The practical scale‐up of renewable energy technologies will require catalysts that are more efficient and durable than present ones. This is, however, a formidable challenge that will demand a new ...capability to tailor the electronic structure. Here, an original electronic structure tailoring of CoO by Ni and Zn dual doping is reported. This changes it from an inert material into one that is highly active for the hydrogen evolution reaction (HER). Based on combined density functional theory calculations and cutting‐edge characterizations, it is shown that dual Ni and Zn doping is responsible for a highly significant increase in HER activity of the host oxide. That is, the Ni dopants cluster around surface oxygen vacancy of the host oxide and provide an ideal electronic surface structure for hydrogen intermediate binding, while the Zn dopants distribute inside the host oxide and modulate the bulk electronic structure to boost electrical conduction. As a result, the dual‐doped Ni, Zn CoO nanorods achieve current densities of 10 and 20 mA cm−2 at overpotentials of, respectively, 53 and 79 mV. This outperforms reported state‐of‐the‐art metal oxide, metal oxide/metal, metal sulfide, and metal phosphide catalysts.
A controlled tailoring of electronic structure of an oxide for the hydrogen evolution reaction (HER) is reported. Dual Ni and Zn doping is shown to be responsible for a significant increase in the HER activity of the host oxide, which was previously considered as catalytically inactive. The engineered oxide nanorods exhibit significantly high HER activity and are amongst the most active reported.
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.
Macromolecular isomerism has been an important yet largely understudied subject. Giant molecules based on molecular nanoparticles exhibit properties highly dependent on the primary structures, ...providing a platform for such studies. Various isomers have been designed, synthesized and characterized, including sequence‐, regio‐, and topo‐isomers. The self‐assembly of these isomers is influenced by the distinct symmetry and collective interaction of each building block in a subtle and delicate way. The results suggest that isomerism may be exploited as a new way for fine‐tuning the structures and properties of macromolecules, which should be of great interest in both fundamental research and technical innovation.
Macromolecular isomerism has been a largely understudied phenomenon. Giant molecules provide an ideal platform for such studies and should help illustrate the structure–property relationships as well as the delicate influence of structural factors on the assembly.
Constructing a heterojunction and introducing an interfacial interaction by designing ideal structures have the inherent advantages of optimizing electronic structures and macroscopic mechanical ...properties. An exquisite hierarchical heterogeneous structure of bimetal sulfide Sb2S3@FeS2 hollow nanorods embedded into a nitrogen-doped carbon matrix is fabricated by a concise two-step solvothermal method. The FeS2 interlayer expands in situ grow on the interface of hollow Sb2S3 nanorods within the nitrogen-doped graphene matrix, forming a delicate heterostructure. Such a well-designed architecture affords rapid Na+ diffusion and improves charge transfer at the heterointerfaces. Meanwhile, the strongly synergistic coupling interaction among the interior Sb2S3, interlayer FeS2, and external nitrogen-doped carbon matrix creates a stable nanostructure, which extremely accelerates the electronic/ion transport and effectively alleviates the volume expansion upon long cyclic performance. As a result, the composite, as an anode material for sodium-ion batteries, exhibits a superior rate capability of 537.9 mAh g–1 at 10 A g–1 and excellent cyclic stability with 85.7% capacity retention after 1000 cycles at 5 A g–1. Based on the DFT calculation, the existing constructing heterojunction in this composite can not only optimize the electronic structure to enhance the conductivity but also favor the Na2S adsorption energy to accelerate the reaction kinetics. The outstanding electrochemical performance sheds light on the strategy by the rational design of hierarchical heterogeneous nanostructures for energy storage applications.
Lightweight, robust, and thin aerogel films with multifunctionality are highly desirable to meet the technological demands of current society. However, fabrication and application of these ...multifunctional aerogel films are still significantly underdeveloped. Herein, we demonstrate a multifunctional aerogel film composed of strong aramid nanofibers (ANFs), conductive carbon nanotubes (CNTs), and hydrophobic fluorocarbon (FC) resin. The obtained hybrid aerogel film exhibits large specific surface area (232.8 m2·g–1), high electrical conductivity (230 S·m–1), and excellent hydrophobicity (contact angle of up to 137.0°) with exceptional Joule heating performance and supreme electromagnetic interference (EMI) shielding efficiency. The FC coating renders the hydrophilic ANF/CNT aerogel films hydrophobic, resulting in an excellent self-cleaning performance. The high electrical conductivity enables a low-voltage-driven Joule heating property and an EMI shielding effectiveness (SE) of 54.4 dB in the X-band at a thickness of 568 μm. The specific EMI SE is up to 33528.3 dB·cm2·g–1, which is among the highest values of typical metal-, conducting-polymer-, or carbon-based composites. This multifunctional aerogel film holds great promise for smart garments, electromagnetic wave shielding, and personal thermal management systems.
