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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