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Converting surplus glycerol into the hydrogen storage material, formic acid, can meet the increasing energy demand, yet its commercial production is hindered by the low efficiency. Herein, a nano-c...

This study demonstrates a new system for the degradation of emerging pharmaceutical contaminants (e.g., ibuprofen) in water by coupling the naturally occurring ilmenite with hydroxylamine (HA) and persulfate (PS). Ilmenite was able to activate persulfate to generate sulfate radicals (SO4−·) and hydroxyl radicals (HO·). The radical generation was greatly improved by adding small amount of hydroxylamine into the solution, due to the efficient Fe(III)/Fe(II) cycle on the ilmenite surface promoted by HA, which was confirmed by X-ray photoelectron spectroscopy and electron paramagnetic resonance (EPR) spectroscopy analysis. SO4−· and HO· contributed comparably to ibuprofen degradation, which was verified by the radical scavenging tests. The degradation was enhanced with increasing ilmenite, PS and HA dosages, but the HA exhibited strong scavenging effect at its high concentrations. The ilmenite/PS/HA process worked well in the real treated wastewater, because the surface-controlled radical generation was less affected by the water matrix. However, the formation of bromate in the bromide-containing water by this process should be concerned. Ibuprofen was partially mineralized, and the degradation products were identified by ESI-tqMS. A radical-induced degradation pathway was proposed based on the product identification. This work provides the mechanistic insights on persulfate activation based on the surface-controlled catalytic processes. It also offers a new strategy to degrade emerging contaminants in water and sheds light on the environmental functions of natural minerals.

V-substituted polymolybdenum phosphoric acid (PVxMo) supported on mesoporous silica was prepared and investigated as a catalyst for the oxidation of glycerol to formic acid in a batch operation. Different synthetic methods for PVxMo supported on mesoporous silica were compared. Detailed characterizations of the final products were carried out by N2 adsorption and desorption, XRD, HR-TEM, SEM, ICP-OES, XANES, NH3-TPD, and FTIR to identify the chemical properties and the porous structure of silica-supported PVxMo, as well as the strong interactions between PVxMo with the silica skeleton. These critical properties explain the bifunctionality of silica-supported PVxMo as a catalyst for the selective oxidation of glycerol to formic acid with standing stability. Keywords: Glycerol, Formic acid, SBA-15, V-substituted heteropoly acid

Rational design of sustainable, cost-efficient and highly efficient deionization electrodes is crucial for the practical applications of capacitive deionization (CDI). Mycelial pellet-derived nitrogen and sulfur heteroatom co-doped three-dimensional (3D) carbon nanosheets (NSHPC) with a hierarchical porous structure have been facilely fabricated via a simple one-step strategy by utilizing sustainable mycelial pellets as a carbon source, glutaraldehyde as a crosslinking agent, zinc chloride as a pore forming agent, and thiourea as a heteroatom supplier. The obtained biomass-derived NSHPC nanosheets, with interconnected hierarchical macro-meso-micropores and a lamellar structure, exhibit outstanding CDI performance with an electrosorption capacity of 18.71 mg g−1 in 500 mg L−1 NaCl solution and a high reversibility (stable up to 10 cycles). The performance of NSHPC significantly surpasses that of the bulk mycelial pellet-derived carbon without activation and modification. The efficient CDI performance of NSHPC can be attributed to its unique features, including the 3D network structure formed by bundled nanosheets to provide multi-dimensional ion diffusion pathways and interlayer ion storage, the hierarchical pores to assist efficient ion diffusion and capture, the surface functional groups derived from mycelial pellets, and the hydrophilicity contributed by the heteroatom co-doping. The design of NSHPC nanosheets paves an avenue for developing efficient sustainable materials for CDI applications.

