This work systematically investigates the catalytic performance of perovskite BaTiO3-supported alkali metal nitrates for the condensation of lactic acid to 2,3-pentanedione. By varying the alkali metal nitrate type and employing comprehensive characterization techniques including X-ray diffraction, N2 physisorption, and temperature-programmed desorption, the relationships among catalyst composition, structural properties, surface acid-base characteristics, and the reaction pathway were established. The introduction of alkali metal nitrates (with KNO3 exhibiting the highest activity) significantly enhances both the conversion of lactic acid and the selectivity to 2,3-pentanedione. In situ-formed alkali metal lactates act as key intermediates that promote the nucleophilic addition step, while well-balanced acid-base sites on the catalyst surface facilitate the subsequent dehydration and decarboxylation steps. Alkali metal ions, particularly K* and Cs*, play an essential role in stabilizing crucial reaction intermediates, whereas Na* shows markedly lower effectiveness. Under optimized conditions (270 degrees C, 20 wt% aqueous lactic acid fed at 1.0 mL h-1), the KNO3-loaded catalyst achieves 77.3% lactic acid conversion with 55.0% selectivity to 2,3-pentanedione. The catalyst demonstrates excellent stability, maintaining its performance over 105 h of continuous operation under accelerated testing conditions, indicating its potential for practical application. This study clarifies the synergistic roles of surface acidity-basicity and alkali metal modification, offering a rational basis for designing efficient and durable catalysts for lactic acid valorization via condensation reactions.

The selective catalytic coupling of lactic acid (LA) to value-added chemicals like pyruvic acid (PyA) and propionic acid (PA) represents a promising route for biomass valorization. However, developing efficient, non-precious metal catalysts for this complex transformation remains a challenge. Herein, we demonstrate that phosphorus doping significantly enhances the catalytic selectivity of MoS2 for the coupling reaction of LA. Comprehensive characterization and theoretical calculations reveal that P-doping induces the formation of abundant sulfur vacancies and modulates the electronic structure of MoS2. These sulfur vacancies, particularly at the Mo sites, serve as highly active centers for the adsorption and activation of LA molecules and water, as corroborated by pH measurements and the detection of H-2 in the effluent gas. A synergistic reaction mechanism is proposed: on the S site, one LA molecule undergoes dehydrogenation to form pyruvic acid, while on the adjacent Mo site, a second LA molecule undergoes hydrodeoxygenation. The resulting intermediates subsequently combine to yield propionic acid. The suppression of undesirable side reactions, particularly decarboxylation, is achieved through P-doping, which reduces the number of strong acid sites and collectively enhances the reaction efficiency. At 300 degrees C and LA feed rate of 1 mL h(-1) , the P-MoS2 catalyst achieved a combined selectivity of 87.5% to PA and PyA, significantly outperforming its undoped counterpart. This work underscores the pivotal role of defect engineering via heteroatom doping in tailoring the catalytic properties of MoS2, providing a strategic direction for designing high-performance catalysts for biomass conversion.

Solar-driven interfacial evaporation for seawater and other wastewater is widely viewed as green, environmental technology to generate clean water. Herein, the sulfur vacancy-rich MoS2-sodium alginate-filter cotton aerogel evaporator was designed to purify seawater, heavy metal wastewater and dyestuff wastewater for production of clean water. From analysis of XPS spectra, 2H-MoS2 dominates in BMoS2 (bulk MoS2) while 1 T-MoS2 becomes a major phase in SSMoS2 (ultrathin and sulfur vacancy-rich MoS2). EPR measurement reveals that SSMoS2 possesses far richer sulfur vacancies than BMoS2. SSMoS2 displays a stronger broadband absorption ability and lower reflectance than BMoS2. As a result, SSMoS2-based evaporator offered more excellent water evaporation performance than BMoS2-based evaporator. Under irradiation of 1 sun, the SSMoS2-based evaporator achieves a high evaporation rate of 2.03 kg m- 2h- 1 which is higher than the BMoS2-based evaporator with 1.58 kg m- 2h- 1, demonstrating that sulfur vacancy has an enhanced effect for photothermal conversion. The SSMoS2-based evaporator also displays an excellent evaporation rate of seawater, close to pure water. Besides, this evaporator shows an excellent durability for seawater desalination, and maintains a self-cleaning effect. In addition, this evaporator offers an excellent performance for purifying heavy metal wastewater, in which the heavy metal ionic concentration of the purified water is far lower than drinking water stated by the standard of World Health Organization. Encouragingly, this evaporator can also purify dyestuff wastewater to generate clean water by evaporation, adsorption and photocatalysis. This work presents a novel strategy for desalination of seawater and purification of heavy metal wastewater and dyestuff wastewater to generate clean water by integrating the defected MoS2 into sodium alginate aerogel evaporator.

