Defect modulation currently plays a decisive role in addressing the poor photoabsorption, sluggish electron hole separation, and high CO2 activation barrier in photocatalytic CO2 reduction. However, hunting for a straightforward strategy to balance the concentration of oxygen vacancy and metal cation defect in one photocatalyst is still a great challenge. Herein, a bismuth vacancies BiOBr nanosheets (BiOBr-1) on the exposed [001] facets were constructed via an acetic acid molecule modification strategy, which can repair oxygen defect by bismuth vacancy in low-temperature solid-state chemical method. Benefiting from the formed bismuth defects that can not only broaden light absorption and elevate charge separation efficiency, but also enhance adsorption and activation of CO2 molecules, the evolution rates of photocatalytic CO2 conversion into CO (71.23 µmol·g−1·h−1) and CH4 (8.90 µmol·g−1·h−1) attained by BiOBr-1 are superior 7.1 and 11 times to that of plate-like BiOBr. The photocatalytic mechanisms including adsorption concentration and activation process of CO2 are further revealed by the in situ diffuse reflectance infrared flourier transform spectra (DRIFTS). This finding of the existence of distinct defects in ultrathin nanosheets undoubtedly leads to new possibilities for photocatalyst design using two-dimensional materials with high solar-driven photocatalytic activity.

Electrochemical energy storage devices are pivotal in achieving “carbon neutrality” by enabling the storage of energy generated from renewable sources. To facilitate the development of these devices, it is important to gain insight into the underlying the single-/multi-electron transfer process. This can be achieved through in-time detection under operational conditions, but there are limited tools available for monitoring electron transfer under operando conditions. Electron paramagnetic resonance (EPR) is a powerful technique that can meet these expectations, as it is highly sensitive to unpaired electrons and can detect changes of paramagnetic centres. Despite the long history of in situ electrochemical EPR research, its potential has been surprisingly underutilized due to the need for strict operando cell design under special testing conditions. This review comprehensively summarizes recent efforts to understand energy storage mechanisms using in situ/operando EPR, with the aim of drawing researchers’ attention to this powerful technique. After introducing the fundamental principles of EPR, we describe the critical advances made in detecting batteries using operando EPR, along with the remaining challenges and opportunities for future development of this technology in batteries. We emphasize the need for strict operando cell design and the importance of designing experiments that closely mimic real-world conditions. We believe that this review will provide innovative solutions to solve tough problems that researchers may encounter during their battery research, and ultimately contribute to the development of more efficient and sustainable energy storage devices.

As a new branch of efficient and low-cost mechanical energy conversion technology, triboelectric nanogenerator (TENG) is a potential solution to provide a long-term power supply for the Internet of Things (IoT) sensors and portable electronic devices. However, due to inherent working properties of TENG itself such as extremely high internal impedance, pulse, and alternating current (AC) output, TENG can not directly supply power to loads such as batteries efficiently. Based on these, we describe TENG’s performance from a new perspective of powering ability. It consists of two aspects: the ability to transport charge effectively and the ability to output high power quality current steadily. In order to push forward the developments and applications of TENG, it is necessary to improve its power supply capacity from different perspectives. Fortunately, in recent years, a variety of output signal’s management strategies aiming at effectively managing the generated electricity and significantly improving powering ability of TENG have obtained significantly progress. Herein, this paper discusses the working mechanisms and different load characteristics of TENG at first to clarify the electric performance of TENG. Then, on basis of theoretical analysis, the output signal’s management strategies are elaborated from four aspects: improving the cycle output electricity of TENG, increasing the surface charge density of TENG, improving the power quality of TENG-based energy harvesting system, promoting the application of TENG through integrated circuit (IC) technology and TENG network, and the relevant principles and applications are discussed systematically. Finally, the advantages and disadvantages of the above output signal’s management strategies are summarized and discussed, and the future development of the output signal’s management strategies for TENG is prospected.

