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Fenton-like reactions involving semiconductors and metal-based compounds have been widely reported for wastewater treatment. However, there are still some unknown areas that need to be explored, such as the degradation mechanism, the toxicity of the composite system, and active species. In this article, a series of CuO/g-C3N4 nanocomposites were synthesized via calcination of a mixture of cupric sulfate (CuSO4·5H2O) and melamine. The construction and morphology of CuO/g-C3N4 nanocomposites were characterized at length. In the presence of hydrogen peroxide (H2O2), the catalytic capability of CuO/g-C3N4 for glyphosate degradation was investigated. Our research showed that CuO/g-C3N4 nanocomposites exhibited excellent catalytic performance for the removal of glyphosate within a wide pH scope (3.48–9.69), a high mineralization rate (68.1%), and a superior degradation rate (99.3%). This work revealed that high-valent copper (Cu-(III)), rather than the hydroxyl radical (•OH), played a major role in glyphosate removal. In addition, seed germination experiments confirmed that the biotoxicity of glyphosate to wheat seeds was greatly reduced after degradation via the CuO/g-C3N4/H2O2 system. This study suggests that CuO/g-C3N4/H2O2 can be a promising candidate for efficiently removing glyphosate from wastewater. [ABSTRACT FROM AUTHOR]

Advanced oxidation processes employing peroxymonosulfate (PMS) show significant promise for wastewater treatment. However, PMS activation typically relies on energy- and chemically intensive techniques due to its relatively low reactivity. Hence, the exploration of novel and energy-efficient approaches, such as the piezoelectric effect, for PMS activation is of paramount importance. Herein, we prepared a piezoelectric material (CoMn 2 O 4 ) via a simple hydrothermal method followed by calcination. The degradation experiments of tetracycline (TC) demonstrated that CoMn 2 O 4 exhibited excellent performance under ultrasound, the apparent rate constant k is 0.191 min -1 , and its degradation rate reached 83.63% after 10 min. Piezo force microscopy (PFM) tests confirmed that CoMn 2 O 4 exhibited a piezotronic effect under ultrasound. In situ electron paramagnetic resonance ( in situ EPR) tests revealed that PMS could be activated to form hydroxyl radicals ( • OH) and sulfate radicals (SO 4 •- ) under ultrasound, which are active species for TC degradation. Consequently, CoMn 2 O 4 effectively activated PMS into • OH and SO 4 •- active species, enabling the effective TC degradation. Moreover, biotoxicity experiments using germination tests showed that CoMn 2 O 4 was capable of effectively degrading TC, thereby reducing environmental toxicity. This work not only provides mechanistic insights into piezoelectric material-activated PMS for pollutants degradation but also establishes a basis for the application of piezoelectric materials in pollutant degradation.

Excitonic effects significantly influence the selective generation of reactive oxygen species and photothermal conversion efficiency in photocatalytic reactions; however, the intrinsic factors governing excitonic effects remain elusive. Herein, a series of single-atom catalysts with well-defined M 1 -N 3 C 1 (M = Mn, Fe, Co, and Ni) active sites are designed and synthesized to investigate the structure-activity relationship between photocatalytic materials and excitonic effects. Comprehensive characterization and theoretical calculations unveil that excitonic effects are positively correlated with the number of valence electrons in single metal atoms. The single Mn atom with 5.93 valence electrons exhibits the weakest excitonic effects, which dominate superoxide radical (O 2 •- ) generation through charge transfer and enhance photothermal conversion efficiency. Conversely, the single Ni atom with 9.27 valence electrons exhibits the strongest excitonic effects, dominating singlet oxygen ( 1 O 2 ) generation via energy transfer while suppressing photothermal conversion efficiency. Based on the valence electron number dependent excitonic effects, a reaction environment with hyperthermia and abundant cytotoxic O 2 •- is designed, achieving efficient and stable water disinfection. This work reveals single metal atom dependent excitonic effects and presents an atomic-level methodology for catalytic application targeted reaction environment tailoring.