A novel process for S-VOCs degradation using wet scrubbing coupled with catalytic ozonation was developed for first time. We report redox-robust catalysts consisting of Ag(0)/Ag(I) species decorated rambutan-like MnO2 hollow microspheres (Ag/R-MnO2) with strong metal-metal oxide interaction (MMOI) exhibited superior catalytic ozonation performance for CH3SH elimination. The optimum Ag/R-MnO2 reached a significant improvement in CH3SH elimination of 96.9% conversion over pristine R-MnO2 under GHSV of 75,000 mL h−1 g−1, and O3 utilization rate of 92.3%. An outstanding stability of Ag/R-MnO2 under wet catalytic ozonation process was demonstrated, which outperformed that in gaseous system. CH3SH was captured by aqueous solution and preferentially chemisorbed on Ag, then deeply oxidized to the final products of SO42-/CO32- via catalytic ozonation by multivalent R-MnO2. The excellent performance can be ascribed to efficient electron replenishing interaction between Ag(0)/Ag(I) and multivalent R-MnO2, efficient O3 activation through oxygen vacancies-rich R-MnO2, and enhanced mass diffusion in wet scrubbing process.

A facile, cost-effective approach to obtain sensor electrode materials with excellent electrochemical performance for sensitive and fast detection of 4-nitrophenol (4-NP) is of great importance to the environment and human health. Herein, a smart strategy was proposed for fabrication of nitrogen-doped hierarchical porous carbon (NPC) material with large surface area and unique hierarchical porous structure derived from conveniently available carbohydrates via a facile process. NPC combined with chitosan (CTS) was used to modify an indium-tin oxide (ITO) electrode, referred to as a CTS/NPC/ITO electrode, in which CTS acted as dispersant and immobilization reagent. On the basis of the optimum conditions, 4-NP was successfully deposited on a CTS/NPC/ITO electrode and the cathodic deposit of 4-NP showed reversible characteristics in a potential range between −0.22 and −0.00 V as well as high ionic-electronic conductivity. Moreover, the electrochemical reaction kinetics and mechanism of 4-NP were explored in d...

In this study, Ag deposited three-dimensional MnO2 porous hollow microspheres (Ag/MnO2 PHMSs) with high dispersion of the atom level Ag species are first prepared by a novel method of redox precipitation. Due to the highly efficient utilization of downsized Ag nanoparticles, the optimal 0.3% Ag/MnO2 PHMSs can completely degrade 70 ppm CH3SH within 600 s, much higher than that of MnO2 PHMSs (79%). Additionally, the catalyst retains long-term stability and can be regenerated to its initial activity through regeneration with ethanol and HCl. The results of characterization of Ag/MnO2 PHMSs and catalytic performance tests clearly demonstrate that the proper amount of Ag incorporation not only facilitates the chemi-adsorption but also induces more formation of vacancy oxygen (Ov) and lattice oxygen (OL) in MnO2 as well as Ag species as activation sites to collectively favor the catalytic ozonation of CH3SH. Ag/MnO2 PHMSs can efficiently transform CH3SH into CH3SAg/CH3S-SCH3 and then oxidize them into SO42– and...

Hierarchical porous sludge-derived activated carbon coated on macroporous silicon carbide (SiC) foams substrate has been facilely fabricated via a simple one-step strategy by utilizing sludge as carbon source, and jointly using zinc chloride and hexadecanol as pore forming agents. The sludge-derived carbon has been confirmed to be hierarchical macro-meso-microporous structure based on detailed characterization by scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectra and nitrogen adsorption-desorption measurement. The adsorption tests showed that the hierarchical porous sludge-derived activated carbon fabricated by one-step pore-forming (zinc chloride and hexadecanol microemulsion mixture) possesses excellent adsorption capacity (259.9mgg-1, breakthrough time reach 90min and saturation end-time up to 140min) of methyl mercaptan (CH3SH). The excellent adsorption performance can be attributed to the macroporous SiC foam skeleton and the mesopores channel formed by nonionic surfactant hexadecanol micelles, as well as the micropores activated by ZnCl2 as odor capture sites. The proposed pore-forming strategy paves an avenue for the sludge disposal and even the development of bio-derived materials.

