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BiOCl photocatalysis shows great promise for molecular oxygen activation and NO oxidation, but its selective transformation of NO to immobilized nitrate without toxic NO2 emission is still a great challenge, because of uncontrollable reaction intermediates and pathways. In this study, we demonstrate that the introduction of triangle Cl−Ag1−Cl sites on a Cl‐terminated, (001) facet‐exposed BiOCl can selectively promote one‐electron activation of reactant molecular oxygen to intermediate superoxide radicals (⋅O2−), and also shift the adsorption configuration of product NO3− from the weak monodentate binding mode to a strong bidentate mode to avoid unfavorable photolysis. By simultaneously tuning intermediates and products, the Cl−Ag1−Cl‐landen BiOCl achieved >90 % NO conversion to favorable NO3− of high selectivity (>97 %) in 10 min under visible light, with the undesired NO2 concentration below 20 ppb. Both the activity and the selectivity of Cl−Ag1−Cl sites surpass those of BiOCl surface sites (38 % NO conversion, 67 % NO3− selectivity) or control O−Ag1−O sites on a benchmark photocatalyst P25 (67 % NO conversion and 87 % NO3− selectivity). This study develops new single‐atom sites for the performance enhancement of semiconductor photocatalysts, and also provides a facile pathway to manipulate the reactive oxygen species production for efficient pollutant removal. [ABSTRACT FROM AUTHOR]

Seawater is one of the most important CO2 sequestration media for delivering value‐added chemicals/fuels and active chlorine; however, this scenario is plagued by sluggish reaction rates and poor product selectivity. Herein, we first report the synthesis of nitrogen‐doped BiOCl atomic layers to directly split carbon‐sequestrated natural seawater (Yellow Sea, China) into stoichiometric CO (92.8 μmol h−1) and HClO (83.2 μmol h−1) under visible light with selectivities greater than 90 %. Photoelectrons enriched on the exposed BiOCl{001} facet kinetically facilitate CO2‐to‐CO reduction via surface‐doped nitrogen bearing Lewis basicity. Photoholes, mainly located on the lateral facets of van der Waals gaps, promote the selective oxidation of Cl− into HClO. Sequestrated CO2 also maintains the pH of seawater at around 4.2 to prevent the alkaline earth cations from precipitating. The produced HClO can effectively kill typical bacteria in the ballast water of ocean‐going cargo ships, offering a green and safe way for onsite sterilization. [ABSTRACT FROM AUTHOR]

Photocatalytic reduction of CO2 to value‐added liquid fuels is a promising approach to alleviate the global energy and environmental problems. However, highly selective production of C2+ products from CO2 reduction reaction (CO2RR) is very difficult because of the sluggish CC coupling reaction. An asymmetric coupled heteronuclear photocatalyst is designed to overcome this limitation. The new catalyst contains single atoms of nickel and cobalt loaded on titanium dioxide. It exhibits an impressive 71% selectivity for acetic acid. The experimental data and theoretical calculations reveal that the Ni and Co single atom sites not only significantly lower the energy barrier of electron transfer in photocatalysis but also efficiently promote the CC coupling toward CH3COOH. The high activity of such a heteronuclear catalyst system will shed light on the future development of effective materials for CO2RR. [ABSTRACT FROM AUTHOR]

In the context of sustainable development and carbon neutrality, great efforts have been dedicated to the utilization of green energy such as sunlight and renewable electricity to tackle problems encountered amid energy‐ and emission‐intensive industries like nitrogen fixation. Despite significant progress made in the photocatalytic and electrocatalytic nitrogen fixation, they are still limited by the insufficient activity due to poor N2 activation. Herein, we reviewed our work focusing on the rational design of active sites for the efficient photocatalytic and electrocatalytic activation of molecular N2, including oxygen vacancy of BiOX, plasmonic Ru and Fe on TiO2–xHy, interfacial polarization field of single‐atom Fe and strained core‐shell Ru nanoparticles. Besides, this review also covers our endeavor to deal with environmental pollution based on the iron redox chemistry, including the O2 activation by low‐valent iron species, the acceleration of iron redox cycle to improve Fenton‐like reactivity, and the development of novel zero‐valent iron. What is the most favorite and original chemistry developed in your research group? Environmental chemistry of iron, including Fenton reaction, zero‐valent iron, other iron bearing materials and iron‐based pollutant control methods. How do you get into this specific field? Could you please share some experiences with our readers? I entered the specific field of Environmental chemistry of iron when I started my research career in College of Chemistry, Central China Normal University. Environmental chemistry of iron is a frontier in environmental chemistry and geochemistry. Iron ranks the 4th most abundant element in the Earth's Crust and is ubiquitous in atmospheric aerosols, natural waters and soils as well as animals and plants. Iron could play an important role in the processes of the biogeochemical cycling in the environment and chemical dynamics in organisms because of its abundant existence and redox properties. Iron cycling and its coupling interactions can directly drive the geochemical cycling of some major and trace elements, such as carbon, nitrogen and sulfur, and have strong influence on the fate, transport, transformation and bioavailability of natural contaminants. How do you supervise your students? I always encourage my students to innovate, persist and enjoy their researches. What is the most important personality for scientific research? The most important personality for scientific research is strong interest. What's your hobby? What's your favorite book(s)? My hobby is badminton. My favorite book is World of Plainness. How do you keep balance between research and family? Family is the warm harbor to strongly support my research and sooth pain and anxiety from life. I will stay with family and share my research progress with my family. Who influences you mostly in your life? Professor Jincai Zhao influences me mostly in my life. He guides and supports my research all the time as a godfather. What is your favorite journal(s)? Journal of the American Chemical Society. [ABSTRACT FROM AUTHOR]

