Superoxide radicals mediated by high-spin Fe catalysis for organic wastewater treatment.

Water resources are indispensable basic resources and important environmental carriers; the presence of organic contaminants in wastewater poses considerable risks to the health of both humans and ecosystems. Although the Fenton-like reactions using H2O2 as the oxidant to destroy organic pollutants are attractive, there are still challenges in improving reaction activity under neutral or even alkaline conditions. Herein, we designed a H2O2 activation pathway with O2•- as the main active species and elucidated that the spin interaction between Fe sites and coordinated O atoms effectively promotes the generation of the key intermediate Fe-*OOH. Furthermore, we successfully captured and analyzed the Fe-*OOH intermediate by in situ Raman spectroscopy. When applying FBOB to a continuous-flow reactor, CIP removal efficiency remained at around 90% within 600 min of continuous operation, achieving excellent efficiency, stability, and pH tolerance in removing pollutants.

Superexchange-induced Pt-O-Ti3+ site on single photocatalyst for efficient H2 production with organics degradation in wastewater.

Efficient photocatalytic H2 production from wastewater instead of pure water is a dual solution to the environmental and energy crisis, but due to the rapid recombination of photoinduced charge in the photocatalyst and inevitable electron depletion caused by organic pollutants, a significant challenge of dual-functional photocatalysis (simultaneous oxidative and reductive reactions) in single catalyst is designing spatial separation path for photogenerated charges at atomic level. Here, we designed a Pt-doped BaTiO3 single catalyst with oxygen vacancies (BTPOv) that features Pt-O-Ti3+ short charge separation site, which enables excellent H2 production performance (1519 µmol·g-1·h-1) while oxidizing moxifloxacin (k = 0.048 min-1), almost 43 and 98 times than that of pristine BaTiO3 (35 µmol·g-1·h-1 and k = 0.00049 min-1). The efficient charge separation path is demonstrated that the oxygen vacancies extract photoinduced charge from photocatalyst to catalytic surface, and the adjacent Ti3+ defects allow rapid migration of electrons to Pt atoms through the superexchange effect for H* adsorption and reduction, while the holes will be confined in Ti3+ defects for oxidation of moxifloxacin. Impressively, the BTPOv shows an exceptional atomic economy and potential for practical applications, a best H2 production TOF (370.4 h-1) among the recent reported dual-functional photocatalysts and exhibiting excellent H2 production activity in multiple types of wastewaters.

Tailoring of electronic and surface structures boosts exciton-triggering photocatalysis for singlet oxygen generation.

Arising from reduced dielectric screening, excitonic effects should be taken into account in ultrathin two-dimensional photocatalysts, and a significant challenge is achieving nontrivial excitonic regulation. However, the effect of structural modification on the regulation of the excitonic aspect is at a comparatively early stage. Herein, we report unusual effects of surface substitutional doping with Pt on electronic and surface characteristics of atomically thin layers of Bi3O4Br, thereby enhancing the propensity to generate 1O2 Electronically, the introduced Pt impurity states with a lower energy level can trap photoinduced singlet excitons, thus reducing the singlet-triplet energy gap by ∼48% and effectively facilitating the intersystem crossing process for efficient triplet excitons yield. Superficially, the chemisorption state of O2 causes the changes in the magnetic moment (i.e., spin state) of O2 through electron-mediated triplet energy transfer, resulting a spontaneous spin-flip process and highly specific 1O2 generation. These traits exemplify the opportunities that the surface engineering provides a unique strategy for excitonic regulation and will stimulate more research on exciton-triggering photocatalysis for solar energy conversion.

Regulating Spin Polarization through Cationic Vacancy Defects in Bi4 Ti3 O12 for Enhanced Molecular Oxygen Activation.

