Absence Of H2 Research Articles

Exogenous MgH2-derived hydrogen alleviates cadmium toxicity through m6A RNA methylation in rice

Cadmium (Cd) contamination poses a substantial threat to crop yields and human health. While magnesium hydride (MgH2) has been reported as a hydrogen (H2) donor that promotes plant growth under heavy metal contamination, its role in rice remains elusive. Herein, seedlings of Oryza sativa L. Japonica variety Zhonghua 11 (ZH11) were selected and exposed to 20 µL of 1-mol/L cadmium chloride (CdCl2) solution via hydroponics to simulate Cd stress. Meanwhile, 0.1 mg of MgH2 was used to slow-release H2 to the experimental group to explore its potential effects on rice over a 2-week period. The results indicated that Cd exposure severely inhibited the growth and development of ZH11 rice seedlings. However, the exogenous slow-release of H2 from MgH2 effectively mitigated this inhibitory effect by restoring the balance of reactive oxygen species (ROS), maintaining endogenous H2 homeostasis, and supporting the photosynthetic system. High-performance liquid chromatography analysis revealed that exogenous H2 reduces m6A RNA methylation levels in mRNA under Cd stress. Consequently, MeRIP-seq was conducted to investigate the effect of Cd exposure in rice in the presence and absence of H2. The m6A modifications were enriched at the start codon, stop codon, and 3′ UTR. By integrating RNA-seq data, 118 transcripts were identified as differentially methylated and expressed genes under Cd stress. These gene annotations were associated with ROS, biological stress, and hormonal responses. Notably, 297 differentially methylated and expressed genes were identified under Cd stress in the presence of H2, linked to heavy metals, protein kinases, and calcium signaling regulation. Cd strongly activates the MAPK pathway in response to stress. Exogenous H2 reduces Cd accumulation as well as enhances plant tolerance and homeostasis by lowering m6A levels, thereby decreasing the mRNA stability of these genes. Our findings indicate that MgH2, by supplying H2, regulates gene expression through m6A RNA methylation and confers Cd tolerance in rice. This study provides potential candidate genes for studying the remediation of heavy metal pollution in plants.

Effect of the reorganization of acid sites induced by metal species on TiO2 supports on the conversion of furfural to acetals and ethers

For the catalytic hydrogenation of furfural (FFR) over supported metal catalysts, acetals and ethers were often observed as by-products when alcohols were used as solvents. The presence of specific acid sites on the catalyst led to the conversion of FFR to acetals and ethers. To understand the effect of the interaction between metal species and oxide supports on the acid properties of catalysts and the conversion of FFR to acetals and ethers, anatase TiO2 (TiO2-A), rutile TiO2 (TiO2-R) and these TiO2 supported Ni catalysts were studied as models. The relationship between the acid properties of these samples and FFR conversion pathways in isopropanol was revealed. The interaction between Ni species and TiO2 supports was found to selectively remove Brønsted acid sites on the TiO2 supports in the absence of H2, thereby inhibiting the conversion of FFR to acetals and ethers in N2. However, the presence of high-pressure H2 during the reaction induced the formation of new Brønsted acid sites on Ni/TiO2 catalysts via hydrogen spillover, promoting the acetalization of FFR to acetals and the hydrogenolysis of acetals to ethers. The Ni/TiO2-A catalyst exhibited higher activity in catalyzing the conversion of FFR to acetals and ethers compared to the Ni/TiO2-R catalyst. This work provides reference information for the selective regulation of acid-catalyzed reaction pathways of FFR in alcohols.

