Search

A polymeric heterojunction hybrid composed of a C6-FDTP conjugated polymer and graphitic carbon nitride via π–π interactions exhibits superior photocatalytic hydrogen generation under visible light irradiation.

In order to improve the performance of the active vibration isolation system (AVIS) with electromagnetic actuator, several problems of vibration control are studied. Position control is a critical component in suspension systems, and the position sensor noise can extremely affect the stability of the system, so a tracking differentiator (TD) is proposed to obtain effective differential signal from relative position sensor. In vibration control, the feedback of acceleration combined with PD position feedback is presented to suppress transmission of periodic vibrations. Then, taking the acceleration transmission as the evaluation index, the acceleration transmission under the presented control method is derived, and the influence of control parameters on vibration isolation performance is discussed in detail. The vibration isolation performance is improved from 24.47 dB to 2.4 dB at resonance frequency, and −34 dB attenuation is achieved at 100 Hz with respect to vibration isolation mount system tested on the ground. The experimental results demonstrate that the performance of active vibration isolation system are improved by the proposed acceleration feedback control.

The colour centre platform holds promise for quantum technologies, and hexagonal boron nitride has attracted attention due to the high brightness and stability, optically addressable spin states and wide wavelength coverage discovered in its emitters. However, its application is hindered by the typically random defect distribution and complex mesoscopic environment. Here, employing cathodoluminescence, we demonstrate on-demand activation and control of colour centre emission at the twisted interface of two hexagonal boron nitride flakes. Further, we show that colour centre emission brightness can be enhanced by two orders of magnitude by tuning the twist angle. Additionally, by applying an external voltage, nearly 100% brightness modulation is achieved. Our ab initio GW and GW plus Bethe-Salpeter equation calculations suggest that the emission is correlated to nitrogen vacancies and that a twist-induced moiré potential facilitates electron-hole recombination. This mechanism is further exploited to draw nanoscale colour centre patterns using electron beams.

The efficient removal of persistent organic pollutants (POPs) in natural waters is vital for human survival and sustainable development. Photocatalytic degradation is a feasible and cost-effective strategy to completely disintegrate POPs at room temperature. Herein, we develop a series of direct Z-scheme BiOIO

Rigid, solid-state components represent the current paradigm for electronic systems, but they lack post-production reconfigurability and pose ever-increasing challenges to efficient end-of-life recycling. Liquid electronics may overcome these limitations by offering flexible in-the-field redesign and separation at end-of-life via simple liquid phase chemistries. Up to now, preliminary work on liquid electronics has focused on liquid metal components, but these devices still require an encapsulating polymer and typically use alloys of rare elements like indium. Here, using the self-assembly of jammed two-dimensional titanium carbide (Ti

With the development of the GEN-IV nuclear reactors in the 21st Century, as a substitute for the steam cycle, the supercritical carbon dioxide (SCO2) Brayton cycle has been widely used in a variety of power generation scenarios and has attracted widely attention from the scholars. However, the previous research mainly focused on the basic thermodynamics research, parameter optimizations and system design. Considering the load variability and control flexibility of the power generation system, the dynamic performance research of the SCO2 cycle is necessary. In the numerous layouts of SCO2 Brayton cycle, the SCO2 simple recuperated cycle stands out for its simple structure and high efficiency, which is also the main focus in this paper. In this paper, a dynamic model of SCO2 simple recuperated brayton cycle is developed with the Simulink software. The overall system includes a turbine (T), compressor (CM), regenerator (Re), intermediate heat exchanger (IHE), pre-cooler (PC), surge tank (ST), and heater. The models could be able to realize independent physical functions and be mathematically independent. The SCO2 recuperated cycle is then built with the developed models. Based on the simple recuperated system, the comparative calculation with the design value is carried out to verify the models and the results are very positive. Since the components are tightly coupled in the closed-loop cycle, the error of the main parameters for each component is relatively large. In the steady calculation, the maximum error of the component parameter is 7.72%, and the error of the cycle efficiency is about 1.45%. The results are very promising that the developed model has the ability to evaluate the thermal-hydraulic characteristics of the SCO2 Brayton circulation system.

