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The highly efficient photo-oxidation of alcohols has sparked significant potential to cope with environmental pollution and the ever-increasing energy crisis. This study reports a unique Ti 3 C 2 /BiOBr (TB) heterojunction with a rich inter-face based on in situ exfoliation of MXene and subsequently anchored onto BiOBr sheets. The TB nano-composites exhibited substantially improved photo-catalytic activity towards the photo-oxidation of benzyl alcohol (BA) to benzaldehyde and achieved a formation rate of 1.73 mmol g -1  h -1 , greater than pristine BiOBr. The ultra-thin inter-facial contact boosted the oxygen vacancies (O v ) and Ti 3+ and possessed the most negative adsorption energy, which boosted the transfer and separation of inter-facial charge carriers and the adsorption and dissociation of BA. Overall, the successful synthesis of TB composite, along with its exceptional photo-catalytic performance, offers valuable insights for applications in green chemistry and environmental remediation., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

The development of novel semiconductor photo-catalysts for the efficient degradation of antibiotics poses a considerable challenge in the context of ever-increasing environmental pollution. Herein, an S-scheme photo-catalyst consisting of TiO 2 quantum dots (QDs, size ∼4-6 nm) anchored on Bi 2 O 2 CO 3 nano-sheets was synthesised via a facile hydrothermal protocol. TiO 2 /Bi 2 O 2 CO 3 (TB) nano-composite exhibits enhanced photo-catalytic removal of tetracycline, achieving ∼0.0158 min -1 photo-degradation rates using visible light, which is 3- and 53-fold greater than that of pristine TiO 2 and Bi 2 O 2 CO 3 , respectively. The theoretical calculations substantiate that the built-in electric field in the TB nano-composite is conducive to the separation and transfer of photo-excited carriers. Notably, the generated superoxide radicals rather than hydroxyl were identified as the responsible species for tetracycline degradation. In addition, the corresponding degradation pathway and eco-toxicity analysis were also elucidated. In conclusion, this work contributes valuable insights and presents a feasible approach for the fabrication of S-scheme photo-catalysts (TiO 2 QDs and bismuth-based nano-materials), thereby enabling the efficient removal of water pollutants., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

The rational heterojunctions for antibiotics degradation have sparked significant attention in wastewater purification. In this study, we report a unique S-scheme photocatalytic system by in-situ growth of CuBi 2 O 4 quantum dots (QDs) onto {101} facet of TiO 2 spindles (TiO 2 -P) via hydrothermal transformation of Na-titanate nanotubes, which is observed by transmission electron microscopy technology. The CuBi 2 O 4 /TiO 2 -P effectively achieves photo-degradation of tetracycline (TC) using visible light (e.g. an 82% TC degradation efficiency at 60 min), which is attributed to the promotion of the charge separation and retaining strong redox capacity at the heterojunction interfaces via the active species of O 2 - , OH, and h + . Moreover, density functional theory (DFT) calculations show that a built-in electric field forms at the interface of the S-scheme heterojunction. In all, this work introduces a straightforward in-situ hydrothermal growth method to construct S-scheme photocatalysts for effective water treatment., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Inc. All rights reserved.)

