The Influence of Supervisor-Postgraduate Relationship on Master's Students' Research Learning Engagement-The Mediating Effect of Academic Aspiration.

Research learning engagement is the basic element of master's students' innovation output, and the supervisor is the first responsible body for master's students' cultivation. Exploring the influence of the supervisor-postgraduate relationship on master's students' research learning engagement, with a focus on the mediating role of academic aspiration, is of great significance for the improvement of master's students' cultivation quality. We surveyed 569 master's students at a university in Wuhan, China, using 3 measurement tools: the Supervisor-Postgraduate Relationship Scale, the Research Learning Engagement Scale, and the Academic Aspirations Scale. The results showed that: (1) The supervisor-postgraduate relationship positively and significantly predicted master's students' research learning engagement, and academic aspiration played a fully mediating role in the process. (2) There were differences in the effects of the three dimensions of the supervisor-postgraduate relationship on master's students' research learning engagement, with research collaboration having the greatest total effect on the impact of master's students' research learning engagement. This study emphasizes the importance of the supervisor-postgraduate relationship and academic aspirations and provides some implications for improving the research learning engagement of master's students.

The ionic liquids upon perchlorate to promote the C-C/C-O bonds cleavage in alkali lignin under photothermal synergism.

Transforming lignin into aromatic monomers is critically attractive to develop green and sustainable energy supplies. However, the usage of the additional catalysts like metal or base/acid is commonly limited by the caused repolymerized and environmental issues. The key step is to mediate electron transfer in lignin to trigger lignin C-C/C-O bonds cleavage without the catalysts mentioned above. Here, we report that the ionic liquids [BMim][ClO4] was found to trigger lignin electron transfer to cleave the C-C/C-O bonds for aromatic monomers without any additional catalyst. The proton transfer from [BMim]+ to [ClO4]- could polarize the anion and decrease its structure stability, upon which the active hydroxyl radical generated and induced lignin C-C/C-O bonds fragmentation via free radical-mediated routes with the assistance of photothermal synergism. About 4.4 wt% yields of aromatic monomers, mainly composed of vanillin and acetosyringone, are afforded in [BMim][ClO4] under UV-light irradiation in the air at 80 °C. This work opens the way to produce value-added aromatic monomers from lignin using an eco-friendly, energy-efficient, and simple route that may contribute to the sustainable utilization of renewable natural resources.

Jahn-Teller Distortions Induced by in situ Li Migration in λ-MnO2 for Boosting Electrocatalytic Nitrogen Fixation.

Lithium-mediated electrochemical nitrogen reduction reaction (Li-NRR) completely eschews the competitive hydrogen evolution reaction (HER) occurred in aqueous system, whereas the continuous deposition of lithium readily blocks the active sites and further reduces the reaction kinetics. Herein, we propose an innovative in situ Li migration strategy to realize that Li substitutes Mn sites in λ-MnO2 instead of evolving into the dead Li. Comprehensive characterizations corroborate that the intercalation of Li+ at high voltage breaks the structural integrity of MnO6 octahedron and further triggers unique Jahn-Teller distortions, which promotes the spin state regulation of Mn sites to generate the ameliorative eg orbital configuration and accelerates N≡N bond cleavage via eg -σ and eg -π* interaction. To this end, the resulted cationic disordered LiMnO4 delivers the recorded highest NH3 yield rate of 220 µg h-1 cm-2 and a Faradaic efficiency (FE) 83.80 % in organic electrolyte.

Rational design of artificial Lewis pairs coupling with polyethylene glycol for efficient electrochemical ammonia synthesis.