Impact of Co-Fed Hydrogen on High Conversion Propylene Aromatization on H-ZSM-5 and Ga/H-ZSM-5

The expanded production of shale gas has increased the desire for developing methods for converting light alkanes, especially propane and ethane, into aromatic compounds (i.e., benzene, toluene, and xylene) for petrochemicals and fuels. The Cyclar process is one example of an industrial process that has been demonstrated for the conversion of butane to aromatics; however, the conversion of lower molecular weight alkanes remains elusive. A multi-step process for the conversion of light alkanes to aromatics may be developed, where the first stage converts light alkanes into olefins and hydrogen, and the second stage converts olefins into aromatics. However, to determine the viability of this process, a better understanding of the performance of olefin aromatization in the presence of equimolar hydrogen is necessary. Herein, H-ZSM-5 and Ga-modified H-ZSM-5 are compared for propylene aromatization in the presence and absence of equimolar hydrogen at 1.9 kPa and 50 kPa partial pressures. The presence of H2 has no impact on the product distribution with H-ZSM-5 at either pressure. At 1.9 kPa with Ga/H-ZSM-5, similar product distributions are observed regardless of the presence or absence of H2 since Ga is not sufficiently active for hydrogenation to inhibit aromatics formation. However, at 50 kPa of H2 with Ga/H-ZSM-5, there is an increased selectivity to C4 products and a decrease in toluene and xylene selectivities at high conversions (i.e., χ > 80%), suggesting that aromatic dehydrogenation of cyclic hydrocarbons has been suppressed.

Lotus Effect Inspired Hydrophobic Strategy for Stable Zn Metal Anodes.

Zn-ion batteries (ZIBs) have long suffered from the unstable Zn metal anode, which faces numerous challenges concerning dendrite growth, corrosion, and hydrogen evolution reaction. The absence of H2 O adsorption control techniques has become a bottleneck for the further development of ZIBs. Using the stearic acid (SA)-modified Cu@Zn (SA-Cu@Zn) anode as an example, this work illustrates how the lotus effect controls the H2 O adsorption energy on the Zn metal anode. In situ integrated Cu nanorods arrays and hydrophobic long-chain alkyl groups are constructed, which provide zincophilic ordered channels and hydrophobic property. Consequently, the SA-Cu@Zn anode exhibits long-term cycling stability over 2000h and high average Coulombic efficiency (CE) of 99.83% at 1mA cm-2 for 1 mAh cm-2 , which improves the electrochemical performance of the Zn||V2 O5 full cell. Density functional theory (DFT) calculations combined with water contact angle (CA) measurements demonstrate that the SA-Cu@Zn exhibits larger water CA and weaker H2 O adsorption than Zn. Moreover, the presence of Cu ensures the selective adsorption of Zn on the SA-Cu@Zn anode, well explaining how the excellent reversibility is achieved. This work demonstrates the effectiveness of the lotus effect on controllable H2 O adsorption and Zn deposition mechanism, offering a universal strategy for achieving stable ZIB anodes.

Ziegler-Natta catalyst particle size control in propylene/α-olefin (co)polymerizations

This study investigates the influence of particle size of Ziegler-Natta (ZN) catalysts on the micro-structure and properties of related polypropylenes. In this regard, three catalysts were synthesized with different particle sizes (PS) including PS < 25, 25 ≤ PS ≤ 45, and PS > 45 μm, but from the same ingredients. The catalyst characterization involved a wide range of methods including TGA, BET, SEM, EDS, XRD, LPS, and N2 adsorption-desorption techniques. Next, a series of propylene homopolymers and their copolymers with 1-hexene were prepared using the as-synthesized catalysts, in the presence or absence of H2 under similar reaction conditions. The synthesized (co)polymers were characterized with DSC, SSA, 13CNMR and TREF techniques. The activity was found to increase with decreasing catalyst particle size in both homo- and copolymerization experiments. Furthermore, a catalyst with a larger particle size provided a polymer with a lower isotacticity index, slightly longer meso sequence length, and higher 1-hexene content of about 10.57 %. This affirms the importance of catalyst/support particle size control during the preparation process in industrial polypropylene plants.

