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Highly efficient mixed H + /e − /O 2− triple conducting air electrodes are indispensable for improving the electrochemical performance of protonic ceramic fuel cells and electrolysis cells (PCFC/ECs) operating at intermediate temperatures. This study demonstrates that single perovskite-type La 0.8 Sr 0.2 Co 1-x Ni x O 3-δ families (LSCN, x = 0−0.3) are efficient H + /e − /O 2− triple conductors due to a pronounced hydration ability at elevated temperatures with a related enthalpy of −107 kJ mol −1 . Thermogravimetry confirmed that the oxides were capable of a 0.01 mole fraction proton uptake at 600 °C and p H2O of 0.023 atm. Reversible protonic ceramic cells were fabricated using these oxides as an air electrode and exhibited promising performance with a peak power density of 0.88 W cm −2 in fuel cell mode and an electrolysis current of 1.09 A cm −2 at a thermal neutral voltage in electrolysis cell mode at 600 °C. Impedance analysis confirmed that the polarization resistance of the La 0.8 Sr 0.2 Co 0.7 Ni 0.3 O 3-δ cell was 0.09 Ω cm 2 under an open circuit potential at 600 °C, which is much smaller than the polarization resistances reported for cells with a single or double perovskite-type triple conductor. The current results indicate that mixed H + /e − / O 2− triple phase conducting LSCN oxides are promising air electrodes for protonic ceramic cells operating in the intermediate temperature region at approximately 600 °C.

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The density functional theory is used to study the effect of the external biaxial strain on the adsorption and diffusion of Li on the graphyne as an anode material in the Li-ion battery (LIB). The increasing adsorption energy of Li on graphyne appears with the larger external biaxial strain. The Li capacity of the Li6C6 configuration for graphyne reaches 2233 mA h/g under the 12% strain, which is six times that of graphite (372 mA h/g) and two times that of graphyne without strain (1117 mA h/g). The average open-circuit voltage is 0.50 V, which is about 0.14 eV lowered by the 12% strain and is ideal for LIBs. Li on the graphyne can diffuse easier under the 12% strain than that without strain. Furthermore, the diffusion coefficient for Li on the multilayer graphyne under the 12% strain at 300 K is fivefold of the value without strain. Excellent performances of Li capacity and Li diffusion make graphyne under the 12% strain a promising anode material for LIBs.

Protonic solid oxide steam electrolysis cells (P-SOECs) based on BaZrxCe0.8-xYb0.1Y0.1O3 proton conductors are promising to produce “green” hydrogen from renewable energy at intermediate temperatures. Herein, we demonstrate that the electrolysis...

A substrate plays a crucial role in controlled growth and property modulation of two-dimensional (2D) transition-metal dichalcogenides (TMDCs). In this work, we report multiple regulation over growth direction, band structure, and dimension of an epitaxial monolayer (1L) WS2 by an m-plane quartz substrate. The as-grown WS2 is oriented on a 2-fold symmetric m-quartz based on an anisotropic lattice match, which is distinct from that on c-sapphire. Owing to the large thermal expansion coefficient, the m-quartz generates a large compressive thermal strain in the as-grown WS2. By manipulating this thermal strain, the band structure of 1L-WS2 can be in situ regulated and a direct–indirect band gap transition occurs when the thermal strain exceeds 0.5%. Moreover, the unique atom distribution of the m-plane quartz established an anisotropic diffusion barrier for adlayer monomers which restricted the growth of WS2 uniaxially. By exploiting this, the dimension of WS2 can be tailored from a 2D triangle to a one-dimensional ribbon with controlled growth time. This work not only deepens the understanding of the relationship between a substrate and a material but also provides an effective way to directly regulate the as-grown TMDCs with desirable structures and properties.

the global energy and environmental issues. [1][2][3] Its half-reaction, oxygen evolution reaction (OER), is considered as the key bottleneck in water splitting owing to its multiple protons and electron transfer. [4,5] Through precious metal oxides such as IrO 2 and RuO 2 exhibit effective OER activity, the scarcity, high cost, and inferior stability hinder their widespread applications. [6] The development of highly active electrocatalysts based on earthabundant elements is a highly promising solution to above predicament. However, at present, few noble-metal-free electrocatalysts can meet the requirements of commercial alkaline water electrolysis: afford the current density of 1000 mA cm −2 with stable operation over 100 h. [7,8] Therefore, developing noble-metal-free electrocatalysts with high efficiency and outstanding durability at the large current densities is imperative yet challenging.Iron (Fe)-based materials, especially FeOOH, have recently drawn great attention as promising OER catalysts due to their abundance, cost-effectiveness, and environmental friendliness. [9][10][11] It is reported that the intrinsic activity of FeOOH for OER is higher than that of NiOOH and CoOOH. [12] Nevertheless, the OER performance of FeOOH is far from satisfactory DevelopingFeOOH as a robust electrocatalyst for high output oxygen evolution reaction (OER) remains challenging due to its low conductivity and dissolvability in alkaline conditions. Herein, it is demonstrated that the robust and high output Zn doped NiOOH-FeOOH (Zn-Fe x Ni (1−x) )OOH catalyst can be derived by electro-oxidation-induced reconstruction from the pre-electrocatalyst of Zn modified Ni metal/FeOOH film supported by nickel foam (NF). In situ Raman and ex situ characterizations elucidate that the pre-electrocatalyst undergoes dynamic reconstruction occurring on both the catalyst surface and underneath metal support during the OER process. That involves the Fe dissolution-redeposition and the merge of Zn doped FeOOH with in situ generated NiOOH from NF support and NiZn alloy nanoparticles. Benefiting from the Zn doping and the covalence interaction of FeOOH-NiOOH, the reconstructed electrode shows superior corrosion resistance, and enhanced catalytic activity as well as bonding force at the catalyst-support interface. Together with the feature of superaerophobic surface, the reconstructed electrode only requires an overpotential of 330 mV at a high-current-density of 1000 mA cm −2 and maintains 97% of its initial activity after 1000 h. This work provides an indepth understanding of electrocatalyst reconstruction during the OER process, which facilitates the design of high-performance OER catalysts.

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