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The design of multifunctional photocatalyst with strong redox performance is the key to achieve sustainable utilization of solar energy. In this study, an elegant S-scheme heterojunction photocatalyst was constructed between metal-free graphitic carbon nitride (g-C

Aqueous aluminum metal batteries (AMBs) are regarded as one of the most sustainable energy storage systems among post-lithium-ion candidates, which is attributable to their highest theoretical volumetric capacity, inherent safe operation, and low cost. Yet, the development of aqueous AMBs is plagued by the incapable aluminum plating in an aqueous solution and severe parasitic reactions, which results in the limited discharge voltage, thus making the development of aqueous AMBs unsuccessful so far. Here, we demonstrate that amorphization is an effective strategy to tackle these critical issues of a metallic Al anode by shifting the reduction potential for Al deposition. The amorphous aluminum (a-Al) interfacial layer is triggered by an in situ lithium-ion alloying/dealloying process on a metallic Al substrate with low strength. Unveiled by experimental and theoretical investigations, the amorphous structure greatly lowers the Al nucleation energy barrier, which forces the Al deposition competitive to the electron-stealing hydrogen evolution reaction (HER). Simultaneously, the inhibited HER mitigates the passivation, promoting interfacial ion transfer kinetics and enabling steady aluminum plating/stripping for 800 h in the symmetric cell. The resultant multiple full cells using Al@a-Al anodes deliver approximately a 0.6 V increase in the discharge voltage plateau compared to that of bare Al-based cells, which far outperform all reported aqueous AMBs. In both symmetric cells and full cells, the excellent electrochemical performances are achieved in a noncorrosive, low-cost, and fluorine-free Al2(SO4)3 electrolyte, which is ecofriendly and can be easily adapted for sustainable large-scale applications. This work brings an intriguing picture of the design of metallic anodes for reversible and high-voltage AMBs. Agency for Science, Technology and Research (A*STAR) Ministry of Education (MOE) C.Y. acknowledges funding supported by the National Natural Science Foundation of China (grant no. 52101246) and the Fundamental Research Funds for the Central Universities (grant no. 5710010721). Q.Y. acknowledges funding support from the Singapore MOE AcRF Tier 1 grant no. 2020-T1-001- 031 and the Singapore A*STAR project A19D9a0096. G.Y. acknowledges funding support from the Camille Dreyfus Teacher-Scholar Award and the Welch Foundation Award F1861.

Synthesizing urea from nitrate and carbon dioxide through an electrocatalysis approach under ambient conditions is extraordinarily sustainable. However, this approach still lacks electrocatalysts developed with high catalytic efficiencies, which is a key challenge. Here, we report the high-efficiency electrocatalytic synthesis of urea using indium oxyhydroxide with oxygen vacancy defects, which enables selective C-N coupling toward standout electrocatalytic urea synthesis activity. Analysis by operando synchrotron radiation-Fourier transform infrared spectroscopy showcases that *CO2NH2 protonation is the potential-determining step for the overall urea formation process. As such, defect engineering is employed to lower the energy barrier for the protonation of the *CO2NH2 intermediate to accelerate urea synthesis. Consequently, the defect-engineered catalyst delivers a high Faradaic efficiency of 51.0%. In conjunction with an in-depth study on the catalytic mechanism, this design strategy may facilitate the exploration of advanced catalysts for electrochemical urea synthesis and other sustainable applications. Agency for Science, Technology and Research (A*STAR) Ministry of Education (MOE) C.Y. acknowledges funding supported by the National Natural Science Foundation of China (Grant 52101246) and the Fundamental Research Funds for the Central Universities (Grant 5710010721). Q.Y. acknowledges funding support from Singapore MOE AcRF Tier 1 Grant 2020-T1-001-031 and Singapore A*STAR project A19D9a0096. G.Y. acknowledges funding support from the Camille Dreyfus TeacherScholar Award and Welch Foundation Award F-1861. The authors acknowledge computing resources from the National Supercomputing Centre, Singapore. This work is also supported by the Users with Excellence program of Hefei Science Center of CAS (2020HSC-UE003) and the Fundamental Research Funds for the Central Universities (WK2310000099).

As the most promising indoor positioning technology, UWB has been widely used in the field of robot positioning. However, in a complex indoor environment, UWB faces problems such as non-line-of-sight, multipath, signal attenuation and scattering. Aiming at the shortcomings of single UWB positioning, this paper proposes a mobile robot integrated navigation algorithm based on template matching VO/IMU/UWB. First, a template matching VO based on IMU assistance is designed, and then the position information calculated by the VO and the UWB position information are calculated. The difference is used as the input of the Kalman filter for filtering estimation. Finally, the estimated The position error corrects the VO position information to obtain the final positioning result of the combined system. Experiments show that the proposed integrated navigation method can significantly improve the positioning accuracy of UWB.