Elaborating the specific reactive oxygen species (ROS) involved in the photocatalytic degradation of atrazine (ATZ) is of great significance for elucidating the underlying mechanism. This study provided conclusive evidence that hydroxyl radicals (·OH) were the primary ROS responsible for the efficient photocatalytic degradation of ATZ, thereby questioning the reliability of widely adopted radical quenching techniques in discerning authentic ROS species. As an illustration, oxygen-modified g-C 3 N 4 (OCN) was prepared to counteract the limitations of pristine g-C 3 N 4 (CN). Comparative assessments between CN and OCN revealed a remarkable 10.44-fold improvement in the photocatalytic degradation of ATZ by OCN. This enhancement was ascribed to the increased content of C-O functional groups on the surface of the OCN, which facilitated the conversion of superoxide radicals (·O 2 - ) into hydrogen peroxide (H 2 O 2 ), subsequently leading to the generation of ·OH. The increased production of ·OH contributed to the efficient dealkylation, dechlorination, and hydroxylation of ATZ. Furthermore, toxicity assessments revealed a significant reduction in ATZ toxicity following its photocatalytic degradation by OCN. This study sheds light on the intricate interconversion of ROS and offers valuable mechanistic insights into the photocatalytic degradation of ATZ.

Restrained by the uncontrollable cleavage process of chemical bonds in methane molecules and corresponding formed intermediates, the target product in the reaction of methane selective oxidation to methanol would suffer from an inevitable overoxidation process, which is considered to be one of the most challenging issues in the field of catalysis. Herein, we report a conceptually different method for modulating the conversion pathway of methane through the selective cleavage of chemical bonds in the key intermediates to suppress the generation of peroxidation products. Taking metal oxides, typical semiconductors in the field of methane oxidation as model catalysts, we confirm that the cleavage of different chemical bonds in CH 3 O* intermediates could greatly affect the conversion pathway of methane, which has a vital role in product selectivity. Specifically, it is revealed that the formation of peroxidation products could be significantly prevented by the selective cleavage of C-O bonds in CH 3 O* intermediates instead of metal-O bonds, which is proved by the combination of density functional theory calculations and in situ infrared spectroscopy based on isotope labeling. By manipulating the lattice oxygen mobility of metal oxides, the electrons transferring from the surface to the CH 3 O* intermediates could directionally inject into the antibonding orbitals of the C-O bond, resulting in its selective cleavage. As a result, the gallium oxide with low lattice oxygen mobility shows a 3.8% conversion rate for methane with a high methanol generation rate (∼325.4 μmol g -1 h -1 ) and selectivity (∼87.0%) under room temperature and atmospheric pressure in the absence of extra oxidants, which is superior among the reported studies (reaction pressure: <20 bar).

Photocatalysis provides an exciting solution to the current growing energy challenge. However, the activity and stability of photocatalysts are two important issues in photocatalytic applications. In this work, we have successfully developed an efficient and stable photocatalyst by loading ReS 2 nanoparticles onto a CdS/ZnS heterojunction. After loading ReS 2 , there is a strong interaction between the CdS/ZnS heterojunction and ReS 2 , which accelerates the photogenerated charge migration and effectively inhibits the recombination of photogenerated electrons and holes. Accordingly, CdS/ZnS-ReS 2 displays excellent photocatalytic activity and stability with the highest hydrogen production rate of 10 722 μmol g -1 h -1 , which is approximately 178 times higher than that of the pure CdS and 5 times better than that of CdS/ZnS. This work not only facilitates solar energy conversion to improve photocatalytic activity and stability but also broadens the application of ReS 2 as a cocatalyst., Competing Interests: The authors declare no competing financial interest., (© 2023 The Authors. Published by American Chemical Society.)