The low mass density and high mechanical strength of graphene make it an attractive candidate for suspended-membrane energy transducers. Typically, the membrane size dictates the operational frequency and bandwidth. However, in many cases it would be desirable to both lower the resonance frequency and increase the bandwidth, while maintaining overall membrane size. We employ focused ion beam milling or laser ablation to create kirigami-like modification of suspended pure-graphene membranes ranging in size from microns to millimeters. Kirigami engineering successfully reduces the resonant frequency, increases the displacement amplitude, and broadens the effective bandwidth of the transducer. Our results present a promising route to miniaturized wide-band energy transducers with enhanced operational parameter range and efficiency.

The photocatalytic CO

AIE/AIEE-active conjugated polymers have shown great potential in bioimaging applications. However, the absorption of many AIE/AIEE polymers poorly matches with the laser excitation used in confocal imaging, which may greatly affect the imaging quality. In this regard, we designed and synthesized a novel conjugated polymer incorporating π-extended boron ketoiminate units. The resulting polymer shows typical aggregation-induced enhanced emission (AIEE) characteristics and a dominant UV absorption of 447 nm in THF, which matches well with the laser excitation. Moreover, the polymer exhibits a Stokes shift up to 100 nm, which makes it a good candidate for cell imaging applications. The polymer was subsequently encapsulated into amphiphilic poly(styrene-co-maleic anhydride) (PSMA) to yield conjugated polymer nanoparticles (CPNs) (∼65 nm), which can emit bright yellow fluorescence in aqueous media with a quantum yield of 15%. Meanwhile, the HeLa cell imaging results demonstrate that the CPNs exhibit low cytotoxicity and high photostability, which are good contrast agents for biological fluorescence imaging.

Nanoscale self-assembly, as a technique to transform two-dimensional (2D) planar patterns into three-dimensional (3D) nanoscale architectures, has achieved tremendous success in the past decade. However, an assembly process at nanoscale is easily affected by small unavoidable variations in sample conditions and reaction environment, resulting in a low yield. Recently, in-situ monitored self-assembly based on ion and electron irradiation has stood out as a promising candidate to overcome this limitation. The usage of ion and electron beam allows stress generation and real-time observation simultaneously, which significantly enhances the controllability of self-assembly. This enables the realization of various complex 3D nanostructures with a high yield. The additional dimension of the self-assembled 3D nanostructures opens the possibility to explore novel properties that cannot be demonstrated in 2D planar patterns. Here, we present a rapid review on the recent achievements and challenges in nanoscale self-assembly using electron and ion beam techniques, followed by a discussion of the novel optical properties achieved in the self-assembled 3D nanostructures.

Plasmonic sensors are commonly defined on two-dimensional (2D) surfaces with an enhanced electromagnetic field only near the surface, which requires precise positioning of the targeted molecules within hotspots. To address this challenge, we realize segmented nanocylinders that incorporate plasmonic (1-50 nm) gaps within three-dimensional (3D) nanostructures (nanocylinders) using electron irradiation triggered self-assembly. The 3D structures allow desired plasmonic patterns on their inner cylindrical walls forming the nanofluidic channels. The nanocylinders bridge nanoplasmonics and nanofluidics by achieving electromagnetic field enhancement and fluid confinement simultaneously. This hybrid system enables rapid diffusion of targeted species to the larger spatial hotspots in the 3D plasmonic structures, leading to enhanced interactions that contribute to a higher sensitivity. This concept has been demonstrated by characterizing an optical response of the 3D plasmonic nanostructures using surface-enhanced Raman spectroscopy (SERS), which shows enhancement over a 22 times higher intensity for hemoglobin fingerprints with nanocylinders compared to 2D nanostructures.

In order to accurately predict the key dangerous parts of the polygonal pressure pipeline in a corrosive environment, based on the stress fatigue theory, a stainless steel pipeline damage calculation model coupled with the coupling of fatigue and corrosion is established, and the cold and operating conditions are carried out for the polygonal pressure pipeline. The analysis of stress and damage fields shows that the fatigue life of the square-shaped pipeline is reduced from 9225 to 42 years after the influence of the stress concentration factor of pitting corrosion. Based on the results of the damage analysis, by defining the dangerous concentration parameters, it is predicted that the key dangerous parts of the zigzag pressure pipeline are mainly the elbow and the long side abdomen. The greater the dangerous concentration parameter is, the more concentrated the dangerous parts are. When the dangerous concentration parameter is greater than 0.5, the elbow of the pipe shoulder and the long side joint are not critical dangerous parts anymore.

