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As the only natural source of aromatic biopolymers, lignin can be converted into value-added chemicals and biofuels, showing great potential in realizing the development of green chemistry. At present, lignin is predominantly used for combustion to generate energy, and the real value of lignin is difficult to maximize. Accordingly, the depolymerization of lignin is of great significance for its high-value utilization. This review discusses the latest progress in the field of lignin depolymerization, including catalytic conversion systems using various thermochemical, chemocatalytic, photocatalytic, electrocatalytic, and biological depolymerization methods, as well as the involved reaction mechanisms and obtained products of various protocols, focusing on green and efficient lignin depolymerization strategies. In addition, the challenges faced by lignin depolymerization are also expounded, putting forward possible directions of developing lignin depolymerization strategies in the future. [ABSTRACT FROM AUTHOR]

N-TiO2/Ni(OH)2 nanofiber was successfully prepared by combining the electrospinning and solvothermal method. It has been found that under visible light irradiation, the as-obtained nanofiber exhibits excellent activity for the photodegradation of rhodamine B, and the average degradation rate reaches 3.1%/min−1. Further insight investigations reveal that such a high activity was mainly due to the heterostructure-induced increase in the charge transfer rate and separation efficiency. [ABSTRACT FROM AUTHOR]

Abstract: To make better use of solar light, a new Bi2WO6/Cu1.8Se photocatalyst active to visible and near‐infrared light has been synthesized by a facile hydrothermal method. The composites were characterized by X‐ray diffractometry (XRD), scanning electron microscopy (SEM), UV‐vis diffuse reflectance spectroscopy (DRS), and photoluminescene (PL). The photocatalytic activities of Bi2WO6/Cu1.8Se are evaluated by degrading Congo red solution and hydrogen generation from water. It was found that the molar percentage of Cu1.8Se had great effects on the morphology and photocatalytic property of the Bi2WO6/Cu1.8Se heterojunctions, and the composite with suitable molar amount of Cu1.8Se exhibits much enhanced photocatalytic activity for Congo red degradation under visible and near‐infrared light irradiation and for hydrogen generation under visible light compared to Bi2WO6. The significant improvement photocatalytic activity of the composite could be attributed to its good light absorption, suitable band gap structure, and effective separation of photogenerated electron‐hole pairs of Bi2WO6/Cu1.8Se heterojunction. This work presents an efficient multifunction photocatalyst owning the activity both for water splitting under visible light and for organic contaminants decomposition under visible‐near‐infrared light. [ABSTRACT FROM AUTHOR]

Bi1- xSm xFe1- yMn yO3 ( BSFMO, x = 0.0, 0.05; y = 0.0, 0.05, 0.10, 0.15, 0.20, 0.25) nanoparticles were synthesized by using double solvent sol-gel method. Photocatalytic activity was investigated under UV and visible-light illumination. The structural, morphological, and optical properties were analyzed by X-ray diffraction, scanning electron microscopy, and UV-vis spectroscopy respectively. The crystallite size of BiFeO3 ( BFO) decreases from (57.3-17.2 nm) with the increase in Sm and Mn-doping concentration. The surface morphology shows that the pure and Sm-doped BFO nanoparticles are irregular in shape but changes to spherical shape after Mn-doping up to 25%. The band-gap engineering of BFO nanoparticles is achieved by co-doping of Sm and Mn. The band-gap of BFO could be tuned successfully from 2.08-1.45 eV, which may be due to the distortion induced in Fe-O octahedron and the rearrangement of molecular orbitals. These results give rise to enhanced photocatalytic activity by degradation of organic dyes ( MB, CR, and MV) under the visible-light illumination. [ABSTRACT FROM AUTHOR]