Photocatalytic CO2 reduction (PCR) is able to convert solar energy into chemicals, fuels, and feedstocks, but limited by the deficiencies of photocatalysts in steering photon-to-electron conversion and activating CO2, especially in pure water. Here we report an efficient, pure water CO2-to-CO conversion photocatalyzed by sub-3-nm-thick BiOCl nanosheets with van der Waals gaps (VDWGs) on the two-dimensional facets, a graphene-analog motif distinct from the majority of previously reported nanosheets usually bearing VDWGs on the lateral facets. Compared with bulk BiOCl, the VDWGs-rich atomic layers possess a weaker excitonic confinement power to decrease exciton binding energy from 137 to 36 meV, consequently yielding a 50-fold enhancement in the bulk charge separation efficiency. Moreover, the VDWGs facilitate the formation of VDWG-Bi-VO••-Bi defect, a highly active site to accelerate the CO2-to-CO transformation via the synchronous optimization of CO2 activation, *COOH splitting, and *CO desorption. The improvements in both exciton-to-electron and CO2-to-CO conversions result in a visible light PCR rate of 188.2 μmol g−1 h−1 in pure water without any co-catalysts, hole scavengers, or organic solvents. These results suggest that increasing VDWG exposure is a way for designing high-performance solar-fuel generation systems. Efficient CO2 photoreduction in pure water remains challenging. Here, the authors propose to use van der Waals gaps-rich BiOCl atomic layers with low exciton binding energy and abundant surface oxygen vacancies for CO2 to CO conversion. [ABSTRACT FROM AUTHOR]

Constructing heterojunctions is an efficient approach for enhancing charge separation to optimize photoreactivity. Although the aligned built‐in electric fields across the heterointerface are generally considered as the main driving force for charge separation, diffusion‐controlled charge separation also happens, which is poorly investigated in photocatalytic heterojunctions. Here, a perylene‐3,4,9,10‐tetracarboxylic diimide (PDI)–bismuth oxyiodide (BiOI) heterojunction is elaborately fabricated by in situ successive ion layer adsorption and reaction (SILAR) methods. Utilizing Kelvin probe force microscopy (KPFM), the local separation of photogenerated charge carriers across the heterointerface is directly mapped, which obeys a Z‐scheme mechanism. Experimental results and theoretical simulations reveal that the differences of electron densities between PDI and BiOI enable a diffusion‐controlled charge separation process, which overwhelm that of built‐in electric fields across heterointerfaces. Benefiting from the effective charge separation driven by a diffusion‐controlled driving force, this PDI/BiOI heterojunction exhibits superior photocatalytic activities even under infrared (IR)‐light irradiation. These findings highlight the importance of diffusion‐controlled charge separation, and also offer useful roadmaps for the design of high‐performance heterojunction photocatalysts for down‐to‐earth applications. [ABSTRACT FROM AUTHOR]

The purification of water and air by semiconductor photocatalysis is a rapidly growing area for academic research and industrial innovation, featured with ambient removal of organic or inorganic pollutants by using solar light as the energy source and atmospheric O2 as the green oxidant. Both charge transfer and energy transfer from excited photocatalysts can overcome the spin-forbidden nature of O2. Layered bismuth oxyhalides are a new group of two-dimensional photocatalysts with an appealing geometric and surface structure that allows the dynamic and selective tuning of O2 activation at the surface molecular level. In this Feature Article, we specifically summarize our recent progress in selective O2 activation by engineering surface structures of bismuth oxyhalides. Then, we demonstrate selective photocatalytic O2 activation of bismuth oxyhalides for environmental control, including water decontamination, volatile organic compound oxidation and nitrogen oxide removal, as well as selective catalytic oxidations. Challenges and opportunities regarding the design of photocatalysts with satisfactory performance for potential environmental control applications are also presented. [ABSTRACT FROM AUTHOR]

Semiconductor photocatalysis is a trustworthy approach to harvest clean solar light for energy conversions, while state-of-the-art catalytic efficiencies are unsatisfactory because of the finite light response and/or recombination of robust charge carriers. Along with the development of modern material characterization techniques and electronic-structure computations, oxygen vacancies (OVs) on the surface of real photocatalysts, even in infinitesimal concentration, are found to play a more decisive role in determining the kinetics, energetics, and mechanisms of photocatalytic reactions. This Review endeavors to clarify the inherent functionality of OVs in photocatalysis at the surface molecular level using 2D BiOCl as the platform. Structure sensitivity of OVs on reactivity and selectivity of photocatalytic reactions is intensely discussed via confining OVs onto prototypical BiOCl surfaces of different structures. The critical understanding of OVs chemistry can help consolidate and advance the fundamental theories of photocatalysis, and also offer new perspectives and guidelines for the rational design of catalysts with satisfactory performance. [ABSTRACT FROM AUTHOR]

