CO2 Production Rate Research Articles

A novel bio-based PAbz@PBA maize structure for improving fire protection, toxic gas suppression and mechanical performance of intumescent flame-retardant epoxy coatings

In recent years, developing bio-based intumescent flame-retardant (IFR) epoxy coatings for fire protection of steel has become a research hotspot. However, how to endow bio-based IFR epoxy coatings with excellent fire protection, toxic gas suppression, and mechanical properties simultaneously remains a formidable challenge. Here, a bio-based IFR hybrid with the maize structure (PAbz@PBA) was easily constructed by an organic-inorganic hybrid strategy and employed to prepare high-performance IFR epoxy coatings. It has been shown that PAbz@PBA hybrids enhance the curing activity of epoxy coatings in addition to their good dispersion and interfacial compatibility. Notably, the epoxy coating containing 5.0 wt% PAbz@PBA (EP-5%PAbz@PBA) exhibits more efficient fire protection (peak heat release rate and total heat release are reduced by 48.3 % and 34.0 %, respectively), smoke suppression (total smoke production is decreased by 35.9 %), and toxic gas suppression (peak CO production rate is reduced by 39.6 %) compared to the virgin epoxy coating. Meanwhile, the heat insulation performance of EP-5%PAbz@PBA shows superiority compared to that of the virgin epoxy coating, as reflected by its lowest backside temperature (66.3 °C). Furthermore, compared with the virgin epoxy coating, EP-5%PAbz@PBA exhibits improved flexural and impact strengths. This work offers a viable idea for designing bio-based PAbz@PBA hybrids and preparing IFR epoxy coatings with various excellent properties.

(Invited) Tuning Photocatalytic Activity with Energetic and Kinetic Asymmetry at Coating-Stabilized Particulate Semiconductors

Semiconductor photocatalysts coevolve reductive and oxidative reactions at nanoscale proximity. The local charge separation and local coevolution have unique advantages: i) photocatalysts can operate in neutral pH water or water vapor instead of strong acid or base; ii) most semiconductors form a self-passivating layer at corroded surfaces to prevent corrosion propagation; and iii) nanoparticulate photoabsorbers or nanocrystalline films have achieved near-unity quantum efficiency, promising scale-up solar-to-chemical conversion. Despite the near-unity quantum efficiency achieved for SrTiO3 particles, the Edisonian approach is applied to the vast majority of photocatalysts, thus limiting progress. Technologically important semiconductors of 1.1 – 2.3 eV bandgaps and properly adjusted band edges, such as GaP and Si, can be ball milled into powder, followed by chemical passivation and protective coating processes. Thus, we introduce the Hu-lab-invented charge-transport coatings to protect semiconductors, such as silicon and gallium indium phosphide. We tune their photocatalytic activity by varying and measuring the energetics and kinetics at local reactive sites, in the following case studies.First, we combine photoelectrochemical cells with local potential-sensing probe microscopy to elucidate photocatalytic processes. In particular, we focus on local energetics and kinetics of multiple concurrent redox processes, i.e., two-redox chemistry. Figure 1A illustrates such a three-terminal photo-electro-catalytic cell setup, where the photoelectrode materials are photocatalysts by themselves. We showcase the efficient charge-separation design by fabricating photocatalysts with particulate semiconductors (e.g., commercial CdS powders, GaInP2 epitaxial layers, and ball-milled GaP nanoparticles), TiO2 coatings, and Rh cocatalysts for the concurring reduction of water and oxidation of reversible redox mediators or sacrificial reagents.We discovered that nanoscale site energetics are mutually dependent on local charge-transfer kinetics.[1] Besides, all known visible-light active photocatalysts of 1.1 – 2.3 eV bandgap photo-oxidize or corrode in water.[2] We discovered multi-functional protective coatings that i) allow for both electrons and holes to transport at tunable energy levels;[3] ii) shift band edges favorably, [4]; iii) reduce charge trapping and recombination,[5] and iv) tune water-oxidation selectivity between O2 and hydrogen peroxide production. [6] We show that in the presence of quinone redox couples in a bicarbonate solution, CO is produced with a 1-atm CO2-free Ar-purged headspace where the only source of CO2 is the (bi)carbonate anions, whilst the quinone redox couples can systematically vary the band edge positions of GaInP photoabsorbers.As shown in Figure 1B, CO evolution rate for both Fe(CN)6 3-/4- and H2BQ/BQ are higher at pH 7 than pH 8.5. The local CO2 concentration at pH 8.5 limited CO production rates. This observation corroborates our hypothesis that photocatalytic redox reactions locally drive pH swing to release CO2 at the oxidative sites, whereas the nearby reductive sites reduce in-situ generated CO2 into CO2R products. We envision direct solar fuel production from natural resources such as sunlight, bicarbonates from the ocean, or moisture in the air in a durable particle reactor.[7] We also processed wood and leaves into pulps and performed photocatalytic H2 production from the CdS/TiO2/Rh/CoOx panel (Figure 1C) using bottom LED illumination, as the glucose solution became colored.In summary, we show the rational design of photocatalysts. These coating-stabilized semiconductor particles present a scalable pathway for making H2 while effectively activating water and biomass as the two most abundant oxidants. We address the timescale mismatch between light absorption and catalysis by effectively accumulating electrons and holes at the respective reductive and oxidative sites.[8] The study paves the way for utilizing biomass to obtain bioenergy with carbon capture and storage.

