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Garnet‐type solid‐state lithium batteries (SSLBs) possess excellent potential owing to their safety and high energy density. However, fundamental barriers are deficient cycling stability and poor rate capability. The main concern lies in generating voids at the Li|garnet interface during Li stripping, stemming from the sluggish diffusion of Li atoms inside the bulk Li metal. Herein, a composite anode (AN@Li) containing Li–Al alloy, Li3N, and LiNO2 is designed by introducing aluminum nitrate into molten Li. The lower interfacial formation energies exhibited by Li–Al alloy, Li3N, and LiNO2 with garnet solid‐state electrolyte (SSE) enhance the wettability of AN@Li toward SSE. Meanwhile, it affords efficient conductive pathways that facilitate Li+ diffusion in the bulk anode (not just on the surface). Impressively, the resulting symmetric cell with AN@Li electrodes achieves high critical current density (1.95 mA cm−2) and long cycle life (6000 h at 0.3 mA cm−2). The SSLB coupled with LiFePO4 cathode and AN@Li anode enables stable cycling for 200 cycles at a high rate of 1 C with a retention of 96% and exhibiting outstanding rate capability (145.9 mAh g−1 at 2 C). This work provides practical insights for producing high‐performance lithium metal anode for advanced garnet‐type SSLBs. [ABSTRACT FROM AUTHOR]

Li1.3Al0.3Ti1.7(PO4)3 (LATP) solid‐state electrolyte has garnered considerable interest owing to its competitive room‐temperature Li‐ion conductivity, air stability, and economic nature. Nevertheless, the successful implementation of LATP in next‐generation Li‐metal solid‐state batteries (SSBs) is impeded by its high incompatibility with Li metal. Herein, combining the Kevlar aramid nanofiber (KANF) membrane with a solidified electrolyte (SE) formed via in situ polymerization, the SE@KANF protective layer for LATP can be constructed. Such a protective layer not only effectively prevents Li metal from reducing LATP but also provides intimate interface contact and limits unnecessary electron transport. Consequently, Li symmetric battery incorporating SE@KANF layer enables an ultrahigh critical current density of 1.4 mA cm−2 and stably cycles for over 2000 h at 0.2 mA cm−2. Moreover, the full SSB coupling with LiFePO4 cathode delivers a capacity retention of 95% after 180 cycles at 0.1 C at 30 °C. The present study underscores the importance of the protective interface layer in stabilizing the LATP|Li interface. [ABSTRACT FROM AUTHOR]

Nanozyme-based colorimetry was suggested to be a rapid method for biomarker (e.g. glutathione) detection, but this method suffers from lack of efficiency and low-toxicity nanozymes till now. Herein, quantum dots of TiO2 loaded on carbon (TiO2/C-QDs) oxidase-like nanozymes were prepared via a hydrothermal treatment of tiny and few-layered Ti3C2Tx MXene nanosheets, which possess abundant thermodynamic metastable Ti atoms on MXene margins as raw materials for the preparation of TiO2/C-QDs. The oxygen vacancy in TiO2 on the surface of the carbon matrix can facilitate O2 adsorption in the solution and generate reactive oxygen species (ROS), thereby quickly oxidizing 3,3′,5,5′-tetramethylbenzidine (TMB) to its oxidized form (TMBox) in the absence of H2O2. After adding glutathione (GSH), TMBox was able to be restored to TMB, which resulted in a corresponding decrease in the UV-vis absorbance value at 652 nm. Furthermore, this assay possesses good selectivity, excellent specificity and high sensitivity (limit of detection: 0.2 μM), which made it possible to efficiently detect GSH in complex biological samples such as human serum. [ABSTRACT FROM AUTHOR]

Electrochemical N2 reduction offers an environmentally benign and sustainable approach for NH3 synthesis under ambient conditions wherein a high-efficiency electrocatalyst is paramount. In this study, we report that TiC/C nanofibers act as an efficient one-dimensional electrocatalyst for N2-to-NH3 conversion. In 0.1 M HCl, such an electrocatalyst achieves a large NH3 yield of 14.1 μg h−1 mg−1cat. and a high faradaic efficiency of 5.8% at −0.5 V vs. the reversible hydrogen electrode. Notably, this electrocatalyst also shows both high electrochemical stability and structural stability during electrolysis. Density functional theory calculations further reveal that TiC can efficiently activate N2 in an enzymatic route with a low energy barrier. [ABSTRACT FROM AUTHOR]