Homogeneous doping can boost solar-to-hydrogen conversion and therefore attracts great attention. Although a great deal of effort has been made to explore the doping-photoreactivity relationship, the doping mechanisms, especially from the perspective of crystal facets, are seldom explored. In this study, a general homogeneous carbon doping strategy is established and then serves as the doping model for a mechanistic investigation, as encouraged by its versatility in enabling homogeneous incorporation of carbon and improving solar-to-hydrogen conversion for typical oxides including TiO2, ZnO, and BiOCl. Using well-defined BiOCl nanosheets of high {001} or {010} facet exposure, we clarify the homogeneous carbon doping mechanism at the level of crystal facets for the first time. This mechanism involves the initial facet-dependent adsorption of the dopant precursor, regulated by the surface atomic structures, and the subsequent facet-dependent diffusion of carbon dopants associated with the facet-related arrangements of bulk atoms. This results in facet-dependent carbon doping behavior and a dopant-concentration-dependent solar-to-hydrogen conversion property of BiOCl nanosheets. These mechanistic insights also suggest that the implantation of the dopant precursor in the shallow lattice of host nanocrystal is vital for the effective homogeneous doping. This new doping model is different from the conventional counterpart based on the organic ligands or gas molecules adsorption onto the surface of host nanocrystals, where surface doping usually occurs. [ABSTRACT FROM AUTHOR]

In this study, we demonstrate that the photoelectrochemical and photocatalytic properties of BiOI strongly depend on their microstructures. Compared to BiOI nanoplates with thickness <100 nm, BiOI nanoplate microspheres of 2-5 μm in size exhibited a superior photocatalytic methyl orange degradation performance, but their photocurrent was only 1/11 of that of BiOI nanoplates. The insights into the microstructure-dependent difference are discussed in detail. We think that the higher photocurrent of BiOI nanoplates film lies in more photogenerated electrons because of narrower band gap and less surface defects and better electron transport between nanoplates owing to good connectivity, while the superior photocatalytic degradation activity of BiOI nanoplate microspheres is attributed to their better methyl orange adsorption ability and abundant surface reaction sites as well as more powerful oxidative ability because of larger band gap. This study provides some clues to enhance photoelectrochemical property and photocatalytic activity of semiconductor materials. [ABSTRACT FROM AUTHOR]

Porous sulfur-doped In(OH) (In(OH)S) hollow nanocubes were fabricated for the first time by taking advantage of a facile solution-phase approach using thioacetamide as the sulfur source at a temperature as low as 80 °C. The phase structures, composition, and morphologies of resulting products were investigated by powder X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, and high-resolution transmission electron microscopy. The characterization results indicated that the addition of thioacetamide in synthetic solution could not only accelerate the hollowing process and tune the size of nanocubes but also facilitate the doping of sulfur in In(OH). We proposed that the cooperative combination of oriented attachment and Ostwald ripening as well as chemical-etching process governed the crystal growth, resulting in the formation of the porous sulfur-doped In(OH) hollow nanocubes in this study. We also found these novel In(OH)-based hollow nanostructures showed evolutional room temperature photolumincence emissions at visible-light region, suggesting their potential application in the optical and photocatalytic fields. [ABSTRACT FROM AUTHOR]

Abstract: Deactivated silver-coated TiO2 photocatalyst can be easily reactivated by ambient light illumination. The process converts Ag0 to Ag(I) in the form of Ag2O. When the activated catalyst is used in photocatalysis, Ag(I) would be eventually reduced to Ag0 forming fresh non-aggregated silver nanoparticles on TiO2. The presence of some transitory Ag+ ions during photocatalysis can help to oxidize species adsorbed on the catalyst and regenerate a clean surface. This simple approach should be very useful for designing maintenance-free photocatalytic air purification systems. [Copyright &y& Elsevier]

Numerous publications have investigated nitric oxide (NO) removal through semiconductor photocatalytic technology. However, few reports are available on the products and mechanisms of the photocatalytic NO removal process. In this study, BiOI hollow microspheres are synthesized for the photocatalytic removal of NO under the visible light irradiation. Results show that NO removal product and NO removal mechanism could interfere with each other. NO removal process could be changed from nonselective oxidation to selective oxidation as the irradiation time increases. Meanwhile, the product of NO removal could be changed from nitrate (NO 3 − ) to nitrogen dioxide (NO 2 ). These interesting changes were attributed to the generated NO 3 − , which was produced from the reactions between NO and OH. The generated NO 3 − could inhibit OH generation, thus leading to a change in the NO removal products and NO removal mechanism. This study can improve our understanding of NO removal on the photocatalyst surface and serve as a guide in using photocatalysts for NO removal. [ABSTRACT FROM AUTHOR]

Highlights: [•] Highly water dispersible TiO2 nanocrystals were synthesized via a facile nonaqueous sol–gel method. [•] TiO2 nanocrystals were 5–10nm in diameter and modified with carbonaceous species. [•] Carbonaceous species endow TiO2 nanocrystals with highly water dispersible property and superior photocatalytic activity. [Copyright &y& Elsevier]

Abstract: In this study, we report the synthesis of hierarchical chlorine-doped rutile TiO2 spherical clusters of nanorods photocatalyst on a large scale via a soft interface approach. This catalyst showed much higher photocatalytic activity than the famous commercial titania (Degussa P25) under visible light (λ>420nm). The resulting sample was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution TEM (HRTEM), nitrogen adsorption, X-ray photoelectron spectroscopy (XPS), UV–vis diffuse reflectance spectroscopy, 1H solid magic-angle spinning nuclear magnetic resonance (MAS-NMR) and photoluminescence spectroscopy. On the basis of characterization results, we found that the doping of chlorine resulted in red shift of absorption and higher surface acidity as well as crystal defects in the photocatalyst, which were the reasons for high photocatalytic activity of chlorine-doped TiO2 under visible light (λ>420nm). These hierarchical chlorine-doped rutile TiO2 spherical clusters of nanorods are very attractive in the fields of environmental pollutants removal and solar cell because of their easy separation and high activity. [Copyright &y& Elsevier]

