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A Zn2SnO4/ZnO nanocomposite is developed for effectively catalyzing the reduction of CO2 to formic acid, owning to the potential capacity to regulate electronic structure by interfacial interaction.

Effective glucose surveillance provides a strong guarantee for the high-quality development of human health. Au nanomaterials possess compelling applications in nonenzymatic electrochemical glucose biosensors owing to superior catalytic performances and intriguing biocompatibility properties. However, it has been a grand challenge to accurately control the architecture and composition of Au nanomaterials to optimize their optical, electronic, and magnetic properties for further improving the performance of electrocatalytic sensing. Herein, ultra-low content Bi-anchored Au aerogels are synthesized via a one-step reduction strategy. Benefiting from the unique structure of aerogels as well as the synergistic effect between Au and Bi, the optimized Au

CeO2/TiO2 (denoted as CeTi) catalysts obtained by solid-phase impregnation behaved better in low-temperature selective catalytic reduction of NOx with NH3 (NH3-SCR) than that by conventional wet impregnation. To explore the main factors for activity distinction, the texture property, CeO2 dispersion and structure changes of TiO2 were comprehensively analyzed. It was found that surface changes of TiO2 had a significant impact on the improved activity. From results of inductively coupled plasma atomic emission spectrometer (ICP-AES), diffuse reflectance UV–vis spectroscopy (UV–vis-DRS) and Raman, it was inferred that Ce ions were partially incorporated into TiO2 lattice, accompanied with the formation of defects and vacancies during solid-phase impregnation. Accordingly, CeTi catalysts from solid-phase impregnation exhibited superiority in adsorption and activation of reactants. Further result from monitoring the preparation process indicated that the evolved NO played an important role in promoting Ce doping through depriving oxygen atoms on TiO2 surface.The interaction between Ce and Ti was enhanced. The catalyst performed better in NH3-SCR, especially at low temperature, which testified the solid-phase impregnation could be an effective method to modulate interface structure for designing efficient catalyst.

The large-scale application of nanozymes remains a significant challenge owing to their unsatisfactory catalytic performances. Featuring a unique electronic structure and coordination environment, single-atom nanozymes provide great opportunities to vividly mimic the specific metal catalytic center of natural enzymes and achieve superior enzyme-like activity. In this study, the spin state engineering of Fe single-atom nanozymes (FeNC) is employed to enhance their peroxidase-like activity. Pd nanoclusters (Pd

A novel aptamer-AuNP-conjugated carboxymethyl chitosan-functionalized graphene oxide (CMC/GO@Apt-Au NP) probe was for the first time developed for the determination of Salmonella typhimurium (S. typhimurium). Owing to the conformational change of the aptamers in the presence of S. typhimurium, the Au NPs, which were pre-adsorbed on the aptamers through van der Waals forces, were released into the solution phase and induced the color change of the solution. As a result, S. typhimurium ranging from 10

Cerium-based catalysts are very attractive for the catalytic abatement of nitrogen oxides (NOx) emitted from stationary sources. However, the main challenge is still achieving satisfactory catalytic activity in the low-temperature range and tolerance to SO2 poisoning. In the present work, two series of Mo-modified CeO2 catalysts were respectively obtained through a wet impregnation method (Mo-CeO2) and a co-precipitation method (MoCe-cp), and the roles of the Mo species were systematically investigated. Activity tests showed that the Mo-CeO2 catalyst displayed much higher NO conversion at low temperature and anti-SO2 ability than MoCe-cp. The optimal Mo-CeO2 catalyst displayed over 80% NO elimination efficiency even at 150 dC and remarkable SO2 resistance at 250 dC (nearly no activity loss after 40 h test). The characterization results indicated that the introduced Mo species were highly dispersed on the Mo-CeO2 catalyst surface, thereby providing more Bronsted acid sites and inhibiting the formation of stable adsorbed NOx species. These factors synergistically promote the selective catalytic reduction (SCR) reaction in accordance with the Eley-Rideal (E-R) reaction path on the Mo-CeO2 catalyst. Additionally, the molybdenum surface could protect CeO2 from SO2 poisoning; thus, the reducibility of the Mo-CeO2 catalyst declined slightly to an adequate level after sulfation. The results in this work indicate that surface modification with Mo species may be a simple method of developing highly efficient cerium-based SCR catalysts with superior SO2 durability.