In this study, gold nanoparticles were dispersed on Co 3 O 4 nanoplates, forming a specific Au-Co 3 O 4 interface. Upon calcination at 300 °C in air, aberration-corrected STEM images evidenced that the gold nanoclusters (NCs) on Co 3 O 4 {111} were maintained at ca. 2.2 nm, which is similar to the size of the parent Au colloidal particles, demonstrating the stronger metal-support interaction (SMSI) on Co 3 O 4 {111}. Au/Co 3 O 4 {111} showed good catalytic activity (a full CO conversion achieved at 80 °C) and durability (over 10 hours) in CO oxidation, which was mainly due to the promotion by the surface oxygen vacancies and intrinsic defects of Co 3 O 4 {111} for activating O 2 and by Au 0 , Au δ + , and Au + species on the surface of gold NCs for CO activation, as evidenced by Raman and Fourier-transform infrared (FT-IR) spectroscopy analysis. Au/Co 3 O 4 catalyzed CO oxidation obeyed the Langmuir-Hinshelwood mechanism at low temperatures., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Plasmonic Au nanoparticles (NPs) employing localized surface plasmon resonance excitation have exhibited superior visible light absorption for many organic transformations. In this work, we prepared a ternary composite catalyst comprising plasmonic Au NPs and a 2D/2D TiO 2 -C 3 N 4 heterojunction via a photoreduction method of chloroauric acid in the presence of TiO 2 -C 3 N 4 . The introduction of plasmonic nanogold particles embedded onto the TiO 2 surface of the TiO 2 -C 3 N 4 heterojunction can significantly improve the photocatalytic performance during photooxidation of benzyl alcohol to benzaldehyde under mild conditions (1 bar air, white LED irradiation at ambient temperature). The productivity over Au/TiO 2 -C 3 N 4 (0.25 mmol reacted BA g cat. -1 h -1 ) is found to be ∼5.6, 8.3, and 8.2-fold of these over the Au/TiO 2 , TiO 2 -C 3 N 4 , and C 3 N 4 -Au-TiO 2 heterojunctions, respectively. Trapping experiments and electron spin resonance (ESR) spectroscopy confirm that the superoxide ( · O 2 - ) and hydroxyl radicals ( · OH) act as the reactive oxygen species during photooxidation. Furthermore, the experimental results combined with density functional theory calculations reveal that the chemisorbed benzyl alcohol population, surface oxygen vacancies, and lifetime of photoexcited electrons and holes are largely improved by plasmonic Au NPs. This study on nanogold composites provides some hints for developing new efficient and practical photocatalysts.

We here demonstrate the controlled synthesis of BiOBr quantum dots (QDs) decorated Na 2 Ti 3 O 7 necklaces via a hydrothermal transformation of sodium titanate nanotubes. The BiOBr QDs are deposited on the surface of Na 2 Ti 3 O 7 necklaces, forming a heterogeneous interface of BiOBr(200) and Na 2 Ti 3 O 7 (110), which promotes the separation efficiency of photogenerated charges, thus resulting in its superior catalytic performance in the photo-oxidation of benzyl alcohol. The BiOBr/Na 2 Ti 3 O 7 -1.0 exhibiting highest oxygen defect population gives best photocatalytic activity with a promising conversion rate of 3.32 mmol reacted BA g catal. -1 h -1 , which is substantially higher than the corresponding reported photocatalysts. DFT results corroborate the superior performance of BiOBr/Na 2 Ti 3 O 7 is mainly due to the formation of a built-in electric field and given efficiently the charge transfer between BiOBr(200) and Na 2 Ti 3 O 7 (110). In all, this study reports a simple in-situ hydrothermal growth protocol to efficiently construct BiOBr/Na 2 Ti 3 O 7 heterojunction composites and offers guidelines for design of a new synthetic strategy to prepare efficient photocatalysts., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Inc. All rights reserved.)

In this work, an InVO 4 /TiO 2 heterojunction composite catalyst was successfully synthesized through a facile hydrothermal method. The structural and optical characteristics of InVO 4 /TiO 2 heterojunction composites are investigated using a variety of techniques, including powder X-ray diffraction (XRD), transmission electron microscopy (TEM), and spectroscopy techniques. The addition of InVO 4 to TiO 2 considerably enhanced the photocatalytic performance in selective photo-oxidation of benzyl alcohol (BA). The 10 wt% InVO 4/ TiO 2 composite photocatalyst provided a decent 100% BA conversion with over 99% selectivity for benzaldehyde, and exhibited a maximum conversion rate of 3.03 mmol g -1 h -1 , which is substantially higher than bare InVO 4 and TiO 2 . The excellent catalytic activity of the InVO 4/ TiO 2 photocatalyst is associated with the successful assembly of heterostructures, which promotes the charge separation and transfer between InVO 4 and TiO 2 .

Monolithic silica and polymer capillary columns with ultrahigh column efficiencies were prepared. Permeability and electrochromatography performances of these two kinds of columns were compared. Monolithic silica columns bear higher permeability than polymer counterparts by two orders of magnitude. Furthermore, the van Deemter plots of alkylbenzenes on these two kinds of columns demonstrate that monolithic silica columns produce much lower plate heights of alkylbenzes than polymer columns do. Within the range of electroosmotic flow (EOF) velocity investigated, no uptrend of plate height with the increase of EOF was observed suggesting the great capacity of fast separation and high efficiency. The plate height of thiourea on monolithic silica columns is as low as 2.67 μm, representing its corresponding column efficiency is over 430,000 plates/m. As far as we know, it is the highest ever column efficiency reported in the literature. Moreover, the separation of butylbenzene isomers was obtained on the monolithic silica column., (© The Author(s) 2021. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

