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Hydrogen evolution reaction is catalysed efficiently with precious metals, such as platinum; however, transition metal dichalcogenides have recently emerged as a promising class of materials for electrocatalysis, but these materials still have low activity and durability when compared with precious metals. Here we report a simple one-step scalable approach, where MoO x /MoS 2 core-shell nanowires and molybdenum disulfide sheets are exposed to dilute aqueous hydrazine at room temperature, which results in marked improvement in electrocatalytic performance. The nanowires exhibit ∼100 mV improvement in overpotential following exposure to dilute hydrazine, while also showing a 10-fold increase in current density and a significant change in Tafel slope. In situ electrical, gate-dependent measurements and spectroscopic investigations reveal that hydrazine acts as an electron dopant in molybdenum disulfide, increasing its conductivity, while also reducing the MoO x core in the core-shell nanowires, which leads to improved electrocatalytic performance. Transition metal dichalcogenides are promising hydrogen evolution catalysts however they can require expensive processing steps to enhance their activity. Here, the authors report a one-step activation step in which room temperature hydrazine treatment results in much enhanced electrocatalytic performance.

In this paper, we introduce an environmentally friendly approach to recycle used batteries and recover highly valuable manganese-based cathode materials. This study demonstrates the feasibility of fast plasma pyrolysis to recover LiMn2O4 electrode materials (e.g., lithium manganese oxide, LMO) and demonstrate their reuse in newly assembled Li-ion cells. The electrochemical performance of as-recycled cathodes shows an initial discharge capacity of 72 mAh/g and is stable for 100 cycles at 0.1 C. After adding 20 mole % of excess LiOH, the recycled LMO after relithiation at 660 °C can deliver an initial discharge capacity of 96 mAh/g and retain a decent discharge capacity of 88 mAh/g after 50 cycles at a 0.2 C rate. Without relithiation, the as-recycled LMO cathode after heating at 1000 °C delivers the best electrochemical cycling performance, including an initial discharge capacity of 94 mAh/g and 50th cycle capacity of 91 mAh/g at a 0.2 C rate. This study highlights a feasible approach for recycling electrode materials in spent LIBs. Recycling of lithium-ion batteries and especially electrode materials is crucial for the sustained growth of the lithium-ion battery industry and reduced environmental issues.

Development in high-rate electrode materials capable of storing vast amounts of charge in a short duration to decrease charging time and increase power in lithium-ion batteries is an important challenge to address. Here, we introduce a synthesis strategy with a series of composition-controlled NMC cathodes, including LiNi0.2Mn0.6Co0.2O2(NMC262), LiNi0.3Mn0.5Co0.2O2(NMC352), and LiNi0.4Mn0.4Co0.2O2(NMC442). A very high-rate performance was achieved for Mn-rich LiNi0.2Mn0.6Co0.2O2 (NMC262). It has a very high initial discharge capacity of 285 mAh g−1 when charged to 4.7 V at a current of 20 mA g−1 and retains the capacity of 201 mAh g−1 after 100 cycles. It also exhibits an excellent rate capability of 138, and 114 mAh g−1 even at rates of 10 and 15 C (1 C = 240 mA g−1). The high discharge capacities and excellent rate capabilities of Mn-rich LiNi0.2Mn0.6Co0.2O2 cathodes could be ascribed to their structural stability, controlled particle size, high surface area, and suppressed phase transformation from layered to spinel phases, due to low cation mixing and the higher oxidation state of manganese. The cathodic and anodic diffusion coefficient of the NMC262 electrode was determined to be around 4.76 × 10−10 cm2 s−1 and 2.1 × 10−10 cm2 s−1, respectively.

In order to make fast-charging batteries a reality for electric vehicles, durable, more energy dense and high-current density resistant anodes need to be developed. With such purpose, a low lithiation potential of 0.2 V vs. Li/Li + for MoO 3 nanoplatelet arrays is reported here for anodes in a lithium ion battery. The composite material here presented affords elevated charge capacity while at the same time withstands rapid cycling for longer periods of time. Li 2 MoO 4 and Li 1.333 Mo 0.666 O 2 were identified as the products of lithiation of pristine MoO 3 nanoplatelets and silicon-decorated MoO 3 , respectively, accounting for lower than previously reported lithiation potentials. MoO 3 nanoplatelet arrays were deposited using hot-wire chemical vapor deposition. Due to excellent voltage compatibility, composite lithium ion battery anodes comprising molybdenum oxide nanoplatelets decorated with silicon nanoparticles (0.3% by wt.) were prepared using an ultrasonic spray. Silicon decorated MoO 3 nanoplatelets exhibited enhanced capacity of 1037 mAh g −1 with exceptional cyclablity when charged/discharged at high current densities of 10 A g −1 .

