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Noble metal electrocatalysts (e.g., Pt, Ru, etc.) suffer from sluggish kinetics of water dissociation for the electrochemical reduction of water to molecular hydrogen in alkaline and neutral pH environments. Herein, we found that an integration of Ru nanoparticles (NPs) on oxygen-deficient WO3-x manifested a 24.0-fold increase in hydrogen evolution reaction (HER) activity compared with commercial Ru/C electrocatalyst in neutral electrolyte. Oxygen-deficient WO3-x is shown to possess large capacity for storing protons, which could be transferred to the Ru NPs under cathodic potential. This significantly increases the hydrogen coverage on the surface of Ru NPs in HER and thus changes the rate-determining step of HER on Ru from water dissociation to hydrogen recombination. While water splitting electrolysis offers an appealing means to produce H2 fuel, catalysts show sluggish reaction rate in neutral media. Here, authors utilize hydrogen spillover from oxygen-deficient tungsten oxides to Ru nanoparticles to boost the neutral-pH H2 evolution performances. [ABSTRACT FROM AUTHOR]

Non‐polar diatomic molecule activation is of great significance for catalysis. Despite the high atomic efficiency, the catalytic performance of single‐atom catalysts is limited by insufficient receiving sites for diatomic molecule adsorption. Here, Fe2 dimers were successfully synthesized through precisely regulating the metal loading on metal‐organic frameworks. The unique role of metal dimers in activating diatomic O2 molecules was explored. In alkaline electrolytes, the specific oxygen reduction reaction activity of Fe2 dimers was 7 times higher than that of Fe1 counterparts. The hydrogen atom transfer probes indicated a different activation mode for O2 on Fe1 and Fe2 dimers, respectively. Theoretical calculation results revealed that Fe2 dimers opened up a new reaction pathway by promoting the direct breaking of O=O bonds, thus avoiding the usual formation of *OOH intermediates, which helped explain the lower H2O2 yield and higher specific activity. [ABSTRACT FROM AUTHOR]

Most land plants can establish symbiosis with arbuscular mycorrhizal (AM) fungi to increase fitness to environmental challenges. The development of AM symbiosis is controlled by intricate procedures involving all phytohormones. However, the mechanisms underlying the auxin‐mediated regulation of AM symbiosis remains largely unknown. Here, we report that AM colonisation promotes auxin response and indole‐3‐acetic acid (IAA) accumulation, but downregulates IAA biosynthesis genes in tomato (Solanum lycopersicum). External IAA application modulates the AM symbiosis by promoting arbuscule formation at low concentrations but repressing it at high concentrations. An AM‐induced GH3 gene, SlGH3.4, encoding a putative IAA‐amido synthetase, negatively regulates mycorrhization via maintaining cellular auxin homoeostasis. Loss of SlGH3.4 function increased free IAA content and arbuscule incidence, while constitutively overexpressing SlGH3.4 in either tomato or rice resulted in decreased IAA content, total colonisation level and arbuscule abundance in mycorrhizal roots. Several auxin‐inducible expansin genes involved in AM formation or resistance to pathogen infection were upregulated in slgh3.4 mycorrhizal roots but downregulated in the SlGH3.4‐overexpressing plants. Taken together, our results highlight a positive correlation between the endogenous IAA content and mycorrhization level, particularly arbuscule incidence, and suggest that the SlGH3.4‐mediated auxin homoeostasis and regulation of expansin genes is involved in finely tuning the AM development. [ABSTRACT FROM AUTHOR]

[Display omitted] • The rod-like CuO/Cu 2 O heterojunction obtained by pyrolytic derivatization of rod-like copper based metal organic framework. • The rod-like CuO/Cu 2 O heterojunction act as an effective photoelectrochemical active interface. • A simple photoelectrochemical sensing platform was developed for the homogeneous detection of L-cysteine. Due to their outstanding advantages, photoelectrochemical (PEC) sensors have gained significant attention, which can realize the rapid and accurate detection of target. However, the semiconductor as its core component has a strong influence on the analysis and detection performance. Herein, we developed a simple and efficient method to prepare heterojunction for the construction of PEC sensor detecting L-cysteine (L-Cys). The rod-like copper-based metal organic framework was prepared by room temperature synthesis method, which was used to derive rod-like CuO/Cu 2 O/C heterojunction with excellent photoelectric property. Due to L-Cys interacts with CuO/Cu 2 O/C heterojunction to form steric hindrance effect through Cu-S bond, which reduces the photocurrent signal and realizes the selective and homogeneous detection of L-Cys. Inspired by this steric strategy, a PEC sensing platform was fabricated by CuO/Cu 2 O/C heterojunction for the homogeneous detection of L-Cys, showing linear responses in the range of 0.2 μM to 50 μM with the detection limit of 0.12 μM. Our work shed light on the advancement of better PEC sensor and the method of constructing heterojunction. [ABSTRACT FROM AUTHOR]