BiFeO3 nanofibers doped with divalent barium have been fabricated using electrospinning technique. Phase transition from space group R3c to C222 can be observed by the Ba doping. Our results indicate that these BiFeO3 nanofibers show obvious room temperature ferromagnetic behaviors, which can be enhanced remarkably with the increment of Ba doping. Microstructure and composition analysis indicates that barium effectively affected the magnetism after doping content was more than 5% and optical properties. [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]

Highlights: [•] Plasmonic Ag@AgBr was intercalated in the layered space of K4Nb6O17. [•] Ag@AgBr greatly increased visible light absorption for K4Nb6O17. [•] The plasmonic photocatalysts exhibited enhanced activity for the degradation of RhB. [ABSTRACT FROM AUTHOR]

In the synthesis of organic hybrid metal chalcogenides, piperazine (pip) has been widely applied as a template or charge-balancing agent in the structure assembly, but application of piperazine as a solvent to synthesize organic hybrid metal chalcogenides has not been reported. In this work, two new two-dimensional layered organic hybrid silver chalcogenidoantimonates, namely [pipH 2 ] 0.5 [Ag 2 SbS 3 ] (1), [pipH 2 ] 0.5 [Ag 2 SbSe 3 ] (2), have been synthesized by using piperazine as reaction medium. Both compounds possess the similar honeycombed anionic bilayers, and the biprotonated piperazine cations are resided between the bilayers. Thermal stabilities and optical properties of compounds 1 and 2 have been studied. Moreover, compounds 1 and 2 exhibited excellent photocatalytic activities for reducing aqueous Cr(VI) under visible light irradiation. [Display omitted] • Two new silver chalcogenidoantimonates were prepared by using piperazine as reaction medium. • Both compounds showed excellent photocatalytic activity for reducing Cr(VI) under visible light irradiation. • The effects of pH value and initial concentration on the catalytic performance were studied. [ABSTRACT FROM AUTHOR]

Photocatalytic H 2 production from methanol is sustainable, yet challenges remain in avoiding carbon-containing gaseous by-products. Titanium silicalite-1 (TS-1) zeolite possesses attractive photocatalytic performance, but lack of modification strategies due to its microporous framework. Herein, we developed a pre-anchoring strategy to confine ultra-small Pt clusters inside TS-1 with ultra-low loading (0.2 mol%), in which Pt were anchored in Ti−OH nests by electronic metal-support interaction (EMSI). The optimal catalyst achieved a remarkable H 2 generation rate of 63.2 mmol g–1 h–1 in CH 3 OH solutions, along with the production of high-value chemical HCHO as the oxidation product with 96.9% selectivity. Investigations reveal that the EMSI between Pt and Ti facilitated the selective decomposition of CH 3 OH to H 2 and HCHO, leading to a nearly zero-carbon-emission process. Accordingly, we propose a light-driven carbon-negative "CO 2 →CH 3 OH→H 2 " route, coupling CO 2 utilization and green H 2 production with CH 3 OH as the intermediate, therefore offering a new perspective for "liquid sunshine". [Display omitted] • Pt clusters were successfully encapsulated inside TS-1 by a pre-anchoring method. • The optimal catalyst achieved a remarkable photocatalytic H 2 generation activity. • HCHO is the main oxidation product with nearly 100% selectivity. • The strong EMSI between Pt and Ti facilitated CH 3 OH decomposition to H 2 and HCHO. • A potential light-driven carbon-negative "CO 2 →CH 3 OH→H 2 " route was proposed. [ABSTRACT FROM AUTHOR]

