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[Display omitted] A series of BiO(OH) x I 1–x solid solution (SS) catalysts were successfully prepared by ion exchange of I− and OH− between the [Bi 2 O 2 ]2+ layers. The morphology and microstructure were studied in depth using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and Brunauer-Emmett-Teller (BET) method, etc. Tunable absorption in the visible-light region was achieved by changing the proportion of OH– to I−. Due to the etching effect of OH−, oxygen vacancies (OVs) greatly increased for the SS catalysts, and were confirmed by X-ray photoelectron spectroscopy (XPS), UV–vis diffuse reflectance spectroscopy (DRS), and electron paramagnetic spectroscopy (EPR). The unique composition of OH−, I−, OV, and [Bi 2 O 2 ]2+ layers in BiO(OH) x I 1–x materials resulted in diverse photoexcitations. The BiO(OH) 0.45 I 0.55 photocatalyst displayed a 10-fold-improved 2-chlorophenol (2-CP) degradation rate compared to BiOI. The interfacial reaction process by the photoinduced valence-band holes and conduction-band electrons proved to be a more efficient pathway for organic pollutant degradation by the BiO(OH) x I 1–x SS photocatalyst. The OVs in the SS photocatalyst facilitated photoexcited and electron migration and transformation. [ABSTRACT FROM AUTHOR]

The solid-solid or solid-liquid interfaces are vital for the photocatalytic reaction. Herein, AgI nanoparticles (NPs) attached on the (0 1 1) plane of Ag 2 WO 4 nanorods were synthesized by a facile method at room temperature. The co-crystalization of the two components caused their phase transformation and the existence of a strong interface interaction. Meanwhile, the porous batt-like morphology of AgI NPs provided more contact sites for organic pollutants to induce a strong interaction at the solid-liquid interface. The heterojunction nanocatalyst was found to be highly effective for the degradation and mineralization of various pollutants, including the endocrine-disrupting chemical bisphenol A, the antibiotics sulfamethoxazole and ciprofloxacin, and the azo-dye methyl orange under visible light (λ > 420 nm). Its photocatalytic rate was 91, 52, and 39 times higher than that of bulk AgI, standard TiO 2- x N x , and the physical mixture of the two components, respectively. Further studies demonstrated that the strong interactions between the two components and the pollutants promoted the electron transfer from organic pollutants to AgI NPs and then from AgI NPs to Ag 2 WO 4 nanorods, resulting in the rapid oxidation of pollutants and the formation of Ag NPs. The newly formed Ag NPs further accelerated the degradation of pollutants due to a SPR effect and an empty levels feeding role to produce h+ on Ag 2 WO 4 , which can oxidize surface-adsorbed H 2 O into OH. This photocatalytic system provided a platform for understanding solid-solid and solid-liquid interface interaction and a novel design idea for water pollutants removal. [ABSTRACT FROM AUTHOR]

[Display omitted] Herein, a novel metal-free catalyst consisting of multiporous oxygen-rich carbon–nitrogen graphene-like nanosheets (O LAA -CN NSs) is first developed through a staged temperature-programmed calcination of l -ascorbic acid (LAA)-modified dicyandiamide precursor. It is found that the oxygen species from l -ascorbic acid (O LAA) are introduced into the graphene-like basic matrix and replace partial N atoms to form the C O C-R structure, leading to the non-uniform distribution of electrons on the catalyst surface, and the formation of electron-rich centers around the C O C microareas according to a series of characterization techniques. As a result, O LAA -CN NSs exhibits excellent performance for refractory pollutant removal in the presence of peroxymonosulfate (PMS) and dissolved oxygen. Some pollutants with complex structures are even completely degraded within only 1 min. The interface reaction mechanism is further revealed that PMS mainly acts as an active inducer to drive the electron donation of pollutants over O LAA -CN NSs. These electrons are finally utilized by dissolved oxygen to generate reactive oxygen species (ROS) through the interface process. This reaction system results in pollutants that can either be cleaved directly by surface oxidation process or degraded by the attack of the generated ROS, such as singlet oxygen (1O 2) and superoxide radicals (O 2 •−), through oxygen activation, which significantly reduces the resource and energy consumption in advanced wastewater treatment by harnessing the energy of pollutants and dissolved oxygen in the water. [ABSTRACT FROM AUTHOR]