Investigation of process parameters for solar fuel production using earth-abundant materials

Photoreduction of CO2 to solar fuels and chemicals offers a sustainable method to produce net zero energy vectors. For large-scale applications, it is crucial to develop an improved understanding of the influence of reaction conditions on the design and optimisation of the photoreactor. The performance of CuO impregnated on BaTiO3 photocatalyst was investigated and compared to pristine BaTiO3, and CuO impregnated on commercial P25 (CuO/P25) and ZnO. The influence of irradiance, CO2 and H2O flow and partial pressure, and CO2/H2O ratio on the product yield and selectivity were examined. Using Design of Experiments and Computational Fluid Dynamic modelling, the optimised reaction conditions were irradiance of 125 mW cm−2, with a CO2 flow of 0.09 mL min−1, and water bubbler temperature of 25 °C. At these conditions, a 2 and 10-fold increase of CO and CH4 production, respectively, were obtained, compared to baseline conditions as well as exhibited the highest CO and CH4 production rate compared to previous reports. Among the earth-abundant photocatalysts, CuO/P25 had the highest quantum yield for CH4 (φCH4: 0.47), whilst CuO/BaTiO3 exhibited highest φCO (0.09) and stability for CO production. The under-performing of BaTiO3 and CuO/BaTiO3 was attributed to the presence of amorphous phase in BaTiO3. This work reveals that the combination of catalyst design, reaction engineering, and modelling can improve the efficiencies of CO2 photoreduction.

Hydrogen bonding induced polyphosphazene/MXenes 2D/2D structure loaded with MOFs enabling fire-safe epoxy composite

High thermal runway hazard has been the blocking stone on the way of extended usage of epoxy resin (EP). In such context, the method of preparing fire retardant EP composite with inorganic filler has been adapted, and the shining star of transition metal carbides (MXenes, denoted as MX) has evoked the ardent concern. Nevertheless, the inferior flame retardation efficiency, severe agglomeration, surface scarcity of organic groups have collectively appealed to design MX based flame retardant (FR) with high efficiency. Here, the hydrogen bonding induced strategy and in-situ growth method are utilized to gain FR of P-MX@UIO. Under 2.0 wt% loading, the reductions on peak heat release rate and total heat release reach 48.9% and 45.4%. Meanwhile, the decreases in peak smoke production and total smoke production approach 48.6% and 43.6%. Also, the peak CO production rate is impaired by 48.3%. Such strengths both in suppressing heat and toxicants emissions, are vividly validated via comparison with previous works. Ulteriorly, the inhibited releases of NO and HCN are detected. Peculiarly, the storage modulus is promoted by 75.6% after incorporating P-MX@UIO. This work may inspire the judicious design of MX based FR and fire-safe polymer composites.