Metal-free 2D phosphorus-based materials are emerging catalysts for ammonia (NH3 ) production through a sustainable electrochemical nitrogen reduction reaction route under ambient conditions. However, their efficiency and stability remain challenging due to the surface oxidization. Herein, a stable phosphorus-based electrocatalyst, silicon phosphide (SiP), is explored. Density functional theory calculations certify that the N2 activation can be realized on the zigzag Si sites with a dimeric end-on coordinated mode. Such sites also allow the subsequent protonation process via the alternating associative mechanism. As the proof-of-concept demonstration, both the crystalline and amorphous SiP nanosheets (denoted as C-SiP NSs and A-SiP NSs, respectively) are obtained through ultrasonic exfoliation processes, but only the crystalline one enables effective and stable electrocatalytic nitrogen reduction reaction, in terms of an NH3 yield rate of 16.12 µg h-1 mgcat. -1 and a Faradaic efficiency of 22.48% at -0.3 V versus reversible hydrogen electrode. The resistance to oxidization plays the decisive role in guaranteeing the NH3 electrosynthesis activity for C-SiP NSs. This surface stability endows C-SiP NSs with the capability to serve as appealing electrocatalysts for nitrogen reduction reactions and other promising applications. Agency for Science, Technology and Research (A*STAR) Ministry of Education (MOE) Submitted/Accepted version Q.Y. acknowledges the funding support from Singapore MOE AcRF Tier 1 under grant no. 2020-T1-001-031 and Singapore A*STAR project A19D9a0096. C.X. thanks the support from the Ministry of Education Singapore under AcRF-Tier1 (2021-T1-002-012, RG65/21.

Artificial nitrogen conversion reactions, such as the production of ammonia via dinitrogen or nitrate reduction and the synthesis of organonitrogen compounds via C-N coupling, play a pivotal role in the modern life. As alternatives to the traditional industrial processes that are energy- and carbon-emission-intensive, electrocatalytic nitrogen conversion reactions under mild conditions have attracted significant research interests. However, the electrosynthesis process still suffers from low product yield and Faradaic efficiency, which highlight the importance of developing efficient catalysts. In contrast to the transition-metal-based catalysts that have been widely studied, the p-block-element-based catalysts have recently shown promising performance because of their intriguing physiochemical properties and intrinsically poor hydrogen adsorption ability. In this Perspective, we summarize the latest breakthroughs in the development of p-block-element-based electrocatalysts toward nitrogen conversion applications, including ammonia electrosynthesis from N

Rational electrode structure design is of great significance for realizing superior Na+ storage performance. Herein, a metal salt-induced polymer blowing-bubble approach followed by selenization procedure is developed to in-situ generate abundant sub-10 nm CoSe2 nanocrystals on 3D Se/N co-doped carbon networks (CoSe2@3DSNC). The phase transition from Co to CoSe2 and the incorporation of Se into the carbon layer are realized simultaneously to establish above configuration, in which the CoSe2 nanocrystals are anchored on interlayer expanded carbon networks. Such unique configuration endows electrode with lower Na+ diffusion energy barrier, higher Na+ storage capability and better structural durability. Reflected in SIBs, the optimized CoSe2@3DSNC delivers superior rate capability (310 mAh g−1 at 10 A g−1) and excellent long-term cycling stability (409 mAh g−1 after 1200 cycles at 5 A g−1). Moreover, this configuration can also be obtained in other metal selenides-carbon composite through a similar approach.

Insufficient separation of photogenerated electron–hole and feeble CO2 activation remain the main obstacles in the access to high-performance CO2 reduction nowadays. Single-atom active sites engine...

The high cost and scarcity of lithium resources have prompted researchers to seek alternatives to lithium-ion batteries. Among emerging "Beyond Lithium" batteries, rechargeable aluminum-ion batteries (AIBs) are yet another attractive electrochemical storage device due to their high specific capacity and the abundance of aluminum. Although the current electrochemical performance of nonaqueous AIBs is better than aqueous AIBs (AAIBs), AAIBs have recently gained attention due to their low cost and enhanced safety. Extensive efforts are devoted to developing AAIBs in the last few years. Yet, it is still challenging to achieve stable electrodes with good electrochemical performance and electrolytes without side reactions. This review summarizes the recent progress in the exploration of anode and cathode materials and the selection of electrolytes of AAIBs. Lastly, the main challenges and future research outlook of high-performance AAIBs are also presented. Ministry of Education (MOE) Q.Y. acknowledges the funding support from Singapore MOE AcRF Tier 1 under grant no. 2020-T1-001-031

