Graphite carbon nitride (g‐C₃N₄) nanotubes have received extensive attention due to its unique morphology and electronic migration. Herein, the defective porous g‐C₃N₄ nanotube (DTCN) is prepared through a simple thermal reduction process. The construction of N vacancy and tubular structure can synergistically promote the separation of photogenerated charge carriers. As a result, DTCN demonstrates a higher photocatalytic hydrogen evolution rate (1440 μmol·g⁻¹·h⁻¹), which is 5 times higher than that of the initial g‐C₃N₄ nanotube (TCN). Importantly, combined with density functional theory calculations and experimental results, it is the first time to prove that the synergy of curvature effect and N vacancy of nanotubes can enhance the adsorption energy of hydrogen and decrease the work function, resulting in more superior photocatalytic performance than the layered structure. This work provides more in‐depth comprehension for the photocatalytic mechanism of nanotube materials, which has inspirational significance for the design of the g‐C₃N₄ photocatalyst with high performance.

Titanium dioxide (TiO₂) nanomaterials have been widely used in photocatalytic energy conversion and environmental remediation due to their advantages of low cost, chemical stability, and relatively high photo-activity. However, applications of TiO₂ have been restricted in the ultraviolet range because of the wide band gap. Broadening the light absorption of TiO₂ nanomaterials is an efficient way to improve the photocatalytic activity. Thus, black TiO₂ with extended light response range in the visible light and even near infrared light has been extensively exploited as efficient photocatalysts in the last decade. This review represents an attempt to conclude the recent developments in black TiO₂ nanomaterials synthesized by modified treatment, which presented different structure, morphological features, reduced band gap, and enhanced solar energy harvesting efficiency. Special emphasis has been given to the newly developed synthetic methods, porous black TiO₂, and the approaches for further improving the photocatalytic activity of black TiO₂. Various black TiO₂, doped black TiO₂, metal-loaded black TiO₂ and black TiO₂ heterojunction photocatalysts, and their photocatalytic applications and mechanisms in the field of energy and environment are summarized in this review, to provide useful insights and new ideas in the related field.

Photocatalytic elimination of antibiotics from the environment and drinking water is of great significance for human health. However, the efficiency of photoremoval of antibiotics such as tetracycline is severely limited by the prompt recombination of electron holes and slow charge migration efficacy. Fabrication of low-dimensional heterojunction composites is an efficient method for shortening charge carrier migration distance and enhancing charge transfer efficiency. Herein, 2D/2D mesoporous WO₃/CeO₂ laminated Z-scheme heterojunctions were successfully prepared using a two-step hydrothermal process. The mesoporous structure of the composites was proved by nitrogen sorption isotherms, in which sorption-desorption hysteresis was observed. The intimate contact and charge transfer mechanism between WO₃ nanoplates and CeO₂ nanosheets was investigated using high-resolution transmission electron microscopy and X-ray photoelectron spectroscopy measurements, respectively. Photocatalytic tetracycline degradation efficiency was noticeably promoted by the formation of 2D/2D laminated heterojunctions. The improved photocatalytic activity could be attributed to the formation of Z-scheme laminated heterostructure and 2D morphology favoring spatial charge separation, confirmed by various characterizations. The optimized 5WO₃/CeO₂ (5 wt.% WO₃) composites can degrade more than 99% of tetracycline in 80 min, achieving a peak TC photodegradation efficiency of 0.0482 min⁻¹, which is approximately 3.4 times that of pristine CeO₂. A Z-scheme mechanism is proposed for photocatalytic tetracycline by from WO₃/CeO₂ Z-scheme laminated heterojunctions based on the experimental results.

Introducing a sulfone group into COF structure induces electron accumulation and separated redox centers for efficient water oxidation and oxygen reduction reaction, thus accelerating the overall photocatalytic H ₂ O ₂ synthesis in pure water.