Frontiers in Photoelectrochemical Catalysis: A Focus on Valuable Product Synthesis.

Photoelectrochemical (PEC) catalysis provides the most promising avenue for producing value-added chemicals and consumables from renewable precursors. Over the last decades, PEC catalysis, including reduction of renewable feedstock, oxidation of organics, and activation and functionalization of C─C and C─H bonds, are extensively investigated, opening new opportunities for employing the technology in upgrading readily available resources. However, several challenges still remain unsolved, hindering the commercialization of the process. This review offers an overview of PEC catalysis targeted at the synthesis of high-value chemicals from sustainable precursors. First, the fundamentals of evaluating PEC reactions in the context of value-added product synthesis at both anode and cathode are recalled. Then, the common photoelectrode fabrication methods that have been employed to produce thin-film photoelectrodes are highlighted. Next, the advancements are systematically reviewed and discussed in the PEC conversion of various feedstocks to produce highly valued chemicals. Finally, the challenges and prospects in the field are presented. This review aims at facilitating further development of PEC technology for upgrading several renewable precursors to value-added products and other pharmaceuticals.

Ce4+-Substituted Ni-Al mixed oxide: fluoride adsorption performance and reusability.

In this study, Ce4+-doped Ni-Al mixed oxides (NACO) were synthesized and comprehensively characterized for their potential application in fluoride adsorption. NACOs were examined using Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM), revealing a sheet-like morphology with a nodular appearance. X-ray diffraction (XRD) analysis confirmed the formation of mixed oxides of cubic crystal structure, with characteristic planes (111), (200), and (220) at 2θ values of 37.63°, 43.61°, and 63.64°, respectively. Further investigations using X-ray Photoelectron Spectroscopy (XPS) identified the presence of elements such as Ni, Al, Ce, and O with oxidation states +2, +3, +4, and -2, respectively. The Brunauer-Emmett-Teller (BET) analysis indicated that NACO followed a type IV physisorption isotherm, suggesting favorable surface adsorption characteristics. The adsorption kinetics was studied, and the experimental data exhibited a good suit to both pseudo-first order and pseudo-second order, as indicated by high R2 values. Moreover, the Freundlich isotherm model demonstrated a good fit to the experimental data. The result also revealed that NACO has a maximum capacity for adsorption (qmax) of 132 mg g-1. Thermodynamic studies showed that fluoride adsorption onto NACO was feasible and spontaneous. Additionally, NACO exhibited excellent regeneration capabilities, as evidenced by a remarkable 75.71% removal efficiency at the sixth regeneration stage, indicating sustained adsorption capacity even after multiple regeneration cycles. Overall, NACOs displayed promising characteristics for fluoride adsorption, making them potential candidates for efficient and sustainable water treatment technologies.

Kinetics, isotherm, mechanism, and recyclability of novel nano-sized Ce4+-doped Ni-Al layered double hydroxide for defluoridation of aqueous solutions.

Excessive fluoride removal from aqueous solutions is of utmost importance as it has an adverse impact on human health. This study investigates the defluoridation efficiency of a novel nano-sized Ce+4-doped Ni/Al layered double hydroxide (Ni-Al-Ce LDH) for aqueous solutions. The synthesized Ni-Al-Ce LDH exhibited a well-defined nanoscale plate-like morphology and a high surface area with an average size of 11.51 nm, which contributed to its enhanced fluoride adsorption capacity. XRD, SEM, HRTEM, and BET studies confirmed these characteristics. XPS analysis confirmed the presence of Ce4+ ions within the Ni-Al LDH. The experimental results indicated that the process of defluoridation followed a pseudo-second-order model of kinetics, suggesting a chemisorption mechanism. The fluoride adsorption isotherms demonstrated well fits to the Freundlich, Langmuir, and Jovanovic models, indicating both monolayer and multilayer fluoride adsorption on the Ce-doped Ni-Al LDH. The maximum adsorption capacity was found to be 238.27 mg/g (Langmuir) and 130.73 mg/g (Jovanovic) at pH 6.0 and 25 °C. The proposed mechanisms for fluoride adsorption on the LDH include ion exchange, surface complexation, hydrogen bonding, and ligand exchange. The Ni-Al-Ce LDH nanomaterial exhibited good recyclability, maintaining 71% of the fluoride adsorption efficiency even after four consecutive cycles. This study highlights the significant role of Ce doping in improving the performance of Ni-Al LDH as a defluoridation adsorbent.