Interfacial evaporation of seawater and other wastewater is used to produce clean water by the infinite solar energy which attracts an intense interest and displays a great prospect. An efficient and robust photothermal evaporator is a key to solar-driven interfacial evaporation. Herein, the oxygen vacancy-rich MoO3 aerogel evaporator is designed to purify seawater and wastewater. Hydrogen etching is used to construct oxygen vacancies of MoO3, which regulate its optical and thermophysical properties. MoO3* possesses stronger broadband absorption and lower reflectance than MoO3 across the wavelength ranges of 200 nm-2500 nm, which insures more energy input. Besides, band gap energy of MoO3* decreases from 2.90 eV of MoO3 to 1.92 eV, which is more beneficial for the visible light absorption and its degradation of organic pollutant. As a result, the MoO3*based evaporator displays a higher evaporation rate of 1.78 kg m- 2 h- 1 as well as 92.6 % of efficiency for pure water at 1 sun illumination, in contrast to the MoO3-based evaporator with an evaporation rate of 1.04 kg m- 2 h- 1 and 60.0 % efficiency, suggesting that oxygen vacancies induced by hydrogen etching improve photothermal conversion efficiency. In practical application, the MoO3*-based evaporator also displays an excellent purification performance for seawater, heavy metal wastewater and tetracycline wastewater, in which the evaporation rates are close to pure water, and the quality of the purified water is better than drinking water specified by WHO standard. In addition, the defected MoO3*-based aerogel evaporator not only possesses an excellent thermal management, but also offers an excellent salt self-cleaning ability. This work convincingly demonstrates that the "defect chemistry" is perfect for constructing the defected MoO3* aerogel evaporator for sustainable production of clean water from seawater, heavy metal wastewater and tetracycline wastewater by means of the solar-driven interfacial evaporation.

Controlling regioselectivity in lactic acid conversion is a key for production of bio-based chemicals due to biolactic acid molecule containing active bifunctional groups such as hydroxyl (-OH) and carboxyl (-COOH). Here, we report that the Ru-stabilized MoO3-x overlayers with rich oxygen vacancies overturn lactic acid hydrogenation regioselectivity to propionic acid (PA) via C-OH hydrodeoxygenation, achieving a high PA selectivity of 95.9%, which is completely different from the catalytic feature of the Ru particle surfaces with dominating 1,2-propanediol selectivity through hydrogenation of -COOH. Furthermore, the activity on the encapsulating oxide layers can be extended to other hydroxy acids such as glycolic acid, 3-hydroxypropionic acid, and DL-2-hydroxybutylic acid to generate their corresponding carboxylic acids, displaying a unique ability for hydrodeoxygenation of -OH group. The encapsulating oxide layers with rich oxygen vacancies can be dynamically generated in the presence of the reductive atmosphere such as H2-Ar mixture, and efficiently stabilized by Ru nanoparticles, thus endowing more excellent activity of Ru-MoO3-x than that of MoO3, MoO3-x and Ru-MoO3. Encouragingly, lactic acid conversion and propionic acid selectivity have hardly decayed during running 5 cycles due to Ru-stabilized MoO3-x overlayers. This work provides an efficient strategy for constructing the defective encapsulation oxide layers with rich oxygen vacancies, which helps to produce the desired biobased chemical of PA from bio-lactic acid.

Peroxymonosulfate (PMS) activation is a powerful method for eliminating tetracycline (TC) from water. Herein, the morphology and phosphorization were investigated for efficient PMS activation toward TC degradation over magnetic Fe3O4 catalysts. For three kinds of Fe3O4 catalyst with different morphologies, phosphorization dramatically enhanced the catalytic performance for TC degradation. A unique morphological effect was also observed for the TC degradation process. By regulation of morphology and phosphorization, the P-RC-Fe3O4/PMS system achieved the highest TC degradation efficiency among evaluated catalyst systems. Due to phosphorization, electron transfer occurred from Fe to P, generating a charge imbalance between Fe delta+ and P delta-, which reacted with PMS to produce rich active species such as (OH)-O-center dot, SO4(center dot)-, O2(center dot)- and 1O2 for TC degradation. These active species were confirmed by using quenching experiments with different scavengers and ESR measurements. These results revealed that the nonradical (1O2) pathway was dominant in the P-RC-Fe3O4/PMS system for TC degradation, but simultaneously the radical ((OH)-O-center dot, SO4(center dot)- and O2(center dot)-) pathway made a certain contribution. Cyclic experiments demonstrated not only the excellent stability of the P-RC-Fe3O4/PMS system for TC degradation but also facile magnetic separation between the catalyst and the reaction system. This work provides an efficient strategy for constructing novel catalytic platforms by regulation of morphology and phosphorization to activate PMS for eliminating TC from water.

