2D Nanomaterials, with unique structural and electronic features, have shown enormous potential toward photocatalysis fields. However, the photocatalytic behavior of pristine 2D photocatalysts are still unsatisfactory, and far below the requirements of practical applications. In this regard, surface defect engineering can serve as an effective means to tune photoelectric parameters of 2D photocatalysts through tailoring the local surface microstructure, electronic structure, and carrier concentration. In this review, recent progress in the design of surface defects with the classified anion vacancy, cation vacancy, vacancy associates, pits, distortions, and disorder on 2D photocatalysts to boost the photocatalytic performance is summarized. The strategies for controlling defects formation and technique to distinguish various surface defects are presented. The crucial roles of surface defects for photocatalysis performance optimization are proposed and advancement of defective 2D photocatalysts toward versatile applications such as water oxidation, hydrogen production, CO 2 reduction, nitrogen fixation, organic synthesis, and pollutants removal are discussed. Surface defect modulated 2D photocatalysts thus represent a powerful configuration for further development toward photocatalysis.

The controlled exfoliation of hexagonal boron nitride (h-BN) into single- or few-layered nanosheets remains a grand challenge and becomes the bottleneck to essential studies and applications of h-BN. Here, we present an efficient strategy for the scalable synthesis of few-layered h-BN nanosheets (BNNS) using a novel gas exfoliation of bulk h-BN in liquid N2 (L-N2 ). The essence of this strategy lies in the combination of a high temperature triggered expansion of bulk h-BN and the cryogenic L-N2 gasification to exfoliate the h-BN. The produced BNNS after ten cycles (BNNS-10) consisted primarily of fewer than five atomic layers with a high mass yield of 16-20 %. N2 sorption and desorption isotherms show that the BNNS-10 exhibited a much higher specific surface area of 278 m(2)  g(-1) than that of bulk BN (10 m(2)  g(-1) ). Through the investigation of the exfoliated intermediates combined with a theoretical calculation, we found that the huge temperature variation initiates the expansion and curling of the bulk h-BN. Subseqently, the L-N2 penetrates into the interlayers of h-BN along the curling edge, followed by an immediate drastic gasification of L-N2 , further peeling off h-BN. This novel gas exfoliation of high surface area BNNS not only opens up potential opportunities for wide applications, but also can be extended to produce other layered materials in high yields.

One-pot extraction combined with the metal-free photochemical aerobic oxidative deep-desulfurization of fuels in deep eutectic solvents was successfully achieved.

Metal-free graphene-like boron nitride (BN) samples were prepared and applied as adsorbents for removing dibenzothiophene (DBT) in model oil. The results showed that the graphene-like BN exhibited a remarkable adsorption performance. The adsorption capacity could reach 28.17 mg S g −1 adsorbent. Experiments have been carried out to investigate the effects of the number of BN layers, DBT initial concentration, and temperature on DBT adsorption. Langmuir and Freundlich isotherm models were used to study the adsorption of DBT on BN. The kinetic results showed that the adsorption process was best described by the pseudosecond-order kinetic model. Density functional theory (DFT) was employed to prove that the Lewis acidbase interaction plays an important role in removing DBT over graphene-like BN.

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Hexagonal boron nitride nanosheets (h-BNNs) with rather high specific surface area (SSA) are important two-dimensional layer-structured materials. Here, a solvent-mediated synthesis of h-BNNs revealed a template-free lattice plane control strategy that induced high SSA nanoporous structured h-BNNs with outstanding aerobic oxidative desulfurization performance.

Engineering strong metal–support interactions (SMSI) is an effective strategy for tuning structures and performances of supported metal catalysts but induces poor exposure of active sites. Here, we demonstrate a strong metal–support interaction via a reverse route (SMSIR) by starting from the final morphology of SMSI (fully-encapsulated core–shell structure) to obtain the intermediate state with desirable exposure of metal sites. Using core–shell nanoparticles (NPs) as a building block, the Pd–FeOx NPs are transformed into a porous yolk–shell structure along with the formation of SMSIR upon treatment under a reductive atmosphere. The final structure, denoted as Pd–Fe3O4–H, exhibits excellent catalytic performance in semi-hydrogenation of acetylene with 100% conversion and 85.1% selectivity to ethylene at 80 °C. Detailed electron microscopic and spectroscopic experiments coupled with computational modeling demonstrate that the compelling performance stems from the SMSIR, favoring the formation of surface hydrogen on Pd instead of hydride.

The potentials of deteriorated mountain pine beetle (Dendroctonus ponderosae)-killed lodgepole pine (Pinus contorta) trees for cellulosic ethanol production were evaluated using the sulfite pretreatment to overcome recalcitrance of lignocellulose (SPORL) process. The trees were harvested from two sites in the United States Arapaho-Roosevelt National Forest, Colorado. The infestation age of the trees varied from zero to about 8 years. Mild (170 °C) and harsh (180 °C) SPORL pretreatments were conducted. The chemical charges were sulfuric acid of 2.21% and sodium bisulfite of 8% on oven dry wood for the harsh and half of those for the mild pretreatment. The results suggest that beetle-caused mortality enriched glucan content by as much as 3 percentage points (or 7.5%) in wood. The glucan enrichment seems to increase with infestation age. The enriched glucan can be captured after SPORL pretreatment followed by enzymatic hydrolysis. The killed trees are more susceptible to SPORL pretreatment, which enhanced substrate enzymatic digestibility (SED). Enzymatic hydrolysis glucose yields (EHGY) from killed trees were about 5-20% higher than those from their corresponding live trees. Total fermentable sugar productions from dead trees (including a tree laying on the ground) were 4-14% higher than corresponding production from live trees, depending on pretreatment conditions and infestation age. An ethanol yield of 267 L/metric ton of wood or 69% theoretical value was achieved from a tree infested 4 years, 7% higher than the 250 L/metric ton of wood from the corresponding live tree. The results also demonstrated the robustness of SPORL pretreatment for lodgepole pine.