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Single‐atom photocatalysts have shown their fascinating strengths in enhancing charge transfer dynamics; however, rationally designing coordination sites by metal doping to stabilize isolated atoms is still challenging. Here, a one‐unit‐cell ZnIn2S4 (ZIS) nanosheet with abundant Cu dopants serving as the suitable support to achieve a single atom Pt catalyst (Pt1/Cu–ZIS) is reported, and hence the metal single atom–metal dopant interaction at an atomic level is disclosed. Experimental results and density functional theory calculations highlight the unique stabilizing effect (Pt–Cu interaction) of single Pt atoms in Cu‐doped ZIS, while apparent Pt clusters are observed in pristine ZIS. Specifically, Pt–Cu interaction provides an extra coordination site except three S sites on the surface, which induces a higher diffusion barrier and makes the single atom more stable on the surface. Apart from stabilizing Pt single atoms, Pt–Cu interaction also serves as the efficient channel to transfer electrons from Cu trap states to Pt active sites, thereby enhancing the charge separation and transfer efficiency. Remarkably, the Pt1/Cu–ZIS exhibits a superb activity, giving a photocatalytic hydrogen evolution rate of 5.02 mmol g−1 h−1, nearly 49 times higher than that of pristine ZIS. [ABSTRACT FROM AUTHOR]

Defects in nanomaterials often lead to properties that are absent in their pristine counterparts. To date, most studies have focused on the effect of single defects, while ignoring the synergy of multiple defects. In this study, a model of photocatalytic O2 activation was selected to unravel the role of dual defects by decorating bismuth oxide with surface O vacancies and bulk O substitution simultaneously. The introduction of dual defects led to a spatial and electronic synergistic process: i) O substitution induced a local electric field in the bulk of BiO2−x, which promoted bulk separation of electrons and holes immediately after their generation; ii) O vacancies efficiently lowered the conduction band, served as the capture center for electrons, and thus facilitated the adsorption and activation of O2. This effect was greatly promoted by the coexistence of bulk O substitution, and DFT calculations showed that only O substitution near an O vacancy could have this effect. [ABSTRACT FROM AUTHOR]

A highly efficient Z‐scheme photocatalytic system constructed with 1D CdS and 2D CoS2 exhibited high photocatalytic hydrogen‐evolution activity of 5.54 mmol h−1 g−1 with an apparent quantum efficiency of 10.2 % at 420 nm. More importantly, its interfacial charge migration pathway was unraveled: The electrons are efficiently transferred from CdS to CoS2 through a transition atomic layer connected by Co–S5.8 coordination, thus resulting in more photogenerated carriers participating in surface reactions. Furthermore, the charge‐trapping and charge‐transfer processes were investigated by transient absorption spectroscopy, which gave an estimated charge‐separation yield of approximately 91.5 % and a charge‐separated‐state lifetime of approximately (5.2±0.5) ns in CdS/CoS2. This study elucidates the key role of interfacial atomic layers in heterojunctions and will facilitate the development of more efficient Z‐scheme photocatalytic systems. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • The Ag/ZnO/g-C 3 N 4 composite was used to clean Escherichia coli. • It displayed considerably increased bactericidal activity. • The bactericidal effect was enhanced obviously. • The conduction band levels and surface plasmon resonance (SPR) were key factors. Abstract The Ag/ZnO/g-C 3 N 4 composite photocatalyst, which was synthesized by thermal polymerization of a melamine precursor combined with solvothermal reaction, was used as a visible-light-driven biocide toward Escherichia coli (E. coli). The Ag/ZnO/g-C 3 N 4 composite displayed considerably increased visible-light-driven bactericidal activity compared to g-C 3 N 4 , Ag/g-C 3 N 4 , and ZnO/g-C 3 N 4 powders. The photocatalytic destruction of E. coli cells was verified by fluorescence-based cell live/dead analysis and SEM. The mechanism of increased bactericidal effect was studied by UV–vis diffuse reflectance spectroscopy, photoluminescence spectroscopy, photocurrent response, and electrochemical impedance spectroscopy (EIS). The enhanced photocatalytic bactericidal effect was attributed to the matching conduction band levels of g-C 3 N 4 and ZnO and the surface plasmon resonance (SPR) effect of Ag nanoparticles, which resulted in enhanced adsorption of visible light, reduced recombination of free charges, and rapid separation and transportation of photogenerated electrons-holes. The disinfection mechanism was investigated using different chemical scavengers and electron spin-resonance spectroscopy (ESR), and indicating the important role of h+ and H 2 O 2. Furthermore, taking into account the bulk availability and better bactericidal effect of Ag/ZnO/g-C 3 N 4 , this work provides a new pathway to develop advanced materials for water disinfection. [ABSTRACT FROM AUTHOR]

Recently, developing high-efficiency photocatalytic hydrogen generation photocatalysts and clarifying the inherent mechanism behind the enhancement of hydrogen generation activity have been the research focus. Here, we present a step-wise strategy to prepare Pt/TiO 2 /reduced graphene oxide photocatalysts and the inherent mechanism of the enhanced photocatalytic activities were systematically investigated. Experimentally, the 2 wt% rGO doped rGO/Pt-TiO 2 nanocomposites showed the superior solar-driven hydrogen generation rate (1075.68 μmol h −1 g −1 ), which was 81 times and 5 times higher than bare TiO 2 and Pt/TiO 2 samples, respectively. X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectra (FT-IR) demonstrated the formation of Ti O C bonds in the hybrid, which drove the shifting upwards of the valence band edge from +2.2 eV to +1.83 eV. Furthermore, photoelectrochemical tests indicated the electron density of PTG-2 was about one order of magnitude higher than TiO 2 . Moreover, DFT calculations displayed that the bandgap had been successfully narrowed from 2.88 eV to 2.76 eV and the original blank energy region located at TiO 2 bandgap was filled with C2p orbitals, which resulted in excited electrons in TiO 2 efficiently transferring to graphene. Consequently, the DFT calculations are in good agreement with the experimental results and physical characterizations. This study affords us a rational design of a high efficiency photocatalytic system for solar energy conversion. [ABSTRACT FROM AUTHOR]

