Due to its remarkable impermeability to gases, vapours, and liquids, graphene (G) is used as an excellent coating for metal protection. However, due to its high conductivity, recent studies have reported that G fails to prevent metal corrosion under long-term air exposure. Here, we obtained B-doped graphene (BG) and N-doped graphene (NG) with electron donating/withdrawing elements and then used them to modify the waterborne polyurethane (PU) resin. Our work reveals that embedding BG into a PU matrix greatly improves anticorrosion performance. The results revealed that graphene (BG) doped with electron accepting dopants exhibits a long-term corrosion resistance based on the suppression of galvanic corrosion, while graphene (NG) doped with electron donating dopants exhibits corrosion promotion due to its enhanced conductivity. Typically, the impedance modulus of BG/PU at Z_f=0.01Hz was up to 10⁸ Ω cm², increasing by approximately three orders of magnitude compared to that of neat PU, G/PU, and NG/PU (∼10⁶ Ω cm²) after immersion for 240 h in 3.5 wt% NaCl_(aq). The present investigation provides important future implications for the fabrication of graphene-based anticorrosive coatings with excellent durability.

Due to the strong ‘lip–lip’ interactions between neighboring nanosheets layers, the scalable exfoliated fabrication of few-layer-thick boron nitride nanosheets (BNNSs) from the bulk hexagonal boron nitride (h-BN) is more challenging than these graphene nanosheets. In this work, few-layer (generally less than 10 layers) BNNSs were efficiently synthesized through a simple ball milling technique with the 2-furoic acid (FA) as a modifier. The BNNSs as-prepared with a average thickness of about 2.0 nm and an extremely high production yield (~98%) as well as unprecedentedly high dispersed concentration (~35 mg ml ⁻¹ ) in water. The stable aqueous dispersions of BNNSs can be directly used to fabricate ultralight aerogels with a low density of 2.0 mg cm ⁻³ and thermally conductive film with a highly thermal conductivity of 25.2 W m ⁻¹ K ⁻¹ . This approach provided us with an environmentally friendly agent with high efficiency for few-layer BNNSs synthesis and demonstrated promising applications for ultralight aerogels and heat dissipation in electronic components.

The unique properties of graphene are highly desired for printing electronics, coatings, energy storage, separation membranes, biomedicine, and composites. However, the high efficiency exfoliation of graphene into single- or few-layered nanoplates remains a grand challenge and becomes the bottleneck in essential studies and applications of graphene. Here, we report a scalable and green method to exfoliate graphene nanoplatelets (GNPs) from nature graphite in pure water without using any chemicals or surfactants. The essence of this strategy lies in the facile liquid exfoliation route with the assistance of vapor pretreatment for the preparation of edge hydroxylated graphene. The produced graphene consisted primarily of fewer than ten atomic layers. Such the water soluble graphene can be stored in the form of dispersion (~0.55 g L⁻¹) or filter cake for more than 6 months without the risk of re-stacking. This method paves the way for the environmentally friendly and cost-effective production of graphene-based materials.