Exploiting the valley degrees of freedom as information carriers provides new opportunities for the development of valleytronics. Monolayer transition metal dichalcogenides (TMDs) with broken space-inversion symmetry exhibit emerging valley pseudospins, making them ideal platforms for studying valley electronics. However, intervalley scattering of different energy valleys limits the achievable degree of valley polarization. Here, we constructed WSe2/yttrium iron garnet (YIG) heterostructures and demonstrated that the interfacial magnetic exchange effect on the YIG magnetic substrate can enhance valley polarization by up to 63%, significantly higher than that of a monolayer WSe2 on SiO2/Si (11%). Additionally, multiple sharp exciton peaks appear in the WSe2/YIG heterostructures due to the strong magnetic proximity effect at the magnetic–substrate interface that enhances exciton emission efficiency. Moreover, under the effect of external magnetic field, the magnetic direction of the magnetic substrate enhances valley polarization, further demonstrating that the magnetic proximity effect regulates valley polarization. Our results provide a new way to regulate valley polarization and demonstrate the promising application of magnetic heterojunctions in magneto-optoelectronics.

Rechargeable sodium-ion batteries (SIBs) are considered as the next-generation secondary batteries. The performance of SIB is determined by the behavior of its electrode surface and the electrode–electrolyte interface during charging and discharging. Thus, the characteristics of these surfaces and interfaces should be analyzed to realize large-scale energy storage systems with high energy density and long-cycle stability. Although various studies have investigated the properties of electrode materials, few studies have focused on the construction of stable and efficient SIB interfaces, and even fewer have explored the mechanisms of interfacial effects; however, the strategies of regulating interfacial effects are yet to be completely developed. Moreover, the results obtained thus far are insufficient to draw systematic conclusions. The present study reviews the literature on the mechanism of interfacial effects in Na+ storage devices. The interfaces in a sodium-ion storage device include a heterogeneous interface between electrode materials, a solid electrolyte interphase, and a cathode electrolyte interphase. The interfacial effects during the intercalation, transformation, and alloy reactions and the resulting overall battery performance were theoretically analyzed. In this review, we aim to provide a theoretical basis for optimizing the structures of electrode surface and electrode–electrolyte interface to optimize the performance of SIBs. In addition, the challenges of investigating interfacial effects and several possible helpful methods and opportunities for studying the mechanisms of interfacial effects in SIBs will be presented.

The earth-abundant and robust aluminum ferrite, AlFeO3 (AFO), is mainly studied in the context of ferroelectrics. Herein, we demonstrate that AFO can be used as a stable solar absorber in photoelectrochemical cells for solar water splitting, exhibiting attractive performance. This is the first report on the photoelectrochemical activity of AFO. AFO thin-film photoelectrodes prepared by solution-processing methods are composed of vertically oriented thin nanosheets, featuring the rhombohedral symmetry (R3c) and n-type conductivity. The as-prepared AFO photoanodes generate a photocurrent density of +0.78 mA·cm−2 at 1.23 V vs. reversible hydrogen electrode (RHE) with the photocurrent onset potential (Uonset) close to the flat band potential of 0.5 V vs. RHE in the presence of hole scavengers. Remarkably, the Uonset of AFO for solar water splitting coincides with the flat band potential as well, which is rare in n-type inorganic absorbers. We also report other properties of AFO associated with photoelectrochemical performance. AFO films exhibit a band gap energy of 2.31 eV and positive band edges with low dispersion. Moreover, the carrier lifetimes in AFO films are up to millisecond timescales under the mediation of defect traps. Based on the photoelectrochemical behavior and optoelectronic properties, we believe that AFO has great potential for application in photoelectrochemical cells.