The application of photocatalytic sterilization technology for the sterilization of water has been broadly studied in recent years. However, developing photocatalysts with high disinfection efficiency remains an urgent challenge. Tungsten trioxide with coexisting oxygen vacancies and carbon coating (WO 3- x /C) has been successfully synthesized toward the photothermal inactivation of Escherichia coli . Oxygen vacancies and carbon coating bring WO 3- x /C strong absorption in the infrared region and enhance the carrier separation efficiency. As a result, a higher sterilization rate is obtained compared to WO 3 . WO 3- x /C can completely inactivate E. coli under infrared light within 40 min through photothermal synergy process. During the process of inactivating bacteria over WO 3- x /C, E. coli is killed by the destruction of their cell membrane to decrease the activity of enzymes and release the cell contents, which can be ascribed to the efficient generation of reactive oxygen species (O 2 •- and • OH) and thermal effect. This work demonstrates a novel approach for engineering efficient and energy-saving catalysts for water sterilization.

Phosphorus-doped graphitic carbon nitrides (P-g-C 3 N 4 ) have recently emerged as promising visible-light photocatalysts for both hydrogen generation and clean environment applications because of fast charge carrier transfer and increased light absorption. However, their photocatalytic performances on CO 2 reduction have gained little attention. In this work, phosphorus-doped g-C 3 N 4 nanotubes are synthesized through the one-step thermal reaction of melamine and sodium hypophosphite monohydrate (NaH 2 PO 2 ·H 2 O). The phosphine gas generated from the thermal decomposition of NaH 2 PO 2 ·H 2 O induces the formation of P-g-C 3 N 4 nanotubes from g-C 3 N 4 nanosheets, leads to an enlarged BET surface area and a unique mesoporous structure, and creates an amino-rich surface. The interstitial doping phosphorus also down shifts the conduction and valence band positions and narrows the band gap of g-C 3 N 4 . The photocatalytic activities are dramatically enhanced in the reduction both of CO 2 to produce CO and CH 4 and of water to produce H 2 because of the efficient suppression of the recombination of electrons and holes. The CO 2 adsorption capacity is improved to 3.14 times, and the production of CO and CH 4 from CO 2 increases to 3.10 and 13.92 times that on g-C 3 N 4 , respectively. The total evolution ratio of CO/CH 4 dramatically decreases to 1.30 from 6.02 for g-C 3 N 4 , indicating a higher selectivity of CH 4 product on P-g-C 3 N 4 , which is likely ascribed to the unique nanotubes structure and amino-rich surface.

Exciton and carrier photocatalytic processes have been proved in bismuth oxyhalogen photocatalysts. But, there are no reports about how to regulate the different mechanisms to improve photocatalytic activity for different reaction. Here, we found that the photocatalytic mechanisms could be regulated by changing the assembly method of bismuth, oxygen, and halogen atoms. Reactive oxygen species (ROS) experimentals results concluded that solid solution BiOBr 0.5 I 0.5 showed enhanced exciton photocatalytic process, and coupling 0.5BiOBr/0.5BiOI displayed improved carrier photocatalytic proces. This work promoted the understanding about solid solution and coupling for bismuth oxyhalogen.

Bismuth-rich bismuth oxyhalides (Bi-O-X; X = Cl, Br, I) display high photocatalytic reduction activity due to the promoting conduction band potential. In this work, two Bi 5 O 7 I nanosheets with different dominant facets were synthesized using either molecular precursor hydrolysis or calcination. Crystal structure characterizations, included X-ray diffraction patterns (XRD), field emission electron microscopy and fast Fourier transformation (FFT) images, showed that hydrolysis and calcination resulted in the dominant exposure of {100} and {001} facets, respectively. Photocatalytic data revealed that Bi 5 O 7 I-001 had a higher activity than Bi 5 O 7 I-100 for N 2 fixation and dye degradation. Photoelectrochemical data revealed that Bi 5 O 7 I-001 had higher photoinduced carrier separation efficiency than Bi 5 O 7 I-100. The band structure analysis also used to explain the underlying photocatalytic mechanism based on the different conduction band position. This work presents the first report about the facet-dependent photocatalytic performance of bismuth-rich Bi-O-X photocatalysts.