Macroporous nanocrystalline YFeO3 was prepared by a self-propagating combustion method using yttrium nitrate and iron nitrate as precursors and glycine as a fuel. The phase structure of the product can be selectively controlled to be hexagonal or orthorhombic by simply adjusting the ratio of glycine to nitrate. The samples were characterized by X-ray diffraction (XRD) analysis, N2 adsorption, micro-Raman spectroscopy, Fourier transform infrared absorption spectroscopy (FT-IR), thermal analysis (TGA/DSC), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), and magnetic property analysis. Photocatalytic activity for the degradation of methylene blue in water under visible light irradiation shows that the orthorhombic YFeO3 is superior to the hexagonal form. More adsorbed oxygen and ferromagnetism of the orthorhombic sample may explain its high activity. [Copyright &y& Elsevier]

Nanocrystalline TiO2 (sample S1) was prepared from a titanium oxo cluster (Ti7O4(OEt)20) precursor via a sol–gel route. This photocatalyst showed a higher photocatalytic activity than the TiO2 (sample S2) obtained from titanium tetraisopropoxide. The samples were characterized by thermal analysis (TGA/DSC), X-ray diffraction, micro-Raman spectroscopy, transmission electron microscopy, N2 adsorption (BET surface area), infrared absorption spectroscopy (FT-IR) and X-ray photoelectron spectroscopy. The characterization results show that both samples are anatase nanocrystals with particle sizes of about 12 nm, but the more photocatalytically active sample S1 has more surface hydroxyl groups and larger surface area and pore volume than sample S2. [Copyright &y& Elsevier]

A simple method for preparing highly photoactive nano-sized TiO2 photocatalyst with anatase and brookite phase was developed by hydrolysis of titanium tetraisopropoxide in pure water or the EtOH/H2O mixed solution under ultrasonic irradiation. The prepared TiO2 powders were characterized by differential thermal analysis (DTA), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and BET surface areas. The photocatalytic activity was evaluated by the photocatalytic oxidation of acetone in air. The results showed that the photocatalytic activity of TiO2 powders prepared by this method from pure water or the EtOH/H2O mixed solutions with the molar ratio of EtOH/H2O=1 exceeded that of Degussa P-25. The molar ratios of EtOH/H2O obviously influenced the crystallization, crystallite size, BET surface areas and photocatalytic activity of the prepared TiO2 powders. Ultrasonic irradiation obviously enhanced the photocatalytic activity of TiO2 powders whether the solvent is pure water or the EtOH/H2O mixed solutions. This may be ascribed to the fact that ultrasonic irradiation enhances hydrolysis of titanium alkoxide and crystallization of TiO2 gel. [Copyright &y& Elsevier]

Rational engineering of oxygen vacancy (V O) at atomic precision is the key to comprehensively understanding the oxygen chemistry of oxide materials for catalytic oxidations. Here, we demonstrate that V O can be spatially confined on the surface through a sophisticated surface hydrogen bond (HB) network. The HB network is constructed between a hydroxyl-rich BiOCl surface and polyprotic phosphoric acid, which remarkably decreases the formation energy of surface V O by selectively weakening the metal–oxygen bonds in a short range. Thus, surface-confined V O enables us to unambiguously distinguish the intrafacial and suprafacial oxygen species associated with NO oxidation in two classical catalytic systems. Unlike randomly distributed bulk V O that benefits the thermocatalytic NO oxidation and lattice O diffusion by the dominant intrafacial mechanism, surface V O is demonstrated to favor the photocatalytic NO oxidation through a suprafacial scheme by energetically activating surface O 2 , which should be attributed to the spatial confinement nature of surface V O. [ABSTRACT FROM AUTHOR]

The relationship between oxygen vacancy (OV) concentration of semiconductors and their photocatalytic performances is far from clarified. In this study, by tuning the OV concentration of BiOCl (001) surface via a novel H 2 O 2 treatment coupled infrared irradiation method, we demonstrate that OV concentration of BiOCl (001) surface strongly determine its surface atomic and electronic structures to modulate the photocatalytic pathways. Being of shorter Bi Bi and Bi O bond lengths as well as more electrons being less localized, BiOCl (001) surface with higher OV concentration favored molecular oxygen activation to generate O 2 2− via a two-electron transfer pathway, while the generated O 2 2− could prevent the over oxidation of amines and thus achieve high selectivity in the oxidation of amines to imines. Similar phenomena were also observed for other semiconductor photocatalysts such as TiO 2 and Nb 2 O 5 , suggesting the generality of oxygen vacancy concentration mediated selectivity enhancement. These findings shed light on the relationship between the oxygen vacancy concentration and the surface structure of semiconductor photocatalysts and offer a novel pathway to realize photocatalytic selective oxidation of amines to imines. [ABSTRACT FROM AUTHOR]