Controllable Doping of Mn into Ni0.075-xMnxAl0.025(OH)2(CO3)0.0125·yH2O for Efficient Adsorption of Fluoride Ions.

Here, the structural, optical, and adsorptive behaviors of Ni0.075-xMnxAl0.025(OH)2(CO3)0.0125·yH2O (Ni-Mn/Al) layered double hydroxides (LDHs) are investigated to capture fluoride from aqueous media. The 2D mesoporous plate-like Ni-Mn/Al LDHs are successfully prepared via a co-precipitation method. The molar ratio of divalent to trivalent cations is maintained at 3:1 and the pH at 10. The X-ray diffraction (XRD) results confirm that the samples consist of pure LDH phases with a basal spacing of 7.66 to 7.72 Å, corresponding to the (003) planes at 2θ of 11.47o and the average crystallite sizes of 4.13 to 8.67 nm. The plate-like Mn-doped Ni-Al LDH consists of many superimposed nanosheets with a size of 9.99 nm. Energy-dispersive X-ray and X-ray photoelectron spectroscopies confirm the incorporation of Mn2+ into the Ni-Al LDH. UV-vis diffuse reflectance spectroscopy results indicate that incorporating Mn2+ into LDH enhances its interaction with light. The experimental data from the batch fluoride adsorption studies are subjected to kinetic models such as pseudo-first order and pseudo-second order. The kinetics of fluoride retention on Ni-Mn/Al LDH obey the pseudo-second-order model. The Temkin equation well describes the equilibrium adsorption of fluoride. The results from the thermodynamic studies also indicate that fluoride adsorption is exothermic and spontaneous.

Confinement Accelerates Water Oxidation Catalysis: Evidence from In Situ Studies.

Basic insight into the structural evolution of electrocatalysts under operating conditions is of substantial importance for designing water oxidation catalysts. The first-row transition metal-based catalysts present state-of-the-art oxygen evolution reaction (OER) performance under alkaline conditions. Apparently, confinement has become an exciting strategy to boost the performance of these catalysts. The van der Waals (vdW) gaps of transition metal dichalcogenides are acknowledged to serve as a suitable platform to confine the first-row transition metal catalysts. This study focuses on confining Ni(OH)2 nanoparticle in the vdW gaps of 2D exfoliated SnS2 (Ex-SnS2 ) to accelerate water oxidation and to guarantee long term durability in alkaline solutions. The trends in oxidation states of Ni are probed during OER catalysis. The in situ studies confirm that the confined system produces a favorable environment for accelerated oxygen gas evolution, whereas the un-confined system proceeds with a relatively slower kinetics. The outstanding OER activity and excellent stability, with an overpotential of 300 mV at 100 mA cm-2 and Tafel slope as low as 93 mV dec-1 results from the confinement effect. This study sheds light on the OER mechanism of confined catalysis and opens up a way to develop efficient and low-cost electrocatalysts.

Facile Electron Transfer in Atomically Coupled Heterointerface for Accelerated Oxygen Evolution.

An efficient and cost-effective approach for the development of advanced catalysts has been regarded as a sustainable way for green energy utilization. The general guideline to design active and efficient catalysts for oxygen evolution reaction (OER) is to achieve high intrinsic activity and the exposure of more density of the interfacial active sites. The heterointerface is one of the most attractive ways that plays a key role in electrochemical water oxidation. Herein, atomically cluster-based heterointerface catalysts with strong metal support interaction (SMSI) between WMn2 O4 and TiO2 are designed. In this case, the WMn2 O4 nanoflakes are uniformly decorated by TiO2 particles to create electronic effect on WMn2 O4 nanoflakes as confirmed by X-ray absorption near edge fine structure. As a result, the engineered heterointerface requires an OER onset overpotential as low as 200 mV versus reversible hydrogen electrode, which is stable for up to 30 h of test. The outstanding performance and long-term durability are due to SMSI, the exposure of interfacial active sites, and accelerated reaction kinetics. To confirm the synergistic interaction between WMn2 O4 and TiO2 , and the modification of the electronic structure, high-resolution transmission electron microscopy (HR-TEM), X-ray photoemission spectroscopy (XPS), and X-ray absorption spectroscopy (XAS) are used.