The occurrence of oxygen in lignite derivatives and residue from catalytic ethanolysis of Shengli lignite under an inert atmosphere

Lignite is rich in aromatic structures and oxygen atoms, which have the potential to produce organic oxygen-containing compounds. Investigating the cleavage of the >CH–O– bond and oxygen transfer behavior in the catalytic ethanolysis of lignite is indispensable. Herein, A difunctional catalyst composed of HZSM-5 and Ni nanoparticles was fabricated for splitting the >CH–O– bond in the absence of H2. It is found that the >CH–O– bond in Benzyloxy benzene (BOB) could be completely broken with ethanol in the absence of H2. Ethanol can be activated and release H+ over Ni/HZSM-5, which transfers and attacks the >CH–O– bond for obtaining toluene and phenols. The soluble portions from ethanolysis of Shengli lignite were analyzed with fourier transform infrared spectrometer and gas chromatograph/mass spectrometer for tracking the migration of oxygen atoms. It is apparent that esters with higher relative content (32.6 %) were detected in soluble portion 1 (SP1), while alcohols (35.3 %) dominate catalytically soluble portion 1 (CSP1). Moreover, a large number of alkyl-substituted phenols were identified in both SP1 and CSP1. Additionally, related analysis of SL and residual coal manifested that >CH–O– and >C=O bonds were the main forms of existence in residue from catalytic ethanolysis of SL. In a word, exploring the occurrence of oxygen in catalytic ethanolysis of lignite has the potential to produce lignite-derived organic oxygenated chemicals.

Influence of the Ethanol Content of Adduct on the Comonomer Incorporation of Related Ziegler-Natta Catalysts in Propylene (Co)polymerizations.

The aim of this work is to investigate the influence of the ethanol content of adducts on the catalytic behavior of related Ziegler-Natta (ZN) catalysts in propylene homo- and copolymerizations (with 1-hexene comonomer) in terms of activity, isotacticity, H2 response, and comonomer incorporation. For this purpose, three MgCl2.nEtOH adducts with n values of 0.7, 1.2, and 2.8 were synthesized and used in the synthesis of related ZN catalysts. The catalysts were thoroughly characterized using XRD, BET, SEM, EDX, N2 adsorption-desorption, and DFT techniques. Additionally, the microstructure of the synthesized (co)polymers was distinguished via DSC, SSA, and TREF techniques. Their activity was found to enhance with the adduct's ethanol content in both homo- and copolymerization experiments, and the increase was more pronounced in homopolymerization reactions in the absence of H2. Furthermore, the catalyst with the highest ethanol content provided a copolymer with a lower isotacticity index, a shorter meso sequence length, and a more uniform distribution of comonomer within the chains. These results were attributed to the higher total surface area and Ti content of the corresponding catalyst, as well as its lower average pore diameter, a larger proportion of large pores compared to the other two catalysts, and its spherical open bud morphology. It affirms the importance of catalyst/support ethanol-content control during the preparation process. Then, molecular simulation was employed to shed light on the iso-specificity of the polypropylene produced via synthesized catalysts.

Effect of Hydrogen on the Dissolution of Uranium Dioxide in Peroxide-Containing Environments

The ability of hydrogen (H2) to scavenge hydroxy radicals (OH•) created by the dissociation of hydrogen peroxide (H2O2) on the surface of uranium dioxide (UIVO2) has been studied in a chloride/bicarbonate (pH = 9.5) solution. The oxidation/reduction of the oxide surface was monitored by measuring the corrosion potential as a function of time in this solution, containing various concentrations of H2O2 sparged with either Ar or an Ar/H2 mixture. The surface oxidation was subsequently determined using X-ray photoelectron spectroscopy. In the absence of H2, the peroxide oxidized the surface to UIV 1–2xUV 2xO2+x with x varying with H2O2 concentration and eventually achieved a composition of UIV 0.34UV 0.66O2.33. At this surface composition, the surface becomes unstable with respect to dissolution, but the dominant reaction is H2O2 decomposition. In the presence of H2, the initial oxidation of the UIVO2 when H2O2 was added was reversed by the ability of H2 to scavenge the OH• with the H• radicals formed. This led to a reduction of the oxidized surface. The efficiency of this process is determined by the relative concentrations of H2O2 and H2.