Molecular oxygen (O2 ) activation technology is of great significance in environmental purification due to its eco-friendly operation and cost-effective nature. However, the activation of O2 is limited by spin-forbidden transitions, and efficient molecular oxygen activation depends on electronic behavior and surface adsorption. Herein, we prepared cationic defect-rich Bi4 Ti3 O12 (BTO-MV2) catalysts containing Ti vacancies (VTi ) for O2 activation in water purification. The VTi on BTO nanosheets can induce electron spin polarization, increasing the number of spin-down photogenerated electrons and reducing the recombination of electron-hole pairs. An active surface VTi is also formed, serving as a center for adsorbing O2 and extracting electrons, effectively generating ⋅OH, O2 ⋅- and 1 O2 . The degradation rate constant of tetracycline achieved by BTO-MV2 is 3.3 times faster than BTO, indicating a satisfactory prospect for practical application. This work provides an efficient pathway to activate molecular oxygen by constructing new active sites through cationic vacancy modification technology.

Accelerating FeIII-Aqua Complex Reduction in an Efficient Solid-Liquid-Interfacial Fenton Reaction over the Mn-CNH Co-catalyst at Near-Neutral pH.

The sluggish regeneration rate of FeII and low operating pH still restrict the wider application of classical Fenton process (FeII/H2O2) for practical water treatment. To overcome these challenges, we exploit the Mn-CNH co-catalyst to construct a solid-liquid interfacial Fenton reaction and accelerate the FeIII/FeII redox cycle at the interface for sustainably generating •OH from H2O2 activation. The Mn-CNH co-catalyst exhibits an excellent regeneration rate of FeII (∼65%) and a high tetracycline removal rate (Kobs) of 0.0541 min-1, which is 19.0 times higher than that of the FeII/H2O2 system (0.0027 min-1) at a near-neutral pH (pH ≈ 5.8), and it also attains 100% degradation of sulfamethoxazole, rhodamine B, and methyl orange. The cyclic mechanism of FeIII/FeII is further elucidated in an atomic scale by combining characterizations and density functional theory calculations, including FeaqIII specific adsorption and the electron-transfer process. Mn active sites can accumulate electrons from the matrix and adsorb FeaqIII to form Mn-Fe bonds at the solid-liquid interface, which accelerate electron transfer from Mn-CNH to FeaqIII and promote the regeneration of FeII at a wide pH range with a lower energy barrier. The regeneration rate of FeII in the Mn-CNH/FeII/H2O2 system outperforms the benchmark Fenton system and other typical metal nanomaterials, which has great potential to be widely applied in actual environment remediation.

Response of microbial community composition and function to land use in mining soils of Xikuang Mountain in Hunan.

Nine land types in the northern mining area (BKQ) (mining land, smelting land, living area), the old mining area (LKQ) (whole-ore heap, wasteland, grassland), and southern mining area (NKQ) (grassland, shrubs, farmland) of Xikuang Mountain were chosen to explore the composition and functions of soil bacterial communities under different habitats around mining areas. The composition and functions of soil bacterial communities were compared among the sampling sites using 16S rRNA high-throughput sequencing and metagenomic sequencing. α diversity analysis showed the soil bacterial diversity and abundance in the old mining area were significantly higher than those in the northern mining area. ß diversity analysis demonstrated that the soil bacterial community composition was highly similar among different vegetation coverages in the southern mining area. Microbial community function analysis showed the annotated KEGG function pathways and eggNOG function composition were consistent between the grassland of the old mining area and the grassland of the southern mining area. This study uncovers the soil bacterial community composition and functions among different habitats in the mining areas of Xikuang Mountain and will underlie soil ecosystem restoration in different habitats under heavy metal pollution around the mining areas there.

Dynamic active-site induced by host-guest interactions boost the Fenton-like reaction for organic wastewater treatment.

In heterogeneous catalysis, uncovering the dynamic evolution of active sites in the working conditions is crucial to realizing increased activity and enhanced stability of catalyst in Fenton-like activation. Herein, we capture the dynamic changes in the unit cell of Co/La-SrTiO3 catalyst during the exemplary peroxymonosulfate activation process using X-ray absorption spectroscopy and in situ Raman spectroscopy, revealing the substrate tuned its structural evolution, which is the reversible stretching vibration of O-Sr-O and Co/Ti-O bonds in different orientations. This process effectively promotes the generation of key SO5* intermediates, which is beneficial to the formation of 1O2 and SO4•- from persulfate on the Co active site. Density functional theory and X-ray absorption spectroscopy show that the optimized structural distortion enhanced the metal-oxygen bond strength by tuning the eg orbitals and increased the number of transferred electrons to peroxymonosulfate by about 3-fold, achieving excellent efficiency and stability in removing organic pollutants.