Industrial synthesis of NH3 relies mainly on the traditional Haber–Bosch process, which is highly energy-intensive with enormous greenhouse gas emission. Electrochemical N2 reduction provides an eco-friendly approach for energy-saving NH3 synthesis, but it requires highly efficient electrocatalysts under ambient conditions. In this communication, an MnO2-decorated Ti3C2Tx (T = F, OH) MXene nanohybrid (MnO2–Ti3C2Tx) is proposed as a highly active electrocatalyst for the N2 reduction reaction with strong durability. In addition, only the NH3 product without N2H4 can be detected during the NRR, revealing the excellent selectivity of MnO2–Ti3C2Tx for NH3 formation. A high NH3 yield of 34.12 μg h−1 mgcat−1 and a high faradaic efficiency of 11.39% are achieved at −0.55 V vs. a reversible hydrogen electrode in 0.1 M HCl. Density functional theory calculations further reveal that the unsaturated surface Mn atoms act as active sites to adsorb and activate the inert N2 molecules for the NRR process, and the rate-determining step is the first hydrogenation process. [ABSTRACT FROM AUTHOR]

Electrocatalytic N2 reduction represents a promising alternative to the conventional Haber–Bosch process for ambient N2-to-NH3 fixation, but it is severely challenged by competitive hydrogen evolution, which limits the current efficiency for NH3 formation. In this work, a nanosheet array of metallic Bi, an environmentally benign elemental substance previously predicted theoretically to have low hydrogen-evolving activity, is proposed as a superior catalyst for N2 reduction electrocatalysis. Electrochemical tests show that the Bi nanosheet array on Cu foil as a stable 3D catalyst electrode achieves a high faradaic efficiency of 10.26% with an NH3 yield rate of 6.89 × 10−11 mol s−1 cm−2 at −0.50 V vs. the reversible hydrogen electrode in 0.1 M HCl, rivalling the performances of most reported noble-metal-free catalysts operating in acids. Density functional theory calculations suggest that Bi effectively activates the N≡N bond and the alternating mechanism is energetically favourable. [ABSTRACT FROM AUTHOR]

Electrocatalytic N2 reduction as an alternative approach to the energy-intensive and large CO2-producing Haber–Bosch process for NH3 synthesis under mild conditions has attracted extensive attention. Current research efforts on N2 reduction have mainly focused on metal-based catalysts, but metal-free alternatives can avoid the issue of metal ion release. In this work, oxygen-doped hollow carbon microtubes (O-KFCNTs) derived from natural kapok fibers are reported as a metal-free NRR electrocatalyst for N2-to-NH3 conversion with excellent selectivity. In 0.1 M HCl, the O-KFCNTs achieve a high faradaic efficiency of 9.1% at −0.80 V vs. a reversible hydrogen electrode (RHE) and a NH3 yield rate of 25.12 μg h−1 mgcat.−1 at −0.85 V vs. RHE under ambient conditions. Notably, this catalyst also demonstrates high stability. [ABSTRACT FROM AUTHOR]

As a sustainable alternative technology to the Haber–Bosch process, electrochemical N2 reduction offers the hope of directly converting N2 to NH3 at ambient conditions. However, its efficiency greatly depends on screening high‐active electrocatalysts for the N2 reduction reaction (NRR). Here, the recent experimental finding that V is an effective dopant to greatly improve the NRR performances of TiO2 toward ambient N2‐to‐NH3 fixation with excellent selectivity is reported. In 0.5 m anhydrous lithium perchlorate, V‐doped TiO2 nanorods attain a high Faradic efficiency of 15.3% and a large NH3 yield of 17.73 µg h−1 mgcat.−1 at −0.40 and −0.50 V versus reversible hydrogen electrode, respectively, rivaling the performances of most reported aqueous‐based NRR electrocatalysts. Density function theory (DFT) calculations are performed to gain further insight into the catalytic mechanism. [ABSTRACT FROM AUTHOR]