Photocatalytic water splitting is a promising method to produce clean and renewable energy, which provides an alternative solution to solve environmental and resource problems. New catalysts based on semiconductor nanoparticles have received increasing attention since they facilitate all the reactions needed for “artificial photosynthesis”. In recent decades, hollow microspheres have provided an ideal platform for efficient utilization. Scientists are working to understand the basic principles, band structures, and modification strategies of hollow microspheres to enhance photocatalytic performance. In this paper, the research progress of hollow microsphere photocatalysts in the field of water splitting is reviewed. In particular, the photocatalytic principles of hollow microspheres and the methods to improve the performance of semiconductor photocatalysts are discussed in depth. The structural advantages and defects of hollow microspheres and modification methods of semiconductor band structure are introduced. Finally, the remaining challenges are summarized, and some insights into new trends and improvement directions for hollow materials are provided. This review will provide new insights for understanding hollow microspheres and help researchers in related fields to have a deeper and more comprehensive understanding of hollow microspheres in photocatalytic water splitting.

Graphite carbon nitride (g-C3N4) is a significant non-metal photocatalyst, but still challenging for photocatalytic degradation of pollutants because of its poor visible light utilization, easy recombination of photo-generated carriers and low surface reactive reaction sites. In this paper, perylene diimide (PDI), an electron-deficient building block for constructing n-type organic semiconductors, was introduced into the framework of g-C3N4 (PDI-g-C3N4) to build polymer with donor–acceptor structure for energy band amelioration, achieving the most expanded visible light response up to date. Besides, a large dihedral angle (90°) induced by PDI moiety in PDI-g-C3N4 changes the molecular aggregation behavior according to calculations, which is advantageous to increase surface area for the reactive site exposure. The most promising functional photocatalyst PDI-g-C3N4/MIL is constructed by in-situ generation of NH2-MIL-53(Fe) on the surface of PDI-g-C3N4 to further facilitate the separation and transfer of interfacial photo-induced carriers. Through a finely adjusting ratio of PDI-g-C3N4 in heterojunction, the target material of PDI-g-C3N4/MIL exhibits superior activity for the photodegradation of organic pollutants in the presence of H2O2 and visible light illumination, providing potential direction in practical application for wastewater treatment.

The conventional cathodic electrochemiluminescence (ECL) always requires a more negative potential to trigger strong emission, which inevitably damages the bioactivity of targets and decreases the sensitivity and specificity. In this work, iron single-atom catalysts (Fe-N-C SACs) were employed as an efficient co-reaction accelerator for the first time to achieve the impressively cathodic emission of a luminol-H

Rational design and construction of electrochemical sensing platforms with high sensitivity and selectivity is one of the challenges in practical application. Although single-atom catalysts (SACs) have attracted extensive attention, atomically dispersed metal catalysts (ADCs) with multi-atom sites can further compensate for the deficiencies of SACs, which have gradually been a research hotspot in recent years. Herein, atomically dispersed Ru

The rational construction of advanced sensing platforms to sensitively detect H2O2 produced by living cells is one of the challenges in both physiological and pathological fields. Owing to the extraordinary catalytic performances and similar metal coordination to natural metalloenzymes, single atomic site catalysts (SASCs) with intrinsic peroxidase (POD)-like activity have shown great promise for H2O2 detection. However, there still exists an obvious gap between them and natural enzymes because of the great challenge in rationally modulating the electronic and geometrical structures of central atoms. Note that the deliberate modulation of the metal-support interaction may give rise to the promising catalytic activity. In this work, an extremely sensitive electrochemical H2O2 biosensor based on single atomic Fe sites coupled with carbon-encapsulated Fe3C crystals (Fe3C@C/Fe-N-C) is proposed. Compared with the conventional Fe SASCs (Fe-N-C), Fe3C@C/Fe-N-C exhibits superior POD-like activity and electrochemical H2O2 sensing performance with a high sensitivity of 1225 μA/mM·cm2, fast response within 2 s, and a low detection limit of 0.26 μM. Significantly, sensitive monitoring of H2O2 released from living cells is also achieved. Moreover, the density functional theory calculations reveal that the incorporated Fe3C nanocrystals donate electrons to single atomic Fe sites, endowing them with improved activation ability of H2O2 and further enhancing the overall activity. This work provides a new design of synergistically enhanced single atomic sites for electrochemical sensing applications.