The interfacial perimeter is generally viewed as the catalytically active site for a number of chemical reactions over oxide-supported nanogold catalysts. Here, well-defined CeO 2 nanocubes, nanorods and nanopolyhedra are chosen to accommodate atomically precise clusters ( e.g. Au 25 (PET) 18 ) to give different Au cluster-CeO 2 interfaces. TEM images show that Au particles of ∼1.3 nm are uniformly anchored on the ceria surface after annealing in air at 120 °C, which can rule out the size hierarchy of nanogold in CO oxidation studies. The gold nanoclusters are only immobilized on the CeO 2 (200) facet in Au 25 /CeO 2 -C, while they are selectively loaded on CeO 2 (002) and (111) in the Au 25 /CeO 2 -R and Au 25 /CeO 2 -P catalysts. X-ray photoelectron spectroscopy (XPS) and in situ infrared CO adsorption experiments clearly demonstrate that the gold species in the Au 25 /CeO 2 samples are similar and partially charged (Au δ + , where 0 < δ < 1). It is observed that the catalytic activity decreases in the order of Au/CeO 2 -R ≈ Au/CeO 2 -P > Au/CeO 4 -C in the CO oxidation. And the apparent activation energy over Au 25 /CeO 2 -C (60.5 kJ mol -1 ) is calculated to be about two-fold of that over the Au 25 /CeO 2 -R (28.6 kJ mol -1 ) and Au 25 /CeO 2 -P (31.3 kJ mol -1 ) catalysts. It is mainly tailored by the adsorbed [O] species on the ceria surface, namely, Au 25 /CeO 2 (002) and Au 25 /CeO 2 (111) which were more active than the Au 25 /CeO 2 (200) system in the CO oxidation. These insights at the molecular level may provide guidelines for the design of new oxide-supported nanogold catalysts for aerobic oxidations., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

The feasibility to synthesize the ligand-protected atomically precise nanoclusters with various compositions in sub-nanometer range (≤2 nm) and the determination of their structures is an important step in long-pursuit of well-defined heterogeneous catalysis. Such types of precise catalysts provide an opportunity to understand the fundamentals of catalysis better in terms of: 1) activity and selectivity by metal-core and metal-ligand interface, 2) size-dependent activity, 3) reaction mechanism and 4) active-site identification and activation. It motivated us to develop the novel metal nanoclusters with precise structures as the new catalytic systems, which led to the several significant findings on above mentioned points. We consider that with this gained knowledge, the future research is expected to bring more exciting advancement in deep understanding of the reaction mechanism, specific-site identification and tailoring of catalytic active sites at atomic level., (© 2021 The Chemical Society of Japan & Wiley-VCH GmbH.)

Methyl formate is widely employed as one of the important organic intermediates in C1 chemistry and as an environmentally benign chemical in the emerging area of "green chemistry". We here study the catalytic effectiveness of CuO/TiO 2 -nanotube nanocomposites for the direct synthesis of methyl formate via methanol photo-oxidation in this paper. The CuO/TiO 2 -nanotube nanocomposites with 7% CuO weight loading give a promising photocatalytic performance (over 93.3% methanol conversion and 89.4% methyl formate selectivity) at 25 °C under 365 nm UV irradiation. The turnover frequency and the apparent quantum efficiency reach up to 22.9 mol methanol g cat -1 h -1 and 57.6% over 7% CuO/TiO 2 -nanotube, respectively, which is mainly because of the effective minimization of the recombination of photogenerated electrons and holes by the surface ultrasmall-sized CuO particles. Furthermore, these CuO/TiO 2 -nanotube nanocomposites exhibit excellent durability and robust nature during the catalytic processes of the methanol photo-oxidation to methyl formate. The experimental results demonstrate the promise of the robust CuO/TiO 2 nanocomposites for efficient and green production of methyl formate, which may offer guidelines for the design of efficient catalysts for selective alcohol conversion to other valuable chemicals., Competing Interests: The authors declare no competing financial interest., (Copyright © 2020 American Chemical Society.)