MoS2-catalyzed coupled dehydrogenation and hydrodeoxygenation of lactic acid (LA) enables synergistic production of pyruvic acid and propionic acid. The activity in LA coupled reactions is dominated by phase structure, and 1T-MoS2 presents an excellent activity. Under optimal conditions, the LA conversion reached 72.5% together with 73% selectivity to pyruvic acid and propionic acid.

It is a key to disclose the structure-dependent adsorption capacity for design and optimization of adsorbent toward removal of dyestuff pollutants from wastewater. Due to this, the relationship between the crystal phase structure of MoS2 and adsorption capacity for RhB (Rhodamine B) as a typical dyestuff contaminant was investigated. To compare with the commercial MoS2 (cMoS2), the diffraction peak ascribed to (002) plane evidently moved toward low 2 theta angle in 1T-MoS2, suggesting an enlarged interplanar spacing, which was confirmed by HRTEM characterization. 1T-phase displayed far higher adsorption capacity than 2H-phase, in which qtvalue of 1T-MoS2 achieved 688.30 +/- 10.1 mg/g at 500 mg/L RhB solution, and is 3.0 times larger than cMoS2 containing 90 % 2H-MoS2. Besides, 1T-MoS2 without sulfur vacancy also displays much higher adsorption capacity than the sulfur vacancy-rich ssMoS2, indicating that sulfur vacancy has no contribution to adsorption of RhB. On basis of R2 criterion, the adsorptions for RhB over cMoS2, ssMoS2 and 1T-MoS2 well conformed to the pseudo-second order kinetics, indicating that chemical adsorption dominated during the adsorption process. Analysis of structure-dependent adsorption strongly demonstrated that 1T-MoS2 had more excellent adsorption performance than cMoS2 and ssMoS2 due to the synergistic adsorptions of stronger coordination, electrostatic interaction and physisorption. To compare with other adsorbents, 1T-MoS2 outperformed most of other adsorbents for adsorption of RhB. Cyclic adsorption experiments showed that 1T-MoS2 possessed an excellent reusability. This work afforded an efficient strategy for crystal phase-mediated adsorption to achieve removal of RhB from wastewater.

Solar-driven interfacial evaporation is widely viewed as a promising technology for seawater desalination and other wastewater purifications thanks to its low cost and environmentally friendly features. Here, we proposed high-index-faceted NiS (NiWO4-NiS) as a light absorbent for photothermal conversion. In water evaporation tests, the NiWO4-NiS flat membrane evaporator (NiWO4-NiS 2D evaporator) exhibited a markedly higher water evaporation rate than the ordinary NiS 2D evaporator. To disclose the reason, various characterizations were performed. UV-visible spectra confirmed a semiconductor character with band gap energies of 2.47 and 2.38 eV for NiS and NiWO4-NiS, respectively, in which a narrower band gap favored photothermal conversion by photothermal electronic excitation and localized surface plasmon resonance. The broad band spectra showed that NiWO4-NiS had stronger absorption and less reflectivity for light than NiS, which was more beneficial for effectively harvesting solar energy. The high-index-faceted NiS was confined in sodium alginate (SA) aerogel to form an interfacial water evaporator (NiWO4-NiS-aerogel 3D evaporator) and offered a far higher water evaporation rate than its corresponding NiWO4-NiS 2D evaporator. Under 1 sun, the NiWO4-NiS-aerogel 3D evaporator achieved a higher evaporation rate of 2.43 kg m-2 h-1 as well as an evaporation efficiency of 93.1% for pure water while the NiWO4-NiS 2D evaporator displayed an evaporation rate of 1.32 kg m-2 h-1 together with an evaporation efficiency of 80.6%. Furthermore, the NiWO4-NiS-aerogel 3D evaporator not only showed an excellent evaporation rate for seawater but also exhibited an excellent durability. In addition, for heavy-metal wastewater, the NiWO4-NiS-aerogel 3D evaporator also exhibited an excellent purification ability. More importantly, the water evaporation rate of the NiWO4-NiS-aerogel 3D evaporator achieved 1.54 kg m-2 h-1 under real solar irradiation during the outdoor test process, which outperformed most of the previous work. This work demonstrated that the high-index-faceted NiS possessed an excellent performance for light harvest, photothermal conversion, and water evaporation and presented a novel solution for seawater desalination and other wastewater purification.