Urinary and sexual function changes in benign prostatic hyperplasia patients before and after transurethral columnar balloon dilatation of the prostate.

BACKGROUND: Transurethral columnar balloon dilatation of the prostate (TUCBDP) is a new surgical treatment, but its efficacy remains controversial because of limited clinical application. AIM: To investigate the clinical effect of TUCBDP for benign prostatic hyperplasia (BPH). METHODS: Overall, 140 patients with BPH who underwent surgical treatment were included in the study. A random number table was used to divide the participants into study and control groups (n = 70 per group). The study group underwent TUCBDP. The prostate resection surgical time, intraoperative blood loss, bladder irrigation time, catheter indwelling time, length of hospital stay, International Prostate Symptom Score (IPSS), maximum urine flow rate (Qmax), residual urine volume (RUV), changes in the International Erectile Function Score (IIEF-5) score, serum prostate-specific antigen (PSA), quality of life (QOL) score, and surgical complications were compared in both groups. RESULTS: The operation time, intraoperative blood loss volume, bladder flushing time, urinary catheter indwelling time, and length of hospital stay were significantly lower in the study group than in the control group (P < 0.05). There were no significant differences in the IPSS, Qmax, and RUV measurements between the study and control groups (P > 0.05). However, at 3 mo post-surgery, the IPSS and RUV measurements were both lower (P < 0.05) and Qmax values were higher (P < 0.05) compared to the pre-surgery results in both groups. The IIEF-5 scores before and 3 mo after surgery were not significantly different between the study and control groups (P > 0.05). At 1 mo after surgery, the IIEF-5 score was higher in the study group than in the control group (P < 0.05). The serum PSA levels and QOL scores before treatment and at 1 and 3 mo after treatment were not significantly different between the study and control groups (P > 0.05). However, lower serum PSA levels and QOL scores were observed after 1 and 3 mo of treatment compared to pre-treatment levels in the study group (P < 0.05). The surgical complication rate of the study group (4.29%) was lower than that of the control group (12.86%; P < 0.05). CONCLUSION: TUCBDP for BPH and transurethral resection of the prostate can achieve better results, but the former method is associated with less surgical trauma.

Enhanced carriers separation in novel in-plane amorphous carbon/g-C3N4 nanosheets for photocatalytic environment remediation.

Although carbon-based materials/g-C3N4 heterostructure with an up-down structure in space can inhibit the recombination of charge carriers, the electron transfer is still suppressed by the interlayer van der Waals force. Herein, amorphous carbon is successfully introduced into the g-C3N4 nanosheet (CNS) by a self-conversion process to form an in-plane heterostructure of amorphous carbon/g-C3N4 (CNSC1). Kelvin probe atomic force microscopy (KPFM) and density functional theory (DFT) confirm that g-C3N4 and amorphous carbon are in the same plane, which can generate the surface electric field of CNSC1, providing a driving force for the transfer of electrons from g-C3N4 to amorphous carbon. Meanwhile, the sp2-hybridized π conjugation bond of amorphous carbon can rapidly capture and store photogenerated electrons, inhibiting charge carrier recombination and thus generating more electrons to facilitate the yield of hydroxyl radicals. The photocatalytic activity of CNSC1 for the degradation of tetracycline and rhodamine B is 2.7 times and 4.8 times higher than that of CNS, respectively, due to the efficient interface charge separation. This work is expected to provide a new idea for the combination of carbon materials and g-C3N4.

Identification of the Stable Pt Single Sites in the Environment of Ions: From Mechanism to Design Principle.