Electrocatalytic dinitrogen reduction reaction (N2RR) is an emerging route for ammonia synthesis at ambient conditions. Albeit the “π back-donation” process enables N2RR activity on transition metals with empty d-orbitals, given its dilemma in overcoming hydrogen evolution reaction (HER) competition, exploring p-block-element-based catalysts with relatively inferior HER activity is achievable for high selectivity. The challenge lies in designing rational structure to improve N2RR activity. Here, we synergistically integrate oxygen vacancy (VO) with hydroxyl on Bi4O5I2 (VO-Bi4O5I2-OH), which render this p-block-element-based material active to mimic “π back-donation” behavior because of sufficient vacant orbitals. In neutral media, the electrocatalytic N2RR performance of VO-Bi4O5I2-OH in terms of splendid faradic efficiency (32.4%) is superior to most of the prior reports using p-block-element-based catalysts. Our findings show a new strategy toward standout N2RR activity, which holds great potential in exploiting other p-block-element-based electrocatalysts. Ministry of Education (MOE) Accepted version Q.Y. acknowledges the funding support from Singapore MOE AcRF Tier 1 Grant Nos. RG113/15 and 2016-T1-002-065, and Tier 2 under Grant Nos. 2017-T2-2-069 and 2018-T2-01-010. The authors greatly thank the Facility for Analysis, Characterization, Testing and Simulation (FACTS) of Nanyang Technological University, Singapore, for using their TEM, SEM, and XRD equipment.

Aqueous Al-ion batteries (AAIBs) are the subject of great interest due to the inherent safety and high theoretical capacity of aluminum. The high abundancy and easy accessibility of aluminum raw materials further make AAIBs appealing for grid-scale energy storage. However, the passivating oxide film formation and hydrogen side reactions at the aluminum anode as well as limited availability of the cathode lead to low discharge voltage and poor cycling stability. Here, we proposed a new AAIB system consisting of an Al x MnO2 cathode, a zinc substrate-supported Zn-Al alloy anode, and an Al(OTF)3 aqueous electrolyte. Through the in situ electrochemical activation of MnO, the cathode was synthesized to incorporate a two-electron reaction, thus enabling its high theoretical capacity. The anode was realized by a simple deposition process of Al3+ onto Zn foil substrate. The featured alloy interface layer can effectively alleviate the passivation and suppress the dendrite growth, ensuring ultralong-term stable aluminum stripping/plating. The architected cell delivers a record-high discharge voltage plateau near 1.6 V and specific capacity of 460 mAh g-1 for over 80 cycles. This work provides new opportunities for the development of high-performance and low-cost AAIBs for practical applications. National Research Foundation (NRF) Accepted version

The integration of structural design and compositional modulation has been a hotspot for the optimization of electrocatalytic properties due to their synergistic effect. However, the details of this synergistic effect still lacks deep study. Herein, we fabricated an Ni2P/Ni5P4 electrocatalyst with a Janus nanostructure embedded in N-doped carbon through a controllable phosphidation approach. The as-obtained hybrid catalyst realized an overpotential of 104 mV and Tafel slope of 38.5 mV dec−1, which were smaller than that of the single Ni2P and Ni5P4, at a current density of −10 mA cm−2 in 0.5 M H2SO4 electrolyte. To reveal the reasons for the promotion of electrocatalytic properties, the synergistic effect was analyzed with the difference charge density (DCD), density of state (DOS), ΔGH*, and strength of the internal electric field (IEF) on the interface between Ni5P4 and Ni2P. The results indicated that the composite structures could optimize the ΔGH* due to the change in the DOS instead of DCD. Further calculations indicated that the composite structure could modify the effective electric field, which is often overlooked and may be the reason for the change in the DOS. This study provides new insight for designing multi-component catalysts and deeply illuminating a part of the synergistic effect for high-efficiently electrocatalytic activities.