Predictors of willingness to accept COVID-19 vaccine among adults.

Background: Vaccines are an effective and ultimate solution that can decrease the burden of coronavirus disease 2019 worldwide. However, poor knowledge and unwillingness to accept this vaccine are key barriers to manage the COVID-19 pandemic in different countries including Ethiopia. Control of the pandemic will depend on the acceptance of coronavirus disease vaccine. However, there is a paucity of evidence on coronavirus disease vaccine acceptance in the study area. The current study was aimed to assess willingness to accept the COVID-19 vaccine and associated factors among adult clients attending Bule Hora University Teaching Hospital, West Guji Zone, southern Ethiopia. Methods: An institution-based cross-sectional study was conducted among 385 study participants selected by a systematic random sampling technique. Data was collected through observation and structured questionnaires from April 10 to May 30, 2022. The collected data was cleaned and entered into EpiData 3.1 software before being exported to SPSS 25 statistical software for analysis. Bi-variable and multi-variable binary logistic regression model was used to identify the predictors of COVID-19 vaccine acceptance. The strength of association was measured using AOR with 95% confidence interval and significance was declared at p- value < 0.05. Result: Magnitude of willingness to accept coronavirus disease-19 vaccine was 67.5% (95%Cl: 63-72). Good knowledge [AOR = 2.07, (1.17-3.64)], history of chronic disease [AOR = 2.59, (1.4-4.78)], being a government employee [AOR = 2.35 (1.1-5)], having a favorable attitude [AOR = 14.15 (5.25-37.46)], and good adherence [AOR = 1.74 (1.02-2.97)] were factors that significantly associated with willingness to accept the coronavirus disease 2019 vaccine. Conclusion: Magnitude of willingness to accept the COVID-19 vaccine was considerable and needs to be improved. Knowledge, attitude, chronic illness, adherence, and being a government employee were factors that associated with willingness to accept the vaccine. Community awareness, advocacy, social mobilization and health education should be given at different levels.

Hierarchically heterostructured metal hydr(oxy)oxides for efficient overall water splitting.

The design of highly efficient electrocatalysts containing non-precious metals is crucial for promoting overall water splitting in alkaline media. In particular, Janus catalysts simultaneously facilitating the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) are desirable. Herein, we fabricated a unique hierarchical heterostructure via growing Ni4W6O21(OH)2·4H2O (denoted as Ni-W-O) nanosheets on NiMoO4 rods, which was indispensable for regulating the morphology of the Ni-W-O structure. This heterostructure of Ni-W-O/NiMoO4 could be utilized as an electrocatalyst to realize superior activity for overall water splitting in 1.0 M KOH. It substantially promoted overall water splitting with 1.6 V at 30 mA cm-2, outperforming numerous bifunctional electrocatalysts under the same conditions. Notably, the remarkable stability for continuously splitting water endowed this hierarchical heterostructure with potential applications on a large scale. This work emphasizes the effectively controlled growth of heterostructured non-noble-metal catalysts for energy-conversion reaction.

Ultrathin Magnetic 2D Single-Crystal CrSe.

2D magnetic materials have generated an enormous amount of attention due to their unique 2D-limited magnetism and their potential applications in spintronic devices. Recently, most of this research has focused on 2D van der Waals layered magnetic materials exfoliated from the bulk with random size and thicknesses. Controllable growth of these materials is still a great challenge. In contrast, 2D nonlayered magnetic materials have rarely been investigated, not especially regarding their preparation. Crn X (X = S, Se and Te; 0 < n < 1), a class of nonlayered transition metal dichalcogenides, has rapidly attracted extensive attention due to its abundance of structural compounds and unique magnetic properties. Herein, the controlled synthesis of ultrathin CrSe crystals, with grain size reaching the sub-millimeter scale, on mica substrates via an ambient pressure chemical vapor deposition (CVD) method is demonstrated. A continuous CrSe film can also be achieved via precise control of the key growth parameters. Importantly, the CVD-grown 2D CrSe crystals possess obvious ferromagnetic properties at temperatures below 280 K, which has not been observed experimentally before. This work broadens the scope of the CVD growth of 2D magnetic materials and highlights their significant application possibilities in spintronics.

Heterostructures Based on 2D Materials: A Versatile Platform for Efficient Catalysis.

