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Exploring a combined phototherapeutic strategy to overcome the limitations of a single mode therapy and inducing high anticancer efficiency is highly promising for precision cancer nanomedicine. However, a single-wavelength laser activates dual photothermal/photodynamic therapy (PTT/PDT) treatment is still a formidable challenge. Herein, we strategically design and fabricate a multifunctional theranostic nanosystem based on chlorin e6-functionalized polydopamine (PDA) coated prussian blue/manganese dioxide nanoparticles (PB-MnO2@PDA-Ce6 NPs). Interestingly, the obtained PB-MnO2@PDA NPs not only offer an effective delivery system for Ce6 but also provide strong optical absorption in the near-infrared range, endowing high antitumor efficacy of PTT. More importantly, the as-prepared PB-MnO2@PDA-Ce6 nanoagents exhibit an effective oxygen generation, superior reactive oxygen species (ROS), and outstanding photothermal conversion ability to greatly improve PTT and PDT treatments. As a result, both in vitroand in vivotreatments guided by MR imaging on liver cancer cells reveal the complete cell/tumor eradication under a single wavelength of 660 nm laser irradiation, implying the simultaneous synergistic PDT/PTT effects triggered by PB-MnO2@PDA-Ce6 nanoplatform, which are much higher than individual treatment. Taken together, our phototherapeutic nanoagents exhibit an excellent therapeutic performance, which may act as a nanoplatform to find safe and clinically translatable routes to accelerate cancer therapeutics.

Inspired by the cascade reactions occurring in micro-organelles of living systems, we have developed a hybrid hydrogel, a nanozyme that mimics three key enzymes including peroxidase, superoxide dismutase, and catalase. The organic/inorganic nanostructured hydrogel constituting VOxincorporated hexacyanoferrate Berlin green analogue complex (VOxBG) is prepared by a simple one-step hydrothermal process, and its composition, structure, and properties are thoroughly investigated. Polyvinylpyrrolidone, a low-cost and biocompatible polymer, was utilized as a scaffold to increase the surface area and dispersion of the highly active catalytic centers of the nanozyme. Compared to the widely used horseradish peroxidase in enzyme-linked immunosorbent assay, our VOxBG analogue hydrogel displays an excellent affinity toward the chromogenic substrate that is used in these peroxidase-based assays. This higher affinity makes it a competent nanozyme for detection and oxidation of biomolecules, including glucose, in a cascade-like system which can be further used for hydrogel photolithography. The VOxBG analogue hydrogel also holds a good ability for the rapid and efficient oxidative degradation of environmentally unfriendly recalcitrant substrates under light irradiation. Detailed mechanistic studies of this multifaceted material suggest that different complex catalytic processes and routes are involved in these photo-Fenton and Fenton reactions that are responsible for the generation as well as consumption of reactive oxygen species, which are effectively activated by a multienzyme mimetic of the VOxBG analogue hydrogel.

Graphitic carbon nitride (g-C3N4) is among the most promising metal-free photocatalysts for hydrogen (H2) evolution from water splitting under visible-light irradiation. However, the fast recombination rate of its photogenerated electron–hole pairs limits the photocatalytic activity of g-C3N4. Herein, we have developed highly efficient visible light driven C3N4/CoTPP type-II heterostructures by decorating cobalt(ii) meso-tetraphenylporphine (CoTPP) on the surface of the g-C3N4catalyst through π–π supramolecular interaction. The introduction of CoTPP enhances the migration and transfer of photogenerated charge carriers and inhibits the recombination of electron–hole pairs through the formation of C3N4/CoTPP type-II heterojunctions. The C3N4/CoTPP heterostructured photocatalyst exhibits efficient spatial separation of photogenerated electrons and holes due to the well-matched overlapping band structures of two semiconductors, thus facilitating more electrons to be released for H2evolution. When 4 wt% (weight ratio) CoTPP is loaded onto g-C3N4, the H2evolution rate of the C3N4/CoTPP heterostructured photocatalyst is significantly increased up to 46.93 μmol h−1under visible light irradiation (λ≥ 420 nm), which is 2.73 times higher than that of bare g-C3N4(17.21 μmol h−1). Moreover, the C3N4/4 wt% CoTPP type-II heterostructured photocatalyst shows good stability for H2evolution after five consecutive cycles of continuous irradiation of up to 20 h. Conclusively, the g-C3N4photocatalyst coupled with CoTPP conjugated molecules substantially improves the photocatalytic performance and stability for H2evolution from water under visible light irradiation. This novel strategy sheds light on developing other highly efficient photocatalytic systems for clean energy production.

We prepared the Fe3O4/g-C3N4nanoparticles (NPs) through a simple electrostatic self-assembly method with a 3:97 weight ratio to investigate their Fenton, photo-Fenton and oxidative functionalities besides photocatalytic functionality. We observed an improvement of the Fenton and photo-Fenton activities of the Fe3O4/g-C3N4nanocomposites. This improvement was attributed to efficient charge transfer between Fe3O4and g-C3N4at the heterojunctions, inhibition of electron-hole recombination, a high surface area, and stabilization of Fe3O4against leaching by the hydrophobic g-C3N4. The obtained NPs showed a higher degradation potential for rhodamine B (RhB) dye than those of Fe3O4and g-C3N4. As compared to photocatalysis, the efficiency of RhB degradation in the Fenton and photo-Fenton reactions was increased by 20% and 90%, respectively. Additionally, the horseradish peroxidase (HRP) activity of the prepared nanomaterials was studied with 3,3,5,5-tetramethylbenzidinedihydrochloride (TMB) as a substrate. Dopamine oxidation was also examined. Results indicate that Fe3O4/g–C3N4nanocomposites offers more efficient degradation of RhB dye in a photo-Fenton system compared with regular photocatalytic degradation, which requires a long time. Our study also confirmed that Fe3O4/g-C3N4nanocomposites can be used as a potential material for mimicking HRP owing to its high affinity for TMB. These findings suggest good potential for applications in biosensing and as a catalyst in oxidation reactions.

Electrochemical water splitting is an important process to produce hydrogen and oxygen for energy storage and conversion devices. However, it is often restricted by the oxygen evolution reaction (OER) due to its sluggish kinetics. To overcome the problem, precious metal oxide-based electrocatalysts, such as RuO2and IrO2, are widely used. The lack of availability and the high cost of precious metals compel researchers to find other resources for the development of cost-effective, environmentally friendly, earth-abundant, nonprecious electrocatalysts for OER. Such catalysts should have high OER performance and good stability in comparison to those of available commercial precious metal-based electrocatalysts. Herein, we report an inexpensive fabrication of bimetallic iron–nickel nanoparticles on FeNi-foil (FeNi4.34@FeNi-foil) as an integrated OER electrode using a one-step calcination process. FeNi4.34@FeNi-foil obtained at 900 °C shows superior OER activity in alkaline solution with an overpotential as low as 283 mV to achieve a current density of 10 mA cm–2and a small Tafel slope of 53 mV dec–1. The high performance and durability of the as-prepared nonprecious metal electrode even exceeds those of the available commercial RuO2and IrO2catalysts, showing great potential in replacing the expensive noble metal-based electrocatalysts for OER.