Mo/Fe bimetallic pyrophosphates derived from Prussian blue analogues for rapid electrocatalytic oxygen evolution

Efficient and stable oxygen evolution electrocatalysts are indispensable for industrial applications of water splitting and hydrogen production.Herein,a simple and practical method was applied to fabricate(Mo,Fe)P2O7@NF electrocatalyst by directly growing Mo/Fe bimetallic pyrophosphate derived from Prussian blue analogues on three-dimensional porous current collector.In alkaline media,the developed material possesses good hydrophilic features and exhibits best-in-class oxygen evolution reaction(OER)performances.Surprisingly,the(Mo,Fe)P_(2)O_(7)@NF only requires overpotentials of 250 and 290 mV to deliver 100 and 600 mA cm^(-2)in 1 mol L^(-1)KOH,respectively.Furthermore,the(Mo,Fe)P_(2)O_(7)@NF shows outstanding performances in alkaline salty water and 1 mol L^(-1)high purity KOH.A worthwhile pathway is provided to combine bimetallic pyrophosphate with commercial Ni foam to form robust electrocatalysts for stable electrocatalytic OER,which has a positive impact on both hydrogen energy application and environmental restoration.

Catalytic transfer hydrogenolysis as an efficient route in cleavage of lignin and model compounds

Cleavage of aromatic ether bonds through hydrogenolysis is one of the most promising routes for depolymerisation and transformation of lignin into value-added chemicals. Instead of using pressurized hydrogen gas as hydrogen source, some reductive organic molecules, such as methanol, ethanol, isopropanol as well as formates and formic acid, can serve as hydrogen donor is the process called catalytic transfer hydrogenolysis. This is an emerging and promising research field but there are very few reports. In this paper, a comprehensive review of the works is presented on catalytic transfer hydrogenolysis of lignin and lignin model compounds aiming to breakdown the aromatic ethers including a-O-4, b-O-4 and 4-O-5 linkages, with focus on reaction mechanisms. The works are organised regarding to different hydrogen donors used, to gain an in-depth understanding of the special role of various hydrogen donors in this process. Perspectives on current challenges and opportunities of future research to develop catalytic transfer hydrogenolysis as a competitive and unique strategy for lignin valorisation are also provided.

Realizing optimal hydrogen evolution reaction properties via tuning phosphorous and transition metal interactions

Hydrogen is one of the most attractive renewables for future energy application,therefore it is vital to develop cost-effective and highlyefficient electrocatalysts for the hydrogen evolution reaction(HER)to promote the generation of hydrogen from mild methods.In this work,Co–Mo phosphide nanosheets with the adjustable ratio of Co and Mo were fabricated on carbon cloth by a facile hydrothermal-annealing method.Owing to the unique nanostructures,abundant active surfaces and small resistance were achieved.Excellent electrocatalytic performances are obtained,such as the small overpotential of^67.3 mV to realize a current density of 10 mA cm^(-2) and a Tafel slope of 69.9 mV dec^(-1).Rapid recovery of the current response under multistep chronoamperometry is realized and excellent stability retained after the CV test for 2000 cycles.The change of electronic states of different elements was carefully studied which suggested the optimal electrochemical performance can be realized by tuning phosphorous and metal interactions.

Structural engineering of cathodes for improved Zn-ion batteries

Aqueous zinc-ion batteries(ZIBs) are attracting considerable attention because of their low cost,high safety and abundant anode material resources.However,the major challenge faced by aqueous ZIBs is the lack of stable and high capacity cathode materials due to their complicated reaction mechanism and slow Zn-ion transport kinetics.This study reports a unique 3 D ’flower-like’ zinc cobaltite(ZnCo_(2)O_(4-x)) with enriched oxygen vacancies as a new cathode material for aqueous ZIBs.Computational calculations reveal that the presence of oxygen vacancies significantly enhances the electronic conductivity and accelerates Zn^(2+) diffusion by providing enlarged channels.The as-fabricated batteries present an impressive specific capacity of 148.3 mAh g^(-1) at the current density of 0.05 A g^(-1),high energy(2.8 Wh kg^(-1)) and power densities(27.2 W kg^(-1)) based on the whole device,which outperform most of the reported aqueous ZIBs.Moreover,a flexible solid-state pouch cell was demonstrated,which delivers an extremely stable capacity under bending states.This work demonstrates that the performance of Zn-ion storage can be effectively enhanced by tailoring the atomic structure of cathode materials,guiding the development of low-cost and eco-friendly energy storage materials.

The hydrogenation of levulinic acid to γ-valerolactone over Cu–ZrO2 catalysts prepared by a pH-gradient methodology

A novel pH gradient methodology was used to synthesise a series of Cu–ZrO2 catalysts containing different quantities of Cu and Zr.All of the catalysts were highly selective to the desired product,γ-valerolactone, and are considerably more stable than Cu–ZrO2 catalysts prepared by other co-precipitation methods for this reaction.Characterisation and further investigation of these catalysts by XRD, BET, SEM and XPS provided insight into the nature of the catalytic active site and the physicochemical properties that lead to catalyst stability.We consider the active site to be the interface between Cu/CuOxand ZrOx and that lattice Cu species assist with the dispersion of surface Cu through the promotion of a strong metal support interaction.This enhanced understanding of the active site and roles of lattice and surface Cu will assist with future catalyst design.As such, we conclude that the activity of Cu–ZrO2 catalysts in this reaction is dictated by the quantity of Cu–Zr interface sites.