Curved fluidic channels with a circular cross-section play an important role in biology, chemistry, and medicine. However, in nanofluidics, a problem that is largely unsolved is the lack of an effective fabrication method for curved circular nanotubes (10-1000 nm). In this work, an electron-beam-induced self-assembly process was applied to achieve fine curved nanostructures for the realization of nanofluidic devices. The diameter of the tube could be precisely controlled by an atomic layer deposition process. Fluid transported through the nanochannels was verified and characterized using a dark-field microscope under an optical diffraction limit size. The fluid flow demonstrates that the liquid's evaporation (vapor diffusion) in the nanochannel generates compressed vapor, which pumps the liquid and pushes it forward, resulting in a directional flow behavior in the ∼100 nm radius of tubes. This phenomenon could provide a useful platform for the development of diverse nanofluidic devices.

Constructing direct Z-scheme system is a promising strategy to boost the photocatalytic performance for pollution waters restoration, but it is of great challenge because of the requirement of appropriately staggered energy band alignment and intimate interfacial interaction between semiconductors. Herein, a class of core-shell structured Ag

The pursuing of photosensitizers (PSs) with efficient reactive oxygen species (ROS) especially type I ROS generation in aggregate is always in high demand for photodynamic therapy (PDT) and photoimmunotherapy but remains to be a big challenge. Herein, we report a cationization molecular engineering strategy to boost both singlet oxygen and radical generation for PDT. Cationization could convert the neutral donor-acceptor (D-A) typed molecules with the dicyanoisophorone-triphenylamine core (DTPAN, DTPAPy) to their A-D-A′ typed cationic counterparts (DTPANPF6 and DTPAPyPF6). Our experiment and simulation results reveal that such cationization could enhance the aggregation-induced emission (AIE) feature, promote the intersystem crossing (ISC) processes, and increase the charge transfer and separation ability, all of which work collaboratively to promote the efficient generation of ROS especially hydroxyl and superoxide radicals in aggregates. Moreover, these cationic AIE PSs also possess specific cancer cell mitochondrial targeting capability, which could further promote the PDT efficacy both in vitro and in vivo. Therefore, we expect this delicate molecular design represents an attractive paradigm to guide the design of type I AIE PSs for the further development of PDT.

Conjugated polymers have recently been under active investigation as promising alternatives to traditional inorganic semiconductors for photocatalysis. This is due to their unique advantages of low cost, high chemical stability, and molecularly tunable optoelectronic properties. This critical review summarizes the recent advancements in π-conjugated polymers for visible-light-driven photocatalytic applications including water splitting, CO2 reduction, organic transformation and degradation of organic dyes. Special emphasis is placed on how the changes in the polymer structure could influence their physicochemical properties and photocatalytic activities. This structure–activity relationship analysis should guide rational molecular design of conjugated polymers for improved photocatalytic activity.

A gradient cobalt-doped MgIn2S4 (MgIn2S4-Co) homojunction photocatalyst was reported, creating an oriented built-in electric field for efficient extraction of photogenerated carriers from the inside to the surface of the photocatalyst. The MgIn2S4-Co photocatalysts showed remarkably enhanced photocatalytic CO2 reduction activity compared with pristine MgIn2S4.

Reversible self-assembly that allows materials to switch between structural configurations has triggered innovation in various applications, especially for reconfigurable devices and robotics. However, reversible motion with nanoscale controllability remains challenging. This paper introduces a reversible self-assembly using stress generated by electron irradiation triggered degradation (shrinkage) of a single polymer layer. The peak position of the absorbed energy along the depth of a polymer layer can be modified by tuning the electron energy; the peak absorption location controls the position of the shrinkage generating stress along the depth of the polymer layer. The stress gradient can shift between the top and bottom surface of the polymer by repeatedly tuning the irradiation location at the nanoscale and the electron beam voltage, resulting in reversible motion. This reversible self-assembly process paves the path for the innovation of small-scale machines and reconfigurable functional devices.

Current graphene-based plasmonic devices are restricted to 2D patterns defined on planar substrates; thus, they suffer from spatially limited 2D plasmon fields. Here, 3D graphene forming freestanding nanocylinders realized by a plasma-triggered self-assembly process are introduced. The graphene-based nanocylinders induce hybridized edge (in-plane) and radial (out-of-plane) coupled 3D plasmon modes stemming from their curvature, resulting in a four orders of magnitude stronger field at the openings of the cylinders than in rectangular 2D graphene ribbons. For the characterization of the 3D plasmon modes, synchrotron nanospectroscopy measurements are performed, which provides the evidence of preservation of the hybridized 3D graphene plasmons in the high precision curved nanocylinders. The distinct 3D modes introduced in this paper, provide an insight into geometry-dependent 3D coupled plasmon modes and their ability to achieve non-surface-limited (volumetric) field enhancements.