π Backdonation is the core process to break through the kinetically complex and energetic hurdle for catalyzing effectively the NH3 synthesis but only occurs on certain transition metals with empty and filled d orbitals. Herein, mimicking π backdonation enables MOF-76(Ce) materials to convert N2/NH3 effectively. Note that, by virtue of the intrinsic mechanism of ligand-to-metal charge transfer, metal cerium species in MOF-76(Ce) serve as an electron sink for accumulating the photogenerated electrons. Taken together, experimental and theoretical analyses reveal that such metal cerium species with coordination unsaturated state (Ce-CUS) on a MOF-76(Ce) nanorod surface can also provide unoccupied and occupied 4f orbitals to accept from and then donate electrons back to nitrogen molecules. Remarkably, it shows outstanding photocatalytic nitrogen reduction performance with high average NH3 yield (34 μmol g-1 h-1) under ambient conditions. This work provides fresh insights into rational designing and engineering highly active catalysts with rare earth elements.

Unearthing an ideal model to describe the role of defect sites for boosting photocatalytic CO2 reduction is rational and necessary, but it still remains a significant challenge. Herein, oxygen vacancies are introduced on the surface of Bi24 O31 Cl10 photocatalyst (Bi24 O31 Cl10 -OV) for fine-tuning the photocatalytic efficiency. The formation of oxygen vacancies leads to a new donor level near the conduction band minimum, which enables a faster charge transfer and higher carrier density. Moreover, oxygen vacancies can considerably reduce the energy for the formation of COOH* intermediates during CO2 conversion. As a result, the activity of Bi24 O31 Cl10 -OV for selective photoreduction of CO2 to CO is significantly improved, with a CO generation rate of 0.9 μmol h-1 g-1 , which is nearly 4 times higher than that of pristine Bi24 O31 Cl10 . This study reinforces our understanding of defect engineering in Bi-based photocatalysts and underscores the potential importance of implanting oxygen vacancies as an effective strategy for solar energy conversion.

Lithium-ion batteries (LIBs) are vital energy-storage devices in modern society. However, the performance and cost are still not satisfactory in terms of energy density, power density, cycle life, safety, etc. To further improve the performance of batteries, traditional “trial-and-error” processes require a vast number of tedious experiments. Computational chemistry and artificial intelligence (AI) can significantly accelerate the research and development of novel battery systems. Herein, a heterogeneous category of AI technology for predicting and discovering battery materials and estimating the state of the battery system is reviewed. Successful examples, the challenges of deploying AI in real-world scenarios, and an integrated framework are analyzed and outlined. The state-of-the-art research about the applications of ML in the property prediction and battery discovery, including electrolyte and electrode materials, are further summarized. Meanwhile, the prediction of battery states is also provided. Finally, various existing challenges and the framework to tackle the challenges on the further development of machine learning for rechargeable LIBs are proposed. Energy Market Authority (EMA) Ministry of Education (MOE) National Research Foundation (NRF) National Supercomputing Centre (NSCC) Singapore Accepted version C.L., X.Z., and L.Z. contributed equally to this work. Q.Y. acknowledges the funding support from Singapore MOE AcRF Tier 1 grant nos. 2020-T1-001-031, and Tier 2 grant nos. 2017-T2-2-069. Y.W. acknowledges the Nation Research Foundation, Prime Minister’s Office, Singapore under its Energy Programme (EP Award No. NRF2017EWT-EP003-023) administrated by the Energy Market Authority of Singapore; its Green Data Centre Research (GDCR Award No. NRF2015ENC-GDCR01001-003) administrated by the Info-communications Media Development Authority. M.S. gratefully acknowledges the financial support from National Research foundation of Singapore Investigatorship Award Number NRFI2017-08 and AStar AME programmatic funding number A20H3g2140. S.L. acknowledges the financial support from the Academic Research Fund Tier 1 (RG8/20), Tier 1 (RG104/18) and the computing resources from National Supercomputing Centre Singapore. The authors also like to acknowledge 111 project (D18023) from Zhengzhou University for their support for this work.