One of the primary goals of the global economy is to develop economically effective, scalable, and sustainable technology for converting lignocellulosic biomass to liquid fuels. It is also a key component of a comprehensive plan to attain carbon neutrality. Herein we identify technology to achieve this promise by producing an alternative blendable fuel such as bioethanol from renewable carbon sources by chemocatalytic route which is carbon neutral and provides high atom economy. Moreover, based on the conversion technology and availability of feedstock, biofuels are categorized indicating that second-generation biofuels primarily from non-food crop residue containing cellulosic biomass is suitable to produce ethanol. The significance of hot water in cellulose hydrogenolysis is discussed and reveals that water is capable of self-ionization, due to which cellulose degradation and hydrolysis increase. Additionally, this review aims to provide a comprehensive picture of the chemocatalytic conversion of cellulose to ethanol by understanding the bond functionality for the series of cascade reactions including hydrolysis, retro aldol condensation, hydrogenolysis, and hydrogenation reactions. In this review, we discuss recent improvements in the chemocatalytic conversion of lignocellulosic biomass to ethanol, with an emphasis on analyzing the mechanisms of chemocatalytic routes. We believe that this review will provide fresh insight into the development of sustainable lignocellulosic biomass for direct ethanol synthesis. Graphical Abstract

Pure, porous titania nanowires (TiO 2 -pNW) are produced in bulk amount (~ 250 kg/day, reaction time scale < 1 min) using a unique solvo-plasma oxidation method utilizing microwave plasma with the potential of easy scale up. The prepared nanowire is found to be efficient towards both biotic disinfection and destruction of various abiotic contaminants in wastewaters. In terms of organic contaminants, the TiO 2 -pNW is tested for destruction of Rhodamine B (RhB) dye, tetracycline (TC) antibiotic, and diclofenac (DFC) and caffeine (CAF) drugs. In the case of biotic contaminants, the disinfection of E. coli bacteria is demonstrated. In all of the studies, the photocatalytic performance of anatase TiO 2 -pNW is compared to that of commercially available P25 nanoparticles (TiO 2 -P25), both in the presence and absence of ozone. The excellent photoactivity exhibited by TiO 2 -pNW is a result of low recombination rate of electron–hole pair owing to the spatial separation of electrons and holes within the photoexcited nanowires. Moreover, the scavenger experiments and experiments involving ozone reveal that electron transfer and/or presence of dissolved oxygen are the major limiting factors for both porous titania nanowires and P25 spherical powder under UV exposure with photocatalytic activity towards pollutant degradation.

Electron transport layer (ETL) plays a crucial role on the fabrication of perovskite solar cells (PSCs) by separating and transporting the charge carriers. Titanium dioxide (TiO2) has been extensively used as an ETL in PSCs; however, high temperature thermal annealing requirement impedes its integration with flexible polymer substrates for roll to roll fabrication. Herein, we have demonstrated that SnO2 is a potential ETL candidate when fabricated at low temperature (180 °C) using spin coating technique. XRD and XPS analysis revealed synthesis of rutile SnO2 tetragonal phase. TEM micrographs with SAED pattern proved formation of nanosized (3 to 4 nm) crystals of SnO2 with polycrystalline phase. FESEM analysis revealed the SnO2 nanocrystals fully covered the FTO surface and elemental mapping confirmed the uniformly distribution tin (Sn) and (O) elements throughout the surface. In addition to this, transmission analysis confirmed that SnO2 film exhibited good transmission property. PSCs were fabricated in ambient air (relative humidity ranges from 55% to 65%) with concentrated SnO2 colloidal solution and diluted SnO2 with different concentrations (1:1 v/v, 1:2 v/v, 1:4 v/v and 1:6 v/v). It was found that 1:4 v/v based diluted colloidal solution of SnO2 in DI water film exhibited the highest PSC performance of 8.51% in ambient conditions. Thus, low temperature solution processed SnO2 is an efficient ETL and well-suited for low cost automated fabrication of PSCs at large scale.

The stability of tungsten trioxide (WO 3 ) suspensions in various common polar solvents such as water, acetone, isopropanol (IPA), ethanol, 1-methoxy-2-propanol (1M-2P) and N,N-dimethylformamide (DMF) was investigated. The morphology of WO 3 aggregates formed by irregular nanoparticles ( d  ∼ 40 nm, with 1 μm nominal diameter compact aggregates) and by nanowires of different types (uneven, single or bundled in diameter) and dimensions (nominal lengths of 2, 4, 6, and 10 μm) were described by means of the small angle static light scattering and the elliptically polarized light scattering (EPLS) techniques. Aggregation of low aspect ratio (bundled) 2 μm nanowires monitored through the change in spatial extent of the aggregate was found to be minimal (i.e., radius of gyration, R g  ∼ 1.8–2.2 μm in 1-methoxy-2-propanol), with a minimal change in aggregate structure (i.e., fractal dimension, D f  ∼ 1.8–1.9 in 1-methoxy-2-propanol) in a time period of about 1 week. Fractal dimension was found to be the lowest for the low aspect ratio nanowires when suspended in N,N-dimethylformamide ( D f  ∼ 1.4). Aggregates of very high aspect ratio single nanowires ( L / D  ∼ 250 with 10 μm nominal length) were also observed to form stable dispersions in a period of about a week. Aggregate structures that would lead to observed fractal dimensions were proposed. Information on how well inorganic nanowires are dispersed in various solvents is based singly on the time consuming and intrusive advanced microscopy analyses (such as SEM and TEM) in the literature, and without any reference to the underlying structures. To our knowledge, this study is the first attempt for in-situ description of the underlying causes, such as aggregate morphologies, aggregation rates and solvent types, of the observed dispersion and sedimentation behaviors of inorganic nanowires that were not subjected to any surface treatment or functionalization.