Ammonia (NH3) synthesis at mild conditions by electrocatalytic nitrogen reduction (eNRR) has received more attention and has been regarded as a promising alternative to the traditional Haber-Bosch process. Lewis acid-base pairs (LPs) can chemisorb and react with nitrogen by electronic interaction, while the tuning of the microenvironment near electrode can hinder hydrogen evolution reaction (HER) thus improving the selectivity of the eNRR. Herein, the FeOOH nanorod coupled with LPs on the surface (i.e., Fe, Fe-O) was synthesized, which could effectively drive eNRR. Meanwhile, polyethylene glycol (PEG) was introduced to serve as a local non-aqueous electrolyte system to inhibit HER. The prepared FeOOH-150 catalyst achieved outstanding eNRR performance with an NH3 yield rate of 118.07 µg h-1mgcat-1 and a Faradaic efficiency of 51.4 % at -0.6 V vs. RHE in 0.1 M LiClO4 + 20 % PEG. Both the experiment and DFT calculations revealed that the interaction of PEG with Lewis base sites could optimize nitrogen adsorption configuration and activation.

Ternary PtZrNi nanorods for efficient multifunctional electrocatalysis towards oxygen reduction and alcohol oxidation.

Pt-based alloys with precise structure and composition design have been considered to be effective and robust novel electrocatalysts for fuel cells. Whereas, the sluggish kinetics of oxygen reduction reaction (ORR) and low intrinsic activity of Pt limited their real application on a large scale. Herein, a novel ternary PtZrNi nanorods (PtZrNi NRs) was synthesized via a facile wet-chemical method to achieve high electrocatalytic performance for both ORR and alcohol oxidation reaction owing to the synergism of chosen three elements and prominent one-dimensional morphology. Specifically, the PtZrNi NRs show enhanced mass and specific activities of 0.755 A mgPt-1 and of 0.97 mA/cm2 at 0.9 VRHE towards ORR in acidic media, which are 4.7 and 4.4 times of those of commercial Pt/C, respectively. Additionally, in alkaline media, the PtZrNi NRs also exhibit superior ORR mass and specific activities of 3.216 A mgPt-1and 4.13 mA/cm2, enhanced by 34.6 and 31.3 times compared with those of commercial Pt/C, respectively. The PtZrNi NRs retain the nanorod shape well without agglomeration after an accelerated durability test (20000 cycles). This work may offer a new perspective for engineering high-performance Pt-based electrocatalysts for commercial fuel cells.

Tailored nitrogen-defect induced by diels-alder reaction for enhanced electrochemical hydrogen evolution reaction.

Electrocatalytic water splitting in an alkaline medium is recognized as the promising technology to sustainably generate clean hydrogen energy via hydrogen evolution reaction (HER), while the sluggish water dissociation and subsequent *H adsorption steps greatly retarded the reaction kinetics and efficiency of the overall hydrogen evolution process. Whilst nitrogen (N)-doped carbon-based materials are attractive candidates for promoting HER activity, the facile fabrication and gaining a deeper insight into the electrocatalytic mechanism are still challenging. Herein, inspired by the Diels-Alder reaction, we precisely tailored six-membered pyridinic N and five-membered pyrrolic N sites at the edge of the carbon substrates. Comprehensive analysis validates that the participation of pyridinic N (electron-withdrawing) and pyrrolic N (electron-releasing) will induce the charge rearrangements, and further generate local electrophilic and nucleophilic domains in adjacent carbon rings, which guarantees the occurrence of water dissociation to generate protons and the subsequent adsorption of *H intermediates through electrostatic interactions, thereby facilitating the overall reaction kinetics. To this end, the optimal NC-ZnCl2-25 % electrocatalysts present excellent alkaline HER activity (η10 = 45 mV, Tafel slop of 37.7 mV dec-1) superior to commercial Pt/C.

Monolithic coherent LABS lidar based on an integrated transceiver array.