Synthetic nitrogen fertilizer such as urea has been key to increasing crop productivity and feeding a growing population. However, the conventional urea production relies on energy-intensive processes, consuming approximately 2% of annual global energy. Here, we report on a more-sustainable electrocatalytic approach that allows for direct and selective synthesis of urea from nitrate and carbon dioxide with an indium hydroxide catalyst at ambient conditions. Remarkably, Faradaic efficiency, nitrogen selectivity and carbon selectivity reach 53.4%, 82.9% and ~100%, respectively. The engineered surface semiconducting behaviour of the catalyst is found to suppress hydrogen evolution reaction. The key step of C–N coupling initiates through the reaction between *NO2 and *CO2 intermediates owing to the low energy barrier on {100} facets. This work suggests an appealing route of urea production and provides deep insight into the underlying chemistry of C–N coupling reaction that could guide sustainable synthesis of other indispensable chemicals. Agency for Science, Technology and Research (A*STAR) Ministry of Education (MOE) National Supercomputing Centre (NSCC) Singapore Accepted version Q.Y. acknowledges funding support from Singapore MOE AcRF Tier 1 grant no. 2020-T1-001-031, Tier 2 grant no. 2017-T2-2-069 and Singapore A*STAR project A19D9a0096. G.Y. acknowledges funding support from the US Department of Energy (grant number: DE-SC0019019) and Welch Foundation Award F-1861. S.L. acknowledges financial support from the Academic Research Fund Tier 1 (RG8/20), Tier 1 (RG104/18) and computing resources from the National Supercomputing Centre Singapore. This work is also supported by the Users with Excellence programme of Hefei Science Center of CAS(2020HSC-UE003). We greatly thank the Facility for Analysis, Characterization, Testing and Simulation (FACTS) of Nanyang Technological University, Singapore, for using their TEM, SEM and XRD equipment. We acknowledge NTU Center of High Field NMR Spectroscopy and Imaging. We also thank the National Synchrotron Radiation Laboratory for help in characterizations.

Constructing heterojunctions holds huge potential for tuning material properties owing to the built-in charge transfer driving force, which is beneficial for the migration behavior of Li-ions. While both the electrochemistry and heterojunctions of alloying-type anodes have been studied, the role of heterojunctions in improving the Li-ion storage performance of conversion-type anodes is unclear. In this work, porous Co3O4/TiO2 nanosheets (P-Co3O4/TiO2 NSs) were fabricated to successfully construct a p–n junction by coating n-type TiO2 on p-type Co3O4 NSs. The formation of the built-in electric field in the p–n junction significantly facilitates the charge transfer kinetics and the amorphous TiO2 layer accommodates the volume change of the Co3O4 NSs, manifesting the superiority of applying the p–n junction in a conversion-type anode for the first time. When evaluated as lithium-ion battery (LIB) anodes, the P-Co3O4/TiO2 NSs deliver high specific capacity, long-term cycling stability and remarkable rate capability (801 mA h g−1 after 1600 cycles at a current density of 2 A g−1).

The quasi-layered VS4 is the stacked linear chain structure in which parallel chains are bonded by Van der Waals forces. Considering its wide interlayer and high sulfur content, VS4 is supposed to be a potential high-performance anode material for Na-ion storage. Herein, a novel and efficient low-temperature solid-state method is developed to synthesize interlayer engineered VS4 (IE-VS4). The intercalation of [NCN]2- anion expands the interlayer of VS4 to accelerate the Na-ion diffusion. Furthermore, The intercalated anion also reduces the band gap of VS4 and enhances the electronic conductivity. Thanks to these merits, the IE-VS4 enables standout Na-ion storage performance in terms of ultrafast rate capability (500 mAh g-1 at 20 A g-1), high capacity and superior cycle stability (550 mAh g-1 at 5 A g-1 after 2500 cycles). The developed large-scale synthesis method and the interlayer engineering strategy can synergistically promote the practical application of VS4 in electrochemical energy storage.

Metal-free graphite carbon nitride (g-C3N4) is an ideal catalyst in the field of photocatalytic hydrogen evolution due to its visible light response, thermochemical stability and low cost. However, limited by the high photogenerated electron-hole recombination rate and poor light trapping ability of bulk g-C3N4 prepared by thermal condensation, it remains a great challenge in boosting the photocatalytic hydrogen (H2) evolution performance. Herein, a broom-like O-doped g-C3N4 nanoreactor (O-CN-NTs) oriented by tube-in-tube was developed for the first time through the “calcination-hydrothermal-calcination” method. The tube-in-tube nanoreactor not only can facilitate the scattering of incident light inside the cavity to enhance the utilization of light, but also can reduce the transport distance of carriers from the bulk to the surface to facilitate electron-hole separation. The morphology design of the tube-in-tube nanoreactor plays a very important role in improving the performance of photocatalytic H2 production. Furthermore, the density functional theory (DFT) calculation results manifest that the charge redistribution around the doped oxygen atoms accelerates the separation of electron-hole. The doping of oxygen atoms in g-C3N4 nanoreactor further enhanced the photocatalytic H2 production performance. Attributed to above advantages, the visible-light-driven (≥ 420 nm) photocatalytic H2 production rate of O-CN-NTs can achieve 13.61 mmol g-1 h-1, which is approximately 71.63 times that of bulk g-C3N4 (CN550).