CoNi alloy on the surface of rGO-SWCNT can regulate the electron structure, promoting HER performance. CoNi21 alloy exhibited the most notable HER efficiency with an overpotential of 83.5 mV and 291.8 mV at 10 mA cm−2 and 100 mA cm−2, respectively.

Solar -driven interfacial evaporation for sustainable production of clean water from seawater and organic wastewater is viewed as a cutting-edge and practical technology to solve the shortage of fresh water. Here, we provide a novel strategy for constructing oxygen vacancy-rich In2O3/TiO2 composite to apply in water purification. It is found that oxygen vacancy enhances light absorbance, reduces light reflection, and decreases the thermal conductivity, being beneficial for photothermal conversion and heat confinement. On the other hand, oxygen vacancy-rich In2O3/TiO2 composite offers an excellent photocatalytic degradation, which can improve the quality of the purified water and keep surface and interface clean, and thus enhance durability of photothermal material. To compare with In2O3/TiO2, In2O3/TiO2* with rich oxygen vacancies markedly enhances the evaporation rate of pure water from 1.04 to 1.51 kg m- 2h-1 under 1 sun illumination, corresponding photothermal conversion efficiencies of 58.6% and 90.3%, respectively. Furthermore, the evaporator constructed with In2O3-TiO2* displayed 1.47 and 1.49 kg m- 2h-1 for seawater and lake water, respectively, close to pure water under 1 sun illumination. Besides, this evaporator also offered an excellent purification and photocatalytic degradation for organic wastewater during the solar -driven evaporation. Importantly, this evaporator also could synergistically generate electricity, achieving a maximum electrical power of 1.23 W m- 2 under 1 sun. This work demonstrates the preponderance of the oxygen vacancy-rich material, and expands the application of the defected In2O3/TiO2 composite in solar -driven interfacial evaporation.

Regulation of MoO3 microstructure was explored at different atmospheres, which was further evaluated for catalytic performance on lactic acid hydrodeoxygenation. Catalyst structure was characterized by XRD, FT-IR, HRTEM, and oxygen vacancies were measured by EPR and XPS spectra. It was found that the direct H-2-Ar treatment generated an obvious change in MoO3 microstructure to form rich oxygen vacancies in MoO3-H, and the succedent H-2-Ar treatment had negligible influence in MoO3-A-H, indicating that the non-crystallizing MoO3 is effortless to generate oxygen vacancy with H-2-Ar atmosphere treatment. Correspondingly, MoO3-H achieved 58.6 % of lactic acid conversion and 64.7 % of propionic acid selectivity much higher than MoO3-A-H with 41.7 % of lactic acid conversion and 56.9 % of propionic acid selectivity, which also outperformed most of the LA hydrodeoxygenation catalysts in propionic acid selectivity. This work demonstrates that the calcined atmospheres can efficiently regulate MoO3 microstructure to form rich oxygen vacancies for lactic acid hydrodeoxygenation to propionic acid.

A series of h-MoO3/SiO2 catalysts for the synthesis of pentaerythritol tetra(2-ethylthylhexoate)(POE) from pentaerythritol (PER) and 2-ethylhexanoic acid (i-EHA) were prepared by solid-phase milling and characterized and tested by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), N-2 adsorption-desorption, scanning electron microscope (SEM) and transmission electron microscope (TEM). The results showed that (200) crystalline facet-selectively oriented h-MoO3/SiO2 with h-MoO3 loading of 15% is an excellent catalyst for the synthesis of POE. Under the suitable reaction process conditions (n(i-EHA)/n(PER)=4.3, m(h-MoO3/SiO2)/m(PER)=0.003, T=220 degrees C, t=4 h), the esterification rate was up to 90.83% and the selectivity of POE was up to 100%.

2D MoS2 with narrow lateral size and thickness distributions was introduced to promote the anti-friction and anti-wear properties of the bentonite grease (BG) in a state of boundary lubrication. Optical microscopy (OM), and 3D optical profilers (3D OP), Raman spectrometry (Raman), scanning electron microscope, energy dispersion spectrum (SEM-EDS), and X-ray photoelectron spectroscopy (XPS) were applied to characterize the wear surface of the GCr15 bearing steel/GCr15 bearing steel contact. It is found that the average friction coefficient (AFC), wear scar diameter (WSD), surface roughness and average wear scar depth of BG + 1.2 wt.% 2D MoS2 were effectively reduced by approximately 22.15%, 23.14%, 55.15%, and 21.1%, respectilvely, compared with BG under the working condition of 392N, 75 °C, 1 h, and 1200 rpm. Raman, EDS and XPS results jointly demonstrated that a stable adsorbed film and a robust tribochemical film composed of Fe2O3, FeSO4, Fe2(SO4)3, FeSO3, FeS, FeO and MoO3, which further contributes to the enhancement of lubrication performance.