Haber–Bosch thermal ammonia synthesis is of energy-intensive nature. Using solar energy for ammonia synthesis is idealized for both energy and environment problems, but remains great challenges. Generally, the diffuse solar flux and inefficient utilization cannot meet the energy demand for NH 3 production. Here we develop a solar thermal avenue, realizing highly efficient solar ammonia synthesis over K/Ru/TiO 2-x H x . The supported Ru is efficient for nitrogen activation because of the electron donation from TiO 2-x H x and free from H 2 poisoning, because the interfacial TiO 2-x H x accepts H atoms from Ru and then delivers them to the Ru activated N 2 to form Ti-NH x (x = 1–3) even at room temperature. When only irradiated with sunlight, this catalyst absorbs sunlight in the whole UV–vis-NIR region and reaches 360 °C by its plasmonic behavior, exhibiting a Haber–Bosch thermocatalysis-comparable NH 3 generation rate. This solar thermal approach with K/Ru/TiO 2-x H x provides a promising renewable way for ammonia synthesis. [ABSTRACT FROM AUTHOR]

In this study, we demonstrated that the reactive species generation of Bi 2 MoO 6 under visible light can be regulated by Bi self-doping via a simple soft-chemical method. Density functional theory calculations and systematical characterization results revealed that Bi self-doping could not only promote the separation and transfer of photogenerated electron–hole pairs of Bi 2 MoO 6 but also alter the position of valence and conduction band without changing its preferential crystal orientations, morphology, visible light absorption as well as band gap energy. The photocatalytic removal of NO and products determination revealed that the enhanced generation of superoxide could improve the oxidation of NO to NO 2 while OH and photogenerated holes mainly contributed to the further oxidation of NO 2 to NO 3 − . Photostability and NO absorbtion tests demonstrated that NO 3 − on the surface of catalysts occupied the NO absorption sites and caused the deactivation of catalysts. This study provides new insight into the different effects of photogenerated reactive species on NO removal and sheds light on the design of highly efficient visible light-driven photocatalysts for NO removal. [ABSTRACT FROM AUTHOR]

Phosphate modification over semiconductor photocatalyst was an effective route to promote photodegradation of organic pollutants. Studies on promoted O 2 adsorption, better charge separation, and free ∙OH radicals raised from phosphate modification are clear, whereas O 2 activation and the generated reactive oxygen species (·O 2 -, H 2 O 2 , and 1O 2) have been ignored. Herein, the hydrogen bond network constructed between BiOCl surface and phosphate weaken the surface Bi-O bond thus benefit the formation of oxygen vacancy (OVs). OVs not only facilitate the adsorption of organic pollutants but also promote the O 2 activation to generate H 2 O 2 and 1O 2. Another route for 1O 2 generation relies on the H 2 O 2 reacted with HClO from lattice chlorine oxidation was demonstrated. The directly attack of surface adsorbed 4-CP via h+, in addition with the selective oxidation via 1O 2 , synergetically contribute excellent photodegradation performance. This study systematically reveals the O 2 activation and 1O 2 generation for efficient photodegradation over phosphate modified BiOCl. [Display omitted] • Better O 2 activation is achieved over P-BOC with oxygen vacancy. • The major ROSs produced via O 2 activation are H 2 O 2 and 1O 2 over P-BOC. • 1O 2 generation from H 2 O 2 and HClO (H 2 O 2 + HClO→ 1O 2 + Cl- + H 2 O + H+) is demonstrated over P-BOC. • Both h+ and 1O 2 make great contribution on the efficient photodegradation over P-BOC. [ABSTRACT FROM AUTHOR]

The photo-Fenton reaction was widely used in the removal of pollutants in waste water, which makes it exhibit great potential in the field of environmental remediation. Hence, it is crucial to explore a new efficient and stable photo-Fenton catalyst driven by visible light. In this work, a simple two-step calcination method was used to synthesize sheet-like stacked Ultra-thin g-C 3 N 4 /FeOCl (CNF) materials. The morphology, composition, photo-Fenton performance, and antibacterial properties were systematically analyzed. Research results exhibited that the synthesized CNF catalysts showed enhanced visible light absorption capacity and excellent photo-Fenton performance. Compared with FeOCl alone, CNF displayed stronger degradation ability for rhodamine B (RhB) and could achieve 97% degradation within 9 min, which was about 10 times that of pure FeOCl. At the same time, the composite catalysts exhibited excellent antibacterial effects under photo-Fenton conditions. The antibacterial rate of CNF composite catalyst under photo-Fenton conditions can reach almost 99%, which was 3 times that of photocatalysis alone and 2 times that of Fenton alone. The heterojunction formed between Ultra-thin g-C 3 N 4 and FeOCl promoted the separation of e− and h+. Simultaneously, the presence of e− promoted the cycle of Fe3+ and Fe2+ in FeOCl, thereby promoting the generation of hydroxyl radicals (OH) from H 2 O 2 and improving the photo-Fenton activity to achieve the effect of degrading pollutants and antibacterial. The photo-Fenton catalysis and degradation mechanism were analyzed in detail. This work provided a theoretical basis for the application of CNF material in the removal of wastewater. [Display omitted] • Ultra-thin g-C 3 N 4 /FeOCl is synthesized by a simple two-step calcination method. • Ultra-thin g-C 3 N 4 /FeOCl as a visible light driving surface Fenton catalyst. • Electrons act as bridges promoting photocatalysis and Fenton reactions. • Ultra-thin g-C 3 N 4 /FeOCl can efficiently remove pollutants and antibacterial. [ABSTRACT FROM AUTHOR]