Nanozyme-based colorimetry was suggested to be a rapid method for biomarker (e.g. glutathione) detection, but this method suffers from lack of efficiency and low-toxicity nanozymes till now. Herein, quantum dots of TiO2 loaded on carbon (TiO2/C-QDs) oxidase-like nanozymes were prepared via a hydrothermal treatment of tiny and few-layered Ti3C2Tx MXene nanosheets, which possess abundant thermodynamic metastable Ti atoms on MXene margins as raw materials for the preparation of TiO2/C-QDs. The oxygen vacancy in TiO2 on the surface of the carbon matrix can facilitate O2 adsorption in the solution and generate reactive oxygen species (ROS), thereby quickly oxidizing 3,3',5,5'-tetramethylbenzidine (TMB) to its oxidized form (TMBox) in the absence of H2O2. After adding glutathione (GSH), TMBox was able to be restored to TMB, which resulted in a corresponding decrease in the UV-vis absorbance value at 652 nm. Furthermore, this assay possesses good selectivity, excellent specificity and high sensitivity (limit of detection: 0.2 μM), which made it possible to efficiently detect GSH in complex biological samples such as human serum.

The Haber-Bosch process for industrial-scale NH3 production suffers from harsh conditions and serious CO2 release. Electrochemical N2 reduction is an alternative approach to synthesize NH3 under ambient conditions, but it requires highly-efficient electrocatalysts for the N2 reduction reaction (NRR). In this Communication, we demonstrate that WO3 nanosheets rich in oxygen vacancies (R-WO3 NSs) exhibit greatly enhanced NRR performances. In 0.1 M HCl, such R-WO3 NSs achieve a large NH3 yield of 17.28 μg h-1 mgcat.-1 and a high faradaic efficiency of 7.0% at -0.3 V vs. a reversible hydrogen electrode, much superior to the WO3 nanosheets deficient in oxygen vacancies (6.47 μg h-1 mgcat.-1 and 1.02%). Remarkably, R-WO3 NSs also show high electrochemical stability.

The production of ammonia (NH 3 ) in the industrial scale basically relies on the traditional technology of Haber-Bosch, which is operated under harsh conditions with high energy consumption and a huge number of greenhouse gas emissions. Electrochemical N 2 reduction reaction (NRR) is a promising route for artificial N 2 -to-NH 3 fixation with less energy consumption. However, an effective electrocatalyst, as a prerequisite of the NRR, is of significance. Here, we report that a spinel LiMn 2 O 4 nanofiber acts as a noble-metal-free electrocatalyst for NH 3 synthesis with excellent performance under ambient conditions. The electrocatalyst, which was tested in 0.1 M HCl, has an excellent Faradaic efficiency of 7.44% and a NH 3 yield of 15.83 μg h -1 mg cat. -1 at -0.50 V versus reversible hydrogen electrode. Moreover, it also possesses excellent electrochemical and structure stability.

Electrocatalytic N 2 reduction represents a promising alternative to the conventional Haber-Bosch process for ambient N 2 -to-NH 3 fixation, but it is severely challenged by competitive hydrogen evolution, which limits the current efficiency for NH 3 formation. In this work, a nanosheet array of metallic Bi, an environmentally benign elemental substance previously predicted theoretically to have low hydrogen-evolving activity, is proposed as a superior catalyst for N 2 reduction electrocatalysis. Electrochemical tests show that the Bi nanosheet array on Cu foil as a stable 3D catalyst electrode achieves a high faradaic efficiency of 10.26% with an NH 3 yield rate of 6.89 × 10 -11 mol s -1 cm -2 at -0.50 V vs. the reversible hydrogen electrode in 0.1 M HCl, rivalling the performances of most reported noble-metal-free catalysts operating in acids. Density functional theory calculations suggest that Bi effectively activates the N[triple bond, length as m-dash]N bond and the alternating mechanism is energetically favourable.

Electrocatalytic N2 reduction as an alternative approach to the energy-intensive and large CO2-producing Haber-Bosch process for NH3 synthesis under mild conditions has attracted extensive attention. Current research efforts on N2 reduction have mainly focused on metal-based catalysts, but metal-free alternatives can avoid the issue of metal ion release. In this work, oxygen-doped hollow carbon microtubes (O-KFCNTs) derived from natural kapok fibers are reported as a metal-free NRR electrocatalyst for N2-to-NH3 conversion with excellent selectivity. In 0.1 M HCl, the O-KFCNTs achieve a high faradaic efficiency of 9.1% at -0.80 V vs. a reversible hydrogen electrode (RHE) and a NH3 yield rate of 25.12 μg h-1 mgcat.-1 at -0.85 V vs. RHE under ambient conditions. Notably, this catalyst also demonstrates high stability.