Development of machine learning-based models for describing processes in a continuous solar-driven biomass gasifier

The synergy of two renewable and efficient sources in producing clean fuels, i.e., solar energy and biomass, can result in high efficiency. In this regard, developing syngas production systems based on solar biomass gasification has attracted much attention. However, experimental setups on solar-driven gasifier processes are costly and time-intensive. In such a situation, an accurate and low-cost alternative is to develop data-driven machine learning (ML) models to predict the processes involved in solar-driven biomass gasifiers. In the present study, several ML models, including random forest (RF), RANdom SAmple Consensus (RANSAC), stochastic gradient descent (SGD), automatic relevance determination (ARD) regression, and elastic net linear (ENL) regression, were developed to accurately predict the various processing of a continuous solar-driven biomass gasifier, including CO production rate and H2 production rate (H2), carbon feeding rate, solar power input, thermochemical reactor efficiency, solar-to-fuel energy conversion efficiency, solar energy input, and carbon consumption rate. Using efficient ML methods, the eight formulas and the eight models for H2, CO production rate, carbon feeding rate, carbon consumption rate, solar energy input, solar power input, thermochemical reactor efficiency, and solar-to-fuel energy conversion efficiency are made in this study. Using the linear form can be reached the best R-Squared (R2) values for all formulas and the model, and the best R2 values are between 0.998 and 0.999 for the formulas by the elastic net and the ARD regression, and also the best R2 values are between 0.998 and 0.999 for the models by the RF and the RANSAC regressor. The R2 values for H2, CO production rate, carbon consumption rate, solar energy input, solar power input, thermochemical reactor efficiency, and solar-to-fuel energy conversion efficiency for formulas, respectively, are 0.998, 0.998, 0.999, 0.999, 0.999, 0.996, and 0.998 by the elastic net. For temperature of the carbon feeding rate, this value is 0.999 by the ARD regressor.

Heterophase junction engineering: Enhanced photo-thermal synergistic catalytic performance of CO2 reduction over 1T/2H-MoS2

Photocatalytic CO2 reduction technology has been proposed as a promising solution to the greenhouse effect and energy crisis. However, the lower quantum efficiency limits its practical applications. Here, we have significantly improved the photocatalytic CO2 reduction performance of MoS2 by coupling the heterophase junction (1T/2H-MoS2) construction and photo-thermal synergy strategies. At 200 °C and 42 mW·cm−2 of 420 nm LED irradiation, the CO production rate of 1T/2H-MoS2 reached 35.3 μmol·g−1·h−1, which was 3.5 and 2.8 times that of 1T-MoS2 and 2H-MoS2, respectively. In addition, only faint CO was detected under sole photo- or sole thermal catalysis conditions. Mechanism studies showed that COOH* was the key intermediate in the photo-thermal synergistic catalytic CO2 reduction over 1T/2H-MoS2. The heterophase junction engineering significantly facilitated the separation of photogenerated carriers, and the introduction of heat accelerated the charge migration and surface reaction rates. Our work provides innovative insights into the catalyst design and mechanism studies for photo-thermal synergistic catalytic CO2 reduction.

CdS-assisted ultrathin porous nitrogen-vacancy carbon nitride nanosheets for visible-light photocatalytic CO2 reduction

Obtaining highly active and selective target products is both promising and challenging, and can be achieved by regulating the adsorption and desorption energy of reaction intermediates, as well as the transfer of electrons under visible light. Herein, an efficient CNGA/CdS photocatalyst based on ultrathin porous nitrogen vacancies carbon nitride (CNGA) nanosheets (thickness <1 nm) with CdS nanoparticles was synthesized by a facile route for visible-light photocatalytic CO2 reduction. As a result, the rate of CO production was 32.75 μmol g−1 h−1, which was 17.24 and 32.75 times that of CN and CdS under visible light (λ ≥ 420 nm) without sacrificial agents and cocatalysts. Importantly, introducing CdS nanoparticles into CNGA could improve the selectivity of CO2 to CO by nearly 100% (yield-based selectivity). Finally, the photocatalytic mechanism was explored by in-situ FTIR spectra and DFT calculations, and the results presented that the formation of heterostructures facilitated the generated *CO groups to modulate the reaction pathway of photocatalytic CO2 reduction. This work is expected provide a reference for the design of photocatalysts for photoreduction CO2 with accurate products under visible light.