NiCo-layered double hydroxides (LDHs) have recently emerged as potential oxygen evolution reaction (OER) catalysts in alkaline solutions. However, their preferred active sites have been ill-defined until now. In this work, hierarchical hollow nanopolyhedra assembled by NiCo-LDH nanosheets with adjustable composition and nanostructure are prepared via a facile self-templated strategy. DFT calculations indicate that Co3+ hollow sites are the preferred adsorption and active sites. The resultant hierarchical NiCo-LDH hollow nanopolyhedra realize superior OER activity by optimizing the composition of NiCo-LDH, which achieves a 10 mA cm–2 current density at an overpotential of 314 mV. This work not only presents deeper insights into the intrinsic OER electrocatalytic activity for NiCo-LDH but also elucidates on the further optimization of the OER properties of other bimetallic electrocatalysts.

It remains a challenge to obtain active sites on semiconductor-based photocatalysts for nitrogen fixation. Herein, we decorate Bi2WO6 by cyclized polyacrylonitrile (c-PAN) to craft a hybrid photocatalyst with superior nitrogen fixation performance (160 μmol·h–1·g–1). The unsaturated N in c-PAN can serve as active sites to achieve strong N2 absorption and activation. This facile approach provides new insight into the reasonable design of elegant photocatalysts with abundant active sites.

Electrocatalytic nitrogen reduction reaction (NRR) under ambient conditions provides an intriguing picture for the conversion of N2 into NH3 . However, electrocatalytic NRR mainly relies on metal-based catalysts, and it remains a grand challenge in enabling effective N2 activation on metal-free catalysts. Here we report a defect engineering strategy to realize effective NRR performance (NH3 yield: 8.09 μg h-1 mg-1cat. , Faradaic efficiency: 11.59 %) on metal-free polymeric carbon nitride (PCN) catalyst. Illustrated by density functional theory calculations, dinitrogen molecule can be chemisorbed on as-engineered nitrogen vacancies of PCN through constructing a dinuclear end-on bound structure for spatial electron transfer. Furthermore, the N-N bond length of adsorbed N2 increases dramatically, which corresponds to "strong activation" system to reduce N2 into NH3 . This work also highlights the significance of defect engineering for improving electrocatalysts with weak N2 adsorption and activation ability.

Oxide defect engineering in semiconductors is of growing interest and considered as an important strategy for promoting photocatalytic performance, as it enables to couple solar energy into oxygen activation. Herein, the surface oxygen vacancies are introduced into bismuth-rich Bi4O5I2 nanosheets (Bi4O5I2-OV) via a facile solvothermal route. By introducing oxygen vacancies into Bi4O5I2, the molecule oxygen adsorption is significantly improved. More importantly, attributed to the molecular oxygen adsorption, an instantaneous surface-bulk homojunction is constructed, which facilitates the separation and transport of photogenerated charge carriers. Therefore, noticeable molecular oxygen activation and N2 fixation are achieved in Bi4O5I2-OV. These findings may shed light on designing highly efficient photocatalysts and provide fresh insights into understanding the charge migration mechanism in oxygen vacancies-related photocatalytic system.

N2 fixation by the electrocatalytic nitrogen reduction reaction (NRR) under ambient conditions is regarded as a potential approach to achieve NH3 production, which still heavily relies on the Haber-Bosch process at the cost of huge energy and massive production of CO2 . A noble-metal-free Bi4 V2 O11 /CeO2 hybrid with an amorphous phase (BVC-A) is used as the cathode for electrocatalytic NRR. The amorphous Bi4 V2 O11 contains significant defects, which play a role as active sites. The CeO2 not only serves as a trigger to induce the amorphous structure, but also establishes band alignment with Bi4 V2 O11 for rapid interfacial charge transfer. Remarkably, BVC-A shows outstanding electrocatalytic NRR performance with high average yield (NH3 : 23.21 μg h-1 mg-1cat. , Faradaic efficiency: 10.16 %) under ambient conditions, which is superior to the Bi4 V2 O11 /CeO2 hybrid with crystalline phase (BVC-C) counterpart.

Exploiting highly efficient and stable photocatalysts for Cr(VI) reduction is of great importance. Herein, both homojunction and heterojunction are introduced into a novel QDs self-decorated Bi2MoO6 coupled with two-dimensional BCN (BCN-BMO(Q)) photocatalyst to achieve an enhanced performance of Cr(VI) reduction. Owing to the unique structure of the ternary system, electron-hole pairs are efficiently separated and transfer from the Bi2MoO6 QDs to Bi2MoO6 to BCN under visible-light excitation. Interestingly, 5% BCN-BMO(Q) shows stable and optimal performance for Cr(VI) photo-reduction activity within 20 min, which is almost 7.14, 2.28 and 1.66 times higher than that of BCN, BMO and BMO(Q) respectively under visible light irradiation. This work provides an alternative route to improve the photocatalytic activity of Bi2MoO6-based or some other nanocomposites.

