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The multifunctional photocatalysts (Au-Pd/SnNb 2 O 6 ultrathin nanosheets) are developed for selective hydrogenation of cinnamaldehyde to hydrocinnamaldehyde under visible light. The superior catalytic performance is attributed to a synergistic effect of Au, Pd nanoparticles, and SnNb 2 O 6 ultrathin nanosheets. [Display omitted] • Au-Pd/SnNb 2 O 6 (SN) as photocatalysts for selective hydrogenation of cinnamaldehyde. • The C = C of cinnamaldehyde would be absorbed on the surface Lewis acid sites of SN. • Photogenerated electrons promoted H 2 dissociation on Pd, Au reduced overhydrogenation. • The superior performance is attributed to a synergistic effect of catalyst component. Au-Pd bimetallic nanoparticles (NPs) supported on SnNb 2 O 6 ultrathin nanosheets (SN) were developed as multifunctional photocatalysts for the selective hydrogenation of cinnamaldehyde (CAL) to hydrocinnamaldehyde (HCAL) under visible light irradiation. A representative catalyst (Au 6 -Pd 1 /SN) exhibits optimum performances with 99.8% conversion and 91.0% selectivity. The structure and surface properties of the prepared samples were revealed by SEM, TEM, BET, TPD, XPS, and EPR. The results of in situ FTIR spectra and NH 3 -TPD reveal that the rich surface Lewis acid sites on SN can chemisorb and activate CAL via the C = C...Nb coordination. EPR experiments indicate that H 2 would dissociate to activated H atoms on Pd NPs following a photopromoted surface catalytic process. Experimental results suggest that Au NPs reduce the over hydrogenation of HCAL by inhibiting the formation of Pd-H species. The superior catalytic performance is attributed to a synergistic effect of Au, Pd NPs and SN. Finally, a possible synergetic mechanism for Au-Pd/SN is proposed to illustrate the photocatalytic process. This work offers a reference to guide a novel and more effective photocatalyst design for precise organic synthesis driven by sunlight. [ABSTRACT FROM AUTHOR]

The defect-rich ultrathin WO 3 nanosheets are successfully prepared as photocatalysts via heating treatment for the pristine WO 3 nanosheets (NS) in vacuum (NSV) and N 2 atmosphere (NSN). The increment of degradation efficiencies of levofloxacin (LVX) over NS (49.9 %) ... O C and W ... N-C coordination. LC - MS result further demonstrates that the LVX molecules breakdown are mainly initiated by cleaving the activated C O and C-N bonds. More O VS can adsorb and activate more O 2 molecules which shall be converted to •O 2 − by photogenerated electron. The photogenerated holes are transferred on the catalysts surface to form •OH via oxidizing water or directly degrade the activated LVX molecules. Finally, a possible mechanism is proposed to understand the pathway for photocatalytic degradation LVX at molecular scale. This study highlights the significant role of coordination activation for the photocatalytic degradation of antibiotics. [Display omitted] • Defect-rich ultrathin WO 3 nanosheets (≈ 4.8 nm) are synthesized as an active photocatalyst for the efficient degradation of levofloxacin (LVX). • LVX molecules are activated on the catalysts via W ... O C and W ... N-C coordination, improving the degradation efficiency of antibiotics. • Oxygen vacancies can adsorb more O 2 molecules which is converted to •O 2 − by photogenerated electron reduction. • A mechanism is proposed to understand the pathway for photocatalytic degradation LVX at molecule scale. [ABSTRACT FROM AUTHOR]