Potential-Dependent Competitive Adsorption of Electrolytes Kinetically Inhibits High-Current Hydrogen Oxidation in Non-Aqueous Media

Performing electrochemical transformations in non-aqueous media can unlock new reactivities and selectivities unattainable in aqueous media. For instance, non-aqueous media (e.g. acetonitrile (MeCN), dimethylformamide (DMF), dimethylsulfoxide (DMSO)) allow the dissolution of organic compounds and enable water-incompatible organic electrosynthesis reactions. On the other hand, the lithium-mediated nitrogen reduction reaction (NRR) carried out electrochemically in tetrahydrofuran (THF) is one of the most promising routes towards electrifying the Haber-Bosch reaction and thus eliminating the need for hundreds of atmospheres of pressure and high temperatures. However, many cathodic non-aqueous electrochemical reactions either do not operate with well-defined anodic reactions (e.g. unproductive solvent and/or electrolyte oxidation) or are often coupled with the sacrificial oxidation of a dissolving metal electrode (e.g. magnesium, zinc). Hence, the development of a non-sacrificial anodic reaction is essential for engineering practical, sustainable non-aqueous electrochemical transformations. In this study, we investigate the hydrogen oxidation reaction (HOR) in a variety of non-aqueous solvents (MeCN, DMF, DMSO, THF) and buffers (AcO-/AcOH, Cl-/HCl, etc.) whose base serves as the proton acceptor for HOR. The reason why HOR can be sustainable is because it produces protons, which can be paired with a number of proton-demanding electro-reductions such as NRR, carbon dioxide reduction (CDR) to form oxalic acid or carboxylic acids, and more. Hydrogen is also stoichiometrically cheaper and less greenhouse-emitting than sacrificial metals, making HOR both cheaper and greener. First, we demonstrate a fabricated gas diffusion electrode (GDE) architecture that supports high H2 transport-limited current densities in non-aqueous solvents at ambient pressure. We find that the maximum HOR current density obtained is not H2 transport-limited but instead depends on the kinetics influenced by the pKa and steric profile of the buffer electrolytes present. By also varying the buffer electrolyte concentration and H2 partial pressure and conducting voltametric studies in the absence of H2, we demonstrate that the HOR current density reaches a maximum due to a competitive adsorption mechanism of the buffer electrolytes, limiting the surface concentration of adsorbed hydrogen atoms from H2 dissociative adsorption and thus inhibiting HOR. Based on these findings, we outline strategies for mitigating HOR inhibition via this competitive adsorption mechanism to unlock higher HOR current densities.

Toward a hydrogen-free reductive catalytic fractionation of wheat straw biomass.

The reductive catalytic fractionation (RCF) of lignocellulosic biomass is an attractive method for the conversion of lignin toward valuable low-molecular weight aromatics. A limitation to the upscaling of such technology is represented by the use of pressurized hydrogen gas. Here, the role of hydrogen gas within the RCF of wheat straw biomass is investigated. The use of H2 is shown to enhance lignin depolymerization, by virtue of an improved hydrogenolysis and hydrogenation of lignin fragments, with a yield of phenolic monomers that increased from ~12 wt% of acid-insoluble lignin in the initial biomass under inert atmosphere, up to ~25 wt% under H2 (in methanol, at 250 °C, with Ru/C). The adoption of methanol, ethanol or isopropanol as hydrogen-donor solvents was also investigated in the absence of H2. Ethanol was found to give the highest yield of monophenolics (up to ~20 wt%) owing to a better balance between solvolysis, hydrogenolysis, and hydrogenation of lignin. Nevertheless, a substantial loss of the carbohydrate fraction was observed. The use of a lower temperature (200 °C) in combination with H3PO4 resulted in an improved recovery of cellulose in the pulp and in the solubilization of hemicellulose and lignin, with the formation of monosaccharides (~14 wt% of polysaccharides in the initial biomass) and phenolic monomers (up to 18 wt%, in the absence of H2). Overall, a tradeoff exists between the removal of H2 from the process and the production of low-MW phenolics during RCF.