The coordination motif of alkynly with a metal atom is versatile and plays a pivotal role in tailoring the kernel configuration of the atomically precise metal nanoclusters. In this study, we synthesized a new mono-valent Au(I) 2 Ag(I) 2 (C 10 H 6 NO) 4 (Ph 3 P) 2 alloy cluster with a very high yield of >90%, which is well characterized by a serial of technologies, e.g. UV-vis, X-ray single crystal diffraction (SCXRD) and FT-IR. The SCXRD analysis shows the alloy cluster is composed of a quadrangular Au 2 Ag 2 kernel protected by four alkynyl and two phosphine ligands. Intriguingly, a new divergent alkyne-metal coordination model is revealed in this cluster, the alkynyl ligands selectively bind to Au and Ag atoms via σ- and π-bond configurations and adopt a VI-shaped alkynyl-M motif. It is distinct from the convergent motif observed in big clusters featuring an IV- or V-shaped alkynyl-M motif due to the steric effect. Finally, the titanium oxide-supported Au 2 Ag 2 cluster catalysts show good catalytic performance in the multicomponent coupling reaction of alkynes, aldehydes and amines., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Transformation chemistry is a systematic methodology for achieving new atomically precise gold nanoclusters with specific physical and chemical properties. In this work, we have developed a new synthetic approach to prepare an aromatic thiolate-capped Au38(SNap)24 nanocluster via ligand exchange, size and structure transformation from the aliphatic thiolate-capped Au144(SC6H13)60 parent clusters triggered by the addition of a pyridine additive in the presence of excess 2-naphthalenethiol at thermal conditions (80 °C for 6 h). The Au38(SNap)24 nanoclusters have been well characterized by UV-vis spectroscopy and electrospray ionization mass spectrometry. The transformation pathway from Au144(SC6H13)60 to Au36(SNap)24 and Au38(SNap)24 undergoes different conversion pathways tailored by the pyridine additive in the etching system. Furthermore, the catalytic activity and selectivity of the Au cluster are largely influenced by the chemical nature of the protecting thiolate ligands in the Ullmann hetero-coupling reaction of iodobenzene and nitroiodobenzene. The aromatic ligands result in not only higher conversion but also remarkable increase in the selectivity toward the hetero-coupling product. The study provides new hints for the design and synthesis of new gold nanoclusters in transformation chemistry.

Synthesis of liquid biofuels (C 11 -C 13 ) from cellulosic ethanol is regarded as a promising and versatile protocol. In this study, oxide-supported nanogold catalysts exhibit good catalytic performance in ethanol conversion with cinnamaldehyde and finally give rise to the C 11 -C 13 hydrocarbon. High selectivity (70%) for C 11 -C 13 hydrocarbons is achieved over Au/NiO via a one-pot cascade reaction, viz. cross-aldol condensations in the presence of oxygen and base (K 2 CO 3 ) and then full hydrodeoxygenation with hydrogen gas. EtOH-TPD and TGA analyses show that the ethanol is activated to acetaldehyde (CH 3 CHO*) over the surface oxygen vacancies of the NiO support. The CH 3 CHO* then reacts with cinnamaldehyde at the interfacial perimeter of the Au/NiO composite during the cascade reactions, as evidenced by comparison of the catalytic performance with that over another oxide-supported Au NP, chemo-adsorption investigations, and in situ infrared spectroscopy investigations. This work may provide new guidelines for designing efficient catalysts to convert bioethanol into biofuels with high energy density., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Au clusters with the precise numbers of gold atoms, a novel nanogold material, have recently attracted increasing interest in the nanoscience because of very unique and unexpected properties. The unique interaction and electron transfer between gold clusters and reactants make the clusters promising catalysts during organic transformations. The Au n L m nanoclusters (where L represents organic ligands and n and m mean the number of gold atoms and ligands, respectively) have been well investigated and developed for selective oxidation, hydrogenation, photo-catalysis, and so on. These gold clusters possess unique frameworks, providing insights into the catalytic processes and an excellent arena to correlate the atomic frameworks with their intrinsic catalytic properties and to further investigate the tentative reaction mechanisms. This review comprehensively summarizes the very latest advances in the catalytic applications of the Au nanoclusters for the C-C cross-coupling reactions, e.g., Ullmann, Sonogashira, Suzuki cross-couplings, and A 3 -coupling reactions. It is found that the proposed catalytically active sites are associated with the exposure of gold atoms on the surface of the metal core when partial capping organic ligands are selectively detached under the reaction conditions. Finally, the tentative catalytic mechanisms over the ligand-capped Au nanoclusters and the relationship of structure and catalytic performances at the atomic level using computational methods are explored in detail.