Facile interconversion between CO2 and formate/formic acid (FA) is of broad interest in energy storage and conversion and neutral carbon emission. Historically, electrochemical CO2 reduction reaction ...to formate on Pd surfaces was limited to a narrow potential range positive of −0.25 V (vs RHE). Herein, a boron-doped Pd catalyst (Pd–B/C), with a high CO tolerance to facilitate dehydrogenation of FA/formate to CO2, is initially explored for electrochemical CO2 reduction over the potential range of −0.2 V to −1.0 V (vs RHE), with reference to Pd/C. The experimental results demonstrate that the faradaic efficiency for formate (ηHCOO– ) reaches ca. 70% over 2 h of electrolysis in CO2-saturated 0.1 M KHCO3 at −0.5 V (vs RHE) on Pd–B/C, that is ca. 12 times as high as that on homemade or commercial Pd/C, leading to a formate concentration of ca. 234 mM mg–1 Pd, or ca. 18 times as high as that on Pd/C, without optimization of the catalyst layer and the electrolyte. Furthermore, the competitive selectivity ηHCOO–/ηCO on Pd–B/C is always significantly higher than that on Pd/C despite a decreases of ηHCOO– and an increases of the CO faradaic efficiency (ηCO) at potentials negative of −0.5 V. The density functional theory (DFT) calculations on energetic aspects of CO2 reduction reaction on modeled Pd(111) surfaces with and without H-adsorbate reveal that the B-doping in the Pd subsurface favors the formation of the adsorbed HCOO*, an intermediate for the FA pathway, more than that of *COOH, an intermediate for the CO pathway. The present study confers Pd–B/C a unique dual functional catalyst for the HCOOH ↔ CO2 interconversion.
Most electrocatalysts for the ethanol oxidation reaction suffer from extremely limited operational durability and poor selectivity toward the CC bond cleavage. In spite of tremendous efforts over ...the past several decades, little progress has been made in this regard. This study reports the remarkable promoting effect of Ni(OH)2 on Pd nanocrystals for electrocatalytic ethanol oxidation reaction in alkaline solution. A hybrid electrocatalyst consisting of intimately mixed nanosized Pd particles, defective Ni(OH)2 nanoflakes, and a graphene support is prepared via a two‐step solution method. The optimal product exhibits a high mass‐specific peak current of >1500 mA mg−1Pd, and excellent operational durability forms both cycling and chronoamperometric measurements in alkaline solution. Most impressively, this hybrid catalyst retains a mass‐specific current of 440 mA mg−1 even after 20 000 s of chronoamperometric testing, and its original activity can be regenerated via simple cyclic voltammetry cycles in clean KOH. This great catalyst durability is understood based on both CO stripping and in situ attenuated total reflection infrared experiments suggesting that the presence of Ni(OH)2 alleviates the poisoning of Pd nanocrystals by carbonaceous intermediates. The incorporation of Ni(OH)2 also markedly shifts the reaction selectivity from the originally predominant C2 pathway toward the more desirable C1 pathway, even at room temperature.
A hybrid electrocatalyst material is reported, which features small Pd nanoparticles abundantly interfaced with Ni(OH)2 and uniformly supported on graphene nanosheets. The synergy between Pd and Ni(OH)2 leads to dramatically improved electrocatalytic performance of the precious metal for the ethanol oxidation reaction and markedly shifts its selectivity toward the C1 pathway in alkaline solution.
Catenanes are intriguing molecular architectures with unique properties. Herein, we report the cellular synthesis of protein catenanes containing folded structural domains, aided by synergy between ...p53 dimerization and SpyTag/SpyCatcher chemistry. Concatenation of green fluorescent protein (GFP) was shown to increase chemical stability without disrupting the fluorescence properties, and concatenated dihydrofolate reductase (DHFR) exhibited a melting temperature around 4 °C higher and catalytic activity around 27 % higher than the wild‐type DHFR and the cyclic/linear controls. Catenation also confers considerable proteolytic resistance on DHFR. The results suggest that catenation could enhance both the stability and activity of folded proteins, thus making topology engineering an attractive approach for tailoring protein properties without varying their native sequences.
We go together: Cellular synthesis of protein catenanes containing folded structural domains was effectively achieved by using p53 dimerization and SpyTag/SpyCatcher chemistry. Catenation was found to endow the purified proteins of interest (POIs) with several valuable attributes, including enhanced thermal stability, increased proteolytic resistance, and enhanced enzymatic activity.
A technique combining ion mobility spectrometry‐mass spectrometry (IMS‐MS) and supercharging electrospray ionization (ESI) has been demonstrated to differentiate protein chemical topology ...effectively. Incorporating as many charges as possible into proteins via supercharging ESI allows the protein chains to be largely unfolded and stretched, revealing their hidden chemical topology. Different chemical topologies result in differing geometrical sizes of the unfolded proteins due to constraints in torsional rotations in cyclic domains. By introducing new topological indices, such as the chain‐length‐normalized collision cross‐section (CCS) and the maximum charge state (zM) in the extensively unfolded state, we were able to successfully differentiate various protein chemical topologies, including linear chains, ring‐containing topologies (lasso, tadpole, multicyclics, etc.), and mechanically interlocked rings, like catenanes.
The topological features of complex proteins, previously concealed by their inherent complexity, can now be easily classified through the application of supercharging electrospray ionization coupled with ion mobility spectrometry‐mass spectrometry. By overcharging the protein backbones, limitations in protein elongation depending on the protein topology become evident, thereby establishing a visual standard for discerning protein topologies.
Herein, we report the biosynthesis of protein heterocatenanes using a programmed sequence of multiple post‐translational processing events including intramolecular chain entanglement, in situ ...backbone cleavage, and spontaneous cyclization. The approach is general, autonomous, and can obviate the need for any additional enzymes. The catenane topology was convincingly proven using a combination of SDS‐PAGE, LC‐MS, size exclusion chromatography, controlled proteolytic digestion, and protein crystallography. The X‐ray crystal structure clearly shows two mechanically interlocked protein rings with intact folded domains. It opens new avenues in the nascent field of protein‐topology engineering.
Protein heterocatenanes could be readily and modularly synthesized in cellulo using a programmed sequence of post‐translational processing events, including intramolecular chain entanglement, in situ backbone cleavage, and spontaneous cyclization. The catenane topology of the designed protein was rigorously proven by X‐ray crystallography.
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