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• Prominent behaviors such as EPSC, PPF, and SFPD are successfully simulated with power consumption as low as 22 pJ. • Owning to its good short-term (STP) and tunable amplitude-frequency characteristics, the as-constructed device can function as a biomimetic high-pass filter for picture edge detection. • After photoelectric-synergistic modulation, the high synaptic weights enable the device to simulate complex neural learning rules for neuromorphic applications, including gesture recognition, image perception in the visual system and classically conditioned reflexes. The development of high-performance neuromorphic phototransistors is of paramount importance for image perception and depth memory learning. Here, based on metal-oxide heterojunction architecture, artificial synaptic phototransistors with synaptic plasticity have been achieved, demonstrating an artificial synapse that integrates central and optic nerve functions. Thanks to the sensitive light-detection properties, the optical power consumption of such photonic artificial synapses can be as low as 22 pico-joules, which is extremely competitive compared with other pure metal oxide photoelectric synapses ever reported. What is more, owing to its good short-term (STP) and tunable amplitude-frequency characteristics, the as-constructed device can function as a biomimetic high-pass filter for picture edge detection. Dual-mode synaptic modulation has been performed, combining photonic pulse with gate voltage stimulus. After photoelectric-synergistic modulation, the high synaptic weights enable the device to simulate complex neural learning rules for neuromorphic applications, including gesture recognition, image perception in the visual system, and classically conditioned reflexes. These results suggest that the current oxide-based heterojunction architecture displays potential application in future multifunction neuromorphic devices and systems. [Display omitted] [ABSTRACT FROM AUTHOR]

• A model was developed to quantify the hydrogen adsorption of tungsten oxide. • Effect of oxygen vacancies on surface activity was disclosed by calculations. • Mechanisms of surface modification for enhancement of H adsorption were revealed. • A new approach was proposed to design excellent gas-sensitive metal oxide materials. A model for describing the adsorption process of hydrogen on surface of tungsten oxide was proposed based on the first-principle calculations. Multiple factors such as type of active surface, adsorption site and distribution of oxygen vacancies were considered to evaluate the hydrogen adsorption capability of tungsten oxide. The adsorption Gibbs free energies, electronic structures and bonding characteristics under various conditions were examined to reveal the influence of oxygen vacancies on the surface. It is found that the capability of hydrogen adsorption of tungsten oxide can be significantly enhanced by adjusting the oxygen vacancy on the outermost layer of certain active surfaces. The modeling predicts that the surface structure stability and gas adsorption ability of tungsten oxide can be simultaneously improved through the formation of W H bonds. The proposed strategy for moderating surface provides a new approach to obtain excellent gas-sensitive metal oxide materials. The effects of oxygen vacancies on the surface activity have been disclosed by modelling of hydrogen adsorption on metal oxide. [Display omitted] [ABSTRACT FROM AUTHOR]

• The alloy design and simple process are based on unique properties of the atomically random distribution. • The TiCuNiSn was designed to form a functional oxide with the capability for water splitting. • The TiCuNiSn was fabricated multi-layered functional structures using one-step process. • Each layer exhibits different functional roles and is formed with a systematic and stable structure. • Metallic glass shows a new possibility for PEC cells applied to both the photoanode and photocathode for water splitting. In this study, metallic glass is designed tunable for promising functional applications via a facile and stable, one-step process. Creative approach about alloy design and process is based on the unique properties of the Ti-Cu-Ni-Sn metallic glass that are afforded by the varying oxygen affinities of the four constituent elements. This metallic glass exhibits homogeneous nucleation of oxides and uniform formation of the various metal oxides. The alloy design and hydrothermal synthesis to customize the metallic glasses are the most critical factors that determine the characteristics of the metal oxides and the resulting nanostructures and photoelectrode properties. This enables the desired element to be selectively grown via a facile single-step process. These results provide a promising road map for the application of metallic glasses to photoelectrochemical (PEC) solar water splitting, as well as various other new possibilities. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • Amorphous WO 3-x is grown by DC sputtering, with x controlled by the oxygen pressure. • The most oxidized films show interband absorption at E g = 3.37 eV and N ∼ 1015 cm−3. • For 0 < x ≤ 0.2, W5+ states increase absorption at 1.5 eV and the electron density. • For x > 0.2, W4+ states produce absorption at 3.3 eV but no higher electron density. Tungsten oxides are interesting for a variety of applications due to their versatile optoelectronic characteristics, which can be tuned changing the composition and/or the crystalline structure. Coloration due to sub-bandgap absorption is often achieved by ion intercalation or doping in WO 3 :M films (with M = H+, Li+, Na+, etc. introducing extra electrons), but a more direct way is creating charged oxygen vacancies (V O + and/or V O 2+) in sub-stoichiometric WO 3- x forms. Here, amorphous WO 3- x thin films are obtained by reactive DC sputtering of a pure W target, on unheated glass substrates, changing the oxygen to argon pressures ratio. The control of intrinsic defects (oxygen vacancies and tungsten valence states) by the oxygen partial pressure allows tuning the morphology, sub-bandgap absorption and carrier density in these WO 3- x films, as it is proven by Raman spectroscopy, atomic force microscopy, optical spectrophotometry and Hall effect measurements. [ABSTRACT FROM AUTHOR]