We demonstrate a monolithic frequency-modulated continuous-wave (FMCW) lidar chip with an integrated transceiver array based on lens-assisted beam steering (LABS) technology. It enables beam emitting, steering, receiving, and coherent detecting on a single chip with simultaneous distance and velocity detection. An integrated transceiver is designed with a composite structure of a Bragg grating in the middle and a U-shaped photodetector (PD) surrounding it. For a proof-of-concept demonstration, a chip with 2 × 2 switchable transceiver array is fabricated. A monolithic coherent LABS lidar system with a scanning angle of 2.86° and a scanning speed of 5.3 µs is implemented for 5 m ranging and 0.45 m/s velocity detection.

Boosted polysulfides regulation by iron carbide nanoparticles-embedded porous biomass-derived carbon toward superior lithium-sulfur batteries.

Lithium-sulfur (Li-S) batteries are greatly expected to be the favored alternatives in the next-generation energy-storage technologies due to their exceptional advantages. However, the shuttle effect and sluggish reaction kinetics of polysulfides largely hamper the practical success of Li-S batteries. Herein, a unique iron carbide (Fe3C) nanoparticles-embedded porous biomass-derived carbon (Fe3C-PBC) is reported as the excellent immobilizer and promoter for polysulfides regulation. Such a distinctive composite strongly couples the vast active sites of Fe3C nanoparticles and the conductive network of porous biomass-derived carbon. Therefore, Fe3C-PBC is endowed with outstanding adsorptivity and catalytic effect toward inhibiting the shuttle effect and facilitating the redox kinetics of polysulfides, demonstrated by the detailed experimental demonstrations and theoretical calculation. With these synergistic effects, the Fe3C-PBC/S electrode embraces a superb capacity retention of 82.7% at 2C over 500 cycles and an excellent areal capacity of 4.81 mAh cm-2 under the high-sulfur loading of 5.2 mg cm-2. This work will inspire the design of advanced hosts based on biomass materials for polysulfides regulation in pursuing the superior Li-S batteries.

Cr-Doped Pd Metallene Endows a Practical Formaldehyde Sensor New Limit and High Selectivity.

Electrochemical sensors for detecting micromolecule organics are desirable for improving the perception of environmental quality and human health. However, currently, the electrochemical sensors for formaldehyde are substantially limited on the market due to the long-term unsolved problems of the low electrooxidation efficiency and CO poisoning issue of commercial Pd catalysts. Here, a 2D Cr-doped Pd metallene (Cr-Pdene) with few atomic layers is shown as an advanced catalyst for ultrasensitive and selective sensing of formaldehyde via a highly efficient formaldehyde electrooxidation. It is found that the doping of Cr into Pd metallene can efficiently optimize the electronic structure of Pd and weaken the interaction between Pd and CO, providing an anti-poisoning means to favor CO2 production and suppress CO adsorption. The Cr-Pdene-based electrochemical sensor exhibits one order of magnitude higher detection range and, especially, much higher anti-interference for formaldehyde than that of the conventional sensors. Most importantly, it is demonstrated that the Cr-Pdene can be integrated into commercializable wireless sensor networks or handheld instruments for promising applications relating to the environment, health, and food.

InOOH as an efficient bidirectional catalyst for accelerated polysulfides conversion to enable high-performance lithium-sulfur batteries.

Lithium-sulfur (Li-S) batteries with the prominent advantages are greatly expected to be the attractive alternatives in the next-generation energy-storage systems. However, the practical success of Li-S batteries suffers from the shuttle effect and depressed redox kinetics of polysulfides. Herein, for the first time, InOOH nanoparticles are employed as a potent catalytic additive in sulfur electrode to overcome these issues. As demonstrated by the theoretical and experimental results, the strong interactions between the InOOH nanoparticles and sulfur species enable the effective adsorption of polysulfides. More significantly, InOOH nanoparticles not only effectively expedite the reduction of sulfur during the discharge process, but also dramatically accelerate the oxidation of Li2S during the charge process, presenting the marvelous bidirectional catalytic effects. Benefited from these distinctive superiorities, the cells with InOOH nanoparticles harvest an excellent capacity retention of 69.5% over 500 cycles at 2C and a commendable discharge capacity of 891 mAh g-1 under a high-sulfur loading of 5.0 mg cm-2. The detailed investigations in this work provide a novel insight to ameliorate the Li-S electrochemistry by the bidirectional catalyst for high-performance Li-S batteries.