For single-atom (SA)-based catalysis, it is urgent to understand the nature and dynamic evolution of SA active sites during the reactions. In this work, an example of Pt SA-Zn0.5 Cd0.5 S (Pt SA-ZCS) is found to display interesting phenomena when facing the Brownian collision of ions in aqueous photocatalysis. Via synchrotron radiation, surface techniques, microscopy, and theory calculations, the results show that two kinds of Pt sites exist: PtZn-sub -S3 (Pt substituting the Zn site) and Ptads -S2 (Pt adsorbing on the surface). In Na2 S, the S2- can coordinate with Pt atoms and peel them from the Ptads -S2 sites, but leaves more stable PtZn-sub -S3 sites, bringing a low but stable catalytic activity (19.40 mmol g-1 h-1 ). Meanwhile, in ascorbic acid, the ascorbic acid ions show less complex ability with Pt atoms, but can decrease the migration barrier of Ptads -S2 sites (67.18 down to 35.96 mmol g-1 h-1 , 52.03% drop after 6 h). Therefore, the Ptads -S2 sites gradually aggregate into nanoclusters, bringing a high but decayed catalytic activity. Moreover, a Pt SA-ZCS-Sulfur composite is designed mainly covered by PtZn-sub -S3 sites accordingly (max: 79.09 mmol g-1 h-1 , 5% drop after 6 h and QE: 14.0% at 420 nm), showing a beneficial strategy "from mechanism to design principle."

Large-Scale Synthesis of Spinel Nix Mn3-x O4 Solid Solution Immobilized with Iridium Single Atoms for Efficient Alkaline Seawater Electrolysis.

Seawater electrolysis not only affords a promising approach to produce clean hydrogen fuel but also alleviates the bottleneck of freshwater feeds. Here, a novel strategy for large-scale preparing spinel Nix Mn3-x O4 solid solution immobilized with iridium single-atoms (Ir-SAs) is developed by the sol-gel method. Benefitting from the surface-exposed Ir-SAs, Ir1 /Ni1.6 Mn1.4 O4 reveals boosted oxygen evolution reaction (OER) performance, achieving overpotentials of 330 and 350 mV at current densities of 100 and 200 mA cm-2 in alkaline seawater. Moreover, only a cell voltage of 1.50 V is required to reach 500 mA cm-2 with assembled Ir1 /Ni1.6 Mn1.4 O4 ‖Pt/C electrode pair under the industrial operating condition. The experimental characterizations and theoretical calculations highlight the effect of Ir-SAs on improving the intrinsic OER activity and facilitating surface charge transfer kinetics, and evidence the energetically stabilized *OOH and the destabilized chloride ion adsorption in Ir1 /Ni1.6 Mn1.4 O4 . This work demonstrates an effective method to produce efficient alkaline seawater electrocatalyst massively.

Pauling-type adsorption of O2 induced electrocatalytic singlet oxygen production on N-CuO for organic pollutants degradation.

Due to environmentally friendly operation and on-site productivity, electrocatalytic singlet oxygen (1O2) production via O2 gas is of immense interest in environment purification. However, the side-on configuration of O2 on the catalysts surface will lead to the formation of H2O, which seriously limits the selectivity and activity of 1O2 production. Herein, we show a robust N-doped CuO (N-CuO) with Pauling-type (end-on) adsorption of O2 at the N-Cu-O3 sites for the selective generation of 1O2 under direct-current electric field. We propose that Pauling-type configuration of O2 not only lowers the overall activation energy barrier, but also alters the reaction pathway to form 1O2 instead of H2O, which is the key feature determining selectivity for the dissociation of Cu-O bonds rather than the O-O bonds. The proposed N dopant strategy is applicable to a series of transition metal oxides, providing a universal electrocatalysts design scheme for existing high-performance electrocatalytic 1O2 production.

Macro Modeling of V-Shaped Electro-Thermal MEMS Actuator with Human Error Factor.

The V-shaped electro-thermal MEMS actuator model, with the human error factor taken into account, is presented in this paper through the cascading ANSYS simulation model and the Fuzzy mathematics calculation model. The Fuzzy mathematics calculation model introduces the human error factor into the MEMS actuator model by using the BP neural network, which effectively reduces the error between ANSYS simulation results and experimental results to less than 1%. Meanwhile, the V-shaped electro-thermal MEMS actuator model, with the human error factor included, will become more accurate as the database of the V-shaped electro-thermal actuator model grows.