• The Fe-doped TiO 2 S-scheme anatase/rutile homojunction (F-T-A/R) was synthesized by a typical solvothermal-annealing method. • The optimized F-T-A/R photocatalyst (A/R = 98:2, Fe-2 wt%) exhibits an unprecedented NH 3 generation rate of 358 μmol gcat-1h−1. • The charge transfer mechanism of S-scheme homojunction and NH 3 production path were investigated. • The synergistic effect of S-scheme homojunction and Fe doping improved the photocatalytic nitrogen fixation. The presence of efficient catalytic active sites and an ample supply of electrons are the two indispensable factors for achieving photocatalytic nitrogen fixation. Herein, the Fe-doped TiO 2 S-scheme anatase/rutile homojunction (F-T-A/R) was synthesized as a brilliant photocatalyst for photocatalytic nitrogen fixation from N 2 to NH 3 under ambient atmosphere. The optimized F-T-A/R photocatalyst (A/R = 98:2, Fe-2 wt%) exhibits an unprecedented NH 3 generation rate of 358 μmol g cat -1h−1 in water solvent and under simulated solar light irradiation. Experimental and theoretical studies reveal that the constructed S-scheme homojunction in F-T-A/R is conducive to fluent charge separation and adequate supply of electrons on rutile with higher nitrogen fixing activity, while the tuned local electronic structure of oxygen vacancy with Fe doping is engineered to strengthen active sites, synergistically enhancing the photocatalytic nitrogen fixation. [ABSTRACT FROM AUTHOR]

Graphical abstract The Lewis acid sites (Ti) in TNS would selectively adsorb OH in cinnamyl alcohol forming surface C O···Ti O coordination species. Under visible light irradiation, interface charge transfer occurs from C O to Ti O , resulting in the activation of cinnamyl alcohol and the charge enrichment in Ti atoms of TiO 6. The molecule O 2 would be adsorbed on the electron enriched Ti atoms and reduced to O 2 − for the oxidation of alcohol. Due to the hybrid electronic states of Cu-Cu 2 O, the interface electronic transfer kinetics are tuned to inhibit the intramolecular hydrogen transfer for dominating the selectivity towards cinnamaldehyde. The synergistic effect of surface coordination-activation-photocatalysis enables an efficient and green synthesis. Highlights • The coordination of hydroxyl in alcohol with surface Lewis acid sites of H 1.4 Ti 1.65 O 4 ·H 2 O nanosheets. • Directional interface charges transfer from alcohol to nanosheet occur via surface coordination species. • The hybrid electronic states of Cu-Cu 2 O tune interface charges transfer kinetics. • Synergistic surface coordination-activation-photocatalysis for precies synthesis. Abstract A multifunctional photocatalyst is constructed based on Cu-Cu 2 O hybrid and monolayer H 1.4 Ti 1.65 O 4 ·H 2 O nanosheets via an in situ photo-deposition process (Cu-Cu 2 O/TNS). The prepared sample enables the oxidation of cinnamyl alcohol to cinnamaldehyde with over 95% of selectivity under visible light irradiation using molecule O 2 as the oxidant. In situ FTIR spectra suggest that the Lewis acid sites in TNS would selectively adsorbed the hydroxyl of cinnamyl alcohol forming surface C O∙∙∙Ti O coordination species. UV-DRS spectra reveal that light adsorption of TNS can be extended to visible light region due to the interface charges transfer from C OH to Ti O via the surface coordination, resulting in the activation of OH in alcohol. In situ ESR further indicates that directional interface charge transfer induces the charge enrichment in Ti atoms of TiO 6 , facilitating O 2 adsorption. XAFS results reveal that the hybrid electronic states of Cu-Cu 2 O efficiently improve the interface electronic transfer kinetics to inhibit the intramolecular hydrogen transfer for dominating the selectivity towards cinnamaldehyde. This work highlights the synergistic effect of surface coordination-activation-photocatalysis for selective photosynthesis of fine chemicals. [ABSTRACT FROM AUTHOR]