The p-n heterojunction Co 3 O 4 /RuO 2 anchored on carbon matrix (Co 3 O 4 /RuO 2 -C) is constructed for acidic water oxidation, wherein the electron could diffuse from RuO 2 to Co 3 O 4 to pre-modify electronic structure of RuO 2 , facilitating redox of Ru sites and dominating adsorbate evolution mechanism of oxygen evolution to endow Co 3 O 4 /RuO 2 -C with excellent activity in water oxidation without trade-off stability. [Display omitted] • A p-n heterojunction of Co 3 O 4 /RuO 2 anchored on carbon matrix is facilely developed for improved acidic oxygen evolution reaction. • The experimental and theoretical results indicate electron flow could occur from RuO 2 to Co 3 O 4 , achieving pre-modifying electronic structure of RuO 2. • In situ total reflection infrared (ATR-IR) can validate adsorbate evolution mechanism of oxygen generation for heterojunction of Co 3 O 4 /RuO 2. • In situ Raman test suggest facile evolution of Ru active sites after formation of p-n heterojunction of Co 3 O 4 /RuO 2. Development of Ru-based electrocatalysts for acidic oxygen evolution reaction without a trade-off between activity and durability remains challenging. Herein, we constructed Co 3 O 4 /RuO 2 heterojunctions anchored on carbon (Co 3 O 4 /RuO 2 -C) with a low Ru loading (2.74 wt%), in which strong coupled p-n junctions facilitated electron transfer from RuO 2 to Co 3 O 4. The Co 3 O 4 /RuO 2 -C demonstrated a low overpotential of 170 mV at 10 mA cm−2 and long-term stability in 0.1 M HClO 4 due to its unique structure. The origin of its high performance in acidic OER was revealed by the combination of in-situ attenuated total reflection infrared and Raman tests. Concretely, oxygen generation for Co 3 O 4 /RuO 2 -C was dominated by the adsorbate evolution mechanism, and the introduction of Co 3 O 4 facilitated the redox of RuO 2 , generating active sites for OER. Theoretical calculations further substantiated that the Co 3 O 4 /RuO 2 heterojunctions possessed lower energy barriers for OER. This work provides a compelling synthesis route for effective and stable electrocatalysts for acidic OER. [ABSTRACT FROM AUTHOR]

[Display omitted] • Tracking the void nucleation and growth of dual phase steel by Computed Tomography. • New voids were observed to nucleate throughout the straining process. • The average size of void grows only slowly with straining. • New damage model is proposed for void nucleation and growth in dual phase steel. In situ synchrotron radiation X-ray computed tomography (CT) is used to understand the void nucleation and growth behaviour of dual phase (DP) steel, DP800, during uniaxial tensile deformation. The voids were identified post mortem as having nucleated primarily in the (41 vol%) martensite phase. The behaviour of individual voids was found to be broadly in line with a Rice and Tracey style growth model (their volume increasing by a factor of 10), while the mean void size was broadly in line with a model that included the continuous nucleation of new voids, as well as the growth of existing voids, throughout straining. Voids tended to elongate during uniaxial (low stress triaxiality) straining, but then to dilate more isotropically as necking led to increased triaxiality. One large pre-existing void was found to elongate quicky at first, but then for growth to slow, presumably because it was not located in the highest triaxial stress (necked) region. Perhaps surprisingly the average size of the void population grows only slowly (by a factor of 2) during straining; this is because while the size of each void grows, new small voids are always being nucleated. Finally, the changes of stress triaxiality and shear stress state during tensile deformation of the square cross-section smooth tensile specimen are investigated via finite element modelling, to qualitatively assess the impact of sample geometry on void nucleation behaviour and fracture strain in the current study. [ABSTRACT FROM AUTHOR]

Most land plants can form symbiosis with arbuscular mycorrhizal (AM) fungi to enhance uptake of mineral nutrients, particularly phosphate (Pi) and nitrogen (N), from the soil. It is established that transport of Pi from interfacial apoplast into plant cells depends on the H+ gradient generated by the H+‐ATPase located on the periarbuscular membrane (PAM); however, little evidence regarding the potential link between mycorrhizal N transport and H+‐ATPase activity is available to date. Here, we report that a PAM‐localized tomato H+‐ATPase, SlHA8, is indispensable for arbuscule development and mycorrhizal P and N uptake. Knockout of SlHA8 resulted in truncated arbuscule morphology, reduced shoot P and N accumulation, and decreased H+‐ATPase activity and acidification of apoplastic spaces in arbusculated cells. Overexpression of SlHA8 in tomato promoted both P and N uptake, and increased total colonization level, but did not affect arbuscule morphology. Heterogeneous expression of SlHA8 in the rice osha1 mutant could fully complement its defects in arbuscule development and mycorrhizal P and N uptake. Our results propose a pivotal role of the SlHA8 in energizing both the symbiotic P and N transport, and highlight the evolutionary conservation of the AM‐specific H+‐ATPase orthologs in maintaining AM symbiosis across different mycorrhizal plant species. SlHA8, encoding a periarbuscular membrane‐localized H+‐ATPase, is not only indispensable for maintaining arbuscule development but also essential for both mycorrhizal phosphate and nitrogen uptake in tomato. [ABSTRACT FROM AUTHOR]