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Lightweight yet strong paper with high toughness is desirable especially for impact protection. Herein we demonstrated electrically conductive and mechanically robust paper (AP/PB-GP) made of reduced graphene oxide via interfacial crosslinking with 1-aminopyrene (AP) and 1-pyrenebutyrat (PB) small molecules. The AP/PB-GP with thickness of over ten micrometer delivers a record-high toughness (∼69.67 ± 15.3 MJ m−3 in average), simultaneously with superior strength (close to 1 GPa), allowing an impressive specific penetration energy absorption (∼0.17 MJ kg−1) at high impact velocities when used for ballistic impact protection. Detailed interfacial and structural analysis reveals that the reinforcement is synergistically determined by π-π interaction and H-bonding linkage between adjacent graphene lamellae. Especially, the defective pores within the graphene platelets benefit the favorable adsorption of the pyrene-containing molecules, which imperatively maximizes the interfacial binding, facilitating deflecting crack and plastic deformation under loading. Density functional theory simulation suggests that the coupling between the polar functional groups, e.g., −COOH, at the edges of graphene platelets and −NH2 and −COOH of AP/PB are critical to the formation of hydrogen bonding network.

Summary The controlled generation of reactive oxygen species (ROS) to selectively epoxidize styrene is a grand challenge. Herein, cyano-group-modified carbon nitrides (CNCYx and CN-Ty) are prepared, and the catalysts show better performance in regulating ROS and producing styrene oxide than the cyano-free sample. The in situ diffuse reflectance infrared and density functional theory calculation results reveal that the cyano group acts as the adsorption and activation site of oxygen. X-ray photoelectron spectroscopy and NMR spectrum results confirm that the cyano group bonds with the intact heptazine ring. This unique structure could inhibit H2O2 and ⋅OH formation, resulting in high selectivity of styrene oxide. Furthermore, high catalytic activity is still achieved when the system scales up to 2.7 L with 100 g styrene under solar light irradiation. The strategy of cyano group modification gives a new insight into regulating spatial configuration for tuning the utilization of oxygen-active species and shows potential applications in industry., Graphical Abstract, Public summary • Surface group modification is a significant strategy to improve catalyst activity • Cyano groups are incorporated on the surface of carbon nitride via copolymerization • Cyano group reactive sites allow high selectivity of styrene oxide for aerobic oxidation • The system can be scaled up under solar light irradiation

Photoelectric performance of (C, S) co-doped SnO2 was explored by an integrated strategy combining first principle calculation with experimental measurement. The exploration began with theoretical calculation upon geometry characteristic and electronic structure of pure and (C, S) co-doped SnO2, then follow by experimental measurement. Namely, pure and different ratios of (C, S) co-doped SnO2 were prepared and characterized by X-ray powder diffraction (XRD), scanning electron microscope (SEM), and X-ray photoelectron spectroscopy (XPS). And photoelectric performance of the prepared pure and (C, S) co-doped SnO2 electrodes was studied. Theoretical calculation result indicate that carbon and sulfur atom interact intensely to each other by lattice distortion. Fully filled energy levels are introduced to the top of the valence band, resulting effective reduction of band gap value and suppression of charged defects. Consequently, the photoelectric performance of SnO2 is improved. Double-hole-assisted coupling mechanism of dopants in SnO2 is interpreted to reveal the interaction of C and S. Besides, experimental results indicate that all samples are rutile phase with the dopants carbon and sulfur entered into SnO2 crystal by substituting oxygen. 5% co-doped sample shows the most homogeneous spherical shape and dispersed character, which is provided with the maximum photocurrent value (6.8 μA/cm2) and minimum electrochemical impedance. Theoretical calculation and experiment jointly indicate that (C, S) co-doped SnO2 possess superior photoelectric performance. The doping method of double-hole-assisted coupling may contribute to the design of highly active tin oxide-based photoelectric materials, and also pave the way for modification of other congener materials.

The electronic structure of Sb-N co-doped SnO2 was explored by first principles calculation. The results show that Sb (donor) and N (acceptor) introduce new energy levels in the band gap, which reduce the band gap of SnO2 obviously. Besides, the carrier separation rate of the system is improved owing to the charge compensation effect of Sb and N. Consequently, the photoelectric performance of SnO2 is improved. Based on the results of theoretical calculation, the intrinsic and different ratios of Sb-N co-doped SnO2 were prepared by hydrothermal method. And the samples were characterized by X-ray powder diffraction (XRD), scanning electron microscope (SEM), and x-ray photoelectron spectroscopy (XPS). The photoelectric performance of the prepared intrinsic and Sb-N co-doped SnO2 electrodes was studied. The results prove that all samples are rutile phase with the dopants Sb and N entered into SnO2 lattice by substituting Sn and O. Besides, the 5% co-doped sample has uniform spherical shape and dispersed character. The photoelectric performance tests indicate that photoelectric performance of SnO2 is enhanced by Sb-N co-doping. The maximum photocurrent value (9 μA/cm2) and minimum electrochemical impedance is achieved at the doping ratio of 5%. Theoretical calculation and experiment results indicate that Sb-N co-doped SnO2 possesses superior photoelectric performance.

The electronic structures and conducting mechanism of (Mg, S) co-doped rutile SnO2 were explored through density functional theory (DFT) calculation. Results showed that the acceptor metal Mg assisted the coupling of the incorporated S with a neighbouring O in SnO2, which introduced new energy levels into the forbidden band of SnO2 and thereby improved the photoelectric performance of SnO2. Based on this result, we proposed an integrated strategy that combines DFT calculations with experiments to study the photoelectric performance of (Mg, S) co-doped SnO2 prepared through hydrothermal method. Conducting glass (FTO) was used for the preparation of (Mg, S) co-doped SnO2 electrode. Scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and ultraviolet–visible diffuse reflectance spectroscopy results confirmed the incorporation of Mg and S elements into the SnO2 cell. Furthermore, photoelectric performance tests revealed that (Mg, S) co-doping can improve photoelectric performance. The maximum photocurrent (0.50 μA/cm2) and smallest impedance were obtained at a co-doping ratio of 5%. Therefore, the (Mg, S) co-doped SnO2 is a strong candidate for photoelectrocatalysis.