The effective, stable, and secure catalysts are essential for sulfate radical (SO4·−)-based advanced oxidation processes (SR-AOPs) to the degradation of organic contaminants in water. Heterogeneous supported cobalt-based catalysts are commonly used to activate peroxymonosulfate (PMS) to achieve the degradation. In this work, we synthesized Co3O4@Al2O3 three-dimensional (3D) mesoporous nanocomposite (denoted as Co3O4@Al2O3 3DPNC) in just one step by calcining cheap and green deep eutectic solvent (DES) solution containing Co salt. Co3O4@Al2O3 3DPNC with the high specific surface area (93.246 m2/g), uniform pore distribution (3.829 nm) and rich porosity (0.255 cm3/g) were attained in a beautiful hierarchical structure which exhibited the open 3D propeller-like microstructure, two-dimensional lamellar substructure with rich folds, as well as the decoration of highly dispersed Co3O4 nanoparticles on mesoporous amorphous Al2O3. The excellent chemical and thermal stability of Al2O3 ensures the high stability of the catalyst, and the formation of the complex hierarchical structure makes the active Co3O4 be homogenously dispersed for effective catalysis. The catalyst demonstrated outstanding performance for catalytic degradations of organic pollutants (acetaminophen, oxytetracycline, 5-sulfosalicylic acid, orange G and Rhodamine B) by generated SO4·−, ·OH and 1O2. With a very low cobalt content (equal to 28.2 mg/L of Co), the catalyst exhibited very high stability and excellent reusability in the recycling usages, while the leaching of the cobalt element (< 0.145 mg/L) was also at a low level. Our catalyst achieved effective degradations of acetaminophen in cycles without losing its stable hierarchical nanostructure.

Shape memory photonic crystals (SMPCs) are smart composite materials with changeable structural color integrated by shape memory polymer and photonic crystals. SMPC can produce one or more temporary shapes through nanoscale deformation, memorizing current states. SMPC can be recovered to their original shapes or some intermediate states under external stimuli, accompanied by the variation of structural color. As porous carriers with built-in sensing properties, SMPCs promoted the interdisciplinary development of nanophotonic technology in materials science, environmental engineering, biomedicine, chemical engineering, and mechanics. Herein, the recent progress on multifunctional SMPCs and practical applications, including traditional and cold programmable SMPCs, is summarized and discussed. The primary concern is shape programming at the nanoscale that has demonstrated numerous attractive functions, including smart sensing, ink-free printing, solvent detection, reprogrammable gradient wetting, and controllable bubble transportation, under variations of the surface nanostructure. It aims to figure out the nanoscale shape memory effects on structural color conversion and additional performance, inspiring the fabrication of the next generation of SMPCs. Finally, perspectives on future research directions and applications are also presented. It is believed that multifunctional SMPCs are powerful nanophotonic tools for the interdisciplinary development of numerous disciplines in the future.

Carbon dots (CDs) have wide application potentials in optoelectronic devices, biology, medicine, chemical sensors, and quantum techniques due to their excellent fluorescent properties. However, synthesis of CDs with controllable spectrum is challenging because of the diversity of the CD components and structures. In this report, machine learning (ML) algorithms were applied to help the synthesis of CDs with predictable photoluminescence (PL) under the excitation wavelengths of 365 and 532 nm. The combination of precursors was used as the variable. The PL peaks of the strongest intensity (λs) and the longest wavelength (λl) were used as target functions. Among six investigated ML models, the random forest (RF) model showed outstanding performance in the prediction of the PL peaks.

Nanozymes are nanomaterials with enzyme-mimicking catalytic activity. Compared to natural enzymes, nanozymes show various properties such as easy to manufacture, stable, adjustable, and inexpensive. Nanozymes play key roles in biosensing, biocatalysis, and disease treatment. As an important kind of nanozymes, metal-organic framework (MOF)-based nanozymes are receiving a lot of attention due to their structural properties and composition. Rationally developing MOF with enzymes-like catalytic properties has opened new perspectives in biosensing. This review summarizes the up-to-date developments in synthesizing two-dimensional and three-dimensional MOF-based nanozymes and their applications in biosensing. Firstly, classification of nanozymes obtained by MOFs is categorized, and different properties of MOF-based nanozymes are described. Then, the distinctive applications of MOF-based nanozymes in identifying various analytes are thoroughly summarized. Finally, the recent challenges and progressive directions in this area are highlighted.