The unique structural and electronic properties of 2D materials, including the metal and metal-free ones, have prompted intense exploration in the search for new catalysts. The construction of different heterostructures based on 2D materials offers great opportunities for boosting the catalytic activity in electo(photo)chemical reactions. Particularly, the merits resulting from the synergism of the constituent components and the fascinating properties at the interface are tremendously interesting. This scenario has now become the state-of-the-art point in the development of active catalysts for assisting energy conversion reactions including water splitting and CO2 reduction. Here, starting from the theoretical background of the fundamental concepts, the progressive developments in the design and applications of heterostructures based on 2D materials are traced. Furthermore, a personal perspective on the exploration of 2D heterostructures for further potential application in catalysis is offered.

Edge-Epitaxial Growth of 2D NbS2 -WS2 Lateral Metal-Semiconductor Heterostructures.

2D metal-semiconductor heterostructures based on transition metal dichalcogenides (TMDs) are considered as intriguing building blocks for various fields, such as contact engineering and high-frequency devices. Although, a series of p-n junctions utilizing semiconducting TMDs have been constructed hitherto, the realization of such a scheme using 2D metallic analogs has not been reported. Here, the synthesis of uniform monolayer metallic NbS2 on sapphire substrate with domain size reaching to a millimeter scale via a facile chemical vapor deposition (CVD) route is demonstrated. More importantly, the epitaxial growth of NbS2 -WS2 lateral metal-semiconductor heterostructures via a "two-step" CVD method is realized. Both the lateral and vertical NbS2 -WS2 heterostructures are achieved here. Transmission electron microscopy studies reveal a clear chemical modulation with distinct interfaces. Raman and photoluminescence maps confirm the precisely controlled spatial modulation of the as-grown NbS2 -WS2 heterostructures. The existence of the NbS2 -WS2 heterostructures is further manifested by electrical transport measurements. This work broadens the horizon of the in situ synthesis of TMD-based heterostructures and enlightens the possibility of applications based on 2D metal-semiconductor heterostructures.

2D library beyond graphene and transition metal dichalcogenides: a focus on photodetection.

Two-dimensional layered materials (2DLMs) have attracted a tremendous amount of attention as photodetectors due to their fascinating features, including high potentials in new-generation electronic devices, wide coverage of bandgaps, ability to construct van der Waals heterostructures, extraordinary light-mass interaction, strong mechanical flexibility, and the capability of enabling synthesis of 2D nonlayered materials. Until now, most attention has been focused on the well-known graphene and transition metal dichalcogenides (TMDs). However, a growing number of functional materials (more than 5619) with novel optoelectronic and electronic properties are being re-discovered, thereby widening the horizon of 2D libraries. In addition to showing common features of 2DLMs, these new 2D members may bring new opportunities to their well-known analogues, like wider bandgap coverage, direct bandgaps independence with thickness, higher mechanical flexibility, and new photoresponse phenomena. The impressive results communicated so far testify that they have shown high potentials with photodetections covering THz, IR, visible, and UV ranges with comparable or even higher performances than well-known TMDs. Here, we give a comprehensive review on the state-of-the-art photodetections of two-dimensional materials beyond graphene and TMDs. The review is organized as follows: fundamentals of photoresponse first are discussed, followed by detailed photodetections of new 2D members including both layered and non-layered ones. After that, photodiodes and hybrid structures based on these new 2D materials are summarized. Then, the integration of these 2D materials with flexible substrates is reviewed. Finally, we conclude with the current research status of this area and offer our perspectives on future developments. We hope that, through reading this manuscript, readers will quickly have a comprehensive view on this research area.

High-Yield Production of Monolayer FePS3 Quantum Sheets via Chemical Exfoliation for Efficient Photocatalytic Hydrogen Evolution.

2D layered transition metal phosphorus trichalcogenides (MPX3 ) possess higher in-plane stiffness and lower cleavage energies than graphite. This allows them to be exfoliated down to the atomic thickness. However, a rational exfoliation route has to be sought to achieve surface-active and uniform individual layers. Herein, monolayered FePS3 quantum sheets (QSs) are systematically obtained, whose diameters range from 4-8 nm, through exfoliation of the bulk in hydrazine solution. These QSs exhibit a widened bandgap of 2.18 eV as compared to the bulk (1.60 eV) FePS3 . Benefitting from the monolayer feature, FePS3 QSs demonstrate a substantially accelerated photocatalytic H2 generation rate, which is up to three times higher than the bulk counterpart. This study presents a facile way, for the first time, of producing uniform monolayer FePS3 QSs and opens up new avenues for designing other low-dimensional materials based on MPX3 .

