicochemical properties of nanomaterials and further enhance their performance in various applications. ...However, it remains a great challenge to construct well‐defined crystalline@amorphous core–shell heterostructured nanomaterials with the same chemical components. Herein, the synthesis of binary (Pd‐P) crystalline@amorphous heterostructured nanoplates using Cu3−χP nanoplates as templates, via cation exchange, is reported. The obtained nanoplate possesses a crystalline core and an amorphous shell with the same elemental components, referred to as c‐Pd‐P@a‐Pd‐P. Moreover, the obtained c‐Pd‐P@a‐Pd‐P nanoplates can serve as templates to be further alloyed with Ni, forming ternary (Pd‐Ni‐P) crystalline@amorphous heterostructured nanoplates, referred to as c‐Pd‐Ni‐P@a‐Pd‐Ni‐P. The atomic content of Ni in the c‐Pd‐Ni‐P@a‐Pd‐Ni‐P nanoplates can be tuned in the range from 9.47 to 38.61 at%. When used as a catalyst, the c‐Pd‐Ni‐P@a‐Pd‐Ni‐P nanoplates with 9.47 at% Ni exhibit excellent electrocatalytic activity toward ethanol oxidation, showing a high mass current density up to 3.05 A mgPd−1, which is 4.5 times that of the commercial Pd/C catalyst (0.68 A mgPd−1).
Binary (Pd‐P) and ternary (Pd‐Ni‐P) nanoplates, both with crystalline@amorphous core–shell nanostructures, are synthesized using Cu3−χP nanoplates as templates. The obtained c‐Pd‐Ni‐P@a‐Pd‐Ni‐P heterostructured nanoplates exhibit superior electrocatalytic performance toward the ethanol oxidation reaction in alkaline media compared to c‐Pd‐P@a‐Pd‐P heterostructured nanoplates and commercial Pd/C catalysts.
Zinc–air batteries offer a possible solution for large‐scale energy storage due to their superhigh theoretical energy density, reliable safety, low cost, and long durability. However, their ...widespread application is hindered by low power density. Herein, a multiscale structural engineering of Ni‐doped CoO nanosheets (NSs) for zinc–air batteries with superior high power density/energy density and durability is reported for the first time. In micro‐ and nanoscale, robust 2D architecture together with numerous nanopores inside the nanosheets provides an advantageous micro/nanostructured surface for O2 diffusion and a high electrocatalytic active surface area. In atomic scale, Ni doping significantly enhances the intrinsic oxygen reduction reaction activity per active site. As a result of controlled multiscale structure, the primary zinc–air battery with engineered Ni‐doped CoO NSs electrode shows excellent performance with a record‐high discharge peak power density of 377 mW cm−2, and works stable for >400 h at 5 mA cm−2. Rechargeable zinc–air battery based on Ni‐doped CoO NSs affords an unprecedented small charge–discharge voltage of 0.63 V, outperforming state‐of‐the‐art Pt/C catalyst‐based device. Moreover, it is shown that Ni‐doped CoO NSs assembled into all‐solid‐state coin cells can power 17 light‐emitting diodes and charge an iPhone 7 mobile phone.
A multiscale structure engineering of Ni‐doped CoO nanosheets from micro‐ through nano‐ to atomic scale for high‐power‐density zinc–air batteries is demonstrated. The engineered zinc–air battery based on Ni‐doped CoO nanosheets realizes sufficient mass transport, abundant catalysts active sites, and excellent intrinsic activity simultaneously, affording a record‐high discharge peak power density of 377 mW cm−2.
Developing low‐cost and high‐activity pH‐universal hydrogen evolution reaction (HER) catalysts is very crucial to the industrialization of water electrolysis. However, the high price, low yield, and ...poor stability of current HER catalysts make them difficult to meet practical requirements. Herein, a plasma spraying technique is employed to prepare self‐supported Cu catalysts with tensile strain for the first time. The tensile strain upshifts the d‐band of Cu, improves the water dissociation and H* adsorption, eventually improves the intrinsic HER catalytic activity. As such, Cu electrode achieves overpotentials of 182 mV in 0.5 m H2SO4, 261 mV in 1 M PBS, and 121 mV in 1 M KOH at 10 mA cm–2. In addition, Cu electrode also performs well at high current densities, the overpotentials at 1 A cm–2 are much lower than those of Pt foil in acid, neutral, and alkaline solutions.
The Cu electrode prepared by plasma spraying exhibits an excellent pH‐universal HER catalytic activity, superb long‐term stability, and marvelous corrosion resistance. The superb HER activity is attributed to self‐supported porous structure, abundant active sites, tensile strain enhanced intrinsic catalytic activity, and small charge transfer resistance.
