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A solar-heating sponge, in which the polypyrrole (PPy) coating plays the role of photothermal converter and carbon nanotubes (CNTs) act as the thermal conductor, was fabricated. The sponge can effectively convert sunlight into heat and fast conduct heat so that the temperature can rise to 80 °C within 30s under 1 sun irradiation. Besides, the temperatures of the other parts rise synchronously with the top surface, unlike most reported sponges which had temperature differences between different parts. This advantage can avoid the decrease of diffusion rate of the oil in application. The sponge also exhibits super hydrophobility with a high water contact angle of 151.2°. The excellent solar-heating ability and hydrophobility make the sponge an efficient viscous oil adsorbent. The sponge can continuously and rapidly remove the spilled oil under solar irradiation. The coating composed of interconnected PPy nanosheets is firmly fixed on the surface of the elastic matrix via multiple H bonds. After 10 adsorption-desorption cycles, the adsorption capacity still maintains 97.2%, without any change in hydrophobility. These advantages including fast solar-heating, super hydrophobility and high regenerability demonstrate that the sponge has great potential in oil spill treatment, especially highly viscous oils.

A highly selective and sensitive water-soluble optical probe based on a squarylium dye, 2,3,3-trimethyl-3H-indolenine-5-sulfonate squaraine (SQ) has been successfully synthesized. The as-prepared SQcan efficiently recognize iron(iii) ions in the presence of competing cations (Na+, Mg2+, Al3+, Cr3+, Zn2+, K+, Ca2+, Ba2+, Pb2+, Ni2+, Co2+, Ag+, Cu2+, Cd2+) in deionized water. After Fe3+was added, the absorbance and fluorescence of the SQwater solution changed, and the color changed from sky blue to pale yellow. The binding constant (Ka) of SQ–Fe3+was calculated to be about 1.14 × 104M−1. Correspondingly, the chelating mode of SQ–Fe3+was confirmed by Job's plot, Fourier transform infrared (FT-IR) and 1H nuclear magnetic resonance (1H NMR). “Naked eye” detection was performed, which indicated the potential application of SQfor convenient, selective and fast detection of Fe3+.

The construction of a heterojunction structure is considered a significant route to promote solar-driven H2production. Herein, a CDs/ZnIn2S4/Ni–Al LDHs (CDZNA) ternary heterojunction was elaborately constructed viathe in situgrowth of ZnIn2S4on Ni–Al LDHs with the incorporation of carbon dots (CDs) cocatalyst, which was used as a highly efficient catalyst for the photocatalytic H2generation. Characterizations indicated that 2D ZnIn2S4nanosheet homogeneously dispersed on the surface of Ni–Al LDHs fabricated an intimate hierarchical architecture and provided a high BET surface area (135.12 m2g–1). In addition, the unique embeddable-dispersed CDs as electron mediators possessed numerous active sites and promoted the charge separation on ZnIn2S4/Ni–Al LDHs (ZNA) binary catalyst. By coupling these two features, the CDZNA catalyst exhibited a considerable H2production rate of 23.1 mmol g–1h–1under visible-light illumination, which was 16.4 and 1.4 times higher than those of ZnIn2S4and ZNA, respectively. A proposed mechanism of photocatalytic H2production over the CDZNA catalyst was also discussed. This work provides a promising strategy to achieve highly efficient solar energy conversion in a ternary photocatalytic system.

Solar-driven hydrogen (H2) generation from seawater exhibits great economic value in addressing the urgent energy shortage yet faces challenges from the severe salt-deactivation effect, which could result in the consumption of photoinduced charges and decomposition of catalysts. Herein, a triptycene-based polymer was coated on the surface of a CdxZn1–xS nanorod to form a core–shell heterojunction (TCP@CZS) by using the in situSuzuki reaction for photocatalytic H2production from water/seawater splitting. The introduction of TCP can provide a large surface area, enrich the active site, and boost charge transfer for the proton reduction reaction. Benefiting from it, optimal TCP@CZS indicated a H2evolution rate of 93.88 mmol h–1g–1with Na2S/Na2SO3in natural seawater under simulated solar light irradiation, which was 2.2 and 1.1 times higher than that of pure Cd0.6Zn0.4S and that in pure water, respectively. Besides, the apparent quantum efficiency (AQE) of TCP@CZS-3 under 420 nm light irradiation was 22.6% in seawater. This work highlights the feasibility of the triptycene-based porous organic polymer as an efficient catalyst for solar energy conversion in seawater.