Low Power Bluetooth has been widely used in a variety of electronic devices. In this paper, through theoretical analysis and simulation practice, the indoor positioning problem based on Bluetooth 4.0 technology is studied. Firstly, the application of EWKNN algorithm based on clustering threshold in indoor localization is studied. Meanwhile, a classification and regression model is constructed based on the SVM algorithm. Finally, the localization effect of the two algorithms is verified and compared by simulation in a complex environment with obstacles, which provides a relevant reference for the real area localization problem.

The mid-speed maglev train with a speed of 200 km/h cannot adopt the power supply scheme of collector adding collection rail. Inductive power transfer technology (IPT) as a new type of contactless power supply, it can effectively overcome the drawbacks of contact type power supply mode, such as contact spark, line wear, electric shock and other accidents, which are able to provide the stable and reliable power for mid-speed maglev train. High efficiency and high power are the primary conditions for IPT technology using in engineering operation on mid-speed maglev train. This paper proposes a scheme of IPT system which is suitable for mid-speed maglev train, and establishes the mutual inductance model of IPT system. Through studying the influence of different parameters on the transmission efficiency and power, the scheme of parameter selection is proposed. At the same time, we study the high-frequency series resonant inverter, and analysis the influence of dead time on the inverter performance. Furthermore, we put forward the best setting range of dead time. Finally, an experimental platform was constructed to realize the contactless power transmission with a single pick-up coil power was 4kw and efficiency of more than 80%.

Bluetooh Low Energy Bluetooth technology is a short distance, low-cost, interoperable wireless technology, having been widely used in a variety of electronic devices. This paper takes this as the research object, combined with theoretical analysis and simulation, and studies the area positioning technology based on the algorithm of the Elman_Adaboost. Then a simulation of a space of 11m u 6m u 4m is presented. The results show that Elman_Adaboost algorithm could improve the precision compared with the Elman algorithm and EWKNN algorithm.

A gradient cobalt-doped MgIn

Sequence plays an important role in self-assembly of 3D complex structures, particularly for those with overlap, intersection, and asymmetry. However, it remains challenging to program the sequence of self-assembly, resulting in geometric and topological constrains. In this work, a nanoscale, programmable, self-assembly technique is reported, which uses electron irradiation as "hands" to manipulate the motion of nanostructures with the desired order. By assigning each single assembly step in a particular order, localized motion can be selectively triggered with perfect timing, making a component accurately integrate into the complex 3D structure without disturbing other parts of the assembly process. The features of localized motion, real-time monitoring, and surface patterning open the possibility for the further innovation of nanomachines, nanoscale test platforms, and advanced optical devices.

The relative position sensor of a high-speed maglev train is an important part of train location and speed detection for motor traction, but its output signal is not only related to position but also related to the suspension gap of the maglev train. The fluctuation of the suspension gap will affect the amplitude of the output signal of the sensor (i.e., the suspension wave signal is coupled with the output signal). The prediction normalization method currently used can eliminate the effect of the suspension fluctuation to a certain extent, but there is a limitation. Aiming at this problem, this paper analyzes the frequency characteristics of the suspension gap fluctuation caused by track irregularities and proposes a gap estimation algorithm based on the adaptive filter. The Kalman filter is used to estimate the gap and then the output signal is compensated according to the numerical relationship between the gap and the output signal of the sensor, so as to achieve the decoupling between the gap and the position measurement. Finally, the effectiveness of the method is proved by the comparison experiments.