A novel copper (Cu) and sulfur (S) co-doped SnO2 material prepared by a facile hydrothermal method is demonstrated as an efficient electrocatalyst for the reduction of CO2 to formate. The as-prepared SC10 holds rutile structure, whereas both Cu and S are doped well into the SnO2, in which S2− and Cu2+ replace O2− and Sn4+, respectively. The overpotential observed in CO2-saturated 0.5 M NaHCO3 solution is as low as 130 mV (vs. RHE) at −0.75 V (vs. Ag/AgCl) and the maximum current density also increases to 5.5 mA cm−2 at −1.2 V, which is 7-times higher than pure SnO2. The catalyst is stable for more than 33 h and the Faradic efficiency of formate is 58.5 %. The as-synthesized catalyst will open up a novel route for efficient reduction to formate and has a great potential for relieving the greenhouse effect.

Ruthenium shows unique catalytic properties in selective hydrodeoxygenation of lignin-derived phenols to alkyl cyclohexanols, but seldom exploration has been devoted to the mechanism of phenol hydrogenation on Ru. Herein, the mechanism of phenol hydrogenation to cyclohexanol on Ru is explored combining experiments and density functional theory (DFT) calculations. The experimental results show that the selectivity to cyclohexanol is higher than cyclohexanone over 3% Ru-SiO2 when the conversion is higher than 25%. Mechanistic study by DFT shows that after forming cyclohexenol as an intermediate, the hydrogenation can proceed along both the classical tautomerization pathway and direct hydrogenation pathway, with tautomerization pathway being the dominant one. Further, the hydrogenation pathways producing cyclohexanol without the generation of cyclohexenol could also run parallel to the two pathways through it. These pathways together lead to the high selectivity to cyclohexanol on Ru catalyst. The refreshed hydrogenation pathway can contribute to a new insight into the mechanism of phenol hydrogenation on Ru based catalyst.

In this study, theoretical calculations and experiments have been carried out to investigate the photoelectric performance of (2Al, S) co-doped rutile SnO2. The electronic structures are studied by density functional theory (DFT). It is found that the metal Al can assist the bonding of the incorporated S with the neighboring O in SnO2, introducing new energy levels in the forbidden band of SnO2, which enhance the photoelectric performance. Meanwhile, the experiments are conducted to verify this. The (2Al, S) co-doped SnO2 with different doping ratios are prepared by a hydrothermal method. The samples are characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). Results show that all the samples have rutile structure without any extra phase, and the dopant S2− ion was implanted into the crystalline lattice of (2Al, S) co-doped SnO2 and Al dopants replaced Sn atoms. The photoelectric performance tests show Al and S co-doping can improve the photoelectric performance, especially with a doping ratio of 5%, when the photocurrent reaches maximum of 3.0 μA cm−2 which is almost twice as much as pure SnO2, and the impedance is the smallest. The experiments results are consistent with our theoretical calculations. These findings are expected to be helpful for the design of highly active tin oxide-based photoelectric materials.

The electronic and interfacial properties of catalysts play vital roles in tailoring catalytic performance. Here, we report that the modification of polymeric carbon nitride (PCN) with cyano group ( CN) can achieve excellent catalytic performance in mineralization of phenol. The CN site not only enhances the adsorption and activation of molecular O2 for efficient H2O2 production, but also improves the absorption capability of PCN for phenol in aqueous solution by tuning surface charge states. Subsequently, the surficial adsorbed phenol acts as holes scavenger which promotes the separation efficiency of photogenerated carriers in PCN and in turn facilitates the in-situ decomposition of H2O2 to OH. This reduces the uncontrollable decomposition of H2O2 to OH and inhibits the polymerization of phenolic compounds. The active sites of catalyst, O2 transformation state and pathway on the catalyst surface as well as the firstly attacked sites of phenol are confirmed respectively by in-situ DRIFT spectra, scavengers and Bader charge analysis.

Coordinated Ru species, Ru/LDH, were applied to the reduction of carbonyl compounds via blue light irradiation under mild (45 °C, atmospheric argon pressure), ligand-free, and additive-free conditions. LDH can act as an efficient base catalyst to assist in formation of isopropoxide, requiring no additional base, because basic OH groups form an ordered distribution on LDH surface. The coordinated Ru species containing one OH and three oxygen atoms ligands deriving from the OH groups of LDH are a crucial component, for securing the active electron-deficient Ru species that favours formation of Ru-isopropoxide. The photocatalytic activity is related to the adsorption capacity of isopropyl alcohol near the electron-deficient Ru species and the formation of Ru-isopropoxide. The strong-metal-support interactions between Ru and LDH affect the coordination and the electronic surroundings of the Ru centres and have a significant effect on the photocatalytic activity.

The corrosion resistance of Al-based amorphous alloy can be significantly improved with the addition of NaNO3 into NaCl solution. The growth rates of passive film in the initial stage of immersion are accelerated, and the metastable pitting is inhibited. The pitting potential of Al-based amorphous alloy is increased with the concentration of NaNO3, and the pitting corrosion is completely avoided when the concentration of NaNO3 is above 0.03 M. The transition from pitting to transpassivation can be attributed to the incorporation of NO3− in passive film. Sodium nitrate is an efficient corrosion inhibitor for Al-based amorphous alloy.