The typical conductive polymer of PEDOT:PSS has recently attracted intensive attention in thermoelectric conversion because of its low cost and low thermal conductivity as well as high electrical ...conductivity. However, compared to inorganic counterparts, the relatively poor thermoelectric performance of PEDOT:PSS has greatly limited its development and high-tech applications. Here, we report a dramatic enhancement in the thermoelectric performance of PEDOT:PSS by constructing unique composite films with graphene quantum dots (GQDs). At room temperature, the electrical conductivity and Seebeck coefficient of PEDOT:PSS/GQDs reached to 7172 S/m and 14.6 μV/K, respectively, which are 30.99% and 113.2% higher than those of pristine PEDOT:PSS. As a result, the power factor of the optimized PEDOT:PSS/GQDs composite is 550% higher than that of pristine PEDOT:PSS. These significant improvements are attributed to the ordered alignment of PEDOT chains on the surface of GQDs, originated from the strong interfacial interaction between PEDOT:PSS and GQDs and the separation of PEDOT and PSS phases. This study evidently provides a promising route for PEDOT:PSS applied in high-efficiency thermoelectric conversion.
Chiral ferroelectric crystals with intriguing features have attracted great interest and many with point or axial chirality based on the stereocarbon have been successively developed in recent years. ...However, ferroelectric crystals with stereogenic heteroatomic chirality have never been documented so far. Here, we discover and report a pair of enantiomeric stereogenic sulfur‐chiral single‐component organic ferroelectric crystals, Rs‐tert‐butanesulfinamide (Rs‐tBuSA) and Ss‐tert‐butanesulfinamide (Ss‐tBuSA) through the deep understanding of the chemical design of molecular ferroelectric crystals. Both enantiomers adopt chiral‐polar point group 2 (C2) and exhibit mirror‐image relationships. They undergo high‐temperature 432F2‐type plastic ferroelectric phase transition around 348 K. The ferroelectricity has been well confirmed by ferroelectric hysteresis loops and domains. Polarized light microscopy records the evolution of the ferroelastic domains, according with the fact that the 432F2‐type phase transition is both ferroelectric and ferroelastic. The very soft characteristics with low elastic modulus and hardness reveals their excellent mechanical flexibility. This finding indicates the first stereosulfur chiral molecular ferroelectric crystals, opening up new fertile ground for exploring molecular ferroelectric crystals with great application prospects.
Following the discovery of the first ferroelectric chiral Rochelle salt more than 100 years ago, the first pair of stereogenic heteroatom sulfur‐chiral ferroelectric crystals is reported on this study. The findings provide a perspective for the development of heteroatomic chiral ferroelectric crystals with great application prospects.
A key challenge for electrochemical nitrogen reduction reactions (NRR) is the difficulty for conventional catalysts to achieve high currents at low H* coverage to produce appreciable NH3. Herein, we ...specially designed an Au nanoparticle‐embedded ZnSe photo‐electrode to solve the problem. As‐designed photo‐electrode achieves excellent NRR performance with a high NH3 yield (12.2 μg cm−2 h−1) and Faradaic efficiency (27.3 %). Our work reveals that the unique plasmon resonance effect of embedded Au nanoparticles plays a key role in increasing catalytic current when the H* coverage is decreased. Moreover, we successfully established a correlation between H* coverage and NRR performance based on theoretical calculations and experimental observations. This work paves the path for the future design of catalytic materials to overcome the selectivity and yield challenge of sustainable NH3 production.
A strategy is proposed to address current NH3 yield challenge of NRR by achieving low H* coverages at appreciable current densities based on the unique SPR effect and established a correlation between H* coverage and NRR performance. The specifically designed ZnSe(Au) electrode achieves a high FE and NH3 yield rate of 27.3 % and 12.2 μg cm−2 h−1, respectively.