Owing to its excellent chemical stability and low cost, titanium dioxide (TiO2) has been widely studied as a photoanode for photoelectrochemical (PEC) water splitting. However, TiO2's practical applications in solar energy-to-synthetic fuel conversion processes have been constrained by its inherently poor ability to transport photogenerated electrons and holes. In this paper, we report Ta-doped porous TiO2 nanorod arrays on Ta foil (Ta-PTNA) that do not possess this issue and that can thus efficiently photoelectrocatalyze water oxidation, helping the production of H2 (a clean fuel) from water at the expense of solar light. The materials are synthesized by a new, facile synthetic approach involving the hydrothermal treatment of a TiO2 precursor with Ta foil, without seeds and templates, and followed by calcination of the product. Besides serving as a source of Ta dopant atoms, Ta foil is found to play a vital role in the formation of nanopores in the materials. The material obtained with hydrothermal treatment at 180 °C for 10 h (Ta-PTNA-10), in particular, affords very large photocurrent density and very high photoconversion efficiency (0.32% at 0.79 V vs. RHE, which is better than those of many previously reported photocatalysts and ∼4 times larger than that of undoped TiO2 nanorod arrays). Ta-PTNAs’ remarkable PEC catalytic performance is found to be due to their nanoporous structure and high electronic conductivity.

Solar photocatalysis is a clean and sustainable approach for removing atmospheric NO, but suffers from unsatisfactory removal efficiency. Efficient charge separation and surface reaction are critical factors ensuring the efficiency of solar energy conversion by photocatalysts. To achieve efficient charge steering and an enhanced surface reaction, we synthesized a bicomponent photocatalyst consisting of multivalent Ag species embedded in defect-rich twin-brush ZnO (Ag/TB-ZnO) with strong metal-support interaction (SMSI). The optimum Ag/TB-ZnO with silver loading of 2.0 wt.% achieved NO oxidation efficiency of 71.0% under a GHSV of 1,200,000 mL h−1 g−1, and NO3− selectivity of 94.8%. Outstanding stability of up to 4 h was demonstrated. This superior performance was attributed to the enhanced efficacy of charge separation and surface reaction by the SMSI effect, surface plasmon resonance effect of metallic Ag and the efficient activation of oxygen species through vacancy-rich TB-ZnO.

In this study, a thin membrane with vertically aligned mesoporous silica nanochannels was modified with long silane group molecules (E-MSTF-LTA) supported on an anodic aluminum oxide (AAO) for organic solvent nanofiltration (OSN). The ultrathin thickness, low tortuosity, ordered vertical channels and super-organophilic surface of E-MSTF-LTA endow it with an ultrahigh ethanol permeance (110 LMH/bar) over current state-of-the-art OSN membranes and a high acetone permeance of 360 LMH/bar. Furthermore, a 99% rejection of Evans blue (EB) was demonstrated, and a cut-off of approximately 660 Da was achieved. Besides, the modified Hagen-Poiseuille (HP) equation was applied to evaluate the theoretical permeance, which is consistent with the experimental results. To explore in depth the underlying principle behind the OSN performance of the vertically aligned E-MSTF-LTA membrane, the parameters, including the solvent viscosity, total Hansen solubility, solvent diameter, and solvent polarity were introduced to evaluate their influence on the permeance, while for solute transport behavior, the impact of the size exclusion effect on the solute rejection rate was examined. The results show that the viscosity is the critical factor for determining the solvent permeation, while the size exclusion effect dominates solute rejection. These findings open up a way to design next-generation vertically aligned OSN membranes and shed light on the OSN performance, both empirically and theoretically, using this system.

Mechanically stable titanium dioxide (TiO2) with the abilities of rapidly storing and releasing Li+ can be potentially applied in electric and hybrid electric vehicles, due to its ability to enhance the stability and safety, as well as the high current performance, of lithium ion batteries (LIBs). Herein, we rationally and facilely synthesized oriented anatase TiO2 nanoarrays (OATNs) from the NH4TiOF3 mesocrystal precursor through topotactic conversion and in situ epitaxial growth under moderate conditions. This study proves that the crystallization, porous structure, and orientation of OATNs are controllable, which affect the electronic and electrochemical properties and the Li+ diffusion coefficient. The optimal OATNs formed by hydrothermally treating NH4TiOF3 mesocrystals with an H3BO3 aqueous solution for 10 h (OATNs-10) delivered a high capacity of ca. 115 mA h g−1 at a current density of 50 C (170 mA g−1 of 1 C) even after continuous 2000 cycles with a Coulombic efficiency of ca. 100%. This indicates a high current rate performance and excellent stability. The unique properties of OATNs-10 make them a promising candidate for practical applications in LIBs.