Monolithic transceiver for lens-assisted beam-steering Lidar.

We demonstrate a monolithic transceiver based on a CMOS-compatible silicon photonic platform for lens-assisted beam-steering (LABS) light detecting and ranging (Lidar) application. By implementing an on-chip two-dimensional transceiver array and off-chip lens, beam emitting, steering, and receiving are realized simultaneously on a single chip. The transceiver is designed with a structure of a U-shaped vertical Ge photodetector surrounding a grating for high-efficiency light transmission and reception. The on-chip photodetector has a bandwidth of 87 MHz, a responsivity of 0.3A/W, and a detection sensitivity of -20dBm. For proof-of-concept demonstration, a time-of-flight Lidar system is achieved for target ranging with a detection distance of 5.2 m, a scanning angle of 2.86°, and a scanning speed of 5.3µs . This work demonstrates a feasible solution to integrated Lidar with beam emitting and receiving on one single chip based on LABS.

Trimetallic synergy in dendritic intermetallic PtSnBi nanoalloys for promoting electrocatalytic alcohol oxidation.

Developing effective and robust novel electrocatalysts for direct alcohol fuel cells has been gaining much attention. However, the widely used Pt catalyst suffers from limitations including the sluggish kinetics, severe CO poisoning, and catalyst lost caused by aggregation and Ostwald ripening during alcohol oxidation reaction. Herein, dendritic intermetallic PtSnBi nanoalloys were synthesized via a facile hydrothermal approach with high electrocatalytic performance and enhanced CO resistance for methanol oxidation reaction (MOR) and ethanol oxidation reaction (EOR) owing to the synergism of the chosen three elements and unique three-dimensional morphology. Specifically, the PtSnBi nanoalloys display 4.6 and 6.7 times higher of mass activity (7.02 A mg-1Pt) and specific activity (16.65 mA cm-2) toward MOR than those of commercial Pt/C, respectively. The mass activity of PtSnBi nanoalloys still retains 75.7% of the initial value after 800 cycles of stability test, superior to Pt/C (38.0%). The dual-functional effect of Sn, optimized electronic structure by the ligand effect, and unique atomic arrangement are responsible for the enhanced MOR activity and stability of PtSnBi nanoalloys. Furthermore, the PtSnBi nanoalloys with highlighted anti-CO poisoning capacity also improve the electrocatalytic performance toward EOR, indicating their great promise as broad energy electrocatalysts.

Electrochemical C-N coupling with perovskite hybrids toward efficient urea synthesis.

Electrocatalytic C-N coupling reaction by co-activation of both N2 and CO2 molecules under ambient conditions to synthesize valuable urea opens a new avenue for sustainable development, while the actual catalytic activity is limited by poor adsorption and coupling capability of gas molecules on the catalyst surface. Herein, theoretical calculation predicts that the well-developed built-in electric field in perovskite hetero-structured BiFeO3/BiVO4 hybrids can accelerate the local charge redistribution and thus promote the targeted adsorption and activation of inert N2 and CO2 molecules on the generated local electrophilic and nucleophilic regions. Thus, a BiFeO3/BiVO4 heterojunction is designed and synthesized, which delivers a urea yield rate of 4.94 mmol h-1 g-1 with a faradaic efficiency of 17.18% at -0.4 V vs. RHE in 0.1 M KHCO3, outperforming the highest values reported as far. The comprehensive analysis further confirms that the local charge redistribution in the heterojunction effectively suppresses CO poisoning and the formation of the endothermic *NNH intermediate, which thus guarantees the exothermic coupling of *N[double bond, length as m-dash]N* intermediates with the generated CO via C-N coupling reactions to form the urea precursor *NCON* intermediate. This work opens a new avenue for effective electrocatalytic C-N coupling under ambient conditions.