Currently, enzyme-responsive nanomaterials have shown great promise in prognosis or diagnosis of disease biomarker. However, the great obstacle for conventional enzyme-responsive nanomaterials frequently lies in autofluorescence interference, poor monodispersity, uncontrollable size and morphology, low optical stability, and biotoxicity, which fundamentally impede their practical application in biological systems. To overcome these deficiencies, we proposed a novel strategy for reliable and precise detection of an enzyme disease biomarker, alkaline phosphatase (ALP), through lanthanide (Ln3+) nucleotide nanoparticles (LNNPs) with extremely improved monodispersity and uniformity, which were achieved by the coordination self-assembly between ATP and Ln3+ inside micellar nanoreactor. Specifically, for ATP-Ce/Tb LNNPs, highly improved photoluminescence (PL) emission of Tb3+ can be achieved via efficient Ce3+ sensitization. We demonstrated that ALP could specifically cleave the phosphorus–oxygen (P–O) bonds of ATP and result in the collapse of ATP-Ce/Tb scaffold, finally leading to the PL quenching of Tb3+. By taking advantage of time-resolved (TR) PL technique, the fabricated ATP-Ce/Tb LNNPs presented superior selectivity and sensitivity for the ALP bioassay in complicated serum samples, thus revealing the great potential of ATP-Ce/Tb LNNPs in the areas of ALP-related disease prognosis and diagnosis.

The slot-die coating is recognized as the most compatible method for the roll-to-roll (R2R) processing of large-area flexible organic solar cells (OSCs). However, the photovoltaic performance of the large-area flexible all-polymer solar cells was significantly lagging behind that of polymer donors with small molecule non-fullerene acceptors devices. In this work, the 1 cm2 flexible device of an all-polymer system, PTQ10:PYF-T-o, fabricated by slot-die coating, achieves an excellent efficiency of 11.24% via controlling the coating temperatures. It is found that, compared with the donor, the crystallinity of PYF-T-o plays a crucial role in device performance. The all-polymer flexible devices show superior mechanical bending stability, maintaining an efficiency of over 95% of the initial value during a 1000-cycle bending test.

Synergistic effects between hard carbons and soft carbons are proven to be helpful for improving the electrochemical performance of carbonaceous anode for potassium-ion batteries (PIBs). However, the phase separation of precursors limits the synergistic effects and improvement of electrochemical performance. Here, inspired by the esterification reaction, the precursors of two sorts of carbon are connected at the molecular level, which boosts the synergistic effects in hybrid carbon, resulting in excellent electrochemical kinetics and low charge/discharge voltage. Consequently, the hybrid carbon anode exhibited a high specific capacity of 121 mAh·g−1 at 3.2 A·g−1, a high-rate capability, and stable cycling performance. After 500 cycles at 1 A·g−1, the average capacity fading is only 0.078% per cycle.

