Wuhan University of Technology

About: Wuhan University of Technology is a education organization based out in Wuhan, China. It is known for research contribution in the topics: Microstructure & Catalysis. The organization has 40384 authors who have published 36724 publications receiving 575695 citations. The organization is also known as: WUT.

Nano-silica and silica fume modified cement mortar used as Surface Protection Material to enhance the impermeability

Abstract: In corrosion environment, corrosion ions can easily penetrate from the surface into the inside of the concrete due to the porous structure of the surface; in this case, concrete can inevitably suffer from the damage. In this study, an attempt to use nano SiO2 (NS) and silica fume (SF) modifying cement mortar as a Surface Protection Material (SPM) was made, in order to promote penetration resistance of the whole system. SPM was coated on the surface of matrix, and then interfacial bond strength between matrix and SPM was measured; shrinkage consistency was also considered; the chloride penetrability of the system was examined as well. To reveal the mechanism, effect of NS and SF on pore structure, Interfacial Transition Zone (ITZ), hydration process, and compressive strength of SPM were investigated. The results show that matrix coated with SPM on the surface has a good integrity, with excellent interfacial bond strength and little difference in shrinkage, and chloride diffusion coefficient of the system was considerably declined, in comparison with the matrix, showing an excellent penetration resistance. The mechanism behind is that SPM, which was modified with SF-NS, shows the excellent impermeability, and this kind of material existing on the surface can noticeably obstruct the chloride ions penetrating into the inside. In cement hydration process, SF and NS can not only consume a large amount of CH to form dense C-S-H, but also exert the grading filling effect, resulting in the decline in porosity, the increase in density, the improvement in microstructure of ITZ, and the enhancement in mechanical performance. The findings can provide useful experience for the design of the cement-based materials servicing in high corrosion environment.

Integrating 2D/2D CdS/α-Fe2O3 ultrathin bilayer Z-scheme heterojunction with metallic β-NiS nanosheet-based ohmic-junction for efficient photocatalytic H2 evolution

Abstract: Water splitting for hydrogen production on noble metal-free photocatalysts remains a big challenge. Herein, we present for the first time a 2-dimensional/2-dimensional (2D/2D) Z-scheme photocatalyst formed by in situ growing CdS nanosheets on α-Fe2O3 nanosheets. The former was additionally modified with metallic β-NiS cocatalyst, which creates a Ohmic-based heterojunction and functions as hydrogen-evolution sites. The resultant β-NiS-decorated CdS/α-Fe2O3 ultrathin 2D/2D heterojunction showed a remarkable hydrogen production rate of 45 mmol h−1 g−1 and a high quantum efficiency of 46.9 % at 420 nm. The excellent photocatalytic performance is attributed to: (1) intimate and large interfaces between CdS and α-Fe2O3 nanosheets for facilitated charge transfer, (2) promoted charge separation in the Z-scheme heterojunction, and (3) large quantity of Ohmic-junction hydrogen-evolution sites over metallic β-NiS cocatalyst. Overall, this work demonstrates a promising strategy for improving charge dynamics and hydrogen-production efficiency, through rational design and integration of multiple built-in electric fields over 2D semiconductor nanosheets.

A Novel Dendrite‐Free Mn2+/Zn2+ Hybrid Battery with 2.3 V Voltage Window and 11000‐Cycle Lifespan

Abstract: DOI: 10.1002/aenm.201901469 further development.[2] Hence, exploring novel approaches to achieve more efficient energy storage is highly demanded. Recently, aqueous batteries are attracting unprecedented attention particularly owing to their high safety, high ion conductivity, low cost, and environmental friendliness.[3] To date, numerous aqueous batteries based on Li+, Na+, K+, Mg2+, Ca2+, Zn2+, Al3+, Fe3+, and/or mixed metal ions as charge carriers have been reported,[4] which find potential applications in fields such as grid-scale energy storage, wearable devices, and etc.[5] Among them, as a promising candidate, the rechargeable aqueous Zn-based batteries (AZBs) including Zn-ion batteries (mild electrolyte),[6] Zn–Co/Ag/ Ni alkaline batteries[7] and Zn–air batteries in alkaline electrolyte[8] have been extensively studied due to their unparalleled advantages of Zn anode. In general, metal Zn has the features of high theoretical capacity (820 mAh g−1), high electrical conductivity, nontoxicity, easy processing, and suitable redox potential (−0.76 V vs standard hydrogen electrode).[9] However, most of AZBs reported so far have encountered the same challenges, which are the narrow voltage window, unsatisfactory capacity, and poor cycling performance.[10] For example, all Zn-ion batteries operated in mild electrolyte including Zn//V-based, Zn//Mn-based, and Zn//Prussian blue analogs-based hold a narrow voltage window of 0.3–1.6, 0.9–1.8, and 0.2–1.8 V, respectively.[11] Even though AZBs in alkaline electrolyte display a higher voltage than that achieved in mild medium, their voltage windows are still only about 1.2–1.9 V.[12] Meanwhile, the alkaline electrolytes show stronger corrosion than mild neutral electrolytes, which greatly limit their wide applications. Moreover, the unstable cycling performance in AZBs due to the Zn dendrites and side reaction on the surface of Zn anode is also unsatisfactory.[10] To date, the electrolyte optimization or structural design are the common ways to suppress the growth of Zn dendrite and improve the cycling stability. For example, Chen and co-workers reported that aqueous electrolyte Zn(CF3SO3)2 can suppress the formation of detrimental dendrites in AZBs owing to the better reversibility and faster kinetics of Zn deposition/dissolution than that in ZnSO4 electrolyte.[13] However, Zn(CF3SO3)2 is too expensive (≈$ 8.1 g−1, prices from Sigma-Aldrich) to be applied With the increasing energy crisis and environmental pollution, rechargeable aqueous Zn-based batteries (AZBs) are receiving unprecedented attention due to their list of merits, such as low cost, high safety, and nontoxicity. However, the limited voltage window, Zn dendrites, and relatively low specific capacity are still great challenges. In this work, a new reaction mechanism of reversible Mn2+ ion oxidation deposition is introduced to AZBs. The assembled Mn2+/Zn2+ hybrid battery (Mn2+/Zn2+ HB) based on a hybrid storage mechanism including Mn2+ ion deposition, Zn2+ ion insertion, and conversion reaction of MnO2 can achieve an ultrawide voltage window (0–2.3 V) and high capacity (0.96 mAh cm−2). Furthermore, the carbon nanotubes coated Zn anode is proved to effectively inhibit Zn dendrites and control side reaction, hence exhibiting an ultrastable cycling (33 times longer than bare Zn foil) without obvious polarization. Benefiting from the optimal Zn anode and highly reversible Mn2+/Zn2+ hybrid storage mechanism, the Mn2+/Zn2+ HB shows an excellent cycling performance over 11 000 cycles with a 100% capacity retention. To the best of the authors’ knowledge, it is the highest reported cycling performance and wide voltage window for AZBs with mild electrolyte, which may inspire a great insight into designing high-performance aqueous batteries.