The ceramic-steel-pentaerythritol ester system has a broad application prospect under high temperature conditions, which are respectively in the fields of aviation, aerospace and advanced equipment manufacturing. However, a comprehensive understanding of the friction and wear mechanisms of this system across a broad temperature range remains elusive. The tribological properties of the system at 25–475 °C were studied. With the increase of temperature, the evolution of the tribofilm follows the sequence: discontinuous tribofilm → uniform tribofilm → tribofilm removal. At 200–300 °C, an approximately 100 nm thick amorphous PxOy compound tribofilm is formed, and its nanohardness and modulus are reduced by 81.33 % and 54.02 %, respectively, compared with base steel. The tribofilm effectively reduces shear resistance by blocking friction pair contact. When the temperature exceeds 300 °C, it will lead to high-temperature coking, which adversely affects the lubrication performance. It is worth noting that the system can endure short-term service at a maximum temperature of 475 °C. Therefore, this research can help achieve continuous, stable operation of high-temperature resistant systems, as well as short-term use under extreme conditions encountered by complex equipment.

The disclosure of structure-dependent activity is always of great significance to rationalize the design of catalyst for achieving an excellent catalytic performance. Three clearly shaped and structured alpha-Fe2O3 crystallites (nano-truncated hexagonal bipyramids (THB), nano-cubes (QC) and nano-spheres (RC)) were used as precursors to successfully synthesize their counterparts of three Fe3O4 nano-crystallites, marked as THB-R, QC-R and RC-R, respectively, which remained consistent in shape. HRTEM images reveal that the three as-synthesized Fe3O4 nano-crystallites expose different facets, in which (311) plane is exclusively exposed in RC-R, and the mixed planes of (111) and (222) are exposed in THB-R and QC-R. DFT calculations reveal that the Fe site located at the exposed (311) plane is more preferential to selectively adsorb alpha-hydroxyl group (alpha-C-OH) in lactic acid (LA) molecule than the other two exposed planes of (111) and (222) on basis of adsorption energy of LA molecule, leading to a high activity on C-O cleavage. The thermoanalysis of sample further indicates that the Fe site in RC -R is covered with less organic polymer or coke, than QC-R and THB-R, endowing an excellent activity and stability during the catalytic reaction. At 380 degrees C and LA LHSV of 16 h-1 under the inert atmosphere, the catalyst offered a satisfactory propionic acid selectivity of nearly 70%, and its catalytic performance hardly decayed within 34 h on stream.

The scarcity of fresh water resources necessitates us to develop an efficient technique for sustainable production of clean water from seawater and wastewater. Here, we constructed the 1 T-MoS2/PDA (polyaniline) as a photothermal material for purification of seawater and wastewater to produce clean water through interfacial evaporation by virtue of sunlight. 1 T-MoS2 has a higher evaporation capacity of water than 2 H-MoS2, which was selected to prepare 1 T-MoS2/PDA composite for photothermal conversion. As expected, 1 T-MoS2/PDA composite offers a higher evaporation rate of water than both 1 T-MoS2 and PDA, which owes to an excellent light absorbance, low light reflectance and good wettability. Under irradiation of 1 sun, the evaporation rate of water over the 1 T-MoS2/PDA composite in pure water reached 1.51 kg m � 2h-1, and the photothermal conversion efficiency reached 92%. Encouragingly, 1 T-MoS2/PDA composite can be well used to treat real seawater and various wastewater such as organic dye solution and heavy metal ion solution, in which the evaporation rate of water is close to pure water, and the quality of water is better than the standard of drinking water established by the World Health Organization (WHO). Besides, 1 T-MoS2/PDA composite still maintain an excellent evaporation performance after treatment of acidic solution and alkaline solution, indicating an excellent durability. This work provides a feasible solution for producing clean water by solar-driven interfacial evaporation from seawater and wastewater.

We propose a novel strategy for the synthesis of pyruvic acid from bio-lactic acid in air. Polyvinylpyrrolidone can regulate the growth of the crystal face and formation of oxygen vacancies, in which a synergy of the facet and vacancies boosted the oxidative dehydrogenation of lactic acid into pyruvic acid.

This work provides an efficient strategy for the selective hydrodeoxygenation of lactic acid to propionic acid, with an enhanced propionic acid selectivity from 62.3% to 92.4% by integrating surface defects with the highly dispersed Pd species.