Photocatalytic reduction of CO 2 toward eight-electron CH 4 product with simultaneously high conversion efficiency and selectivity remains great challenging owing to the sluggish charge separation and transfer kinetics and lack of active sites for the adsorption and activation of reactants. Herein, a defective TiO 2 nanosheet photocatalyst simultaneously equipped with AuCu alloy co-catalyst and oxygen vacancies (AuCu-TiO 2−x NSs) was rationally designed and fabricated for the selective conversion of CO 2 into CH 4 . The experimental results demonstrated that the AuCu alloy co-catalyst not only effectively promotes the separation of photogenerated electron−hole pairs but also acts as synergistic active sites for the reduction of CO 2 . The oxygen vacancies in TiO 2 contribute to the separation of charge carriers and, more importantly, promote the oxidation of H 2 O, thus providing rich protons to promote the deep reduction of CO 2 to CH 4 . Consequently, the optimal AuCu-TiO 2−x nanosheets (NSs) photocatalyst achieves a CO 2 reduction selectivity toward CH 4 up to 90.55%, significantly higher than those of TiO 2−x NSs (31.82%), Au-TiO 2−x NSs (38.74%), and Cu-TiO 2−x NSs (66.11%). Furthermore, the CH 4 evolution rate over the AuCu-TiO 2−x NSs reaches 22.47 μmol•g −1 •h −1 , which is nearly twice that of AuCu-TiO 2 NSs (12.10 μmol•g −1 •h −1 ). This research presents a unique insight into the design and synthesis of photocatalyst with oxygen vacancies and alloy metals as the co-catalyst for the highly selective deep reduction of CO 2 .

Polychlorinated thianthrene/dibenzothiophenes (PCTA/DTs) are sulfur analogues compounds to polychlorinated dibenzo-p-dioxin/dibenzofurans (PCDD/Fs). Chlorothiophenols (CTPs) are key precursors to form PCTA/DTs. 2,4-DCTP has the minimum number of Cl atoms to form 2,4,6,8-tetrachlorinated dibenzothiophenes (2,4,6,8-TeCDT), which is the most important and widely detected of the PCDTs. In this paper, quantum chemical calculations were carried out to investigate the homogeneous gas-phase formation of PCTA/DTs from 2,4-DCTP and 2,4,6-TCTP precursors at the MPWB1K/6-311+G(3df,2p)//MPWB1K/6-31+G(d,p) level. Several energetically feasible pathways were revealed to compare the formation potential of PCTA/DT products. The rate constants of the crucial elementary reactions were evaluated by the canonical variational transition-state (CVT) theory with the small curvature tunneling (SCT) correction over a wide temperature range of 600–1200 K. This study shows that pathways that ended with elimination of Cl step were dominant over pathways ended with elimination of the H step. The water molecule has a negative catalytic effect on the H-shift step and hinders the formation of PCDTs from 2,4-DCTP. This study, together with works already published from our group, clearly illustrates an increased propensity for the dioxin formation from CTPs over the analogous CPs.

A combined quantum mechanics/molecular mechanics (QM/MM) computation of the detoxifying mechanism of an epsilon class glutathione transferases (GSTs) toward organochlorine insecticide DDT, 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane, has been carried out. The exponential average barrier of the proton transfer mechanism is 15.2 kcal/mol, which is 27.6 kcal/mol lower than that of the GS-DDT conjugant mechanism. It suggests that the detoxifying reaction proceeds via a proton transfer mechanism where GSH acts as a cofactor rather than a conjugate. The study reveals that the protein environment has a strong effect on the reaction barrier. The experimentally proposed residues Arg112, Glu116 and Phe120 were found to have a strong influence on the detoxifying reaction. The influence of residues Pro13, Cys15, His53, Ile55, Glu67, Ser68, Phe115, and Leu119 was detected as well. It is worth noticing that Ile55 facilitates the detoxifying reaction most. On the basis of the structure of DDT, structure 2, (BrC6H4)2CHCCl3, is the best candidate among all the tested structures in resisting the detoxification of enzyme agGSTe2.