Flame protection capability of waterborne epoxy coatings enhanced by inorganic-organic phenyl zirconium phosphate anchored boron nitride

Zirconium phenyl phosphate (ZrPP) has good compatibility in polymers due to its simultaneous inorganic-organic structure. Here, ZrPP was anchored on high barrier boron nitride (BN) by an in situ synthesis scheme using polyaniline (PANI) as an intermediate, which is expected to yield a high performance multifunctional composite flame retardant. Among them, the formation of a rational composite structure of ZrPP and BN is conducive to the maximum enhancement of its barrier effect. Moreover, the presence of Zr and phosphoric acid molecules can effectively promote the cyclization of cleaved molecules and carbon formation in the burning stage, which reinforced the quality and strength of residual carbon. The results showed that the back side temperature of BP@ZrPP/EP waterborne coating was stabilized at the lowest value (167.2 °C), accounting for the most excellent thermal insulation effect of its residual carbon. The BP@ZrPP/EP composite coating showed the maximum expansion height (23.8 mm), expansion rate (18.03) and residual carbon (31.8 %), which depends on the synergistic barrier function of ZrPP and BN. Further, BP@ZrPP based EP exhibited the smallest smoke density rating (38.2 %), the largest limiting oxygen index (31.4 %), and achieved a V0 rating for the UL-94 test. Compared with EP, the peak heat release rate (PHRR), total heat release rate (THR), peak smoke production rate (PSPR), total smoke production (TSP), and peak CO production rate (PCOPR) of BP@ZrPP-filled EP were reduced by 32.9 %, 30.7 %, 33.3 %, 31.3 %, and 35.4 %, respectively, proving its excellent flame retardant and smoke inhibition ability.

Facile strategy of preparing excellently thermal-insulating and fire-safe building materials based on an aromatic Schiff base dicarboxylic acid without additional flame retardants

Developing excellently fire-safe and thermal-insulating building materials is a critical subject in the building sector. In this work, a novel aromatic Schiff base dicarboxylic acid (FN) was synthesized through a facile strategy to prepare high-performance rigid polyurethane foam (RPUF) composites with excellent thermal insulation and fire safety performance. The uniform dispersion of FN in polyether polyol improved the cellular structure of RPUF composites, which was conducive to increasing the thermal insulation of RPUF composites. Therefore, incorporating only 10 wt% FN into RPUF composite (RPUF/10FN) possessed the lowest wall temperature (51.9 °C) and room temperature (38.8 °C) with the lowest temperature growth rate under the continuous thermal radiation of the heat source among all samples in the small chamber test. Moreover, FN remarkably reduced the peak heat release rate, peak smoke production rate, and peak CO production rate of RPUF/10FN by 41.9%, 58.0%, and 59.6% without additional flame retardants, respectively, compared with those of pure RPUF. In addition, FN endowed RPUF/FN composites with better fire resistance and structural integrity compared with pure RPUF in the building facade fire test and fire protection test. The increased fire safety of RPUF/FN composites is due to the barrier effect of the formation of a dense and continuous char layer and the dilution effect of nonflammable gas generated by the thermal degradation of FN. Furthermore, FN enhanced the water contact angle of RPUF/FN composites from 112.2° for pure RPUF to 120.8° for RPUF/10FN, indicating that FN also enhanced the hydrophobicity of RPUF/FN composites. Therefore, the as-designed RPUF composites containing FN possessed a broad application prospect in the building field.