Transition metal oxides caused much attention owing to the scientific interests and potential applications in energy storage systems. In this study, a free-standing three-dimensional (3D) chestnut-like TiO2@α-Fe2O3 core–shell nanostructure (TFN) is rationally synthesized and utilized as a carbon-free electrode for lithium-ion batteries (LIBs). Two new interfaces between anatase TiO2 and α-Fe2O3 are observed and supposed to provide synergistic effect. The TiO2 microsphere framework significantly improves the mechanical stability, while the α-Fe2O3 provides large capacity. The abundant boundary structures offer the possibility for interfacial lithium storage and electron transport. The as-prepared TFN delivers a high capacity of 820 mAh g–1 even after 1000 continuous cycles with a Coulombic efficiency of ca. 99% at a current of 500 mA g–1, which is better than the works reported previously. A thin gel-like SEI (solid electrolyte interphase) film and Fe0 phase yielded during charge/discharge cycling have bee...

Tandem catalysis can carry out the sequential coupling of multiple reactions in one operation, which is promising for sulfur-containing volatile organic compounds (S-VOCs) control. Herein, a tandem catalyst (CuO/VO-MnO2) consisting of well-dispersed CuO shell and oxygen vacancy-rich (VO) hollow-structured MnO2 core exhibited superior adsorption and catalytic performance under the mild condition for the elimination of CH3SH. The optimum 5CuO/VO-MnO2 can reach a significant improvement in CH3SH elimination of ∼99 % conversion over bare CuO/ pristine MnO2 at 25 ℃ under a GHSV of 60,000 mL h−1 g−1, and an almost 4-fold enhanced catalytic activity of the individual O3 with ∼99 % utilization of the applied O3 in the feed gas. The underlying tandem catalytic mechanism was in-depth identified by XPS, in situ DRIFTs and high-level computational study. The secret to the superior performance of CuO/VO-MnO2 lies in that CH3SH was preferentially chemisorbed on multivalent CuO (Cu(I)/Cu(II)), then deeply oxidized into final product of SO42−/CO32− via the catalytic ozonation by multivalent CuO and oxygen vacancies of neighbouring VO-MnO2. Attributed to the efficient electron replenishing interaction and cycling of active oxygen vacancies at the tandem reactive site of CuO/VO-MnO2 interface ( Mn(IV) + Cu(II) + 2Olatt → Mn(II)/Mn(III) + VO + Cu(I) + O2), its lifetime can extend to 300 min with limited loss of activity. These findings thus open up a way to address current multiple challenges in S-VOCs control using a single hierarchical core-shell structure with tandem catalysis.

Artificial photocatalytic conversion of CO2 into value-added and renewable fuels has been recognized as a promising approach for solving environmental problems and energy crisis. Achieving this goal, developing a photocatalyst to simultaneously manifest high efficiency, selectivity, and durability is urgent need. Herein, one of all-inorganic cesium lead halide perovskite (viz. Cs4PbBr6) with hole-in-microdisk structure hybridized with reduced graphene oxide (rGO) is reported as an effective photocatalyst for reducing of CO2. Our results show that Cs4PbBr6/rGO exhibited high efficiency, selectivity, and durability of CO2 reduction capacity to CO, catalyzing at a rate of 11.4 μmol g-1h-1 with a maintaining stability of 60 h. Residual oxygen impurities as defects in the rGO sheets are demonstrated for facilitating CO2 activation and reduction capacity to CO. This finding provides a facile pathway for designing high performance perovskite photocatalyst with high selectivity and durability with the aid of defects engineering.