Solar driven catalysis by semiconductors is considered as a promising route to mitigate environmental problems caused by the combustion of fossil fuels and water pollution. Surface plasmon resonance (SPR) has offered a new opportunity to overcome the limited efficiency of photocatalysts. Herein we report that the SPR-mediated visible-light-responsive photocatalyst, 0.5 wt.% Au/SO 4 2− –TiO 2 , can achieve over 99% conversion of pollutants (thiophene, thiol, rhodamine B, and phenol) during photocatalytic oxidation with oxygen or air as oxidant under visible light irradiation. The considerable enhancement of photocatalytic activity can be attributed to the synergistic effect of Au SPR and Lewis acidic SO 4 2− –TiO 2 which are beneficial for the efficient separation and transfer of the photo-generated electrons and holes. Such a strategy would be important to the design and preparation of highly photocatalytic active semiconductor catalysts. [ABSTRACT FROM AUTHOR]

A novel ultrasensitive label-free immunosensor based on BiOBr/Ag 2 S composite with high visible-light photoelectrochemical activity was prepared for the detection of insulin. After BiOBr was modified by thioglycolic acid, Ag 2 S nanoparticles were grown in-situ on the surface of BiOBr hierarchical microspheres to first form novel BiOBr/Ag 2 S composite. When ascorbic acid (AA) was used as an efficient electron donor for scavenging photo-generated holes, BiOBr/Ag 2 S composite material showed excellent photoelectrochemical activity. In order to immobilize insulin antibody, adhesive polydopamine (PDA) film formed by self-polymerization of dopamine was fabricated onto BiOBr/Ag 2 S modified electrode. Moreover, PDA film could further enhance the visible light absorption of BiOBr/Ag 2 S. When the solutions of 0.08 mol L −1 AgNO 3 and 0.1 mol L −1 AA were selected respectively during fabrication and detection process of this sensor, the best photocurrent singles were obtained. Under the optimum experimental condition, the specific binding between insulin and antibody resulted in a decrease in photocurrent intensity and the intensity decreased linearly with the logarithm of insulin concentration in the range of 0.001–20 ng mL −1 with a detection limit of 0.2 pg mL −1 . The photoelectrochemical sensor ITO/BiOBr/Ag 2 S/PDA/anti-Insulin/BSA/Insulin revealed facile preparation, high sensitivity, and acceptable reproducibility, which may have practical applications in the biosensor, clinical diagnosis of cancers, photocatalysis, and other related fields. [ABSTRACT FROM AUTHOR]

In this work, Bi 2 S 3 /SnS 2 heterojunction photocatalysts were prepared by combining a hydrothermal technique and a facile in situ growth method. The nanocomposites were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, inductively coupled plasma spectroscopy, X-ray photoelectron spectroscopy, UV–Vis diffusion reflectance spectroscopy and room-temperature photoluminescence spectra. Their photocatalytic performances were evaluated by degrading methyl orange (MO) in aqueous solution (50 mg/L) under visible light (λ > 420 nm) irradiation. It was found that when the mass percentage of Bi 2 S 3 in Bi 2 S 3 /SnS 2 was 7.95 wt%, the as-prepared Bi 2 S 3 /SnS 2 nanocomposite showed the best photocatalytic activity for the degradation of MO. The highly improved performance of the Bi 2 S 3 /SnS 2 nanocomposite was mainly ascribed to the efficient charge separation. [ABSTRACT FROM AUTHOR]

