We report on a facile method to synthesize carbon dots (CDs) using glycerol solvent as a single precursor via a pyrolysis process free from catalysts. This method is extremely simple and economical, and provides a feasible route for mass production of highly emissive CDs. For rationalization, a mechanism incorporating dehydration of glycerol, followed by acrylaldehyde formation is tentatively proposed for CD production. Further systematic improvement of particle homogeneity is made by harnessing the growth of CDs inside the mesoporous silica nanoparticles that act as a nano-reactor to regulate the size distribution. Simultaneously capping a polyethylene glycol (PEG)-derived reactant onto the CDs@SiO₂ enhances their luminescence, stability and bio-compatibility. The as-prepared CDs@mSiO₂–PEG nanocomposites are then loaded with the anti-cancer drug doxorubicin (DOX), so that the controlled release of DOX could be monitored by both time-dependent and spatially resolved ratiometric fluorescence intensity for CDs versus DOX in HeLa cells, successfully demonstrating that the CDs@mSiO₂–PEG nanocomposites are suitable for cell imaging and drug release.

Photocatalytic water splitting is attracting enormous interest for the storage of solar energy but no practical method has yet been identified. In the past decades, various systems have been developed but most of them suffer from low activities, a narrow range of absorption and poor quantum efficiencies (Q.E.) due to fast recombination of charge carriers. Here we report a dramatic suppression of electron-hole pair recombination on the surface of N-doped TiO₂ based nanocatalysts under enhanced concentrations of H⁺ and OH⁻, and local electric field polarization of a MgO (111) support during photolysis of water at elevated temperatures. Thus, a broad optical absorption is seen, producing O₂ and H₂ in a 1:2 molar ratio with a H₂ evolution rate of over 11,000 μmol g⁻¹ h⁻¹ without any sacrificial reagents at 270 °C. An exceptional range of Q.E. from 81.8% at 437 nm to 3.2% at 1000 nm is also reported.

Bio-oil, produced by the destructive distillation of cheap and renewable lignocellulosic biomass, contains high energy density oligomers in the water-insoluble fraction that can be utilized for diesel and valuable fine chemicals productions. Here, we show an efficient hydrodeoxygenation catalyst that combines highly dispersed palladium and ultrafine molybdenum phosphate nanoparticles on silica. Using phenol as a model substrate this catalyst is 100% effective and 97.5% selective for hydrodeoxygenation to cyclohexane under mild conditions in a batch reaction; this catalyst also demonstrates regeneration ability in long-term continuous flow tests. Detailed investigations into the nature of the catalyst show that it combines hydrogenation activity of Pd and high density of both Brønsted and Lewis acid sites; we believe these are key features for efficient catalytic hydrodeoxygenation behavior. Using a wood and bark-derived feedstock, this catalyst performs hydrodeoxygenation of lignin, cellulose, and hemicellulose-derived oligomers into liquid alkanes with high efficiency and yield.