Evidence of production of keV Sn+ ions in the H2 buffer gas surrounding an Sn-plasma EUV source

Charge-state-resolved kinetic energy spectra of Sn ions ejected from a laser-produced plasma (LPP) of Sn have been measured at different densities of the H2 buffer gas surrounding a micro-droplet LPP. In the absence of H2, energetic keV Sn ions with charge states ranging from 4+ to 8+ are measured. For the H2 densities used in the experiments no appreciable stopping or energy loss of the ions is observed. However, electron capture by Sn ions from H2 results in a rapid shift toward lower charge states. At the highest H2 pressure of mbar, only Sn2+ and Sn+ ions are measured. The occurrence of Sn+ ions is remarkable due to the endothermic nature of electron capture by Sn2+ ions from H2. To explain the production of keV Sn+ ions, it is proposed that their generation is due to electron capture by metastable Sn ions. The gateway role of metastable Sn is underpinned by model simulations using atomic collision cross sections to track the charge states of Sn ions while traversing the H2 buffer gas.

Methanobrevibacter boviskoreani JH1T growth on alcohols allows development of a high throughput bioassay to detect methanogen inhibition

Rumen methanogenic archaea use by-products of fermentation to carry out methanogenesis for energy generation. A key fermentation by-product is hydrogen (H2), which acts as the source of reducing potential for methane (CH4) formation in hydrogenotrophic methanogens. The in vitro cultivation of hydrogenotrophic rumen methanogens requires pressurised H2 which limits the ability to conduct high-throughput screening experiments with these organisms. The genome of the hydrogenotrophic methanogen Methanobrevibacter boviskoreani JH1T harbors genes encoding an NADP-dependent alcohol dehydrogenase and a F420-dependent NADP reductase, which may facilitate the transfer of reducing potential from ethanol to F420 via NADP. The aim of this study was to explore the anaerobic culturing of JH1T without pressurised H2, using a variety of short chain alcohols. The results demonstrate that in the absence of H2, JHIT can use ethanol, 1-propanol, and 1-butanol but not methanol, as a source of reducing potential for methanogenesis. The ability to use ethanol to drive CH4 formation in JH1T makes it possible to develop a high throughput culture-based bioassay enabling screening of potential anti-methanogen compounds. The development of this resource will help researchers globally to accelerate the search for methane mitigation technologies for ruminant animals. Global emissions pathways that are consistent with the temperature goal of the Paris Agreement, rely on substantial reductions of agricultural greenhouse gasses, particularly from ruminant animals.

Highly Photosensitive Lead Sulfide Thin Films Grown by H2 S Free MOCVD Using a Single Source Metal-Organic Precursor.

High-quality lead sulfide (PbS)films are deposited on selected substrate chemistries by an H2 S-free metal-organic chemicalvapordeposition (MOCVD) process using a single-source metal-organic complex (Pb(dmampS)2 ). The complex is synthesized via a salt metathesis reaction betweenPbCl2 andlithium1-(dimethylamino)-2-methylpropane-2-thiolate (Li(dmampS))in diethyl ether. Subsequent film deposition is conducted by a simple thermolysis process in the absence of H2 S, yet chemical and structural analysis confirm chemically stoichiometric and homogenous films. Mechanistic studies with electron impact mass spectroscopy (EIMS) and gas chromatography mass spectroscopy (GCMS) suggest the selective cleavage of C-S bonds in the complex as the reason for the facile PbS formation with negligible impurity incorporation. The high crystallinity, low hole concentrations, and charge transport properties comparable and in many cases superior to films produced by atomic layer deposition (ALD) testify to the quality of the films. Lastly, rigid and flexible photodetectors fabricated with the PbS films exhibit considerably high photocurrents, reliable switching characteristics, and high sensitivity over a broad spectral bandwidth, highlighting the potential for realizing practical broadband photodetectors.

Recent Advances on the Valorization of Glycerol into Alcohols

Glycerol, a highly functionalised polyol, can be used as a platform molecule to produce a variety of high-value chemicals. As glycerol production is projected to increase over the coming years, it’s critically important that technology and infrastructure are developed to make use of the inevitable surplus. The catalytic production of ‘green’ mono alcohols from glycerol, in the absence of H2, is an emerging area of research that, in recent years, has generated significant industrial interest. Herein, we provide an update on recent advances in this field and discuss challenges which need to be overcome if this approach is to be considered viable industrially. The economic significance of using crude glycerol as a feedstock for glycerol valorisation strategies is also addressed and suggestions for improving the impact of research conducted in this field are proposed.