Extreme rainstorms change organic matter compositions and regulate greenhouse gas production in mangrove sediments

Extreme rainstorms can flush intertidal sediments and drive the transport of large amounts of organic matter from land to sea. Mangrove wetlands, one of the most important “blue carbon” habitats, are located in the intertidal zone and serve as an ecological corridor connecting land and sea. In this study, we investigated the effects of extreme rainstorms on organic carbon compositions, source-sink processes based on the MixSIAR model, and the production of greenhouse gases, including carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O), using mangrove sediments. The results showed that in the intertidal zone, the total contents of sediment organic carbon, mineral-bound, and fine-particle organic carbon, humic acid, and humin were improved by the influence of an extreme rainstorm. The contents of coarse sediment organic carbon (SOCcoarse) and fulvic acid were decreased and were exported from intertidal zone to the sea. In tidal creek zones, extreme rainstorms enhanced the mean production rates of CH4 and CO2 by 817.4% and 34.3%, respectively, owing to the increased terrestrial organic matter, including SOCcoarse and humic acid. The N2O production rate was decreased by 72.2% in the creek zone because of the loss of total nitrogen after an extreme rainstorm. These findings provide new insights into SOC components, mechanisms of greenhouse gas production, and their response to extreme rainstorms, which will be helpful for the management of coastal wetlands and our understanding of how frequent extreme weather controls wetland biogeochemical processes.

Nitrogen vacancy-induced spin polarization of ultrathin zinc porphyrin nanosheets for efficient photocatalytic CO2 reduction

Metalloporphyrin compounds have excellent electron transfer and visible light absorption ability, demonstrating broad application prospects in the field of photocatalysis. In this work, the nitrogen vacancies (NVs) were successfully introduced into zinc porphyrin (ZnTCPP) ultrathin nanosheets through surface N2 plasma treatment, which is environmentally friendly and can react in low temperatures. Furthermore, the prepared nitrogen vacancies-zinc porphyrin (NVs-ZnTCPP) materials exhibited excellent photocatalytic CO2 reduction activity and selectivity, specifically, the CO production rate of ZnTCPP-1 (N2 plasma treatment, 1 min) achieved as high as 12.5 µmol g–1h−1, which is about 2.7 times greater than that of untreated ZnTCPP. Based on the experimental and density functional theory calculation (DFT) results, it is found that the promoted photocatalytic performance of NVs-ZnTCPP could be mainly attributed to nitrogen vacancy-induced spin polarization by reducing the reaction barriers and inhibiting the recombination of photoexcited carriers. This work provides a new perspective for the construction of vacancy-based metalloporphyrin, and further explores the intrinsic mechanism between the electron spin property and the performance of the photocatalyst.

In-situ synthesis of copper phytate-hierarchically porous MOF-199 hybrid in wood towards multifunctional flame-retardant wood composite

The modern society pays growing attention on global environmental issues, public safety, and individual health, which highlights the necessity of exploring sustainable, energy-saving, flame-retardant, and anti-mildew materials for building applications. Herein, by in-situ preparing copper phytate-hierarchically porous MOF-199 hybrid (PCuM) in natural wood (W) via simple phytate induced defect engineering strategy, we reported a multifunctional low fire-hazard wood composite (PCuM-W). The phytate anion not only acted as a modulator to generate hierarchical porosity in MOF-199, but also offered high flame retardancy due to its six phosphorus groups. The copper phytate anchored on the cell wall exhibited charring and graphitizing effects and enhanced the flame retardancy and smoke suppression performance of wood. By pyrolysis, a hierarchically porous MOF-199-derived carbon formed and offered a considerably enhanced catalytic activity towards the conversion of CO. With a weight percent gain of only 13.5%, the fire growth index, total smoke production, and maximum CO production rate of PCuM-W were 74.2%, 85.4%, and 33.3% lower than that of W, respectively, showing outstanding fire-hazard-reducing efficiency that surpassed most of its counterparts. Furthermore, due to the hierarchical porosity and antimicrobial property of PCuM, PCuM-W showed excellent moisture-buffering ability and mildew resistance. This work brings guidelines for fabricating hierarchically porous MOFs to realize multifunctional materials via phytate induced defect engineering.