Semiconductor 2D-composite heterostructures are of great interest in water splitting due to their unique structure. In this work, we design and synthesize 2D-composite HCa2Nb3O10/CaNb2O6 (HCNO/CNO) heterostructured nanosheets for the first time through sintering with a subsequent ion-exchange procedure. The achievement of such a 2D-composite nanostructure is attributed to the similar crystalline structure and intercalation–exfoliation of the layered bulk by employing tetra-n-butylammonium hydroxide (TBA+OH−). Furthermore, the 2D-composite structure contributes to increasing the interfacial contact area and lattice mismatch occurring in the heterostructure. Benefiting from the construction of a heterostructure and the unique structure characteristics, the as-prepared 2D-composite HCNO/CNO nanosheets exhibit rapid photoinduced charge carrier separation and transfer, leading to significantly enhanced photo-electrochemical current response as well as photocatalytic hydrogen evolution.

The insufficient efficiency of carrier separation and faint exciton generation are the major limitations of photocatalytic performance. We herein report a dual-purpose strategy for enabling the carrier separation and exciton production of Bi24O31Cl10via carbon doping. An impurity state appears after carbon doping in Bi24O31Cl10, which can furnish the charge transport channels and promote carrier separation. DFT calculations confirm that a more localized distribution of conduction and valence band charges strengthens the electron–hole interaction, significantly boosting exciton generation. Besides, the hierarchical structure endows carbon-doped Bi24O31Cl10 with a higher specific surface area. As a consequence, the photoreactivity towards photocatalytic CO2 reduction and singlet oxygen (1O2) generation is dramatically enhanced in carbon-doped Bi24O31Cl10. This study develops an effective pathway to manipulate the behavior of photoexcited species, which allows for the optimum design of excellent photocatalysts with emergent properties in energy conversion and environmental remediation.

Cobalt selenide (CoSe2), a promising anode material for lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs), still encounters the undesirable rate capability and cycling stability. Interface engineering offers a useful strategy to boost the electrochemical performance of electrode materials. Herein, an interface engineered material based on CoSe2/ZnSe nanoparticles confined in the hierarchical branched architecture constructed by N-doped carbon-nanotube-grafted nanorods (CoSe2/ZnSe@NC-NT/NRs) is developed, which delivers extraordinary Li+/Na+ storage capability as reflected in LIBs and SIBs. Large energy band gap difference between CoSe2 and ZnSe builds a strong built-in electric field at as-engineered interfaces. The emergence of built-in electric field can reduce the migration barriers of Li+/Na+ at the interfaces to facilitate the charge transfer behavior and improve the reaction kinetics in bulk phase. Additionally, carbon framework with hierarchical branched architecture can furnish numerous pathways for ions transport and alleviate the structural collapse. The present work could guide the future designing of electrode materials by rational interface engineering for high-performance anode of alkali-ion batteries.

Quantum dots (QDs) have great potential to build heterojunctions for efficient photocatalytic hydrogen production because of the quantum size effects, whereas they are limited by the rigorous preparation. Herein, we report a facile sacrificial coating strategy toward the construction of the NiO QDs/TiO2 heterojunction. Shorter transmission distance of carriers and higher crystallinity between NiO QDs and TiO2 substrate are achieved to minimize the recombination of photoinduced electrons and holes. As a result, excellent performance of 1.35 mmol h–1 g–1 over the NiO QDs/TiO2 sample is achieved, which is 37 times higher than that of NiO/TiO2 and 56 times higher than that of pure TiO2. Furthermore, this is one of the best performances reported in heterojunctions made of NiO and TiO2.

Kinetics-limited solid-state diffusion rate results in low rate capacity, retarding the practical applications of Co3O4 anode materials. Construction of nanonet can introduce sufficient interior transport pathways for rapid charging-discharging. Here, we fabricate one-dimensional Co3O4 nanonet (1D-NN) through a facile hydrothermal method with subsequent heat treatment. The construction of nanonet is achieved by employing carbonyl-β-cyclodextrin (C-β-CD) as a crosslinking agent. With the absence of C-β-CD, 1D Co3O4 is also fabricated, while the constructing blocks are independent nanoparticles (1D-NP). Evaluated as anodes for lithium ion batteries, 1D-NN exhibits better rate capacity than 1D-NP. Furthermore, to extract the key reason of outstanding rate capacity, the kinetic properties with different time constants are studied by EIS, GITT and CV simultaneously. The charge transfer resistance and the apparent chemical diffusion coefficient of 1D-NN are more superior to that of 1D-NP. The results of this work show that the C-β-CD induced 1D nanonet structure is conducive to Li+ transport for enhanced rate performance.