Abstract: In this study, porous N, Si-codoped TiO2 hollow microsphere photocatalysts have been prepared by a facile aerosol flow synthesis method. The prepared photocatalysts were characterized by XRD, SEM, TEM, UV–vis DRS, and XPS. The results indicated that both nitrogen doping and formation of Tih name="sbnd" />Si bond happened in the N, Si-codoped TiO2 hollow microspheres, leading to an enhanced visible-light driven photocatalytic performance on degradation of salicylic acid compared with pure TiO2 and single N or Si doped TiO2 counterpart catalysts. [Copyright &y& Elsevier]

Abstract: In this study, we report that nitrogen doped TiO2 could be achieved via thermal treatment of Degussa P25 TiO2 in NO atmosphere directly (P25–NO). The samples were characterized with XRD, XPS, and FT-IR. The characterization results suggested that nitrogen species were interstitially doped in P25–NO during the NO thermal treatment process. In comparison with P25, the P25–NO exhibited significantly enhanced photocatalytic activities under visible light irradiation (λ >420nm) for gaseous NO removal. On the basis of electronic band structure theory, we proposed a possible mechanism for the enhanced visible light driven photocatalytic oxidation process over the interstitial N doping P25–NO samples. This work could not only deepen understanding of the enhanced photoactivity originated from interstitial N doping in TiO2, but also provide a facile route to prepare nitrogen doped TiO2 for environmental and energy applications. [Copyright &y& Elsevier]

Abstract: In this study, we demonstrate that aerosol assisted flow synthesized B, N-codoped TiO2 photocatalyst possesses superior photocatalytic activity to pure and single element doped counterparts on the degradation of NO in a flow system under both simulated solar light and visible light irradiation. Characterization results revealed that B, N-codoped TiO2 photocatalyst was composed of hollow microspheres. Boron and nitrogen were in the form of Ti–O–B and N–Ti–O structures, respectively. The introduction of B and N into the TiO2 lattice could effectively tune the band gap of TiO2 and extend its optical response to the visible-light region. The synergistic effect of B and N codoping on visible light driven photocatalytic activity enhancement of TiO2 was discussed on the basis of experimental results. [Copyright &y& Elsevier]

Abstract: In this paper, W x Ti1−x O2 solid solutions (x =0.000, 0.005, 0.010, 0.015, and 0.020) microspheres were synthesized with an aerosol-assisted flow synthesis method. The resulting samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), nitrogen sorption, UV–vis diffuse reflectance spectrum (DRS) and X-ray photoelectron spectroscopy (XPS). The photocatalytic activities of the as-prepared catalysts were measured by the degradation of rhodamine B (RhB) under visible light irradiation (λ≥420nm). All the solid solutions exhibited higher photocatalytic activities than pure TiO2 and the W0.015Ti0.985O2 solid solution possessed the highest photocatalytic activity. The degradation constant of RhB on W0.015Ti0.985O2 solid solution catalyst was about 15 times of that of the pure TiO2 and 25 times of that of Degussa P25, respectively. This study provides an effective method to prepare visible light photocatalysts on a large scale. [Copyright &y& Elsevier]

Abstract: The investigation was focused on the visible-light-driven photocatalytic removal of gaseous NO and HCHO at typical indoor air concentration over synthetic α-Bi2O3. Monoclinic α-Bi2O3 was synthesized via calcination of hydrothermally prepared (BiO)2CO3 precursor at 500°C for 4h. The synthetic α-Bi2O3 samples were systematically characterized by XRD, SEM, FT-IR, and UV–vis diffuse reflectance spectra (DRS). The optical band gap energy of the resulting α-Bi2O3 was estimated to be 2.72eV from the UV–vis absorption spectra. Comparing with the commercial Bi2O3 counterpart, the fabricated α-Bi2O3 showed superior visible-light-induced photocatalytic activity on degradation of nitrogen monoxide (NO) and formaldehyde (HCHO) at typical indoor air concentration. No obvious deactivation of synthetic α-Bi2O3 was observed during the prolonged photocatalytic reaction. This work suggests that the synthesized monoclinic α-Bi2O3 with suitable band gap and high activity is promising photocatalyst for indoor air purification. [ABSTRACT FROM AUTHOR]

Abstract: Nanocrystalline Zn2SnO4 microcubes were hydrothermally synthesized and systematically characterized by XRD, SEM, TEM, XPS, N2 adsorption–desorption, and UV–vis DRS analysis. The resulting Zn2SnO4 microcubes with the edge size ranging from 0.8 to 1.2μm were composed of numerous nanoparticles with size of 10–20nm, and their optical band gap energy was estimated to be 3.25eV from the UV–vis diffuse reflectance spectra. On degradation of nitrogen monoxide (NO) and formaldehyde (HCHO) at typical concentrations for indoor air quality, these nanocrystalline Zn2SnO4 microcubes exhibited superior photocatalytic activity to the hydrothermally synthesized ZnO, SnO2, and Degussa TiO2 P25, as well as C doped TiO2 under UV–vis light irradiation. This enhanced photocatalytic activity of the nanocrystalline Zn2SnO4 microcubes was attributed to their bigger surface areas, smaller particle size, special porous structures, and special electronic configuration. The nanocrystalline Zn2SnO4 microcubes were chemically stable as there was no obvious deactivation during the multiple photocatalytic reactions. This work presents a promising approach for scaling-up industrial production of Zn2SnO4 nanostructures and suggests that the synthesized nanocrystalline Zn2SnO4 microcubes are promising photocatalysts for indoor air purification. [Copyright &y& Elsevier]