[Display omitted] • The research progress of metal and metal oxide catalysts in VRFB in recent years was reviewed. • The metal and metal oxide catalysts were classified and their structures were studied. • Analyze and compare different catalysts to help improve battery performance. • 4 The design and development of VRFB catalyst were prospected. Vanadium redox flow battery (VRFB) is a kind of battery with wide application prospect. Electrode material is one of the key components of VRFB, and its stability directly affects the performance of battery. Among all kinds of electrode materials, carbon-based material has the best comprehensive properties. However, carbon-based electrodes still have disadvantages such as poor hydrophilicity and low electrochemical activity which need to be improved. One of the effective ways to improve the performance of electrode is to modify carbon-based material with metals and metal oxides. The metal catalysts have excellent electrical conductivity and high catalytic activity. The metal oxide catalysts have the advantages of low cost, wide variety and strong oxidizing properties. This work introduced the application of metal and metal oxide modified electrodes in VRFB in recent years, classified the catalysts, studied their catalytic performance and mechanism. The metal catalysts were reviewed from precious metals and base metals. The metal oxide catalysts were classified and discussed according to the similar properties of the same group elements. This work compared different modification methods, summarized the research progress of metal and metal oxide modification, and proposes the future development direction of electrodes and catalysts. [ABSTRACT FROM AUTHOR]

With the Internet of Things (IoT) paradigm promising to deploy trillions of sensors, the search is on for effective means to efficiently derive useful information from the flood of sensor data through efficient hardware preprocessing. Of particular interest are computational paradigms that get their inspiration from biological sensory systems that seamlessly extract relevant information through highly efficient analog signal processing. Functions, such as feature extraction, learning, or recognition, could especially benefit from bio-inspired architectures. As an example in the case, this paper presents a bio-inspired analog gas sensing frontend for an artificial olfactory system. The analog front end implements a novel trainable feature extraction algorithm for metal-oxide gas sensor arrays. The algorithm extracts one composite feature of all analytes by performing the gradient decent algorithm during training and transforms the sensor responses into concentration-invariant spike patterns. An integrated circuit realization of the algorithm, implemented in a 65-nm CMOS technology, supports six-input channels, uses subthreshold analog circuits, and consumes 519-nW/channel in the training mode, and 463-nW/channel in the recognition mode. [ABSTRACT FROM PUBLISHER]

The use of a Fe-based metal organic framework (MOF), namely MIL-88B(Fe), as active material for lithium ion batteries (LIBs) is reported for the first time in the present work. Fe-based MOF demonstrated high capacity, excellent cycling stability and rate performance when used as anode. A highly reversible capacity of ~680 mA h g − 1 after 500 cycles at a current density of 200 mA g − 1 was obtained. In addition, Fe 2 O 3 and Fe 3 O 4 /C composites were obtained from Fe-based MOFs through thermal treatment. Both Fe 2 O 3 and Fe 3 O 4 /C composites demonstrated high capacity and excellent cycling stability. [ABSTRACT FROM AUTHOR]