• Au@TiO 2 /Bi 2 WO 6 was synthesized by reverse micelle sol–gel method plus hydrothermal process. • Remarkable photocatalytic performance for degradation of antibiotics was achieved. • The Z-scheme charge transfer mechanism for Au@TiO 2 /Bi 2 WO 6 was verified. • The nanocomposite photocatalyst exhibited superior reusability. Semiconductor photocatalysis can be regarded as one of effective strategies to overcome the great challenges encountered with conventional technologies for environmental remediation. In this research, Z-scheme heterostructure composed of core–shell Au@TiO 2 nanoparticles and flower-like Bi 2 WO 6 nanosheets has been successfully prepared through the reverse micelle sol–gel method followed by a hydrothermal process. The structural characteristics, chemical compositions and photoelectrochemical properties of this ternary composite photocatalyst (Au@TiO 2 /Bi 2 WO 6) were further investigated in detail. Benefitted from the synergy of the heterojunction construction and metallic surface plasmon resonance effect, the Au@TiO 2 /Bi 2 WO 6 with an optimal mass ratio of Au@TiO 2 to Bi 2 WO 6 exhibited the significantly enhanced photocatalytic activity for degradation of antibiotics under visible-light irradiation, in which the degradation efficiency of sulfamethoxazole (SMX) and tetracycline hydrochloride (TC) could be up to 96.9% and 95.0% within 75 min, respectively. The reaction rate constant for SMX and TC degradation was calculated to be around 0.0425 min−1 and 0.0314 min−1, which has 7.2 times and 1.9 times enhancement compared with single Bi 2 WO 6 , respectively. In addition, the cyclic stability and photocatalytic mechanism of Au@TiO 2 /Bi 2 WO 6 were further verified. Our primary results provide a feasible strategy to develop core–shell heterostructured photocatalysts with superior performance for the efficient removal of low-concentration antibiotics in water. [ABSTRACT FROM AUTHOR]

In this study, porous g-C 3 N 4 with structural defects of oxygen atom and cyano group (COCN) prepared by thermal polymerization of directly calcinating the mixture of urea and ascorbic acid, is firstly applied in the H 2 O 2 fuel cell. By employing a nickel mesh coated with COCN as the photoanode and iron phthalocyanine (FeIIPc) mixed with g-C 3 N 4 on carbon paper as the cathode, this COCN-based cell exhibits a maximum power density of 0.298 mW·cm−2 in the water solution including 0.1 M HCl under AM 1.5G solar light at air atmosphere, which has an approximate 5.0 times enhancement compared with that of pristine g–C 3 N 4 –based one. The corresponding solar-to-electricity conversion efficiency (SECE) of above cell is estimated to be 0.248%. In addition, the photocatalytically produced H 2 O 2 (chemical energy) is stored in water with the electrodes disconnected under light irradiation for 3 h, and then is directly used as the fuel in an H 2 O 2 fuel cell by connecting the electrodes in the dark, yielding a specific capacitance of 5900 mF·cm−2. After 6 h of cell operation, the retention rate of specific capacitance is still as high as 76.9%. The primary results provide a facile strategy to introduce structural defects in g-C 3 N 4 for boosting H 2 O 2 fuel cell performance. [Display omitted] • Porous g-C 3 N 4 with structural defects (COCN) is applied in the H 2 O 2 fuel cell. • The structural defects in COCN facilitate the photocatalytic H 2 O 2 generation. • The COCN as the photoanode produces 0.036 M H 2 O 2 under light irradiation for 3 h. • The COCN-based cell converts solar energy to H 2 O 2 fuel for generating electricity. • The specific capacitance keeps 76.9% of initial value after 6 h of cell operation. [ABSTRACT FROM AUTHOR]

Highlights: [•] CdS urchins decorated with α-Fe2O3 or Fe3O4 nanoparticles were synthesized. [•] The heterostructures were used as visible light-driven photocatalysts. [•] Both the heterostructures showed the enhanced photocatalytic cycled activities. [Copyright &y& Elsevier]