Abstract: In this study, C–N–S-tridoped titanium dioxide (TiO2) nanocrystals were synthesized by using a facile hydrothermal method in the presence of a biomolecule l-cysteine. This biomolecule could not only serve as the common source for the carbon, sulfur and nitrogen tridoping, but also could control the final crystal phases and morphology. The resulting materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), nitrogen adsorption and UV–vis diffuse reflectance spectroscopy. XPS analysis revealed that S was incorporated into the lattice of TiO2 through substituting oxygen atoms, N might coexist in the forms of N–Ti–O and Ti–O–N in tridoped TiO2 and most C could form a mixed layer of carbonate species deposited on the surface of TiO2 nanoparticles. The photocatalytic activities of the samples were tested on the removal of NO at typical indoor air level in a flow system under simulated solar light irradiation. The tridoped TiO2 samples showed much higher removal efficiency than commercial P25 and the undoped counterpart photocatalyst. The enhanced visible light photocatalytic activity of C–N–S-tridoped TiO2 nanocrystals was explained on the basis of characterizations. The possible formation process of the monodispersed C–N–S-tridoped anatase TiO2 nanocrystals was also proposed. This study provides a new method to prepare visible light active TiO2 photocatalyst. [Copyright &y& Elsevier]

Abstract: In this study, highly effective B-doped, Ni-doped and B–Ni-codoped TiO2 microspheres photocatalysts were directly synthesized via an aerosol-assisted flow synthesis method. The resulting samples were characterized by XRD, SEM, TEM, UV–vis diffuse reflectance spectroscopy, nitrogen adsorption and XPS. The characterizations revealed hollow microspherical structure of the B-doped and B–Ni-codoped TiO2 photocatalysts, while the Ni-doped and undoped TiO2 products consisted of solid microspheres. It was found that the boron dopant was partially embedded into the interstitial TiO2 structure, existing in the form of Ti–O–B structure. The band gap was enlarged after the boron doping. However, both Ni-doped and B–Ni-codoped TiO2 samples showed obvious red shift in their absorption edges because of the Ni doping. The photocatalytic activities of these samples were evaluated on the photocatalytic removal of NO under simulated solar light irradiation. All the aerosol-assisted flow synthesized samples had much higher photocatalytic activities than P25 and the doped TiO2 microspheres exhibited enhanced photocatalytic activity than the undoped counterparts. More interestingly, the B–Ni-codoped TiO2 photocatalyst possessed superior photocatalytic activity to the as-prepared single doped TiO2 products. The enhanced photocatalytic activity was explained and the formation mechanisms of hollow and solid microspheres were also proposed on the basis of characterizations. We think this general method may be easily scaled up for industrial production of highly active microspherical photocatalysts for efficient NO removal under simulated solar light irradiation. [Copyright &y& Elsevier]

Abstract: In this paper, we report on a nonaqueous synthesis of single crystalline anatase TiO2 nanorods by reaction between TiCl4 and benzyl alcohol at a low temperature of 80°C. The resulting samples were characterized with X-ray diffraction, scanning electron microscopy, transmission electron microscopy, high resolution transmission electron microscopy, nitrogen adsorption, X-ray photoelectron spectrometry and UV–vis diffuse reflectance spectroscopy. We proposed that the TiO2 nanorods were formed through an oriented attachment mechanism. More importantly, these single crystalline anatase TiO2 nanorods exhibited significantly higher photocatalytic activities than commercial photocatalyst P25. This study provides an environmentally friendly and economic approach to produce highly active TiO2 photocatalyst. [Copyright &y& Elsevier]

Abstract: Visible light active carbon-doped Ti0.91Zr0.09O2 solid solution photocatalysts were directly obtained by ultrasonic spray pyrolysis of an aqueous solution containing TiCl4, ZrOCl2·8H2O and CH3(CH2)17NH2. The samples were characterized by X-ray diffraction, scanning electron microscopy, nitrogen adsorption, X-ray photoelectron spectroscopy, UV–vis diffuse reflectance spectroscopy and infrared spectroscopy. The characterizations revealed the spherical structures of the resulting samples and the substitution of Ti4+ by Zr4+ ions and carbon in the TiO2 lattice. Meanwhile, partial carbon and zirconium existed in the form of carbonate and zirconia, respectively. Moreover, the pyrolysis temperature had significant effect on the amount of dopants substituted in the resulting samples. The carbon doping successfully extended the absorption edges of the solid solution to visible light region. We evaluated photocatalytic activities of the doped solid solution photocatalysts on degradation of rhodamine B in aqueous solutions under visible light irradiation (λ ≥420nm). It was found that the carbon-doped solid solution photocatalysts exhibited enhanced photocatalytic activity under visible light irradiation comparing to the undoped counterpart. On the basis of characterization results, we attributed the enhanced visible light activity to the carbonate species in solid solution photocatalysts. This study provides a way to synthesize visible light active solid solution photocatalysts on a large scale. [Copyright &y& Elsevier]

Abstract: In this paper, we prepared TiO2@CdS core–shell nanorods films electrodes using a simple and low-cost chemical bath deposition method. The core–shell nanorods films electrodes were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and UV–vis spectrometry techniques. After applying these TiO2@CdS core–shell nanorods electrodes in photovoltaic cells, we found that the photocurrent was dramatically enhanced, comparing with those of bare TiO2 nanorods and CdS films electrodes. Moreover, TiO2@CdS core–shell nanorods film electrode showed better cell performance than CdS nanoparticles deposited TiO2 nanoparticles (P25) film electrode. A photocurrent of 1.31mA/cm2, a fill factor of 0.43, an open circuit photovoltage of 0.44V, and a conversion efficiency of 0.8% were obtained under an illumination of 32mW/cm2, when the CdS nanoparticles deposited on TiO2 nanorods film for about 20min. The maximum quantum efficiency of 5.0% was obtained at an incident wavelength of 500nm. We believe that TiO2@CdS core–shell heterostructured nanorods are excellent candidates for studying some fundamental aspects on charge separation and transfer in the fields of photovoltaic cells and photocatalysis. [Copyright &y& Elsevier]

