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The recombination of charge carriers arriving from the random charge movement in semiconductor photocatalysts greatly limits the practical application of solar-driven H2 evolution. The design of photocatalytic systems with spatially oriented charge-transfer is a promising route to achieve high charge-separation efficiency for photocatalysts. Herein, novel sea-urchin-like ReS2 nanosheet/TiO2 nanoparticle heterojunctions (SURTHs) are constructed. The unique sea-urchin-like structure endows the ReS2 cocatalyst with an unusual charge edge-collection effect, which leads to a significant acceleration of charge separation and transfer, as evidenced by the well-designed selective photodeposition of Pt quantum dots in SURTHs. The markedly improved charge transfer capacity contributes to a high photocatalytic H2 evolution rate of 3.71 mmol h−1 g−1 for SURTHs (an apparent quantum efficiency (AQE) of 16.09%), up to 231.9 times by contrast with that of P25 TiO2. This work would provide a new platform for designing the high-efficiency cocatalyst/photocatalyst system with excellent charge transfer capacity. This work was funded by the China Postdoctoral Science Foundation (pre-station, No. 2019TQ0050), Applied Basic Research Program of Sichuan Province (No. 2020YJ0068), the China Postdoctoral Science Foundation (No. 2020M673186), National Natural Science Foundation of China (No. 22002014), the Applied Basic Research Program of Sichuan Province (No. 2020ZYD014). Thanks for the technical help from Sichuan Province Key Laboratory of Display Science and Technology, State Key Laboratory of Electronic Thin Films and Integrated Devices. Dr. Xiao Luo acknowledges financial support from the National Natural Science Foundation of China (No. 21903084) and Applied Basic Research Program of Sichuan Province (No. 2021YJ0408). Dr. Qing Liu acknowledges financial support from the National Natural Science Foundation of China (No. 52002051) and the Fundamental Research Funds for the Central Universities, SCUT (No. ZYGX2020J009).

2D metal thiophosphate SnP2S6 was discovered as a new dielectric layer with a high dielectric constant (≈23), realizing a low subthreshold slope down to 69.4 mV dec−1 in the field effect transistor device geometry.

The last decade has witnessed the significant progress of physical fundamental research and great success of practical application in two-dimensional (2D) van der Waals (vdW) materials since the discovery of graphene in 2004. To date, vdW materials is still a vibrant and fast-expanding field, where tremendous reports have been published covering topics from cutting-edge quantum technology to urgent green energy, and so on. Here, we briefly review the emerging hot physical topics and intriguing materials, such as 2D topological materials, piezoelectric materials, ferroelectric materials, magnetic materials and twistronic heterostructures. Then, various vdW material synthetic strategies are discussed in detail, concerning the growth mechanisms, preparation conditions and typical examples. Finally, prospects and further opportunities in the booming field of 2D materials are addressed. Ministry of Education (MOE) National Research Foundation (NRF) Published version This work was supported by the National Research Foundation– Competitive Research Program (NRF-CRP21-2019-0007 and NRF-CRP21-2018-0007); the Singapore Ministry of Education Tier 3 Programme ‘Geometrical Quantum Materials’ (MOE2018-T3-1-002), AcRF Tier 2 (2016-T2-2-153) and AcRF Tier 1 (RG7/18 and RG161/19); the National Key R&D Program of China (2020YFA0309200), the National Natural Science Foundation of China (62074025); the Applied Basic Research Program of Sichuan Province (2020ZYD014 and 2021JDGD0026); the Sichuan Province Key Laboratory of Display Science and Technology and the Postdoctoral Innovative Talent Supporting Program (BX20190060).

In this work, an emulsion method is applied to fill two-dimensional MXenes into polyurethanes (PUs). It shows that the addition of 0.5 wt% MXenes increase the yield stress, tensile strength and hardness of PUs by ∼70%, ∼20% and ∼13%, respectively. The mechanical enhancement is associated with the increase of hardness and reduction of water absorption. Morphologic study shows that a good dispersion of MXenes is achieved, in which ball milling is a key step for ensuring a stability of MXene-filled PU emulsions. Furthermore, FTIR analysis reveals the strong interaction between MXenes and PUs at molecular level.

Since the discovery of surface enhanced Raman scattering (SERS), the choice of SERS-active materials has been limited mainly to metals, especially gold and silver in the visible spectrum. Although non-metals can also be SERS-active by forming nanostructures or composite structures with SERS-active materials, the mechanism behind it is still unclear and there is no perfect technique to study it. In this work, by constructing a SERS structure on a flexible polydimethylsiloxane film, we provide a way to study the effect of non-metallic nanostructures on Raman enhancement by attaching the above film onto flat and nanostructured surfaces. It was found that a nanoporous silicon surface contributes to an additional, up to five times, Raman enhancement. The pore depth and pore size also influence the observed Raman enhancement. These findings will help us not only to understand the mechanism of SERS involving non-metallic nanostructures, but also to design more efficient SERS structures for various applications.