Conversion of model C6–C9 alkanes and straight-run gasoline over Pt(0.1%)-Fe(5%)/Al2O3 catalysts promoted with various additives

Growing demand for hydrogen promotes the research devoted to the development of new catalysts for hydrocarbons processing in absence of H2 or at its low concentration. In the present work, it was shown that during the conversion of straight-run gasoline on a zeolite-containing polyfunctional catalyst in a hydrogen-free environment cracking, dehydrogenation, isomerization and alkylation take place due to the redistribution of H2 between initial and formed products directly on the catalyst surface. Fine particles (≤50 Å) localize in zeolite cavities and pores of aluminum oxide, while larger ones are on their outer surface.

Surface-mediated redox activity in the Pyrite – Nitrate/nitrite – Hydrogen system under conditions relevant for the geological disposal of bituminized waste in Boom Clay

The reactivity of a system with pyrite powder, nitrate or nitrite, and hydrogen in a 15 mM sodium bicarbonate solution was assessed over the course of 2 years in the frame of compatibility studies of nitrate-containing bituminized radioactive waste with the host rock for final disposal. A series of batch tests was performed with pyrite suspensions in bicarbonate solution to which nitrate or nitrite was added before filling the headspace of the recipient with a constant, and non-renewed, volume of 100% pure hydrogen gas (initial PH2 1.5 bara). Under anoxic conditions and at room temperature, hydrogen reacted readily with nitrate and nitrite in the presence of pyrite powder. Ammonia was formed while hydrogen was consumed. Based on the XPS analyses of the pyrite surface and the absence of dissolved pyrite oxidation products, the pyrite surface was not oxidized. Moreover, no reaction between hydrogen and nitrate or nitrite was observed in the absence of pyrite. This reaction was thus clearly mediated by the Boom Clay pyrite surface. The reducing atmosphere kept the pyrite surface intact and protected it from precipitation of carbonates from the medium, thus effectively preventing pyrite surface deactivation, previously observed under anoxic conditions in the absence of H2. Overall, only 5% of the 0.1 M of nitrate that was added to the tests, was reduced over the course of 2 years, without complete consumption of H2. Nitrite was added in a lower concentration of 0.05 M, but was more reactive: about 50% of nitrite was reduced, producing stoichiometric amounts of ammonia, and nearly depleting the H2 in the gas phase. The possible consequences of these processes for the final repository performance are also discussed.

Two step synthesis of ultrathin transition metal tellurides

Transition metal tellurides (TMTs) are an exciting group of two-dimensional materials with a wide variety of polytypes and properties. Here, we demonstrate a simple and versatile two-step method for producing MoTe2, WTe2, and PtTe2 films via tellurization of thin metals at temperatures between 400 and 700 °C. Across this temperature range, monoclinic 1T′ phase of MoTe2, orthorhombic Td phase of WTe2, and hexagonal 2H phase of PtTe2 were formed. Based on x-ray diffraction and Raman analysis, temperatures greater than 600 °C were found to produce the best quality MoTe2 and WTe2. In contrast, lower temperatures (400 °C) were preferred for PtTe2, which becomes discontinuous and eventually decomposes above 650 °C. The presence of H2 in the tellurization process was critical to facilitate the formation of H2Te, which is known to be more reactive than Te vapor. In the absence of H2, neither MoTe2 nor WTe2 formed, and although PtTe2 was formed under pure N2, the crystal quality was significantly reduced. Temperature-dependent resistivity (ρ) measurements were performed on the best quality TMT films revealing all films to be highly conductive. MoTe2 showed metallic behavior up to 205 K where it underwent a phase transition from the semimetallic Td to semiconducting 1T′ phase. WTe2 exhibited a consistent semiconducting behavior with a small positive increase in ρ with decreasing temperature, and PtTe2 showed a metallic dependence from 10 K up to room temperature. Spectroscopic ellipsometry for TMT films provides complex optical constants n and k from ultraviolet to infrared.

