Hornworts, liverworts and mosses are three early diverging clades of land plants, and together comprise the bryophytes. Here, we report the draft genome sequence of the hornwort Anthoceros angustus. ...Phylogenomic inferences confirm the monophyly of bryophytes, with hornworts sister to liverworts and mosses. The simple morphology of hornworts correlates with low genetic redundancy in plant body plan, while the basic transcriptional regulation toolkit for plant development has already been established in this early land plant lineage. Although the Anthoceros genome is small and characterized by minimal redundancy, expansions are observed in gene families related to RNA editing, UV protection and desiccation tolerance. The genome of A. angustus bears the signatures of horizontally transferred genes from bacteria and fungi, in particular of genes operating in stress-response and metabolic pathways. Our study provides insight into the unique features of hornworts and their molecular adaptations to live on land.
Fe–N–C single-atom catalysts (SACs) exhibit high activity for oxygen reduction reaction (ORR). However, it remains controversial how the active center mediates catalysis, and the predicted potential ...deviates from experimental results, hindering development of ideal SACs. Here, using first-principles calculations, we present a microkinetic model for ORR on Fe–N–C SACs, disclosing a self-adjusting mechanism induced by its intrinsic intermediate. The modeling results show that the single-atom Fe site of the FeN4 center of Fe–N–C is covered with an intermediate OH* from 0.28 to 1.00 V. Remarkably, such OH* becomes part of the active moiety, Fe(OH)N4, and can optimize intermediate bindings on the Fe site, exhibiting a theoretical half-wave potential of ∼0.88 V. Partial current density analysis reveals the dominating associative path over the dissociative ones. In addition, ORR on Mn–N–C and Co–N–C SACs is unveiled. This work demonstrates the necessity of assessing the effect of intrinsic intermediates in single-atom catalysis and provides practical guidance for rational design of high-performance SACs.
Despite wide applications of bimetallic electrocatalysis in oxygen evolution reaction (OER) owing to their superior performance, the origin of the improved performance remains elusive. The underlying ...mechanism was explored by designing and synthesizing a series of stable metal–organic frameworks (MOFs: NNU‐21–24) based on trinuclear metal carboxylate clusters and tridentate carboxylate ligands. Among the examined stable MOFs, NNU‐23 exhibits the best OER performance; particularly, compared with monometallic MOFs, all the bimetallic MOFs display improved OER activity. DFT calculations and experimental results demonstrate that introduction of the second metal atom can improve the activity of the original atom. The proposed model of bimetallic electrocatalysts affecting their OER performance can facilitate design of efficient bimetallic catalysts for energy storage and conversion, and investigation of the related catalytic mechanisms.
An iron atom in an Fe3 cluster is replaced by a second metal to form Fe2M clusters, which can serve as nodes to bridge with organic ligands and construct stable bimetallic MOFs. The introduction of the second metal atom can improve the activity of the original atom and thus improve the oxygen evolution reaction performance of electrocatalysts.
Atomically ordered intermetallic nanoparticles exhibit improved catalytic activity and durability relative to random alloy counterparts. However, conventional methods with time‐consuming and ...high‐temperature syntheses only have rudimentary capability in controlling the structure of intermetallic nanoparticles, hindering advances of intermetallic nanocatalysts. We report a template‐directed strategy for rapid synthesis of Pd‐based (PdM, M=Pb, Sn and Cd) ultrathin porous intermetallic nanosheets (UPINs) with tunable sizes. This strategy uses preformed seeds, which act as the template to control the deposition of foreign atoms and the subsequent interatomic diffusion. Using the oxygen reduction reaction (ORR) as a model reaction, the as‐synthesized Pd3Pb UPINs exhibit superior activity, durability, and methanol tolerance. The favored geometrical structure and interatomic interaction between Pd and Pb in Pd3Pb UPINs are concluded to account for the enhanced ORR performance.
This template‐directed synthetic strategy is a universal route for shape‐controlled synthesis of intermetallic nanocrystals and will provide new opportunities for intermetallic nanocatalysts.