Nonvolatile infrared memory in MoS2/PbS van der Waals heterostructures.

Optoelectronic devices for information storage and processing are at the heart of optical communication technology due to their significant applications in optical recording and computing. The infrared radiations of 850, 1310, and 1550 nm with low energy dissipation in optical fibers are typical optical communication wavebands. However, optoelectronic devices that could convert and store the infrared data into electrical signals, thereby enabling optical data communications, have not yet been realized. We report an infrared memory device using MoS2/PbS van der Waals heterostructures, in which the infrared pulse intrigues a persistent resistance state that hardly relaxes within our experimental time scales (more than 104 s). The device fully retrieves the memory state even after powering off for 3 hours, indicating its potential for nonvolatile storage devices. Furthermore, the device presents a reconfigurable switch of 2000 stable cycles. Supported by a theoretical model with quantitative analysis, we propose that the optical memory and the electrical erasing phenomenon, respectively, originate from the localization of infrared-induced holes in PbS and gate voltage pulse-enhanced tunneling of electrons from MoS2 to PbS. The demonstrated MoS2 heterostructure-based memory devices open up an exciting field for optoelectronic infrared memory and programmable logic devices.

Efficient Photocatalytic Hydrogen Evolution via Band Alignment Tailoring: Controllable Transition from Type-I to Type-II.

Considering the sizable band gap and wide spectrum response of tin disulfide (SnS2 ), ultrathin SnS2 nanosheets are utilized as solar-driven photocatalyst for water splitting. Designing a heterostructure based on SnS2 is believed to boost their catalytic performance. Unfortunately, it has been quite challenging to explore a material with suitable band alignment using SnS2 nanomaterials for photocatalytic hydrogen generation. Herein, a new strategy is used to systematically tailor the band alignment in SnS2 based heterostructure to realize efficient H2 production under sunlight. A Type-I to Type-II band alignment transition is demonstrated via introducing an interlayer of Ce2 S3 , a potential photocatalyst for H2 evolution, between SnS2 and CeO2 . Subsequently, this heterostructure demonstrates tunability in light absorption, charge transfer kinetics, and material stability. The optimized heterostructure (SnS2 -Ce2 S3 -CeO2 ) exhibits an incredibly strong light absorption ranging from deep UV to infrared light. Significantly, it also shows superior hydrogen generation with the rate of 240 µmol g-1 h-1 under the illumination of simulated sunlight with a very good stability.

Ultrathin Single-Crystalline CdTe Nanosheets Realized via Van der Waals Epitaxy.

Due to the novel physical properties, high flexibility, and strong compatibility with Si-based electronic techniques, 2D nonlayered structures have become one of the hottest topics. However, the realization of 2D structures from nonlayered crystals is still a critical challenge, which requires breaking the bulk crystal symmetry and guaranteeing the highly anisotropic crystal growth. CdTe owns a typical wurtzite crystal structure, which hinders the 2D anisotropic growth of hexagonal-symmetry CdTe. Here, for the first time, the 2D anisotropic growth of ultrathin nonlayered CdTe as thin as 4.8 nm via an effective van der Waals epitaxy method is demonstrated. The anisotropic ratio exceeds 103 . Highly crystalline nanosheets with uniform thickness and large lateral dimensions are obtained. The in situ fabricated ultrathin 2D CdTe photodetector shows ultralow dark current (≈100 fA), as well as high detectivity, stable photoswitching, and fast photoresponse speed (τrising = 18.4 ms, τdecay = 14.7 ms). Besides, benefitting from its 2D planar geometry, CdTe nanosheet exhibits high compatibility with flexible substrates and traditional microfabrication techniques, indicating its significant potential in the applications of flexible electronic and optoelectronic devices.

Dendritic growth of monolayer ternary WS2(1-x)Se2x flakes for enhanced hydrogen evolution reaction.