Organic π-conjugated polymers (CPs) have been intensively explored for a variety of critical photocatalytic applications in the past few years. Nevertheless, CPs for efficient CO2 photoreduction have been rarely reported, which is mainly due to the lack of suitable polymers with sufficient solar light harvesting ability, appropriate energy level alignment and good activity and selectivity in multi-electron-transfer photoreduction of CO2 reaction. We report here the rational design and synthesis of two novel triphenylamine (TPA) based conjugated microporous polymers (CMPs), which can efficiently catalyze the reduction of CO2 to CO using water vapor as an electron donor under ambient conditions without adding any co-catalyst. Nearly 100% selectivity and a high CO production rate of 37.15 μmol h−1 g−1 are obtained for OXD-TPA, which is significantly better than that for BP-TPA (0.9 μmol h−1 g−1) as a result of co-monomer change from biphenyl to 2,5-diphenyl-1,3,4-oxadiazole. This difference could be mainly ascribed to the synergistic effect of a decreased optical band gap, improved interface charge transfer and increased CO2 uptake for OXD-TPA. This contribution is expected to spur further interest in the rational design of porous conjugated polymers for CO2 photoreduction. NRF (Natl Research Foundation, S’pore) MOE (Min. of Education, S’pore) Accepted version

Three new boron ketoiminate-based conjugated polymers P1, P2, and P3 were designed and synthesized through the Sonogashira coupling reaction of 4,6-bis(4-bromophenyl)-2,2-difluoro-3-phenyl-2H-1,3,2-oxazaborinin-3-ium-2-uide (M1) with 1,4-diethynyl-2,5-bis(octyloxy)benzene (M2), 3,6-diethynyl-9-octyl-9H-carbazole (M3) and 3,7-diethynyl-10-octyl-10H-phenothiazine-S,S-dioxide (M4), respectively. All the resulting polymers showed obvious aggregation-induced emission (AIE) behaviours. Interestingly, it was found that a great difference in the electron-donating abilities of the D–A type polymer linkers can lead to the unique AIE behaviour of the alternating polymers in the aggregate state, which provides us with a practical strategy to design tunable AIE-active conjugated polymers. Most importantly, studies on MCF-7 breast cancer cell imaging revealed that the nanoparticles fabricated from the conjugated polymers could serve as promising fluorescent probes with low cytotoxicity and high photostability.

In marine nuclear power plants based on molten salt reactors, the complexity of core nuclear reactions, fuel fluidity, and the “false” water level characteristics of the steam generator water level make it unrealistic to establish an accurate mathematical model, so it is difficult to implement traditional PID control methods. This has increased substantially. The fuzzy control has a good solution to this feature. Therefore, combined with the fuzzy control that does not depend on the precise mathematical model of the controlled object, the fuzzy controller of the nuclear power plant is designed, and the control research of the core power is obtained respectively through MATLAB/Simulink simulation. It shows that the designed fuzzy controller can achieve good control of nuclear power plants.

Within a total residence time of 9 min, the sodium salt of ciprofloxacin was prepared from simple building blocks via a linear sequence of six chemical reactions in five flow reactors. Sequential offline acidifications and filtrations afforded ciprofloxacin and ciprofloxacin hydrochloride. The overall yield of the eight‐step sequence was 60 %. No separation of intermediates was required throughout the synthesis when a single acylation reaction was applied to remove the main byproduct, dimethylamine., United States. Defense Advanced Research Projects Agency (Grant N666001-11-C-4005)

A three-component, titanium-mediated synthesis of α-branched N-acylamines from commercial or readily accessible amides, aldehydes, and organometallic reagents is reported. The transformation proceeds under mild reaction conditions and tolerates a variety of functional groups (including nitrile, carbamate, olefin, basic amine, furan, and other sensitive heteroaromatics) to generate a large umbrella of α-branched N-acylamine products in high yields. The operationally practical procedure enables the use of this method in parallel chemical synthesis, a valuable feature that can facilitate the screening of bioactive molecules by medicinal chemists.

The ability to transform two-dimensional (2D) materials into a three-dimensional (3D) structure while preserving their unique inherent properties might offer great enticing opportunities in the development of diverse applications for next generation micro/nanodevices. Here, a self-assembly process is introduced for building free-standing 3D, micro/nanoscale, hollow, polyhedral structures configured with a few layers of graphene-based materials: graphene and graphene oxide. The 3D structures have been further modified with surface patterning, realized through the inclusion of metal patterns on their 3D surfaces. The 3D geometry leads to a nontrivial spatial distribution of strong electric fields (volumetric light confinement) induced by 3D plasmon hybridization on the surface of the graphene forming the 3D structures. Due to coupling in all directions, resulting in 3D plasmon hybridization, the 3D closed box graphene generates a highly confined electric field within as well as outside of the cubes. Moreover, since the uniform coupling reduces the decay of the field enhancement away from the surface, the confined electric field inside of the 3D structure shows two orders of magnitude higher than that of 2D graphene before transformation into the 3D structure. Therefore, these structures might be used for detection of target substances (not limited to only the graphene surfaces, but using the entire volume formed by the 3D graphene-based structure) in sensor applications.