Pt clusters supported on monolayer Bi 2 MoO 6 nanosheets (Pt/BMO-NS) are constructed for the photocatalytic selective reduction of 4-nitrostyrene to 4-vinylaniline in the presence of HCOONH 4 and exhibit high conversion (≈100%) of 4-nitrostyrene and high selectivity (≈100%) of 4-vinylaniline. In situ FTIR spectra and XPS spectra of BMO-NS absorbed 4-nitrostyrene further demonstrate that 4-nitrostyrene can be selectively absorbed and activated on surface Mo5+ and Bi2+ sites of BMO-NS via the Bi···O-N or Mo···O-N coordination. The Pt clusters and photogenerated carriers synergistically make the efficient dissociation of HCOO- to form rich ·CO 2 - and active ·H, greatly supporting the selective reduction of 4-nitrostyrene to 4-vinyaniline. This work not only highlights the complete utilization of photo-generated carriers to achieve the selective reduction of 4-nitrostyrene to 4-vinylaniline via photocatalytic hydrogen transfer, but also uses metal/monolayer nanosheets as a molecule platform to deeply study the surface/interface synergetic mechanism at the molecule level. [Display omitted] Efficient selective reduction of 4-nitrostyrene to 4-vinylaniline over Pt/BMO-NS via photocatalytic hydrogen transfer. • Pt clusters decorated monolayer Bi 2 MoO 6 nanosheets (Pt/BMO-NS) with surface Bi2+ and Mo5+ sites are constructed. • The Pt/BMO-NS exhibits near 100% conversion of 4-nitrostyrene and near 100% selectivity of 4-vinylaniline under visible light. • The surface Bi2+ and Mo5+ sites as nucleophilic sites could selective absorb and activate the electron-deficient –NO 2 group. • The photo-generated carriers are completely utilized to make the efficient dissociation of HCOO- to form rich·CO 2 - and active H. [ABSTRACT FROM AUTHOR]

Au nanoparticles-anchored defective DUT-67(Zr) MOF was fabricated for photocatalytic transformation of amines to imines and the synergetic mechanism combining the plasmon with the molecular activation was illustrated. [Display omitted] Designing efficient metal organic frameworks (MOF)-based photocatalysts has recently attracted wide attention. In this work, Au nanoparticles(NPs)-decorated defective DUT-67(Zr) (Au@DUT-67(Zr)) with enlarged channels was successfully fabricated and achieved 7.5 times higher conversion than Au NPs-decorated UiO-66(Zr) (Au@UiO-66(Zr)) for photocatalytic selective oxidation of amines to imines driven by visible light. Au NPs are more effectively fixed on DUT-67(Zr) due to its partially hollow structure. Au@DUT-67(Zr) possesses more active sites including unsaturated Zr atoms and oxygen vacancies (VO) than Au@UiO-66(Zr). In situ Fourier transform infrared (FTIR) spectrum reveals that benzylamine is activated on unsaturated Zr sites via H N ... Zr species, facilitating deprotonation of –CH 2 in benzylamine. VO can not only adsorb and activate oxygen (O 2) but also capture plasmonic hot electrons, enhancing the forming of superoxide radical (O 2 −). Plasmonic hot holes assisted with O 2 − effectively achieve the selective oxidation of benzylamine. Finally, a possible synergetic mechanism combining the plasmon with the molecular activation is presented to illustrate the photocatalytic pathway at the molecular level. [ABSTRACT FROM AUTHOR]

Here, the mixed metal nodes MOFs, Pd/MIL-100(Fe a Cu b), were constructed as photocatalysts for hydrogenation of α, β-unsaturated aldehyde (UAL) under visible light. 1 wt% Pd/MIL-100(Fe 0.81 Cu 0.19) can convert a range of UAL to saturated aldehydes (SAL) with a high efficiency (≈ 100 %) and selectivity (≈ 98 %). The results of XPS and in situ DRIFTS reveal that UAL can be selectively activated via a coordination of -C C- on Cu2+ sites, determining the high selectivity of the photocatalytic reaction. The mixed metal nodes and Pd clusters can improve the transformation and separation of photogenerated electrons-holes. EPR result suggests that photogenerated carriers can facilitate the generation of H·on Pd/MIL-100(Fe 0.81 Cu 0.19), enhancing the catalytic activity. A possible mechanism is proposed for elucidating the catalytic processes at the molecular level. This work provides a valuable strategy for tailoring the selectivity of photocatalytic hydrogenation via selective coordination activation. [Display omitted] • Functionalized Pd/MIL-100(Fe 0.81 Cu 0.19) was successfully constructed. • High cinnamaldehyde conversion (100 %) and saturated aldehydes selectivity (98 %) were obtained. • The coordination of -C C- on Cu2+ sites determines the selectivity. • The mechanism of the selective α, β-unsaturated aldehyde hydrogenation is revealed. [ABSTRACT FROM AUTHOR]