Two-dimensional transition-metal dichalcogenides (TMDs) have attracted much research interest in the hydrogen evolution reaction (HER) due to their superior electrocatalytic properties. Beyond binary TMDs, ternary TMD alloys, as electrocatalysts, were also gradually acknowledged for their remarkable efficiency in HER. Herein, we successfully synthesized monolayer dendritic ternary WS2(1-x)Se2x flakes possessing abundant active edge sites on a single crystalline SrTiO3 (STO(100)). And the obtained dendritic WS2(1-x)Se2x flakes could be transferred intact to arbitrary substrates, for example, SiO2/Si and Au foils. Intriguingly, the transferred dendritic WS2(1-x)Se2x flakes on Au foil demonstrate a significant HER performance, reflected by a rather lower Tafel slope of ∼69 mV dec-1 and a much higher exchange current density of ∼50.1 µA cm-2 outshining other CVD-grown two-dimensional TMD flakes. Furthermore, our new material shows excellent stability in electro-catalyzing the HER, suggestive of its robustness for being an excellent electrocatalyst. We believe that this work broadens the outlook for the synthesis of two-dimensional TMDs toward satisfying the applications in electrocatalysis.

An efficient ternary CoP2xSe2(1-x) nanowire array for overall water splitting.

Developing earth-abundant and efficient bifunctional electrocatalysts for realizing the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) under alkaline conditions is an intriguing challenge. Here, ternary necklace-like CoP2xSe2(1-x) nanowire arrays are synthesized via simultaneously phosphorizing and selenizing Co(OH)2 nanowires. Owing to the substitution of the P atom in the ternary system, the optimal electronic structure of CoP2xSe2(1-x) can be obtained and the stability can also be enhanced for hydrogen evolution. Thus, the ternary CoP2xSe2(1-x) NWs are highly active for electrochemical hydrogen evolution in both acidic and alkaline media, achieving a current density of 10 mA cm -2 at overpotentials of 70 mV and 98 mV, respectively. To realize the overall water splitting, we further performed the experiment using the CoP2xSe2(1-x) NWs as a cathode and Co(OH)2 NWs as an anode, which requires a cell voltage of 1.65 V to afford a water splitting current density of 10 mA cm -2 in strong alkaline media (1.0 M KOH).

Efficient Catalysis of Hydrogen Evolution Reaction from WS2(1-x) P2x Nanoribbons.

The rational design of Earth abundant electrocatalysts for efficiently catalyzing hydrogen evolution reaction (HER) is believed to lead to the generation of carbon neutral energy carrier. Owing to their fascinating chemical and physical properties, transition metal dichalcogenides (TMDs) are widely studied for this purpose. Of particular note is that doping by foreign atom can bring the advent of electronic perturbation, which affects the intrinsic catalytic property. Hence, through doping, the catalytic activity of such materials could be boosted. A rational synthesis approach that enables phosphorous atom to be doped into WS2 without inducing phase impurity to form WS2(1-x) P2x nanoribbon (NRs) is herein reported. It is found that the WS2(1-x) P2x NRs exhibit considerably enhanced HER performance, requiring only -98 mV versus reversible hydrogen electrode to achieve a current density of -10 mA cm-2 . Such a high performance can be attributed to the ease of H-atom adsorption and desorption due to intrinsically tuned WS2 , and partial formation of NRs, a morphology wherein the exposure of active edges is more pronounced. This finding can provide a fertile ground for subsequent works aiming at tuning intrinsic catalytic activity of TMDs.

Synthesis, properties and applications of 2D layered MIIIXVI (M = Ga, In; X = S, Se, Te) materials.

Group III-VI compounds MIIIXVI (M = Ga, In; X = S, Se, Te) are one class of important 2D layered materials and are currently attracting increasing interest due to their unique electronic and optoelectronic properties and their great potential applications in various other fields. Similar to 2D layered transition metal dichalcogenides (TMDs), MIIIXVI also have the significant merits of ultrathin thickness, ultrahigh surface-to-volume ratio, and high compatibility with flexible devices. More impressively, in contrast with TMDCs, MIIIXVI demonstrate many superior properties, such as direct band gap electronic structure, high carrier mobility, rare p-type electronic behaviors, high charge density, and so on. These unique characteristics cause high-performance device applications in electronics, optoelectronics, and optics. In this review, we aim to provide a summary of the state-of-the-art of research activities in 2D layered MIIIXVI materials. The scope of the review covers the synthesis and properties of 2D layered MIIIXVI materials and their van der Waals heterostructures. We especially focus on the applications in electronics and optoelectronics. Moreover, the review concludes with some perspectives on future developments in this field.