Artificial synaptic devices are the essential components of neuromorphic computing systems, which are capable of parallel information storage and processing with high area and energy efficiencies, showing high promise in future storage systems and in-memory computing. Analogous to the diffusion of neurotransmitter between neurons, ion-migration-based synaptic devices are becoming promising for mimicking synaptic plasticity, though the precise control of ion migration is still challenging. Due to the unique 2D nature and highly anisotropic ionic transport properties, van der Waals layered materials are attractive for synaptic device applications. Here, utilizing the high conductivity from Cu+ -ion migration, a two-terminal artificial synaptic device based on layered copper indium thiophosphate is studied. By controlling the migration of Cu+ ions with an electric field, the device mimics various neuroplasticity functions, such as short-term plasticity, long-term plasticity, and spike-time-dependent plasticity. The Pavlovian conditioning and activity-dependent synaptic plasticity involved neural functions are also successfully emulated. These results show a promising opportunity to modulate ion migration in 2D materials through field-driven ionic processes, making the demonstrated synaptic device an intriguing candidate for future low-power neuromorphic applications. Ministry of Education (MOE) National Research Foundation (NRF) Submitted/Accepted version J.C. (Jiangang), C.Z., and G.C. contributed equally to this work. Z.L. acknowledges the support from National Research Foundation Singapore programme NRF-CRP21-2018-0007 and NRF-CRP22-2019-0007, Singapore Ministry of Education via AcRF Tier 3 Programme “Geometrical Quantum Materials” (MOE2018-T3-1-002), AcRF Tier 2 (MOE2016-T2-1-131), and AcRF Tier 1 RG4/17 and RG7/18. G.C. acknowledges the support from China Postdoctoral Science Foundation (2019M663463). P.M. acknowledges the support from Postdoctral Innovatiove Talent Supporting Program (BX20190060). F.L. acknowledges the support from the National Natural Science Foundation of China (62074025) and the National Key Research & Development Program (2020YFA0309200), the Applied Basic Research Program of Sichuan Province (2020ZYD014, 2021JDGD0026), and the Sichuan Province Key Laboratory of Display Science and Technology.

The composite of waterborne poly(urethane-acrylate) (WPUA) and antimony doped tin (ATO) was a promising thermal insulation coatings for energy-saving glass. This work demonstrated a sol-gel approach for fabricating WPUA/ATO composites with improved dispersion of ATO nanoparticles. This approach was mainly concerned with the polymerization of C C bonds pre-attached to WPU and ATO nanoparticles. Surface modification was key for achieving a good dispersion of ATO nanoparticles. With UV-assisted initiation, the conversion of C C bonds reached ∼93% in 40 s. The comparison study demonstrated that resulting ATO-filled WPUA coatings outperformed those made by physical blending method over the mechanical and optical properties owing to a good dispersion of ATO nanoparticles. In particular, the coatings filled with 3 wt% ATO reduced the temperature of a designed “room” by ∼10 °C than un-filled counterparts, but merely blocked ∼16% visible light.

Ti3C2Tx, a typical MXene, was incorporated into alumina (Al2O3) to obtain ceramic composites and its effects on their microstructures and mechanical properties were investigated. The investigation results showed that MXene was well-dispersed in the ceramic matrix and significantly reinforced alumina. At 2 wt% Ti3C2Tx, the fracture toughness, bending strength and hardness was improved by ~300%, ~150%, ~300%, respectively. The toughening mechanisms associated with crack deflection induced by Ti3C2Tx were discussed.

MXene is an emerging class of 2D materials exfoliated from ternary carbide and nitride ceramics. The exfoliation process, which is an acid etching approach, functionalizes the MXene surface with -OH, -O and -F groups. These functional groups offer significant opportunities for tuning the colloidal properties of the MXene nanoblocks; importantly, this tunability points the way towards a facile route for assembling these nanoblocks into 3D architectures that are in demand for many applications. This route, presented for the first time here, uses water/oil interfaces for assembling Ti

MXene is an emerging class of 2D materials exfoliated from ternary carbide and nitride ceramics. The exfoliation process, which is an acid etching approach, functionalizes the MXene surface with –OH, –O and –F groups. These functional groups offer significant opportunities for tuning the colloidal properties of the MXene nanoblocks; importantly, this tunability points the way towards a facile route for assembling these nanoblocks into 3D architectures that are in demand for many applications. This route, presented for the first time here, uses water/oil interfaces for assembling Ti3C2-MXene in 3D architectures. It shows that cetyl trimethylammonium bromide (CTAB) can be used to tune the hydrophilic–hydrophobic balance of Ti3C2-MXene via the interaction of positively charged –N(CH3)3 and –O groups on the MXene surface. Crucially, it is found that this interaction can be controlled via the hydrogen ion concentration in the aqueous phase. Stable oil-in-water emulsions are the only product when the aqueous phase is neutral or basic. This understanding led us to fabricate a high internal phase Pickering emulsion with more than 70 vol% oil droplets and also a solid porous monolith based on this emulsion template.

This report demonstrated the first study on the use of a new 2D nanomaterial (Mxene) for enhancing membrane performance of intermediate temperature (>100 °C) polymer electrolyte membrane fuel cells (ITPEMFCs). In this study, a typical Ti3C2T x -MXene was synthesized and incorporated into polybenzimidazole (PBI)-based membranes by using a solution blending method. The composite membrane with 3 wt% Ti3C2T x -MXene showed the proton conductivity more than 2 times higher than that of pristine PBI membrane at the temperature range of 100 °C-170 °C, and led to substantial increase in maximum power density of fuel cells by ∼30% tested at 150 °C. The addition of Ti3C2T x -MXene also improved the mechanical properties and thermal stability of PBI membranes. At 3 wt% Ti3C2T x -MXene, the elongation at break of phosphoric acid doped PBI remained unaffected at 150 °C, and the tensile strength and Young's modulus was increased by ∼150% and ∼160%, respectively. This study pointed out promising application of MXene in ITPEMFCs.