Herein, an example of Cu‐doped few‐layer ZnIn2S4 nanosheets is used to reveal the origin of optimum and excess doping for photocatalysts at atomic level. Results show that the metal‐S4 coordination maintains well with 0.5 wt% Cu substituted Zn atoms in the lattice. The introduced Cu atoms bring electronic acceptor states close to the valence band (VB) maximum and thus ensures higher charge density and efficient carrier transport, resulting in an optimum hydrogen evolution rate of 26.2 mmol h−1 g−1 and an apparent quantum efficiency of 4.76% at 420 nm. However, a distorted atomic structure and largely upshift of VB maximum with Cu‐S3.6 coordination are found with excess doping concentration (3.6 wt%). These bring the heavy charge recombination and consequentially dramatic reduced activity. This work provides a new insight into elemental doping study and takes an important step toward the development of ultrathin 2D photocatalysts. Few‐layer ZnIn2S4 nanosheets with tunable copper doping are used to disclose the origin of optimum and excess doping for photocatalysis at atomic level. Experimental and theoretical evidence reveal that optimal and excess doping is derived from the different local coordination configuration of dopants, extent of distortion, and the change of electronic structure. [ABSTRACT FROM AUTHOR]

Ordered mesoporous Ag/CeO 2 nanocomposites were prepared by combining nanocasting with photo-assisted reduction. The heterogeneous photoreactivity of the prepared samples was tested for inactivating Escherichia coli ( E. coli ). These mesoporous Ag/CeO 2 nanocomposites exhibited superior photocatalytic disinfection efficiency than mesoporous CeO 2 and bulk CeO 2 , respectively. Doping Ag species could extend the absorption range to visible light area and enhance the concentration of Ce 3+ ions and oxygen vacancies, which had significant influence on the surface properties of CeO 2 . Moreover, it is the first time to verify that created midgap states through doping Ag can significantly lower the threshold of incident photon energy and broaden the adsorption spectrum demonstrated by experimental studies and density functional theory (DFT) calculations. The enhanced disinfection mechanism was attributed to the fact that the novel mesoporous structure can promote the mass transfer process and the interfacial interaction between Ag species and CeO 2 and lead to reduced recombination of free charges, rapid separation and transportation of photogenerated electrons-holes. This work provides a new method to develop novel mesoporous plasmonic photocatlysts for disinfection using solar radiation. [ABSTRACT FROM AUTHOR]

Red phosphorus (RP) has recently attracted much attention in photocatalysis for its low cost, environmental benign and optical properties. However, its photocatalytic activity is still restricted since the low-charge carrier mobility and the high water-solubility. Herein, RP-S-12 h (Combination of RP nanosheet (NS) and bulk RP structure) was prepared by hydrothermal method. Results showed that the multiple reactive active sites, the energy level matching, the emergence of intermediate state and the internal unequal potential for RP-S-12 h ensured higher charge density and efficient carrier transport, improving the photocatalytic activity and stability, emphasizing the role of multiple interfacial effects. The optimum hydrogen evolution rate was 0.33 mmol g−1 h−1, and the quantum efficiency at 420 nm is 0.45%. In addition, RP-S-12 h could completely degrade 50 ppm MO in 12 min. This study provides a novel insight into the interface design of metal-free photocatalyst for environmental remediation. [Display omitted] • The RP NS formed in situ on the bulk RP composites by a simple hydrothermal method. • The imbalance potential of RP-S-12 h accelerated the transfer of photogenerated electrons. • The appearance of intermediate state enhanced the charge separation rate. • The HER rate of RP-S-12 h was 5.3 times and 2.5 times higher than RP bulk and NS. [ABSTRACT FROM AUTHOR]

Herein, an example of Cu‐doped few‐layer ZnIn2S4 nanosheets is used to reveal the origin of optimum and excess doping for photocatalysts at atomic level. Results show that the metal‐S4 coordination maintains well with 0.5 wt% Cu substituted Zn atoms in the lattice. The introduced Cu atoms bring electronic acceptor states close to the valence band (VB) maximum and thus ensures higher charge density and efficient carrier transport, resulting in an optimum hydrogen evolution rate of 26.2 mmol h−1 g−1 and an apparent quantum efficiency of 4.76% at 420 nm. However, a distorted atomic structure and largely upshift of VB maximum with Cu‐S3.6 coordination are found with excess doping concentration (3.6 wt%). These bring the heavy charge recombination and consequentially dramatic reduced activity. This work provides a new insight into elemental doping study and takes an important step toward the development of ultrathin 2D photocatalysts. Few‐layer ZnIn2S4 nanosheets with tunable copper doping are used to disclose the origin of optimum and excess doping for photocatalysis at atomic level. Experimental and theoretical evidence reveal that optimal and excess doping is derived from the different local coordination configuration of dopants, extent of distortion, and the change of electronic structure. [ABSTRACT FROM AUTHOR]