The surface plasmon resonance (SPR) effect of noble nanometals can be utilized to effectively improve the catalytic performance of semiconductor photocatalysts. In this work, a novel composite photocatalyst of BiOBr microspheres simultaneously decorated by Ag and Bi dual nanoparticles (NPs) has been successfully synthesized by the hydrothermal method plus one-step reduction method. And the morphology, structure, chemical composition and photoelectrical properties of this composite photocatalyst (Ag/Bi–BiOBr) were further characterized. Due to the SPR effect of Ag and Bi dual NPs, Ag/Bi–BiOBr showed the high light absorption with narrow band gap, as well as fast charge separation via metal-semiconductor heterojunction so as to realize an efficient degradation of ibuprofen (IBP) under simulated solar irradiation. Through the further optimization of the loading amounts of Ag and Bi dual NPs, the excellent photocatalytic activity in the Ag/Bi–BiOBr has been achieved that 92.3% of IBP was removed within 60 min, which is among the best results reported so far for IBP degradation via photocatalysis. A facile preparation strategy of novel highly-active composite photocatalyst of BiOBr microspheres decorated by Ag and Bi dual nanoparticles has been proposed for efficient degradation of ibuprofen. • A simple one-step reduction strategy was proposed to prepare Ag/Bi dual nanoparticles-decorated BiOBr (Ag/Bi-BiOBr). • Bi nanoparticles were directly reduced from BiOBr without additional Bi precursors. • Ag and Bi nanoparticles increased the light absorbance and decreased the charge recombination. • The Ag/Bi-BiOBr showed efficient and stable photocatalytic activity on ibuprofen degradation. • The holes (h+) and electrons (e−) were the uppermost active species for ibuprofen degradation. [ABSTRACT FROM AUTHOR]

Abstract: Reduced graphene oxide/cadmium sulfide (RGO/CdS) hybrid material was synthesized by a one-step solvothermal method, wherein graphene oxide (GO) was a supporting material on which CdS nanoparticles were distributed homogeneously, and cadmium acetate (Cd(Ac)2·2H2O) was used as the CdS precursor. The supporting material RGO for CdS nanoparticles effectively enhanced their photocatalytic activities for the photodegradation of methylene blue in the aqueous solution. The optimum weight ratio of the GO to CdS in the hybrid material was 5.0%, which exhibited an excellent photodegradation efficiency (94%) and a better removal efficiency of total organic carbon (TOC) (57%), about 2.5 times and 5.1 times higher than that of pure CdS nanoparticles, respectively, under visible light (VL) irradiation. This improved photodegradation efficiency could be attributed to the increased adsorbability for methylene blue molecules, light absorption levels located in visible region, high charge transfer and separation ability, due to the introduction of a two-dimensional RGO network. [Copyright &y& Elsevier]

Ultrathin TiO 2 nanosheet with abundant Ti3+ is constructed as a photocatalyst for CO 2 conversion in the absence of any sacrificial reagents. The exposed Ti3+ as a Lewis base site may activate CO 2 to form bridging Ti···CO 2 −···Ti, resulting highly CH 4 yield via the synergistic effect of coordination-activation and photocatalysis. • Ultrathin TiO 2 nanosheets (NST) with abundant Ti3+ sites are constructed as a photocatalyst for conversion CO 2. • The catalyst (NST) exhibits a high yield (147.2 μmol g−1 h−1) and selectivity (96.8 %) for CH 4. • CO 2 would be selectively activated on the surface of NST via forming the bridging Ti···CO 2 −···Ti coordination species. • The synergistic effect about coordination-activation and photocatalysis can greatly enhance CH 4 yield efficiency. Ultrathin TiO 2 nanosheet (NST) with abundant Ti3+ sites is developed as a photocatalyst which exhibits a high yield (147.2 μmol g−1 h−1) and selectivity (96.8%) for CO 2 to CH 4. The results of in situ FTIR, in situ EPR and density functional theory (DFT) calculation suggest that CO 2 would be selectively activated on NST surface via forming the bridging Ti···CO 2 −···Ti coordination species which not only lowers the activation energy barrier, but also determines the selectivity of CH 4. Additionally, NST with the better separation and transfer ability for photogenerated electrons-holes can fleetly supply the electrons to CO 2 molecules for high efficiently producing CH 4 via the Ti-C coordination bond. Finally, a possible mechanism of the synergistic effect about coordination-activation and photocatalysis is discussed at a molecule level. This work would offer a perspective for designing an effective photocatalyst and tailoring the selectivity of products by coordination activation. [ABSTRACT FROM AUTHOR]