Abstract: A visible-light-active TiO2 photocatalyst was prepared through carbon doping by using glucose as carbon source. Different from the previous carbon-doped TiO2 prepared at high temperature, our preparation was performed by a hydrothermal method at temperature as low as 160°C. The resulting photocatalyst was characterized by XRD, XPS, TEM, nitrogen adsorption, and UV–vis diffuse reflectance spectroscopy. The characterizations found that the photocatalyst possessed a homogeneous pore diameter about 8nm and a high surface area of 126m2/g. Comparing to undoped TiO2, the carbon-doped TiO2 showed obvious absorption in the 400–450nm range with a red shift in the band gap transition. It was found that the resulting carbon-doped TiO2 exhibits significantly higher photocatalytic activity than the undoped counterpart and Degussa P25 on the degradation of rhodamine B (RhB) in water under visible light irradiation (λ >420nm). This method can be easily scaled up for industrial production of visible-light driven photocatalyst for pollutants removal because of its convenience and energy-saving. [Copyright &y& Elsevier]

• A (hydr)oxides/carbon sphere (FeO/CS) composite was prepared and characterized. • FeO/CS rapidly adsorbs PFOA on photoactive sites via corporative binding mechanisms. • FeO/CS effectively defluorinates pre-sorbed PFOA under simulated solar light. • Hybrid Fe-carbon phases of FeO/CS facilitate adsorption and direct oxidation of PFOA. • OH radicals play an important role in PFOA photo-degradation by FeO/CS. Perfluorooctanoic acid (PFOA) has been widely detected in aquatic systems. Yet, cost-effective technologies for degrading PFAS have been lacking. We prepared and tested an adsorptive photocatalyst consisting of iron (hydr)oxides and carbon spheres (FeO/CS) through a one-step hydrothermal process. Characterization results revealed that the presence of carbon spheres affected the crystal formation of iron (hydr)oxides, and resulted in mutually modified mixed phases ferrihydrite and carbon spheres. FeO/CS was able to effectively adsorb and then degrade the pre-sorbed PFOA under simulated solar light. FeO/CS(1:1), prepared at an Fe:Glucose molar ratio of 1:1, showed the highest PFOA adsorption capacity and photoactivity. At a dosage of 1.0 g/L, FeO/CS(1:1) adsorbed nearly all 200 µg/L of PFOA within 1 h, and when the PFOA-laden FeO/CS(1:1) was subjected to simulated solar light at neutral pH, 95.2% of pre-concentrated PFOA was photodegraded and 57.2% defluorinated in 4 h. The efficient degradation also regenerated the material, allowing for repeated uses of the material without chemical regeneration. The much enhanced adsorption and photocatalytic activity of FeO/CS was attributed to: 1) CS facilitated formation of ferrihydrite, leading to adsorption of PFOA via binuclear and bidentate complexation, and 2) a hybrid ferrihydrite-CS structure, enabling multi-point, corporative adsorption of PFOA, and increasing direct electron extraction from PFOA under solar light irradiation. Moreover, OH radicals played an important role in PFOA degradation. Lastly, a photodegradation mechanism is proposed based on experimental findings and density functional theory calculations. [ABSTRACT FROM AUTHOR]

• Tailoring of the quantity and distribution of OVs in WO 3 /TNTs matrix by a simple electrochemical step. • Enhancement of charge-transport and reduction of electron-hole recombination by the incorporation of surface OVs. • 12 times higher photo-current density and an enhanced photocatalytic removal efficiency of VOCs by self-doped R-WO 3 /TNTs. • Excellent durability during the photodegradation process by the R-WO 3 /TNTs with open channel structure of the TiO2 nanotubes. In this study, an electrochemically self-doped WO 3 /TiO 2 nanotubes (R-WO 3 /TNTs) composite film was developed for the photocatalytic degradation of waste gas. The doping of oxygen vacancies (OVs) into the heterojunction of WO 3 /TNTs was conducted by a simple electrochemical approach, by which the quantity and distribution of OVs on surface as well as bulk were tailored with respect to the applied cathodic potential and the duration of the treatment. With an increase of applied cathodic potential as well as the duration, the quantity of OVs on WO 3 /TNTs was observed to be consistently raised, while those presented in the surface were raised initially and further showed a plateau trend as the duration extended at a fixed potential. The incorporation of OVs into WO 3 /TNTs enhanced the charge-transport resistance and reduced the electron-hole recombination, thereby showed an enhanced photocatalytic performance. The R-WO 3 /TNTs prepared by the electrochemical polarization process at −1.4 V (vs SCE) exhibited a 12 times higher photo-current density and obviously, an enhanced efficiency in the photocatalytic degradation of VOCs with a prolonging photostability compared to that of the pristine WO 3 /TNTs, under a simulated solar light irradiation. The single-time purification trial demonstrated the effectiveness of the R-WO 3 /TNTs composite in treating the VOCs for the practical application. [ABSTRACT FROM AUTHOR]