[Display omitted] The heterogeneous Fenton process suffers from low efficiency because of the low electron transfer cycle rate of Fe3+/Fe2+, which often consumes enormous amounts of hydrogen peroxide (H 2 O 2) or other energy. Herein, we report a novel Co-based Fenton-like catalyst (in-situ -Co-g-C 3 N 4) synthesized via the surface complexation method, in which Co species were modified in situ into the framework of the graphitic carbon nitride (g-C 3 N 4) substrate through C–O–Co chemical bonding. The catalyst exhibited higher Fenton-like catalytic activity than pure g-C 3 N 4 in the degradation of various pollutants under neutral conditions, as evidenced by the approximately 150-fold higher Fenton-like reaction rate constant of in-situ -Co-g-C 3 N 4 than that of g-C 3 N 4. Density functional theory (DFT) calculations and a series of experimental and characterization analyses revealed the interfacial reaction mechanism between H 2 O 2 , pollutants and in-situ -Co-g-C 3 N 4. During the Fenton-like reaction, the electron-poor C center on the aromatic ring of g-C 3 N 4 could capture the electrons deprived from pollutants, and subsequently deliver them to around the electron-rich Co center to efficiently reduce H 2 O 2 to hydroxyl radicals (•OH), enabling H 2 O 2 to be used efficiently for the degradation of pollutants. This study provides a strategy for improving Fenton-like degradation efficiency by effectively utilizing the energy of organic pollutants. [ABSTRACT FROM AUTHOR]

• W vacancies containing Bi 2 WO 6 was prepared by a facile hydrothermal method. • V W -Bi 2 WO 6 was highly effective for pollutants removal under visible light. • More reductive photoelectrons were produced to accelerate surface reaction kinetics. • More holes were separated by surface W vacancies to directly degrade pollutants. • The interaction between pollutants and V W -Bi 2 WO 6 at interface was enhanced. W vacancies containing Bi 2 WO 6 (V W -Bi 2 WO 6) was synthesized by a reductant-involved hydrothermal process. The photoactivity of Bi 2 WO 6 was enhanced by 3.3 times and the TOC removal rate increased from 38.3% to 64.7% after the introduction of surface W vacancies. Positron annihilation spectrometry (PAS), XPS, Raman spectra and other characterization results indicated that W vacancies existed on the catalyst surface. The surface W vacancies were proved to widen the band gap and negatively shift CB edge to produce more O 2 •− and photoexcited holes at catalyst surface, as confirmed by ESR and radicals trapping experiments. Further, according to the results of pyridine adsorbed FTIR and Zeta potentials, the enhanced interaction between pollutants and V W -Bi 2 WO 6 was confirmed. As a result, the active species produced at surface were able to be accelerated to directly react with organic pollutants, leading to the highly efficient degradation and mineralization of pollutants in water. [ABSTRACT FROM AUTHOR]