Surface Engineering Improving Selective Hydrogenation of p -Chloronitrobenzene over AuPt alloy/SnNb 2 O 6 ultrathin nanosheets under Visible light. [Display omitted] • Bimetallic alloy AuPt decorated SnNb 2 O 6 nanosheet (AuPt/SN) as a photocatalyst has been constructed successfully. • The catalyst (Au 0.5 Pt 0.5 /SN) exhibits a high catalytic conversion efficiency for p -chloronitrobenzene (99.8%) with a selectivity of p -chloroaniline (99.1%). • SN could activate p -chloronitrobenzene via a Sn2+···–NO 2 coordination. • A synergetic effect among Lewis base sites (Sn2+), AuPt alloy and photogenerated electrons is proposed. • A photocatalytic mechanism is determined at molecule scale. AuPt alloy/SnNb 2 O 6 ultrathin nanosheet (AuPt/SN) as a photocatalyst is constructed for selective hydrogenation of p -chloronitrobenzene (p -CNB) under visible light irradiation. A typical catalyst (Au 0.5 Pt 0.5 /SN) exhibits a high conversion of halonitrobenzenes (99.8%) and selectivity of haloaniline (99.1%). The results of in situ ATR-IR, XPS and Raman indicate a preferential chemoselective adsorption of –NO 2 that Lewis base sites (Sn2+) on the catalyst could selectively coordinate with –NO 2 whereas C-Cl bond is not be bonded, improving the catalytic selectivity. Atom Pt in alloy is responsible for the formation of ·H, while Au inhabits the dissociation of C-Cl via repressing the generation of Pt-H. The photogenerated electrons can accelerate the ·H formation. ·H could be transferred to Sn2+ sites for the hydrogenation of –NO 2 by hydrogen spillover. Therefore, the high performance of the catalyst can be attributed to a surface synergetic effect among Lewis base sites (Sn2+), AuPt alloy and photogenerated electrons. [ABSTRACT FROM AUTHOR]

[Display omitted] • Cu 3 Pd 1 /SN exhibits a high performance for semihydrogenation of phenylacetylene. • Cu 3 Pd 1 /SN could activate phenylacetylene via C≡C → Nb π-bonded coordination. • The photogenerated electrons facilitate the production of active H. Bimetallic alloy of CuPd nanoclusters decorated SnNb 2 O 6 nanosheet (CuPd/SN) as a multifunctional photocatalyst has been constructed successfully. Compared with SN, CuPd/SN achieves an excellent performance for semihydrogenation of phenylacetylene under visible light irradiation. Especially, CuPd/SN with the Cu:Pd molar ratio of 3:1 exhibits the highest catalytic conversion efficiency for phenylacetylene (99.6%) with high selectivity of phenylethylene (99.4%). In situ FTIR result reveals that SN could activate phenylacetylene via a C≡C → Nb π-bonded coordination which improves the selectivity of phenylethylene. Experiment results indicate that atom Pd in alloy is responsible for dissociation H 2 , while Cu represses the overhydrogenation. Electrochemical measurements suggest that CuPd alloy on SN surface could greatly minimize the recombination of photogenerated electron − hole pairs. The separated electrons further facilitate the production of active H. Hydrogen spillover would transfer active H to Nb site for phenylacetylene semihydrogenation. Finally, a synergetic catalytic mechanism is deeply discussed at molecule scale. This work would provide a deep insight for designing a multifunctional photocatalyst. [ABSTRACT FROM AUTHOR]