Opening up a Radical Cross-Coupling Etherification Path by a Defect-Rich Cu/ZrO2 Catalyst for a High-Value Transformation of HMF

In this work, a radical coupling path was opened up for the construction of C–O bonds in the reduction–etherification of 5-hydroxymethylfurfural (HMF) by designing the unpaired electron defect-rich catalyst Cu/ZrO2. A decent 2,5-bis(isopropoxymethyl)furan (BPMF) yield (86.3%) was obtained under the absence of H2 and external pressure. A radical quenching experiment proved that the etherification process, which is the key step for achieving BPMF, indeed belongs to a radical-related route. Subsequently, a series of in situ FTIR, radical capture experiment, and electron spin density analyses were used to elucidate the formation of key radical intermediates at the molecular level in which the O–H dissociation of 2.5-dihydroxymethylfuran and C–O dissociation of isopropanol occurred on the zirconium-vacancy-adjacent lattice oxygen atom (VZr–O–) and oxygen vacancy (VO) sites, respectively. Furthermore, we revealed the induction mechanism of the alkoxy radical intermediate at the electronic level and the electron structure cycle process of the unpaired electron VZr–O– sites via a combination of density functional theoretical calculations and isotope labeling. More importantly, the calculation result from Gaussian showed that radical intermediates do not occur in a chain reaction with unactivated molecules; thus, the optimal path of radical cross-coupling to produce BPMF was clarified. The findings reported by this article reveal the role of unpaired electron defects in opening up a radical coupling path and thus broaden the downstream production of the high-value transformation of HMF. Furthermore, this study could provide a reference for the construction of C–O bonds in other heterogeneous reaction systems.

Highly stable hydrogen sensing properties of Pt–ZnO nanoparticle layers deposited on an alumina substrate for high-temperature industrial applications

Platinum (Pt)-decorated zinc oxide (ZnO) nanoparticle (NP) layers were deposited on an alumina (Al2O3) substrate via a magnetron sputtering method, and the resulting Pt–ZnO NP-based sensor was used to detect hydrogen (H2) gas at a high operating temperature of 300 °C, revealing its extremely stable H2 detection properties. Samples of the sensor were characterized using scanning electron, transmission, and atomic force microscopies; X-ray diffractometry; and X-ray photoelectron spectroscopy to determine the optimal structure that exhibits the best sensing performance, prepared by changing the deposition rate and annealing conditions. At a high working temperature of 300 °C, the sensor exhibits resistance changes in the presence of H2 and perfect reversibility in the absence of H2. The fabricated device exhibits a detection range of 100–40,000 ppm and fast response (recovery) time of 133 (112) s toward 1000 ppm (1 vol%) of H2 at 300 °C, with good selectivity. Moreover, the sensor shows highly stable base resistance (~132.5 Ω) and response towards H2 (~14.9%) over long time periods. Thus, the obtained Pt–ZnO/Al2O3 material shows high potential for use in high-temperature working environments where high-performance H2 gas sensors are required.

Long-term semi-continuous acidogenic fermentation for food wastes treatment: Effect of high organic loading rates at low hydraulic retention times and uncontrolled pH conditions

The present study investigated the effect of high organic loading rates at low hydraulic retention times without pH control on food wastes fermentation. The acidogenic fermentation was robust to the hydraulic retention time drawdown. Hydraulic retention time variation led to compositional changes of fermentation product. Lactic acid and ethanol were always the dominant end-products and achieved the highest proportion (90.9%) at the 1-day hydraulic retention time. CO2 was the dominant biogas with the absence of H2 and CH4. The concentration of total fermentation product decreased with the lower hydraulic retention time, but the highest fermentation products rate was obtained at the lowest hydraulic retention time. The dominant bacteria was Lactobacillus at the genus level. This work demonstrated the feasibility of operating an acidogenic fermentation reactor at a high organic loading rate, low hydraulic retention time, and uncontrolled pH for improved reactor capacity, construction and operation cost-saving, and easy operation.