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The development of high-performance semiconductor photocatalysts using solar energy has become a hot topic, which is crucial for a sustainable future. However, construction of a nontoxic and efficient catalyst still remains an enormous challenge. Here, we uncover a simple hydrothermal recalcination method to prepare a novel potassium (K)-doped porous ultrathin g-C 3 N 4 (denoted as KMCN) photocatalyst with efficient catalytic performance, eco-friendly characteristics, and excellent stability. The obtained KMCN nanosheets were applied to the photodegradation of tetracycline (TC) under different reaction condition to simulate practical wastewater treatment. It was found, that the porous structure and K + addition of g-C 3 N 4 enhanced the pore size and specific surface area, and they increased the photoabsorption region and activity sites. The optical properties of KMCN nanosheets were systematically characterized by PL, UV-DRS, etc. The results revealed that the KMCN(0.05) sample possessed a narrowed band gap, lower recombination of photogenerated charges, and higher electron and hole transfer efficiency. Benefiting from these advantages, KMCN(0.05) photocatalysts demonstrated excellent photocatalytic performance for TC degradation (85.13%), which was approximately a 2.88-fold and 1.40-fold increase compared to bare g-C 3 N 4 (29.60%) and porous ultrathin g-C 3 N 4 (60.84%), respectively. These results suggest a reasonable way for the design of economic and high-efficiency photocatalysis.

Photocatalytic CO 2 reduction into renewable fuels by sustainable and clean solar energy can be considered as an ideal option to decrease the atmospheric CO 2 level and fulfill the energy requirements. Layered double hydroxides (LDHs) with high surface area, tunable composition as well as exposed active sites have received enormous attention for photocatalytic CO 2 reduction. Herein, a novel NiAl-LDH/Ti 3 C 2 T x nanosheet (NiAl-LDH/TNS) with a core−shell structure was synthesized via an in situ hydrothermal method, and 2D NiAl-LDH coupled with the 2D Ti 3 C 2 T x nanosheet to form a Schottky junction can suppress the back-diffusion of electrons and facilitate the transfer of charge carriers. Benefiting from the feature, the optimized sample with the additive Ti 3 C 2 T x amount of 75 mg (NiAl-LDH/TNS-75) has the photocatalytic CO 2 reduction conversion rate of CO (2128.46 μmol h −1 g −1 ) with the selectivity of CO (90.2%) under visible-light irradiation, which is about 8.6 times higher than that of pristine NiAl-LDH. This work provides a new insight into the construction of novel 2D semiconductor photocatalysts.

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The introduction of metal−organic framework materials into photocatalysts is considered to be an effective strategy for improving the transfer and separation efficiency of photogenerated electron−hole pairs. In the present study, we demonstrate the delicate construction of NH 2 -UiO-66/ZnIn 2 S 4 (NU66/ZIS) composites as bifunctional photocatalysts with the degradation efficiency of malachite green (98%) and the hydrogen evolution rate of a 10% NU66/ZIS composite reaching up to 2199 μmol h −1 g −1 . The characterization of unique ZIS/NU66 shows that it can efficiently facilitate the separation and transfer of light-induced charges and exposed rich active sites for photocatalyst redox reaction. Moreover, the results of vitro cytotoxicity assay suggest that NU66/ZIS composites are potential safety photocatalysts to the environment and human beings. Furthermore, the DFT calculation indicates that the Zr site of NU66 and In site of ZnIn 2 S 4 interface should be the main active center in NU66/ZIS heterojunctions.

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