The conventional thermal transformation of metal–organic frameworks (MOFs) for electrocatalysis requires high temperature, an inert atmosphere, and long duration that result in severe aggregation of ...metal particles and non‐uniform porous structures. Herein, a precise and inexpensive laser‐induced annealing (LIA) strategy, which eliminates particle aggregation and rapidly generates uniform structures with a high exposure of active sites, is introduced to carbonize MOFs on conductive substrates under ambient conditions within a few minutes. By systematically considering 8 substrates and 12 MOFs, a series of LIA‐MOF/substrate devices with controllable sizes and good flexibility are successfully obtained. These LIA‐MOF/substrate devices can directly serve as working electrodes. Remarkably, LIA‐MIL‐101(Fe) on nickel foam exhibits an ultralow overpotential of 225 mV at a current density of 50 mA cm−2 and excellent stability over 50 h for facilitating the oxygen evolution reaction, outperforming most recently reported transition‐metal‐based electrocatalysts and commercial RuO2. Physical characterizations and theoretical calculations evidence that the high activity of LIA‐MIL‐101(Fe) arises from the favorable adsorption of intermediates at its Ni‐doped Fe3O4 overlayer that is formed during the laser treatment. Moreover, the LIA‐MOF/substrate devices are assembled for overall water splitting. The proposed LIA strategy demonstrates a cost‐effective route for manufacturing scalable energy storage and conversion devices.
A laser‐induced annealing (LIA) strategy is applied to synthesize a series of LIA‐metal–organic frameworks (MOFs) on conductive substrates under ambient conditions within a few minutes. The obtained LIA‐MOF/substrate devices with controllable sizes and good flexibility exhibit excellent performance for electrochemical water splitting due to the formation of an active Ni‐doped Fe3O4 overlayer during the laser treatment.
As an emerging subclass of 2D materials, Xenes (e.g., borophene, silicene, germanene, stanene, phosphorene, arsenene, antimonene, and bismuthene) consist of one single element and have opened the ...door for various important applications. Benefiting from their impressive characteristics, including ultrathin folded structure, ultrahigh surface–volume ratio, excellent mechanical strength and flexibility, Xenes are considered as promising electrode materials in the field of electrochemical energy with large capacity, high rate, and high safety. This review provides a comprehensive summary of selected properties, synthetic challenges, and the latest theoretical and experimental advances in the energy‐related applications of Xenes, including Li/Na ion batteries, Li–S batteries, electrocatalysis, and supercapacitors. Finally, the challenges and outlook of this emerging field are discussed.
The 2D monoelemental family (Xenes) and their fundamental electrochemistry are comprehensively reviewed and discussed. Strategies and challenges on engineering heterostructures, defects, encapsulation, modification of Xenes are deeply summarized. The relationship/interaction among fundamental electrochemistry, electrocatalysis, and energy storage (Li/Na ion batteries, Li/Na air batteries, supercapacitors, Li–S battery) is concluded and outlooked.
Double-atom catalysts (DACs) have gained more and more attention to achieve efficient catalysts for the electrocatalytic nitrogen reduction reaction (NRR). It is expected that heteronuclear members ...could play an important role in the development of DACs, due to which the vast possible combinations of two different transition metal (TM) elements provide a large chemical composition space for the DAC design. Herein, to screen for efficient NRR DACs and, in particular, to further explore the synergetic effect as well as the TM combination pattern conductive to the NRR in the heteronuclear DACs, we have theoretically studied the NRR on TM dimer embedded N-doped porous graphene (TM = V, Cr, Mn, Fe, Co, Ni, and Cu), denoted as M1M2@NG, and both homonuclear and heteronuclear DACs have been considered. Our results indicate that most of the M1M2@NG systems exhibit comparable or better intrinsic NRR activity than the stepped Ru(0001) surface in terms of the calculated limiting potential. In particular, the heteronuclear DAC VCr@NG exhibiting metallic conductivity and high stability has an ultralow limiting potential of −0.24 V for the NRR and a strong capability of suppressing the competing hydrogen evolution reaction. Moreover, the synergetic effect for the heteronuclear DACs compared with the homonuclear counterparts has been studied in terms of energy and electronic structures. Based on this, we propose that combining a highly chemically active TM element (often the early TM) with another TM to form heteronuclear TM dimers on an appropriate substrate can help achieve efficient heteronuclear DACs for the NRR. Our studies not only highlight the important role of heteronuclear members in the application of DACs, but further provide a promising strategy to design efficient heteronuclear DACs for the NRR from the large chemical composition space.