The relative position sensor provides phase angle information for the traction system. The failure of the sensors directly affects whether the train can operate normally. Based on the analysis of the sensor, the common faults of the sensor are analyzed, and the corresponding fault features are extracted. The fault characteristics of the sensor are presented. Based on the research of the decision tree fault diagnosis method, the improved decision tree based on support vector machine is proposed to realize the fault diagnosis and improve the effect of the diagnosis. Finally, the fault diagnosis platform is designed, and the tests show that the improved decision tree has high diagnosis correct rate.

Precision positioning platform is the key component of semiconductor lithography and precision manufacturing. In this paper, a multi-degree-of-freedom maglev precise positioning platform with a wide range of travel is studied, and the three-degree-of-freedom dynamic modeling and decoupling control of the platform suspension system are studied. The sliding mode variable structure control strategy is introduced to decouple the three-degree-of-freedom coupled system, and the extended state observer is introduced to observe the internal and external disturbances of the system. Using the the three-point levitation system in the laboratory, the control algorithm of the levitation controller of the positioning platform is designed and implemented. The specific experimental results are given and compared.

This paper mainly studies the signal processing problem of position and speed measurement system for the highspeed maglev train. The signals of relative positioning sensors and absolute positioning sensors are fused by the multi-sensor fusion algorithm. A multi-sensor fusion algorithm based on adaptively weighted fusion is proposed and the problem of distortion on magnetic pole phase when sensor passing through the track joints is solved. The signal processing scheme of the position and speed measurement system is implemented systematically. The experimental results verify the feasibility and validity of the proposed signal processing algorithm and scheme.

Position speed detection technology is the key technology of high speed maglev train traction and control system. Signal processing unit is crucial for position speed detection technology. This paper introduces the structural framework of the signal processing part of the position speed detection system. The signal processing of the relative and absolute sensors is described. The internal signal transmission between the crate and the sensors is presented. And the tests are given to validate the performance of system.

In order to improve maintenance efficiency, reduce maintenance costs, reduce the workload of maintenance personnel, and avoid huge economic losses and catastrophic accidents, this paper designs a prognostic and health management (PHM) architecture of maglev train based on distributed hierarchical structure. First, the system is used as a unit to establish a distributed structure, and the hierarchy is divided according to the structure of "train-vehicle-system-subsystem". Then, the data of the maglev train is divided by the hierarchical structure, and the subsystem fault detection model and health assessment model are established, and the system fault diagnosis model and fault prediction model are further established. Based on the fault diagnosis or fault prediction results, the optimal maintenance decision is provided. Finally, a PHM architecture of maglev train based on a distributed and hierarchical structure is proposed.

A series of Sn2+ doped MgIn2S4 photocatalysts were prepared via a facial hydrothermal method. The Sn dopants substitute the sites of Mg atom in MgIn2S4 unit cell, but not alter the crystal structure, demonstrated by the results of XRD and XPS. Compared to pristine MgIn2S4, Sn-doped MgIn2S4 samples exhibit significantly enhanced photocatalytic CO2 reduction activity. With increasing the Sn dopant content, the CO2 conversion rate first ascends, achieving the maximum rate at Sn-MgIn2S4-2 sample, and then decreases. After illumination for 4 h, the highest yield of CO and CH4 for Sn-MgIn2S4-2 sample reaches about 3.35 and 3.33 times higher than that of pristine MgIn2S4. The theoretical results based on density functional theory calculations reveal that Sn doping in MgIn2S4 tunes the band structure from the direct-transition of MgIn2S4 to indirect-transition, diminishes band gap and extends the light absorption range, reduces the effective masses of holes and promotes the migration of photoinduced carriers. The experimental results also demonstrate the positive role of Sn dopant in accelerating the separation and transportation of charges, and improving CO2 adsorption ability. This work systematically investigates and discusses the Sn2+ doping effect in MgIn2S4 on crystal structure, lattice variations, electronic band structures, CO2 adsorption ability, and photocatalytic CO2 reduction activity, which can provide a new hint for the fabrication of efficient photocatalyst by metal ion doping.