Synthesis, structure, electrochemistry and magnetism of cobalt-, nickel- and zinc-containing [M4(OH)3(H2O)2(α-SiW10O36.5)2]13- (M = Co2+, Ni2+, and Zn2+).

Interaction of the trilacunary 9-tungstosilicate [A-α-SiW9O34]10- with cobalt(ii), nickel(ii) and zinc(ii) ions in pH 9 aqueous medium at room temperature led to the formation of the respective M4-containing heteropolytungstates [M4(OH)3(H2O)2(α-SiW10O36.5)2]13- (M = Co2+ (1), Ni2+ (2), and Zn2+ (3)). Polyanions 1-3 were characterized in the solid state by single-crystal XRD, FT-IR spectroscopy, and thermogravimetric and elemental analyses. Electrochemical studies showed that the Co2+ ions in 1 can be oxidized to Co3+ and the CVs of the WVI centers of the polyanions feature well-defined and chemically reversible reduction waves. Magnetic measurements on 1 and 2 showed paramagnetism with complex ferromagnetic and antiferromagnetic interactions. A model was presented for extracting the exchange constants for the magnetic exchange interaction.

Unveiling Electrochemical Urea Synthesis by Co-Activation of CO2 and N2 with Mott-Schottky Heterostructure Catalysts.

Electrocatalytic C-N bond coupling to convert CO2 and N2 molecules into urea under ambient conditions is a promising alternative to harsh industrial processes. However, the adsorption and activation of inert gas molecules and then the driving of the C-N coupling reaction is energetically challenging. Herein, novel Mott-Schottky Bi-BiVO4 heterostructures are described that realize a remarkable urea yield rate of 5.91 mmol h-1 g-1 and a Faradaic efficiency of 12.55 % at -0.4 V vs. RHE. Comprehensive analysis confirms the emerging space-charge region in the heterostructure interface not only facilitates the targeted adsorption and activation of CO2 and N2 molecules on the generated local nucleophilic and electrophilic regions, but also effectively suppresses CO poisoning and the formation of endothermic *NNH intermediates. This guarantees the desired exothermic coupling of *N=N* intermediates and generated CO to form the urea precursor, *NCON*.

Atomically Dispersed Indium Sites for Selective CO2 Electroreduction to Formic Acid.

An atomically dispersed structure is attractive for electrochemically converting carbon dioxide (CO2) to fuels and feedstock due to its unique properties and activity. Most single-atom electrocatalysts are reported to reduce CO2 to carbon monoxide (CO). Herein, we develop atomically dispersed indium (In) on a nitrogen-doped carbon skeleton (In-N-C) as an efficient catalyst to produce formic acid/formate in aqueous media, reaching a turnover frequency as high as 26771 h-1 at -0.99 V relative to a reversible hydrogen electrode (RHE). Electrochemical measurements show that trace amounts of In loaded on the carbon matrix significantly improve the electrocatalytic behavior for the CO2 reduction reaction, outperforming conventional metallic In catalysts. Further experiments and density functional theory (DFT) calculations reveal that the formation of intermediate *OCHO on isolated In sites plays a pivotal role in the efficiency of the CO2-to-formate process, which has a lower energy barrier than that on metallic In.

Polyoxometalate-like sub-nanometer molybdenum(vi)-oxo clusters for sensitive, selective and stable H2O2 sensing.

Polyoxometalate-like molybdenum(vi)-oxo clusters ([Mo-oxo]n, n = 1-20) deposited on high surface-area carbon are developed as a biosensor for non-enzymatic electrochemical H2O2 detection. The sensor exhibits excellent electrocatalytic performance with a low detection limit, wide linear range, excellent sensitivity and stability. The composite can be stably deposited on screen-printed electrodes which combine microlitre analyses, long shelf-life and re-usability.