Present studies highlight the important role of the heteronuclear members for the development of the double-atom catalysts, and further provide a strategy to design efficient heteronuclear double-atom catalysts from the large chemical composition space for the electrocatalytic NRR.
The in‐depth understanding of ions' generation and movement inside all‐inorganic perovskite quantum dots (CsPbBr3 QDs), which may lead to a paradigm to break through the conventional von Neumann ...bottleneck, is strictly limited. Here, it is shown that formation and annihilation of metal conductive filaments and Br− ion vacancy filaments driven by an external electric field and light irradiation can lead to pronounced resistive‐switching effects. Verified by field‐emission scanning electron microscopy as well as energy‐dispersive X‐ray spectroscopy analysis, the resistive switching behavior of CsPbBr3 QD‐based photonic resistive random‐access memory (RRAM) is initiated by the electrochemical metallization and valance change. By coupling CsPbBr3 QD‐based RRAM with a p‐channel transistor, the novel application of an RRAM–gate field‐effect transistor presenting analogous functions of flash memory is further demonstrated. These results may accelerate the technological deployment of all‐inorganic perovskite QD‐based photonic resistive memory for successful logic application.
Resistive random‐access memory (RRAM) and RRAM‐functionalized field‐effect transistors (FETs) based on photon tunable CsPbBr3 quantum dots are demonstrated. The formation and annihilation of metal conductive filaments and bromine‐vacancy filaments in CsPbBr3 quantum dot arrays can be realized under an electric field and light irradiation. The devices exhibit multilevel data storage using light tuning, which may accelerate the technological deployment of all‐inorganic perovskite QD‐based photonic memory.
The spread of the severe acute respiratory syndrome coronavirus has changed the lives of people around the world with a huge impact on economies and societies. The development of wearable sensors ...that can continuously monitor the environment for viruses may become an important research area. Here, the state of the art of research on biosensor materials for virus detection is reviewed. A general description of the principles for virus detection is included, along with a critique of the experimental work dedicated to various virus sensors, and a summary of their detection limitations. The piezoelectric sensors used for the detection of human papilloma, vaccinia, dengue, Ebola, influenza A, human immunodeficiency, and hepatitis B viruses are examined in the first section; then the second part deals with magnetostrictive sensors for the detection of bacterial spores, proteins, and classical swine fever. In addition, progress related to early detection of COVID‐19 (coronavirus disease 2019) is discussed in the final section, where remaining challenges in the field are also identified. It is believed that this review will guide material researchers in their future work of developing smart biosensors, which can further improve detection sensitivity in monitoring currently known and future virus threats.
Piezoelectric and magnetostrictive biosensor materials are presented and discussed. It is found that these advanced materials show great potential for application in the detection of various viruses. Progress related to COVID‐19 (coronavirus disease 2019) and the way to new and emerging sensors for virus detection for home application or wearability are considered.
High‐performance photonic nonvolatile memory combining photosensing and data storage with low power consumption ensures the energy efficiency of computer systems. This study first reports in situ ...derived phosphorene/ZnO hybrid heterojunction nanoparticles and their application in broadband‐response photonic nonvolatile memory. The photonic nonvolatile memory consistently exhibits broadband response from ultraviolet (380 nm) to near infrared (785 nm), with controllable shifts of the SET voltage. The broadband resistive switching is attributed to the enhanced photon harvesting, a fast exciton separation, as well as the formation of an oxygen vacancy filament in the nano‐heterojunction. In addition, the device exhibits an excellent stability under air exposure compared with reported pristine phosphorene‐based nonvolatile memory. The superior antioxidation capacity is believed to originate from the fast transfer of lone‐pair electrons of phosphorene. The unique assembly of phosphorene/ZnO nano‐heterojunctions paves the way toward multifunctional broadband‐response data‐storage techniques.
A solution‐processed phosphorene/ZnO nano‐heterojunction is demonstrated. Light‐tunable broadband resistive switching from UV to NIR is realized through the novel optoelectronic coupling of ZnO and phosphorene in resistive random access memory (RRAM). Superior environmental tolerance together with a synergetic photovoltaic and photogating effect paves the way of this attractive material for next‐generation photonic RRAM devices.
PDF