[Display omitted] For semiconductor-based photocatalytic reactions, defect engineering has been proven as an efficient approach to enhance the photocatalytic performance. In this work, a synergistically PVP/EG-assisted in situ self-assembly strategy has been successfully developed for preparing flowerlike BiOCl nanospheres (NSP) assembled by ultrathin nanosheets (thickness of 3.8 nm) with abundant oxygen vacancies (OVs). During the hydrothermal process, PVP plays a template role in controlling the orientation of the crystallite growth, leading to the forming of nanosheets. Meanwhlie, ethylene glycol would induce the self-assembly of nanosheets into a loose hierarchical architecture duo to its stereo-hindrance effect. NSP achieves a twice higher photocatalytic conversion of benzylamine than BiOCl nanosheets (NST) under visible light. XPS, ESR, NH 3 -TPD results manifest that NSP possesses more active sites including OVs and unsaturated Bi atoms than NST, because of avoiding the accumulation of ultrathin nanosheets. In situ FTIR reveals that benzylamine molecules can be chemisorbed and activated on BiOCl interfaces via forming -N ... Bi- species. The OVs can facilitate the forming of superoxide radicals (•O 2 −), achieving the selective photooxidation. Finally, a possible synergetic mechanism based on the interaction of reactants and catalyst interfaces was proposed to illustrate the photocatalytic process at the molecular level. [ABSTRACT FROM AUTHOR]

Ultrathin TiO 2 nanosheets (NST) containing Ti3+ sites are developed as a photocatalyst that exhibits high degradation efficiencies (98.6%) for the degradation of enrofloxacin (ENR) under visible light. The increment of degradation efficiencies for ENR over NST is mainly due to the increase of Ti3+ and oxygen vacancies (OVs). Ti3+ sites on the surface of NST can be associated with ENR molecules through the formation of surface coordination species -COO∙∙∙Ti- intermediates, resulting in the activation of ENR. OVs on NST can adsorb and activate more O 2 molecules to accelerate the generation of O 2 - by photogenerated electrons reduction. The photogenerated holes quickly transfer to the surface of the catalyst to directly degrade the activated ENR. Finally, a possible mechanism about the synergistic effect of coordination activation and photocatalysis is proposed over NST at a molecule level. This study highlights the significant role of coordination activation in the photocatalytic degradation of antibiotics. [Display omitted] • TiO 2 nanosheets with Ti3+ sites and oxygen vacancies are synthesized for the efficient degradation of enrofloxacin (ENR). • ENR molecules are activated on the catalysts via surface -COO∙∙∙Ti- coordination species. • O 2 molecules can be adsorbed and activated on oxygen vacancies to generate O 2 - by photo-generated electron reduction. • A synergistic mechanism of coordination activation and photocatalysis is proposed. [ABSTRACT FROM AUTHOR]

The nano-TiO 2 samples with different morphologies were prepared for visible-light-driven photocatalytic selective oxidation of benzylamine and the role of active sites between morphologies and photocatalytic performances was discussed. [Display omitted] • Three types of anatase nano-TiO 2 with different morphologies were prepared for visible-light-driven photocatalytic selective oxidation of benzylamine. • The surface properties of the samples were systematically studied by various characterization techniques. • Coordinatively unsaturated Ti atoms can chemisorb and activate benzylamine molecules via forming H-N ... Ti coordination species. • Oxygen vacancies can chemisorb and activate oxygen molecules to form reactive oxygen species. • The role of active sites between morphologies and photocatalytic performances was discussed. Enormous efforts have been devoted to exploring the influence of the materials' morphology on photocatalytic performance, while the role of active site between them attracts less attention. Herein, three types of anatase nano-TiO 2 with different morphologies were successfully prepared for visible-light-driven photocatalytic selective oxidation of benzylamine. The material properties of the samples were systematically studied by various characterization techniques such as XRD, SEM, TEM, AFM, XPS, UV–vis DRS, ESR and in situ FTIR. Due to possessing clear advantages especially for having more active sites (coordinatively unsaturated Ti atoms and oxygen vacancies), the TiO 2 with porous structure shows more excellent photocatalytic performance than the other samples. Coordinatively unsaturated Ti atoms can chemisorb and activate benzylamine molecules via forming H-N ... Ti coordination species, whose absorption property of visible light guarantees that TiO 2 samples can achieve the photocatalytic process under visible light. Oxygen vacancies can chemisorb and activate oxygen molecules to form reactive oxygen species (superoxide radical) by the reduction of photogenerated electrons. Finally, a possible synergetic mechanism based on the interaction of reactants and catalyst interfaces was proposed at the molecular level to illustrate the photocatalytic process. [ABSTRACT FROM AUTHOR]