Efficient Tetra-Functional Electrocatalyst with Synergetic Effect of Different Active Sites for Multi-Model Energy Conversion and Storage.

Energy crisis and global warming due to excessive CO2 emissions are the two major challenges of the world. Conversion of CO2 into useful fuels along with rechargeable metal air batteries and water splitting is one way to combat the energy crisis, which is bottlenecked due to the lack of multifunctional electrocatalyst. Herein simple but multifunctional electrocatalyst, which combined CoNi nanoalloy, N-doped carbon nanotubes, and single atomic Ni sites together is reported. The prepared electrocatalyst has shown remarkable performance for CO2RR, ORR, OER, and HER. The practical utilization of the catalyst is mansifested by a dual model metal CO2/air battery and water electrolyzer. An excellent CO2RR with FE of 99% is achieved in 0.5 M KHCO3 medium. The catalyst exhibits more positive onset (0.98 V) and half wave potential (0.86 V) than Pt/C for ORR, extremely low overpotential (η10) of 250 mV for OER, and thus the lowest ORR/OER potential gap of 0.62 V. In alkaline medium, the catalyst also shows excellent HER performance with η10 of 49 mV, resulting in the smallest cell bias of 1.57 V for overall water splitting to date. This work provides a new pathway to design more stellar multifunctional electrocatalyst for sustainable and clean renewable energy technology.

Bottom-up Design of Bimetallic Cobalt-Molybdenum Carbides/Oxides for Overall Water Splitting.

Earth-abundant transition-metal-based catalysts for electrochemical water splitting are critical for sustainable energy schemes. In this work, we use a rational design method for the synthesis of ultrasmall and highly dispersed bimetallic CoMo carbide/oxide particles deposited on graphene oxide. Thermal conversion of the molecular precursors [H3 PMo12 O40 ], Co(OAc)2 ⋅4 H2 O and melamine in the presence of graphene oxide gives the mixed carbide/oxide (Co6 Mo6 C2 /Co2 Mo3 O8 ) nanoparticle composite deposited on highly dispersed, N,P-doped carbon. The resulting composite shows outstanding electrocatalytic water-splitting activity for both the oxygen evolution and hydrogen evolution reaction, and superior performance to reference samples including commercial 20 % Pt/C & IrO2 . Electrochemical and other materials analyses indicate that Co6 Mo6 C2 is the main active phase in the composite, and the N,P-doping of the carbon matrix increases the catalytic activity. The facile design could in principle be extended to multiple bimetallic catalyst classes by tuning of the molecular metal oxide precursor.

Metal-Free Photochemical Degradation of Lignin-Derived Aryl Ethers and Lignin by Autologous Radicals through Ionic Liquid Induction.

The degradation of lignin into aromatic products is very important, but harsh conditions and metal-based catalysts are commonly needed to cleave the inert bonds. Herein, an efficient self-initiated radical photochemical degradation for lignin-derived aryl ethers through ionic liquids (ILs) induction is demonstrated. The C-C/C-O bonds can be cleaved efficiently through free-radical-mediated reaction in the binary-ILs system 1-propenyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl] imide [PMim][NTf2 ] and the Brønsted acid 1-propylsulfonic-3-methylimidazolium trifluoromethanesulfonate ([PrSO3 HMim][OTf]) under ambient conditions. [PMim][NTf2 ] initiates the reaction by promoting the cleavage of the Cß -H bond, and [PrSO3 HMim][OTf] catalyzes the subsequent C-O-C bond fragmentation. Furthermore, alkyl, hydroxyl, and peroxy radicals are detected, which suggests degradation based on a photochemical free-radical process. Additionally, alkali lignin could also be degraded in the IL system. This work sheds light on sustainable biomass utilization through a self-initiated radical photochemical strategy under metal-free and mild conditions.