Herein, we report the self-assembly of an anionic homochiral octahedral cage by condensing six Ga 3+ cations and four trisacylhydrazone ligands.T he robust nature of the hydrazone bond renders the cage stable in water,where it can take advantage of the hydrophobic effect for host-guest recognition. In addition to the internal binding site,n amely, the inner cavity,the octahedral cage possesses four "windows", each of which represents an external binding site allowing peripheral complexation. These internal and external binding sites endowthe cage with the capability to bind abroad range of guests whose sizes could either be smaller than or exceed the volume of the cage'si nner cavity.U pon accommodation of ac hiral guest, one of the two cage enantiomers becomes more favored than the other,p roducing circular-dichroism (CD) signals.T he CD signal intensity of the cage is observed to be proportional to the ee value of the chiral guest, allowing aquantitative determination of the latter.

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Due to the low charge separation efficiency and high stability of the CO2 molecule, photoreduction of CO2 into a single multielectron product such as CH4 with a simultaneous high conversion rate and selectivity is challenging. Therefore, it is highly desirable to accelerate charge separation and transfer and provide an electron‐enriched catalyst surface for the deep reduction of CO2. Herein, a Pd/Cu2O/TiO2 ternary hybrid photocatalyst consisting of Pd nanoparticles (NPs) and Cu2O NPs‐decorated TiO2 nanosheets is rationally designed, and highly selective photocatalytic photoreduction of CO2 into CH4 is achieved. The Pd/Cu2O/TiO2 photocatalyst shows a high CH4 production rate of 42.8 μmol g−1 h−1 with an extremely high selectivity of 99.5%. This CH4 production rate is 61.1, 5.4, and 2.8 times higher than the bare TiO2, Cu2O/TiO2, and Pd/TiO2, respectively. In this Pd/Cu2O/TiO2 hybrid, a consecutive multistep charge transfer is steered between the Cu2O/TiO2 heterojunction and Pd, ensures accelerated charge separation and transfer, and leads to the formation of a spatially separated electron‐enriched surface (Pd) and hole‐enriched surface (Cu2O). This spatially oriented charge transfer and the charge‐enriched catalyst surface synergistically contribute to the simultaneous high conversion rate and selectivity of CH4.

Aldehydes have been speculated as important precursor species in the formation of new atmospheric particles. In the present work, quantum chemical calculations were performed to investigate the hydrogen bonding interaction and the Gibbs free energy of formation (ΔG) for clusters consisting of sulfuric acid and aldehydes as well as their atmospheric reaction products. Calculations were conducted at 298 K and 1 atm at the M06-2X/6-311+G(3df,3pd) level. The results show that the addition of aldehyde compounds to HSO unlikely contributes to new particle formation. However, their products from aldol condensation, hydration, and polymerization reactions can promote new particle formation by stabilizing sulfuric acid in the first step of nucleation. Moreover, the favorability of the interaction in the absence of water between sulfuric acid and the addition products is as follows: the hydration products > aldol condensation > aldehydes, but the results may be changed if water molecules are added. In particular, the calculated ΔG values imply that the monohydrate of glyoxal is more likely to nucleate with HSO in comparison with ammonia in the presence or absence of water.

Polychlorinated naphthalenes (PCNs) are the smallest chlorinated polycyclic aromatic hydrocarbons (Cl-PAHs) and are often called dioxin-like compounds. Chlorophenols (CPs) are important precursors of PCN formation. In this paper, mechanistic and kinetic studies on the homogeneous gas-phase formation mechanism of PCNs from 3-CP precursor were investigated theoretically by using the density functional theory (DFT) method and canonical variational transition-state theory (CVT) with small curvature tunneling contribution (SCT). The reaction priority of different PCN formation pathways were disscussed. The rate constants of crucial elementary steps were deduced over a wide temperature range of 600−1200 K. The mechanisms were compared with the experimental observation and our previous works on the PCN formation from 2-CP and 4-CP. This study shows that pathways ended with Cl elimination are favored over those ended with H elimination from the 3-CP precursor. The formation potential of MCN is larger than that of DCN. The chlorine substitution pattern of monochlorophenols has a significant effect on isomer patterns and formation potential of PCN products. The results can be input into the environmental PCN controlling and prediction models as detailed parameters, which can be used to confirm the formation routes of PCNs, reduce PCN emission and establish PCN controlling strategies.