Bismuth vanadate (BiVO₄) is a promising photoanode material for efficient photoelectrochemical (PEC) water splitting, whereas its performance is inhibited by detrimental surface states. To solve the problem, herein, a low-cost organic molecule 1,3,5-benzenetricarboxylic acid (BTC) is selected for surface passivation of BiVO₄ photoanodes (BVOs), which also provides bonding sites for Co²⁺ to anchor, resulting in a Co-BTC-BVO photoanode. Owing to its strong coordination with metal ions, BTC not only passivates surface states of BVO, but also provides bonding between BVO and catalytic active sites (Co²⁺) to form a molecular cocatalyst. Computational study and interfacial charge kinetic investigation reveal that chemical bonding formed at the interface greatly suppresses charge recombination and accelerates charge transfer. The obtained Co-BTC-BVO photoanode exhibits a photocurrent density of 4.82 mA/cm² at 1.23 V vs. reversible hydrogen electrode (RHE) and a low onset potential of 0.22 V_RHE under AM 1.5 G illumination, which ranks among the best photoanodes coupled with Co-based cocatalysts. This work presents a novel selection of passivation layers and emphasizes the significance of interfacial chemical bonding for the construction of efficient photoanodes.

Hypoxia is a huge barrier for the development of photodynamic therapy (PDT). Chemodynamic therapy (CDT) could provide a possible solution to this dilemma. In this work, a controlled Schiff-base reaction was conducted between amido groups on the surface of carbon dots (CDs) and aldehyde groups on aldehyde-modified cellulose nanocrystals (mCNCs) as well as aldehyde-mCNCs decorated with Fe₃O₄ nanoparticles. In this process, the mCNCs not only prevent the agglomeration of Fe₃O₄ but also form hydrogels with CDs. The CDs act as both photothermal agent and photosensitizer. The hypoxia could be effectively relieved through the Fenton reaction due to the addition of Fe₃O₄, and the ·OH produced in the reaction further induces CDT and enhances tumor therapy efficiency. The therapy performance was further verified through in vitro cell experiments and in vivo animal experiments. This convenient method provides inspirations for the design and preparation of advanced biomaterials with multiple functions for cancer therapy.

A high-efficiency electro-thermal heater requires simultaneously high electrical and thermal conductivities to generate and dissipate Joule heat efficiently. A low input voltage is essential to ensure the heater's safe applications. However, the low voltage generally leads to low saturated temperature and heating rate and hence a low thermal efficiency. How to reduce the input voltage while maintaining a high electro-thermal efficiency is still a challenge. Herein, a highly electrical and thermal conductive film was constructed using a graphene-based composite which has an internal three-dimensional (3D) conductive network. In the 3D framework, cellulose nanocrystalline (CNC) phase with chiral liquid crystal manner presents in the form of aligned helix between the graphene oxide (GO) layers. Carbon nanodots (CDs) are assembled inside the composite as conductive nanofillers. Subsequent annealing and compression results in the formation of the assembled GO-CNC-CDs film. The carbonized CNC nanorods (CNR) with the helical alignment act as in-plane and through-plane connections of neighboring reduced GO (rGO) nanosheets, forming a conductive network in the composite film. The CDs with ultrafast electrons transfer rates provide additional electrons and phonons transport paths for the composite. As a result, the obtained graphene-based composite film (rGO-CNR-CDs) exhibited a high thermal conductivity of 1, 978.6 W·m^-1·K^-1 and electrical conductivity of 2, 053.4 S·cm^-1, respectively. The composite film showed an outstanding electro-thermal heating efficiency with the saturated temperature of 315 ℃ and maximum heating rate of 44.9 ℃·s^-1 at a very low input voltage of 10 V. The freestanding graphene composite film with the delicate nanostructure design has a great potential to be integrated into electro-thermal devices.