Low‐Coordinated Single‐Atom Catalysts Modulated by Metal Ionic Liquids for Efficient CO2 Electroreduction

AbstractModulating the coordination environment of single‐atom catalysts (SACs) is an attractive approach for maximizing the catalytic activity of single‐atom centers. Currently, the synthesis of low‐coordinated SACs is mainly confined to increasing the pyrolysis temperature (≥900 °C) to control C─N volatile fragments. Herein, a novel and universal strategy for the low‐coordinated SACs modulation is presented using transition metal (e.g., Ni, Co, Zn) ionic liquid precursors under relatively mild temperature of 600 °C, which regulates the L‐shell electronic structure and decreases nearly 50% electrophilic reactivity by ionization of 4‐position N atom, thereby orienting synthesis of the SACs with metal‐N3 centers. The Ni‐N3 SACs exhibit exceptional CO2 electroreduction performance of 99.7% CO Faraday efficiency with an ultra‐high CO partial current density of 467.55 mA·cm−2 as well as a CO production rate up to 10417.51 µmol·h−1·cm−2 in flow cell. The superior catalytic activity achieves over twofold increase compared with the Ni‐N4 SACs prepared by non‐metal ionic liquid precursors due to the lower free energy of the key intermediate *COOH and the stronger adsorption energy.

Effects of water immersion and pre-oxidation on re-ignition characteristics of non-caking coal

Coal spontaneous combustion (CSC) in waterlogged goafs has become an essential threat to coal mine safety production, so it is necessary to comprehensively and deeply evaluate the re-ignition characteristics of residual coal after water immersion and pre-oxidation. The re-ignition process of non-caking coal under the influence of water immersion and pre-oxidation was tested using a temperature-programmed test system (TPTS), and the spontaneous combustion characteristic parameters and limit characteristic parameters of low-temperature oxidation were calculated. The results show that the spontaneous combustion characteristic parameters such as CO production rate, oxygen consumption rate, and heat release intensity positively correlate with temperature. The minimum float coal thickness and lower limit oxygen concentration show a trend of increasing and then decreasing with the temperature increase, while the maximal air leakage intensity is the opposite. In addition, the expansion of pores and cracks caused by water immersion and pre-oxidation processes and the increase of unstable functional groups promote the oxygen consumption and heat generation of immersed and oxidized coal, which reduces the characteristic temperature, and activation energy, and limit characteristic parameters. Meanwhile, water immersion and pre-oxidation can synergistically accelerate the low-temperature oxidation process of non-caking coal, which significantly increases the CSC risk of coal O140I30 and coal O90I30. The results enrich the research on the characteristics of water immersed and oxidation coals re-ignition, which may be applied to prevent CSC in the future.

Highly stable and durable ZnIn2S4 nanosheets wrapped oxygen deficient blue TiO2(B) catalyst for selective CO2 photoreduction into CO and CH4

Developing new and highly stable efficient photocatalysts is crucial for achieving high performance and selective photocatalytic CO2 conversion. In this paper, we designed a one-dimensional oxygen-deficient blue TiO2(B) (BT) catalyst for improved electron mobility and visible light accessibility. In addition, hexagonal ZnIn2S4 (ZIS) nanosheets with a low bandgap and great visible light accessibility are employed to produce effective heterostructures with BT. The synthesized materials are tested for photocatalytic conversion of CO2 into solar fuels (H2, CO and CH4). The optimized composite yields 71.6 and 10.3 μmol g−1h−1 of CO and CH4, three and ten times greater than ZIS, respectively. When ZIS nanosheets are combined with a one-dimensional oxygen-deficient BT catalyst, improved electron mobility and visible light accessibility are achieved, charge carriers are effectively segregated, and the transfer process is accelerated, resulting in efficient CO2 reduction. The photocatalytic CO2 conversion activity of the constructed BT/ZIS heterostructures is very stable over a 10-day (240-hour) period, and CO and CH4 production rates increase linearly with time; however, as time goes on, the rates of H2 production decrease. Further, a five-time recycling test confirmed this, revealing essentially equal activity and selectivity throughout the experiment. As a result, CO2 to CO and CH4 conversion has high selectivity and longer durability. The band structure of the BT/ZIS composite is determined using Mott-Schottky measurement, diffuse reflectance spectroscopy, and valence band X-ray photoelectron spectroscopy. This research demonstrates a novel approach to investigating effective, stable, and selective photocatalytic CO2 reduction systems for solar-to-chemical energy conversion.