Effects of carbon concentration and Cu additive in simulated fly ash (SFA) and real fly ash (RFA) on the formation of polychlorinated dibenzofurans (PCDFs), polychlorinated dibenzo-p-dioxins (PCDDs), chlorobenzenes, and polychlorinated biphenyls which were all regarded as persistent chlorinated aromatics in iron ore sintering were investigated. In the annealing process of SFA with various carbon contents, the yield of chlorinated aromatics and the I-TEQ obtained their maximum at 10 wt% carbon content. Active carbon in SFA acted as the carbon source as well as an adsorbent which led to higher production of PCDD/F in solid phase at 10 wt% carbon content. The increase of carbon content will be beneficial on the formation of 2,3,7,8-Chloro-substituted PCDF compared with 2,3,7,8-Chloro-substituted PCDD. In addition, the CuCl2·2H2O was a much more powerful catalyst in the formation of chlorinated aromatic compounds compared with elementary Cu, since it served as both a catalyst and a chlorine donor. However, the RFA behaved similarly with SFA with elementary Cu in the formation of chlorinated aromatic compounds. The effect of carbon content and copper additives on formation of 2,3,7,8-chloro-substituted congeners displayed similar characteristics with the tetra- to octa-PCDD/F isomers and even the total PCDD/Fs.

The poor reusability of catalysts and secondary pollution are critical issues for sulfur-containing volatile organic compounds (S-VOCs) removal. In this paper, a three-dimensional (3D) hierarchical porous sludge-derived carbon supported on silicon carbide foams (SiC) has been fabricated for deep decomposition of S-VOCs under ambient conditions. The sludge-derived Fenton-like catalyst has been confirmed to be hierarchical 3D porous structure based on detailed characterization by scanning electron microscopy (SEM), X-ray diffraction (XRD), Nitrogen adsorption-desorption measurements and Raman spectroscopy. Significantly, the catalyst after KOH activation (SCFeK-SiC) shows excellent catalytic decomposition of methyl mercaptan (CH3SH) with almost complete CH3SH oxidation into sulfate using hydrogen peroxide as an oxidant under ambient conditions. This catalyst also possesses relative low iron dissolution and excellent cycling performance. The efficient catalytic ability of SCFeK-SiC can be attributed to SiC foam functioned as a stable 3D macroporous skeleton, in which the porous sludge-derived carbon immobilizes the active iron species and promotes the efficient capture of gaseous CH3SH, thus facilitating the decomposition of CH3SH by generating reactive species, specifically ·OH. The reaction mechanism was systematically investigated. Herein, the design of the porous sludge-derived carbonaceous Fenton-like catalyst paves an avenue for efficient VOCs treatment and rational sludge disposal.

In this study, the concentrations of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs), in brief dioxins (PCDD/Fs), were measured in the off-gas and solid by-products from two selected and distinct desulphurisation processes, one operating wet and one dry on sintering off-gas. All samples analysed showed a PCDFs to PCDDs ratio larger than unity. The removal efficiencies obtained in the two facilities were almost identical, about 40%, when based on the toxic equivalent quantity (TEQ), and the removal efficiency of PCDD/Fs was higher. Unexpectedly, the removal efficiency was strongly dependent on chlorination level and far higher for low chlorinated PCDD/Fs than for high chlorinated PCDD/Fs, showing even negative removal efficiency. Moreover, the Hagenmaier profile was markedly different for the gas phase samples than for residue. These findings suggest that during desulphurisation both physical effects, such as adsorption, chemical reactions, as well as memory effects may have occurred.

The subsolidus phase relations of the Bi2O3-Nd2O3-CuO ternary system and its binary systems along with crystallographic parameters of the compounds were investigated by X-ray powder diffraction and differential thermal analysis. The room temperature section of the phase diagram of the Bi2O3-Nd2O3-CuO system can be divided into two diphase regions and six triphase regions. No ternary compound was found. There exist two solid solutions (alpha, beta) and a compound Bi0.55Nd0.45O1.5 in the (Bi2O2)(1-x)(Nd2O3)(x) system. Both solid solution alpha (0.05 less than or equal to x less than or equal to 10.30) and beta (0.53 less than or equal to x less than or equal to 0.73) belong to the rhombohedral system (R (3) over bar m). The lattice parameters represented by a hexagonal cell are a = 3.9832(4), c = 27.536(5) Angstrom for Bi0.8Nd0.2O1.5 (alpha phase) and a = 3.8826(3), c = 9.727(1) Angstrom for Bi0.4Nd0.8O1.5 (beta phase). The Bi0.55Nd0.45O1.5 compound crystallizes in a face-centered cubic (f.c.c.) lattice with a = 5.5480(2) Angstrom.