Chao Wang

A multi-crosslinking network is well-designed using a facile strategy for the fabrication of a low-temperature tolerance hydrogel that exhibits excellent conductivity (0.8 S m⁻¹ even at −80 °C) and sensitivity when applied in sensors at −20 °C.

A cellulose-based flexible double-cross-linked hydrogel with hierarchical porosity (max. 80%) was obtained by a facile solution-phase method by using polydopamine (PDA) as a crosslinker between cellulose and polyacrylamide (PAM). The investigation on the ratio of dopamine/acrylamide (DA/AM) reveals that the π–π stacking of the catechol groups in PDA and the abundant hydrogen bonds distributed in the gel network exert key effects on the hydrogels' mechanical properties. At the premium ratio of 0.4 (C₄-DM-40), the mechanical and self-healing properties of the hydrogel are superior to those of other hydrogels. Fe³⁺-functionalizing endows the hydrogel with enhanced conductivity and sensitivity, as evidenced by the 3-fold increase in resistance variation (ΔR/R₀) in a finger-bending monitoring test. An electric double layer supercapacitor using the KOH-saturated C₄-DM-40 aerogel membrane as a polymer electrolyte presents high capacitance of 172 F g⁻¹ at 1.0 A g⁻¹ and long cycling life of 10 000 cycles with 84.7% capacitance retention due to electrolyte retention of 548.6%. Remarkably, an integrated micro-supercapacitor is fabricated by directly depositing activated carbon materials onto the C₄-DM-40 hydrogel membrane. The device shows areal capacitance of 275.8 mF cm⁻² and volumetric capacitance of 394.1 F cm⁻³ at 10 mV s⁻¹. These findings suggest that the multi-functional cellulose-based hydrogels reported in this study display various potentials for practical applications not only in human health monitoring but also in portable and energy-storage devices.

Cellulose with 15 % fatty oil is converted to a hydrocarbon‐rich oil comprised mainly of alkylbenzenes and aliphatic hydrocarbons through a synergic deoxy reforming (SDR) process. To further decrease the oxygen content and investigate the carbon distribution in the hydrocarbon oil, metal carbides (M₂C, M=Mo, W) supported on molecular sieves (ZSM‐5, MCM‐41, SBA‐15) with different pore structures were synthesized and employed as catalysts. The impacts of the M₂C particles on the pore size of the supports and the catalytic selectivity were investigated. The ZSM‐5 series of catalysts shows a relatively high selectivity for alkylbenzenes, especially Mo₂C/ZSM‐5, because of the abundant acid sites on the catalyst surfaces, whereas the MCM‐41 and SBA‐15 series of catalysts, especially W₂C/MCM‐41, show a relatively high selectivity for alkanes, which is attributed to their mesoporous structure. Additionally, Mo₂C/MCM‐41 catalysts show the highest deoxygenation efficiency of 95.7 %. This research provides a rational catalyst design to control the carbon distribution and components in SDR oil and paves the way for the full utilization of biomass waste and waste/gutter oil.

Face-to-face interfacial assembly of TiO₂-g-C₃N₄ hybrid (2D TCN-A) is developed by surfactant-assisted hydrothermal treatment forming a sandwich structure of anatase TiO₂ nanosheets (TiO₂-A, 5–6 monolayers) and g-C₃N₄ nanosheets (∼3 monolayers). Post air-annealing is found effective for insertion of oxygen to the hybrid, which remedies the oxygen vacancies of TiO₂ (B) nanosheets and converts it to anatase nanosheets. The enhanced light adsorption, increased donor density, and prolonged life of charge carries are achieved by variation of bandgap and the formation of heterojuction between the two kinds of nanosheets, facilitating separation and transfer of charge carriers. The 2D TCN-A-70 nanosheets show a high photodegradation rate of methyl orange (k_app ≈ 0.189 min^–1) and photocatalytic evolution rate of hydrogen (18200 μmol g^–1 h^–1). This 2D nanosheets hybrid is potentially useful in alleviating environmental and energy issues.