Cell adhesion in renal tubular epithelial cells:Biochemistry,biophysics or both

Changes in cell-cell and cell-substrate adhesion markers are increasingly used to characterize disease onset and progression.However,these relationships depend on both the biochemical and molecular association between cells and between cells and their extracellular matrix,as well as the biophysical and mechanical properties orchestrated by cytoskeletal,membrane and matrix components.To fully appreciate the role of cell adhesion when determining normal physiology and the impact of disease on cellular function,it is important to consider both biochemical and biophysical attributes of the system being investigated.In this short viewpoint we reflect on our experiences assessing cell-cell and/or cell-matrix interactions in renal tubular epithelial cells.

Geographical location affects size and materials used in the construction of European Pied Flycatcher(Ficedula hypoleuca) nests

Background: Nest construction is a key element of avian reproductive behaviour and the result is often a complex structure that is used for incubation of eggs, which represents an extended phenotype. It is known that nest construction is a plastic behaviour but the extent to which plasticity is observed in a single species with a wide geographical distribution is largely unknown. This study sought to better understand variation in nest size and composition across a very wide geographical area. The hypothesis suggested that location would affect size but not composition of nests of the European Pied Flycatcher (Ficedula hypoleuca). Methods: Nests and reproductive data were collected from seventeen study sites, spread over 6° of latitude and 3.3° of longitude on the island of Great Britain. Dimensions of nests were measured before they were deconstructed to determine the masses and types materials used in the outer nest and the cup lining. Results: Geographical variation was observed in base thickness of nests but not many other dimensions. Nests varied in composition but were mainly made of leaf, moss, bark, grass, root and fern. Moss was used more to the north and east of the study area compared with more leaf mass towards the south and west. The species of leaf and bark used in the nests varied between geographical locations. Additionally, the use of leaves or bark from a particular tree species did not reflect the incidence of the tree species in the immediate territory. Conclusions: This study showed that nest composition was affected by geographical location over a wide area. Variation between nests at each location was high and so it was concluded that differences in nest composition reflect individual selection of materials but evidence is such that it remains unclear whether this is deliberate to fulfil a specific role in the nest, or simply opportunistic with birds simply picking up materials with the appropriate characteristics as they find them outside their nestbox.

原位电化学改性的预插层钒青铜水系锌离子电池正极材料

钒青铜是一种极具潜力的水系锌离子电池正极材料.然而,传统的单离子预插层V_(4)O_(9)材料由于自身结构的限制和储锌过程中发生不可逆的相变使其储锌能力接近上限.本文采用原位阴极氧化法将准层状材料Ca V_(4)O_(9)在特定的电解液中将双离子(Ca^(2+), Zn^(2+))引入δ-V_(4)O_(9)晶体骨架中,形成超薄钒青铜材料Ca^(2+)Zn^(2+)V_(4)O_(9)·n H_(2)O.该材料表现出超高的能量密度(366 W h kg^(-1))和功率密度(6627 W kg^(-1)),并在大电流10 A g^(-1)下循环3000圈后可逆比容量仍高达205 m A h g^(-1).通过多种原位/非原位表征,系统地揭示了材料与Ca^(2+)电解液添加剂的协同作用,使结构、电化学可逆性和反应动力学得到有效提升,并凸显了电解液调控对转化反应过程的重要性.经过理论计算,阐明了双离子预嵌入衍生的“支柱”增强效应、电荷屏蔽效应和调控电子结构对增强电荷储存性能的作用.

自组装杂原子掺杂碳纳米带作为超快充电锌离子混合超级电容器阴极

锌离子混合超级电容器(ZHSs)由于其具有较高安全性,较低成本和超长寿命等优点,适合应用于大型储能设备.然而,目前阴极材料的倍率性能较差,严重阻碍了ZHSs的发展.基于此,本文设计合成了一系列自组装杂原子掺杂(B,N,O)碳纳米带CPTHB-Bx,作为ZHSs的阴极材料.杂原子掺杂可以显著改善碳骨架的化学特性,产生更多的活性位点,并加速电荷传输.除此之外,本文还证明了B–N基团是快速吸附和脱附锌离子的主要活性位点.以CPTHB-B2作为阴极的ZHSs表现出最优异的电化学性能,在0.5 A g^(−1)电流密度下,比电容高达415.3 F g^(−1),当电流密度从0.5增大到100 A g^(−1)时,比电容保留率高达81%,能量密度为131.9 W h kg^(−1),功率密度为42.1 kW kg^(−1).此研究为超快速锌离子存储材料提供了新的设计思路.