Mitochondrial dysfunction leads to reactive oxygen species (ROS) overload, exacerbating injury in myocardial infarction (MI). As a receptor for translocases in the outer mitochondrial membrane (Tom) ...complex, Tom70 has an unknown function in MI, including melatonin‐induced protection against MI injury. We delivered specific small interfering RNAs against Tom70 or lentivirus vectors carrying Tom70a sequences into the left ventricles of mice or to cultured neonatal murine ventricular myocytes (NMVMs). At 48 h post‐transfection, the left anterior descending coronary arteries of mice were permanently ligated, while the NMVMs underwent continuous hypoxia. At 24 h after ischemia/hypoxia, oxidative stress was assessed by dihydroethidium and lucigenin‐enhanced luminescence, mitochondrial damage by transmission electron microscopy and ATP content, and cell apoptosis by terminal deoxynucleotidyl transferase dUTP nick‐end labeling and caspase‐3 assay. At 4 weeks after ischemia, cardiac function and fibrosis were evaluated in mice by echocardiography and Masson's trichrome staining, respectively. Ischemic/hypoxic insult reduced Tom70 expression in cardiomyocytes. Tom70 downregulation aggravated post‐MI injury, with increased mitochondrial fragmentation and ROS overload. In contrast, Tom70 upregulation alleviated post‐MI injury, with improved mitochondrial integrity and decreased ROS production. PGC‐1α/Tom70 expression in ischemic myocardium was increased with melatonin alone, but not when combined with luzindole. Melatonin attenuated post‐MI injury in control but not in Tom70‐deficient mice. N‐acetylcysteine (NAC) reversed the adverse effects of Tom70 deficiency in mitochondria and cardiomyocytes, but at a much higher concentration than melatonin. Our findings showed that Tom70 is essential for melatonin‐induced protection against post‐MI injury, by breaking the cycle of mitochondrial impairment and ROS generation.
The structure engineering of metal–organic frameworks (MOFs) forms the cornerstone of their applications. Nonetheless, realizing the simultaneous versatile structure engineering of MOFs remains a ...significant challenge. Herein, a dynamically mediated synthesis strategy to simultaneously engineer the crystal structure, defect structure, and nanostructure of MOFs is proposed. These include amorphous Zr‐ODB nanoparticles, crystalline Zr‐ODB‐hz (ODB = 4,4′‐oxalyldibenzoate, hz = hydrazine) nanosheets, and defective d‐Zr‐ODB‐hz nanosheets. Aberration‐corrected scanning transmission electron microscopy combined with low‐dose high‐angle annular dark‐field imaging technique vividly portrays these engineered structures. Concurrently, the introduced hydrazine moieties confer self‐reduction properties to the respective MOF structures, allowing the in situ installation of catalytic Pd nanoparticles. Remarkably, in the hydrogenation of vanillin‐like biomass derivatives, Pd/Zr‐ODB‐hz yields partially hydrogenated alcohols as the primary products, whereas Pd/d‐Zr‐ODB‐hz exclusively produces fully hydrogenated alkanes. Density functional theory calculations, coupled with experimental evidence, uncover the catalytic selectivity switch triggered by the change in structure type. The proposed strategy of versatile structure engineering of MOFs introduces an innovative pathway for the development of high‐performance MOF‐based catalysts for various reactions.
A dynamically mediated synthesis strategy achieves versatile structure engineering of crystalline Zr‐ODB‐hz nanosheets and defective crystalline d‐Zr‐ODB‐hz nanosheets. The Pd/Zr‐ODB‐hz catalyst gives partially hydrogenated alcohols as the main products for the catalytic conversion of vanillin. In contrast, the defective Pd/d‐Zr‐ODB‐hz catalyst shows switchable product selectivity and gives further hydrogenolysized alkanes as the only product.
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•The concepts of probabilistic duck curve and probabilistic ramp curve are proposed.•The probabilistic duck curve is modeled considering dependencies among PV and loads.•Probabilistic ...duck curve is used for flexible resource planning.•Empirical analysis is conducted on actual high PV penetration power system in China.
The high penetration of photovoltaic (PV) is reshaping the electricity net-load curve and has a significant impact on power system operation and planning. The concept of duck curve is widely used to describe the timing imbalance between peak demand and PV generation. The traditional duck curve is deterministic and only shows a single extreme or typical scenario during a day. Thus, it cannot capture both the probability of that scenario and the uncertainty of PV generation and loads. These weaknesses limit the application of the duck curve on power system planning under high PV penetration. To address this issue, the novel concepts of probabilistic duck curve (PDC) and probabilistic ramp curve (PRC) are proposed to accurately model the uncertainty and variability of electricity net load and ramp under high PV penetration. An efficient method is presented for modeling PDC and PRC using kernel density estimation, copula function, and dependent discrete convolution. Several indices are designed to quantify the characteristics of the PDC and PRC. For the application, we demonstrate how the PDC and PRC will benefit flexible resource planning. Finally, an empirical study on the Qinghai provincial power system of China validates the effectiveness of the presented method. The results of PDC and PRC intuitively illustrate that the ramp demand and the valley of net load face considerable uncertainty under high PV penetration. The results of flexible resource planning indicate that retrofitting coal-fired units has remarkable performance on enhancing the power system flexibility in Qinghai. In average, reducing the minimal output of coal-fired units by 1 MW will increase PV accommodation by over 4 MWh each day.
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