Bi5+-self-doped Bi4V2O11 (Bi5+-BVO) nanotubes with p–n homojunctions are fabricated via an oxygen-induced strategy. Calcinating the as-spun fibers with abundant oxygen plays a pivotal role in achieving Bi5+ self-doping. Density functional theory calculations and experimental results indicate that Bi5+ self-doping can narrow the band gap of Bi4V2O11, which contributes to enhancing light harvesting. Moreover, Bi5+ self-doping endows Bi4V2O11 with n- and p-type semiconductor characteristics simultaneously, resulting in the construction of p–n homojunctions for retarding rapid electron–hole recombination. Benefiting from these favorable properties, Bi5+-BVO exhibits a superior photocatalytic performance in contrast to that of pristine Bi4V2O11. Furthermore, this is the first report describing the achievement of p–n homojunctions through self-doping, which gives full play to the advantages of self-doping.

Tubular nanostructure becomes the researchful focus in environmental purification because of its unique features, however, the hollow fibrous BiVO4, famous as an efficient photocatalyst for water purification and oxidation, has not been achieved yet. Here, we employ organic vanadium salt to fabricate BiVO4 nanotubes by single-spinneret electrospinning without template. The organic salt can induce electrospinning gradient effect which plays a key role in the achievement of tubular nanostructure. Benefit from the unique structural properties of tubular nanostructure, BiVO4 nanotubes possess hollow interior, leading to strong light harvesting ability and large surface areas. For photocatalytic reduction of Cr(VI), these contributions from tubular nanostructure could promote the photocatalytic performance relative to solid BiVO4 nanofibers. This organic salt induced electrospinning gradient effect is not subject to the usage amount, ratio and kind of as-employed salt, endowing the electrospinning method with bright vista for the fabrication of other materials with tubular nanostructure.

To achieve high-efficiency lithium ion batteries (LIBs), an effective active electrode material is vital. For the first time, mesoporous single crystals cobalt-doped Fe2O3 (MSCs Co-Fe2O3) is synthesized using formamide as a pore forming agent, through a solvothermal process followed by calcination. Compared with mesoporous single crystals Fe2O3 (MSCs Fe2O3) and cobalt-doped Fe2O3 (Co-Fe2O3), MSCs Co-Fe2O3 exhibits a significantly improved electrochemical performance with high reversible capacity, excellent rate capability, and cycling life as anode materials for LIBs. The superior performance of MSCs Co-Fe2O3 can be ascribed to the combined structure characteristics, including Co-doping and mesoporous single-crystals structure, which endow Fe2O3 with rapid Li+ diffusion rate and tolerance for volume change.

Amorphous structure, possessing vast preponderances for boosting the application of lithium-ion batteries (LIBs), has drawn considerable attention as an elegant electrode structure. However, due to its thermal instability, amorphous transition-metal vanadates lack of exploration. In this work, we firstly report the fabrication of Ni3V2O8 amorphous wire encapsulated in crystalline tube nanostructure (NV-aWcT) by single spinneret electrospinning with subsequent heat treatment. The formation of this unique nanostructure is ascribed to shell heat transfer retardation by tuning the pyrolysis balance between “surface locking” and “inward migration” during the calcination process. Benefit from the collective characteristics of interior amorphous wire and outer tubular shell, NV-aWcT possesses mesoporosity, void spaces, defective sites and high surface areas, realizing superior electrochemical performance with high specific capacity, outstanding cycling stability, and superior rate capability (962 mA h g–1 at 300 mA g–1 after 300 cycles).

In view of the deficiencies of GPS in the urban environment, such as signal occlusion, multipath and Non-LOS, this paper proposes a solution that using a low-cost monocular camera instead of inertial navigation system to combine with GPS. Firstly, considering that the actual road conditions of the vehicle are mostly plane and in order to reduce the computational resources of visual odometer (VO), this paper establishes a VO solving model based on plane constraint; then the VO&GPS loose coupling model is proposed. The position error and yaw angle error of the two sensors are taken as input, and the errors are filtered by the adaptive Kalman filter. Experiments show that the positioning effect of VO&GPS loose coupling system is better than that of single GPS, and it can suppress the drift of VO, which can meet the positioning requirements when satellite signals are interfered in a short time.

Unearthing an ideal model to describe the role of defect sites for boosting photocatalytic CO