The effective management of bacterial infections that are resistant to multiple drugs remains a substantial clinical challenge. The eradication of drug-resistant bacteria and subsequent promotion of angiogenesis are imperative for the regeneration of the infected wounds. Here, a novel and facile peptide containing injectable hydrogel with sustained antibacterial and angiogenic capabilities is developed. The antibacterial peptide that consists of 11 residues (CM11, WKLFKKILKVL) is loaded onto acrylate-modified gelatin through charge interactions. A vascular endothelial growth factor mimetic peptide KLT (KLTWQELYQLKYKGI) with a GCG (Gly-Cys-Gly) modification at the N-terminal is covalently coupled through a visible light-induced thiol-ene reaction. In this reaction, the acrylate gelatin undergoes cross-linkage within seconds. Based on the physical/chemical double crosslinking strategy, the bioactive peptides achieve sustained and sequential release. The results show that the hydrogel significantly inhibits methicillin-resistant Staphylococcus aureus (MRSA) growth through the rapid release of CM11 peptides at early stage; it forms obvious growth inhibition zones against pathogenic bacterial strains. Moreover, cell counting kit-8 assay and scratch test confirm that the CM11/KLT-functionalized hydrogels promote cell proliferation and migration through the later release of KLT peptides. In a mouse skin wound infected with self-luminous MRSA, the CM11/KLT-functionalized hydrogels enhance wound healing, with rapidly bacterial infection reduction, lower expression of inflammatory factors, and neovascularization promotion. These results suggest that the rationally designed, sustained and sequential release CM11/KLT-functionalized hydrogels have huge potential in promoting the healing of multi-drug resistant bacterial infected wounds.

The rational design of the catalysts with easily-accessible surface and high intrinsic activity is desirable for electrocatalytic hydrogen evolution reaction (HER). Here, we reported the construction of two-dimensional (2D) Co-Mo nitrides based heterojunctional catalyst for efficient HER based on a “mediated molecular” assisted route. The 2D Co(OH)2 sheet reacted partially with the “mediated molecular” (2-methylimidazole (2-MIM)) to form zeolitic imidazolate framework (ZIF)-67 at surface, giving ZIF-67/Co(OH)2 sheets. The ZIF-67 combines with [PMo12O40]3− cluster (PMo12) due to the interaction of mediated molecular with PMo12, producing 2D Mo-Co-2MIM/Co(OH)2 bimetallic precursor. After controlled nitriding, the Mo2N islands dispersed on 2D porous Co-based sheets were formed. A series of characterizations and density functional theory (DFT) calculation indicated the formation of a close contact interface, which promotes the electron transfer between Mo and Co components, enhances the electron migration/redistribution and redistribution and down-shift of d-band center and thus gives a high intrinsic activity. The 2D characteristics make the catalyst more accessible contact sites, which is favourable to promot the HER. The tests showed that the optimized catalyst exhibits an onset potential of 0 mV and an overpotential of 10 mA·cm−2 at 35.0 mV, which is quite close to that of Pt/C catalyst. It also exhibits an activity superior to Pt/C at high current density (> 100 mA·cm−2). A good stability of the catalyst was achieved with no significant decay for 100 h of continuous operation. The electrolytic cell composed of optimized catalyst and P-NiFe-layered double hydroxide (LDH) can be driven by low voltage (only 1.47 V) to reach a current density of 10 mA·cm−2.

The contradiction between the high number of visually handicapped people and the scarcity of guide dogs has stimulated the demand for electronic guide dogs (EGDs). Here, we demonstrate an EGD by leveraging piezoresistors on a MoS2/Ge heterostructure for simultaneous pressure-sensing and optical-sensing functions. The device has excellent gating capability and exhibits large positive and negative photoresponses under visible (532 nm, 182 A/W) and infrared (1550 nm, 37 A/W) illumination. These characteristics allow the device to efficiently classify different obstacles at all times of day using pressure and light signals. The device reaches nearly 100% accuracy after 48 training sessions when used to classify frequent scenes. The device adopts passive and active detection modes during the day and night, respectively, which improves the battery life of the EGD. This work provides a significant reference for the future design of EGDs, which may help a greater number of visually impaired people by reducing the cost of such devices.