To solve the problem of cooperative encirclement and simultaneous attack of multiple unmanned aerial vehicles, variational method and Hamiltonian optimization are utilized to design an optimal attack trajectory of multiple attackers pursuing a single target that has fixed initial relative state, fixed final relative state and fixed duration of the attack under condition that the acceleration of the target being estimable. When terminal relative state and attack duration are unknown, online calculation algorithm is used to compute a chain of key intermediate points to create the guidance law and ensure successful deliverance of multiple attackers’ simultaneous attack of the target. The only requirement for the multi-attacker communication network is that it contains a directed spanning tree. The guidance laws can function properly as long as one or more attacker can observe the target. The novel guidance laws practicability are verified by simulation results.

Atmospheric treatment of a photocatalyst is of great significance to the activity. In this work, oxidizing, inert and reducing atmospheres were employed to treat CeO2/g-C3N4 photocatalysts, denoted as CeCN, CeCN-N2, and CeCN-H2. Interestingly, after N2 treatment, CeCN-N2 showed the best photoreduction CO2 performance, while the poorest activity was observed on CeCN-H2. The obvious reversal of activities was explored. The H2 treatment with stronger reducibility resulted in too many defects, and then bulk defects led to the charge recombination and poor CO2 activation. On the other hand, moderately inert N2 treatment introduced both the surface oxygen defects of CeO2 and amino groups in CN heterocycles, which synergistically enhanced the photoinduced electron–hole separating efficiency and medium base sites for the CO2 activation. Furthermore, a Z-scheme photocatalytic system instead of type II (CeCN) was formed on CeCN-N2, which was provided with stronger redox, and the generated overpotential was beneficial for CO2 photoreduction.

In this paper, a new guidance law based on time-varying terminal sliding mode is proposed to make multi-agent intercept maneuvering target simultaneously. The new approach can make more benefits as follows: (1). Distributed cooperation protocol with accurate time-to-go ensures the simultaneous attack task can be solved within finite time. (2). The disturbance observer and the composite cooperative guidance law can settle the coordinated attack problem with target acceleration unknown (that is in accordance with the unknown uncertainty upper bound). (3). The improved terminal sliding mode can maintain the continuity and stability of flight control, and it can eliminate singularity and chattering of sliding mode to some extent. (4). New guidance law is designed for multi-attackers with different interaction topology, which is suitable for the long distance information communication. By comparison, numerical simulations verify the validity and superiority of the proposed method.

The investigations on the generation, separation, and interfacial-redox-reaction processes of the photoinduced carriers are of paramount importance for realizing efficient photoelectrochemical (PEC) detection. However, the sluggish interfacial reactions of the photogenerated carriers, combined with the need for appropriate photoactive layers for sensing, remain challenges for the construction of advanced PEC platforms. Here, as a proof of concept, well-defined Fe single-atom catalysts (Fe SACs) were integrated on the surface of semiconductors, which amplified the PEC signals

Tremendous efforts have been made in developing single-atomic site catalysts (SASCs) for oxygen reduction reaction (ORR), which is regarded as a pivotal cornerstone in electrochemical energy conversion. However, SASCs for ORR have not been explored for electrochemical sensing. Herein, a template-sacrificed strategy is reported for the synthesis of atomically dispersed Ir SASCs, serving as a sensing platform to detect organophosphorus pesticides (OPs) with high sensitivity and selectivity. Owing to abundant Ir single-atom active sites, Ir SASCs show excellent ORR activity and stability in a neutral medium. It is found that the ORR activity of Ir SASCs can be inhibited by thiocholine, which is the hydrolysate of acetylthiocholine. After being integrated with acetylcholinesterase (AChE), the AChE-Ir SASC-based electrochemical sensor is established and shows a superior sensitivity, which shows a wide detection range of 0.5-500 ng mL

For photocatalytic CO2 reduction, the synergistic effect of Lewis acidity and basicity on CO2 activation is worthy of study. On the basis of a large number of oxygen defects (Lewis acidity) and hyd...