• Mesoporous reduction state cobalt species-doped silica nanospheres are first prepared. • Excellent activity is realized in mp -RSCo-SiO 2 NSs/H 2 O 2 system. • Efficient dual-pathway degradation of pollutant is achieved in Fenton-like process. • Pollutants replace H 2 O 2 as electron donors for the mp -RSCo-SiO 2 NSs system. • A new interfacial Fenton-like reaction mechanism involving pollutants is proposed. A novel heterogeneous Co-containing Fenton-like catalyst consisting of mesoporous reduction state cobalt (RSCo)-doped silica (SiO 2) nanospheres (mp -RSCo-SiO 2 NSs) was prepared by an enhanced hydrothermal process. The catalyst exhibited very high activity and stability for a series of refractory pollutant degradation in a very wide pH range of 3.1–10.9. The Fenton-like reaction rate constant of this Co-containing catalyst was approximately 290 times higher than that of Co 3 O 4 for pollutant degradation under the neutral and mild conditions. Based on the characterization, the catalyst possessed a porous nanosphere morphology, and the reduction state cobalt species, including nano-zero-valent cobalt (nZVCo) and Co2+, were found to be generated in the SiO 2 framework through forming Co O Si bonds. During the Fenton-like reaction, the electron donation effect of organic pollutants was successfully realized through the interaction of "Pollutants → Co2+/0-SiO 2 ". The obtained electrons from pollutants were transferred to the catalyst surface and captured by H 2 O 2 , resulting in the generation of hydroxyl radicals (OH). Therefore, a dual-pathway degradation of the pollutants was realized: (I) oxidation and degradation as the electron donors for the system and (II) attacking and destruction by OH radicals. This work provided a new perspective on the effective utilization of the electrons of pollutants and the improvement of Fenton reaction efficiency. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Mo S C and Mo O Co electron transfer bridges are successfully constructed on CMS-rGO NSs. • CMS-rGO NSs possesses the function of generating and activating H 2 O 2 synchronously. • CMS-rGO NSs shows very high Fenton-like activity for degradation of pollutants. • Dye pollutants can directly act as electron donors for CMS-rGO NSs. Abstract Consumption of additional H 2 O 2 is necessary in classical Fenton catalysis. Herein, we report a novel and special nanocatalyst consisting of CoMoS 2 nanosphere-embedded, reduced graphene oxide (rGO) nanosheets (CMS-rGO NSs). This nanocatalyst was discovered to have an impressive reactivity for in situ generation and synchronistical activation of H 2 O 2 in different active centers, yielding fast and efficient degradation of the pollutants. The reaction rate is ∼21 times higher than that of conventional Fenton catalysts. The characterization shows that countless flower-like CoMoS 2 nanospheres are uniformly embedded in the rGO nanosheets through Mo S C bonding bridges in CMS-rGO NSs, which leads to activation of the π electrons and their transfer from rGO to the metal centers (π → M). The formed Mo O Co further leads to a distribution of orientations of the electrons around the metal centers due to the different electronegativity of Mo and Co. During the reaction, the dissolved O 2 is efficiently reduced to HO 2 /O 2 − around the electron-rich Mo center, and HO 2 /O 2 − is further reduced to H 2 O 2 around the Co center. The generated H 2 O 2 is finally reduced to OH for degrading dyes in the electron-rich metal (Mo or Co) centers of CMS-rGO NSs. The dye pollutants also act as electron donors, and they are directly degraded in the electron-poor π-center of CMS-rGO NSs, which promote the electron transfer cycle and achieve electron gain-loss balance. This discovery provides a new strategy for H 2 O 2 generation-activation and pollutant degradation through constructing electron transfer bridges over the surface of catalysts. [ABSTRACT FROM AUTHOR]

In this paper, a series of nitrogen-doped mesoporous carbons (NMCs) with three-dimensional (3D) interconnected mesopores have been prepared using flour as carbon source, dicyanamide as nitrogen source and colloidal silica as hard template. The optimized material (NMC-4) prepared with the colloidal silica/flour mass ratio of 4 has a high nitrogen doping level of 5.69 at.% and large specific surface area of 995 m 2  g −1 as well as 3D interconnected mesopores (12.9 nm). As the oxygen reduction reaction (ORR) electrocatalyst among various NMCs, NMC-4 exhibits the superior performance and much better stability and methanol crossover with a four-electron dominant reaction pathway compared to commercial 20 wt% Pt/C. Furthermore, as a supercapacitor (SC) electrode material, NMC-4 exhibits a high specific capacitance of 178.5 F g −1 at a current density of 0.5 A g −1 and long cycle life (94.5% capacity retention after 5000 cycles). It also shows a good rate capacity as 76.1% of original specific capacitance remains when the current density increases from 0.5 to 20 A g −1 . The high-performance of NMCs results from the synergetic effects of 3D interconnected mesopores, large surface area, and high N-doping level, enabling fast mass transport and electron transfer during the electrochemical process. This work provides a facile and efficient strategy to heteroatom-doped carbons from extensively available biomass, showing great potentials in electrocatalysis, energy storage, and other applications. [ABSTRACT FROM AUTHOR]

BiOI is widely used as photocatalysts for pollutant removal, water splitting, CO 2 reduction and organic transformation due to its excellent photoelectric properties. Here, we report for the first time that a light-free catalyst consisting of the flower-like BiOI microspheres ( f -BiOI MSs) exposing (1 0 1) and (1 1 0) crystal planes prepared by a hydrothermal method in ethylene glycol environment can rapidly eliminate the refractory BPA within only ∼3 min through a Fenton-like process. The reaction activity is ∼190 times higher than that of the conventional Fenton catalyst Fe 2 O 3 . A series of characterizations and experiments reveal the formation of the dual reaction centers on f -BiOI MSs. The electron-rich O centers efficiently reduce H 2 O 2 to OH, while the electron-poor oxygen vacancies capture electrons from the adsorbed pollutants and divert them to the electron-rich area during the Fenton-like reactions. By these processes, pollutants are degraded and mineralized quickly in a wide pH range. Our findings address the problems of the classical Fenton reaction and are useful for the development of efficient Fenton-like catalysts through constructing dual reaction centers. [ABSTRACT FROM AUTHOR]