When a laser beam writes on a metallic film, it usually coarsens and deuniformizes grains because of Ostwald ripening, similar to the case of annealing. Here we show an anomalous refinement effect of metal grains: A metallic silver film with large grains melts and breaks into uniform, close-packed, and ultrafine (∼ 10 nm) grains by laser direct writing with a nanoscale laser spot size and nanosecond pulse that causes localized heating and adaptive shock-cooling. This method exhibits high controllability in both grain size and uniformity, which lies in a linear relationship between the film thickness (h) and grain size (D), D ∝ h. The linear relationship is significantly different from the classical spinodal dewetting theory obeying a nonlinear relationship (D ∝ h5/3) in common laser heating. We also demonstrate the application of such a silver film with a grain size of ∼ 10.9 nm as a surface-enhanced Raman scattering chip, exhibiting superhigh spatial-uniformity and low detection limit down to 10−15 M. This anomalous refinement effect is general and can be extended to many other metallic films.

The noble metal-based bimetallic clusters with high atom utilization and surface energy have been widely applied in heterogeneous catalysis, but the stabilization of these metastable clusters in harsh reaction conditions is quite challenging. Herein, we synthesize a series of Pt-, Pd-, and Ru-based clusters promoted by a second non-noble metal (Zn, Cu, Sn, and Fe), which are confined inside silicalite-1 (pure silica, S-1) crystals by a ligand-protected method. The second metal could well stabilize and disperse the noble atoms inside the rigid S-1 zeolites via Si-O-M bonds, thus enabling to lower the usage of expensive noble metals in catalysts. The as-synthesized bimetallic catalysts exhibited excellent performance in non-oxidative propane dehydrogenation (PDH) reaction, which is typically operated above 500 °C. The PtZn@S-1, PtCu@S-1, and PtSn@S-1 with only a ∼ 0.17 wt.% Pt loading offer a significant enhancement in PDH performance compared with the conventional PtSn/Al2O3 catalyst with a 0.5 wt.% Pt loading prepared by impregnation method. Notably, the PtSn@S-1 provides a propane conversion of 45% with a 99% propylene selectivity at 550 °C, close to the thermodynamic equilibrium. Furthermore, the PtSn@S-1 exhibits excellent stability during 300 h on stream and high tolerance to regeneration by a simple calcination step.

Propylene carbonate (PC)-based electrolytes have exhibited significant advantages in boosting the low-temperature discharging of graphite-based Li-ion batteries. However, it is still unclear whether they can improve the charging property and suppress lithium plating. Studying this topic is challenging due to the problem of electrochemical compatibility. To overcome this issue, we introduced graphite with phase defects. The results show that the pouch-type full batteries using PC-based electrolyte exhibit steady performance over 500 cycles and can be reversibly charged over 30 times at −20 °C with an average Coulombic efficiency of 99.95%, while the corresponding value for the conventional ethylene carbonate (EC)-based electrolyte sample is only 31.20%. This indicates that the use of PC-based electrolyte significantly suppresses lithium plating during low-temperature charging. We further demonstrate that the improved performance is mainly attributed to the unique solvation structure, where more \({\rm{PF}}_6^ -\) anions participate in solvation, leading to the formation of a stable F-rich solid state electrolyte interface on the graphite surface and a lower reduction tendency of Li+ ions. This work inspires new ideas for the design of PC-based electrolytes for low-temperature charging and fast-charging batteries.

The development of novel and effective methods for the activation of methane is fascinating, which offers a promising potential for the sustainable development of chemical industry and the mitigation of greenhouse effect. Here we successfully synthesize two-dimensional (2D) Zr/5,10,15,20-tetrakis (4-carboxyphenyl) porphyrin (TCPP) ultrathin nanobelts (UNBs) as a high efficiency catalyst for methane (CH4) oxidation to carbon monoxide (CO). The Co-UNBs show well photo-coupled electrocatalytic performances for CH4 activation (CO production rates are 0.171 and 8.416 mmol·g−1·h−1 under dark/visible light, respectively). Density functional theory (DFT) calculations were performed to illustrate the mechanism of photoelectrocatalytic process and the high efficiency oxidation of CH4 to CO. Based on the ultrathin structure and highly efficient catalytic properties, this work provides a prospecting avenue for the design and synthesis of methane oxidation catalyst.