A highly sensitive photoelectrochemical (PEC) sensing platform was constructed for Hg2+ determination based on the Schottky heterojunction between an emerging 2D material Ti3C2TX MXene and a promising semiconductor material BiVO4. Through simply spin-coating the single-layer Ti3C2TX onto the surface of BiVO4 film, the modified electrode exhibited significantly enhanced PEC activity. However, the boost in photocurrent could be noticeably suppressed due to the consumption of hole-scavenging agents (reduced glutathione) by the added Hg2+. Owing to the selective decrease in the photocurrent with the addition of Hg2+, the PEC sensor based on BiVO4/Ti3C2TX displayed a wide linear range from 1 pM to 2 nM with the limit of detection down to 1 pM. Moreover, the PEC sensor also exhibited satisfactory accuracy and repeatability in practical sample water, the Yangtze River water, demonstrating the great potential for monitoring heavy metal ions in natural water resources.

In this work, Co–N-doped carbon nanosheet (Co-NCS), obtained through a self-assembly strategy and subsequent pyrolysis process, was reported as an efficient ORR catalyst. Combining the unique 2D architecture and high N-doping level, the optimized Co-NCS exhibits a superior ORR performance with more positive onset potential (0.96 V) and half-wave potential (0.93 V) than those of commercial Pt/C under alkaline conditions. Additionally, the optimized catalyst also displays desirable ORR activity in acidic media, approaching that of commercial Pt/C. Significantly, the synergistic catalysis is demonstrated through selective etching of active species, holding great potential in an in-depth understanding of the contributions of CoNₓ and Co@C NPs in catalysts. Furthermore, the zinc–air batteries assembled with the optimized Co-NCS as the air cathode outperform the Pt-based zinc–air batteries. This finding sheds light on the synthesis of ORR catalysts and the exploration of their application in energy conversion systems.

With the goal of improving the removal of anionic contaminants, copper oxide (CuO)-modified biochar (BC) nanocomposites were successfully prepared through simply ball milling CuO particles with BC. The physicochemical properties of the fabricated CuO/BC nanocomposites were systematically characterized by a series of techniques; their adsorption performances were assessed, and the main adsorption mechanism was revealed. X-ray powder diffraction, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy analyses of the nanocomposites showed the strong interaction between CuO and BC and confirmed the success of the ball-milling syntheses. Because of strong electrostatic attraction between the embedded CuO nanoparticles and reactive red (RR120), the composited adsorbents exhibited excellent RR120 removal. The 10%-CuO/BC nanocomposite achieved the best RR120 removal efficiency (46%), which is much higher than that of pristine BC (20%). In addition, the adsorption was insensitive to the change of solution initial pH (4-10). The 10%-CuO/BC also showed fast adsorption kinetics (equilibrium time < 3 h) and extremely high adsorption capacity (Langmuir maximum capacity of 1399 mg g-1) to RR120 in aqueous solutions. Findings from this study demonstrate not only the strong feasibility of ball-milling synthesis of BC-based nanocomposites but also the promising potential of the CuO/BC nanocomposites to remove aqueous anionic contaminants.

Tuning electrocatalysts via interface engineering is widely adopted as a valid way to manipulate the electrocatalytic activity. Herein, the interface engineering of PdCu aerogels is successfully achieved by the integration of an ionic liquid (IL), which not only accelerates the gelation kinetics but also leads to the modulation of the interface electronic properties, enabling IL functionalized PdCu aerogels (IL/PdCu) as advanced electrocatalysts for the methanol oxidation reaction (MOR) with splendid electrocatalytic activity. Density functional theory (DFT) calculations also demonstrate that IL-involved interface engineering dramatically reduces the chemisorption energy of CO-containing intermediates and thus significantly boosts the MOR performance. Furthermore, direct methanol fuel cells (DMFCs) using an IL/Pd3Cu1 anode catalyst exhibit a higher power density than those containing Pd3Cu1 and commercial Pd catalysts. This work highlights the superiority of designing advanced electrocatalysts by interface engineering.