A carrot-inspired solar thermal evaporator exhibits a water evaporation rate of 2.04 kg m−2 h−1 and an outstanding durability and stability.

Oxygen vacancy-modified WO3–x nanorods composited with g-C3N4 have been synthesized via the chemisorption method. The crystalline structure, morphology, composition, band structure, and charge separation mechanism for WO3–x/g-C3N4 heterostructures are studied in detail. The g-C3N4 nanosheets are attached on the surface of WO3–x nanorods. The Z-scheme separation is confirmed by the analysis of generated hydroxyl radicals. The electrons in the lowest unoccupied molecular orbital of g-C3N4 and the holes in the valence band of WO3 can participate in the photocatalytic reaction to reduce CO2 into CO. New energy levels of oxygen vacancies are formed in the band gap of WO3, further extending the visible-light response, separating the charge carriers in Z-scheme and prolonging the lifetime of electrons. Therefore, the WO3–x/g-C3N4 heterostructures exhibit much higher photocatalytic activity than the pristine g-C3N4.

A series of the metal ions (Pd, Cu, and Mn) modified TiO2 photocatalysts are synthesized via simple sol–gel method. Characterized by X-ray diffraction, Raman, UV–vis absorption spectra, X-ray photoelectron spectroscopy, energy-dispersive X-ray spectroscopy, time-resolved photoluminescence (PL) decay curves, and PL, it was revealed these introduced metal ions existed as O–Me–O species (Me: Pd, Cu, and Mn) on the surface of TiO2. The corresponding theory calculation is used to investigate the electronic density of states and band structure of the metal ions (Pd, Cu, and Mn) modified TiO2. The modified TiO2 photocatalysts exhibit an improved photocatalytic performance on reduction of CO2 and H2O into methane (CH4), attributed to the contribution of surface species by enhancing the visible absorption efficiently, separating charge carriers, and matching of the redox potential on the photoreduction of CO2 into CH4. This article could provide a wider understanding about the adjustment and matching of the energy level for the synthesis and design of functional materials with excellent photocatalytic performance.

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