In-situ producing CsPbBr3 nanocrystals on (001)-faceted TiO2 nanosheets as S‑scheme heterostructure for bifunctional photocatalysis

Fabricating a cost-effective yet highly active photocatalyst to reduce CO2 to CO and oxidize benzyl alcohol to benzaldehyde simultaneously, is challenging. Herein, we construct an S-scheme 0D/2D CsPbBr3/TiO2 heterostructure for bifunctional photocatalysis. An in-situ synthetic route is used, which enables the precise integration between CsPbBr3 nanocrystals and ultrathin TiO2 nanosheets exposed with (001) facets (termed as TiO2-001), resulting in a tightly coupled heterointerface and desirable band offsets. The as-prepared CsPbBr3/TiO2-001heterojunctions exhibit boosted charge carrier kinetics, particularly, quick carrier separation/transfer and efficient utilization. Experimental results and theoretical calculations validate the S-scheme route in CsPbBr3/TiO2-001, which allows the enrichment of strongly conserved electrons-holes at conduction and valence bands of CsPbBr3 and TiO2-001, respectively. Consequently, compared to its counterparts, an excellent bifunctional activity (with 24 h reusability) is realized over CsPbBr3/TiO2-001, where the production rate of CO and benzaldehyde reach up to 78.06 μmol g-1h−1 and 1.77 mmol g-1h−1 respectively, without employing any sacrificial agents. This work highlights the development of perovskite-based heterostructures and describes the efficient harnessing of redox potentials and charge carriers towards combined photocatalytic systems.

Effects of nitrification and urease inhibitors on ammonia-oxidizing microorganisms, denitrifying bacteria, and greenhouse gas emissions in greenhouse vegetable fields

Soil microorganisms and N cycling are important components of biogeochemical cycling processes. In addition, the study of the effects of nitrification and urease inhibitors on N and microorganisms in greenhouse vegetable fields is essential to reducing N loss and greenhouse gas emissions. The effects of nitrification inhibitors [2-chloro-6-(trichloromethyl) pyridine (CP), dicyandiamide (DCD)], and urease inhibitor [N-(n-butyl) thiophosphoric triamide (NBPT)] on soil inorganic N (NH4+-N, NO2−-N and NO3−-N) concentrations and the production rates of greenhouse gases (N2O, CH4, and CO2) in greenhouse vegetable fields were investigated via indoor incubation experiments. Polymerase chain reaction amplification and high-throughput sequencing technology (Illumina Miseq) were used to explore the community structure and abundance changes of ammonia-oxidizing archaea (AOA), ammonia-oxidizing bacteria (AOB), and denitrifying bacteria (nirK and nirS). The results showed that CP and DCD obviously inhibited NH4+-N conversion, and NO2−-N, and NO3−-N accumulation, NBPT slowed down urea hydrolysis and NH4+-N production, and the apparent nitrification rates of soil were in the following order: NBPT > DCD > DCD + NBPT > CP + NBPT > CP. Compared with urea treatment, the peak N2O production rate of inhibitor treatment decreased by 73.30–99.30%, and the production rate of CH4 and CO2 decreased by more than 66.16%. DCD and CP reduced the abundance of AOA and AOB, respectively. Furthermore, NBPT hindered the growth of ammonia-oxidizing microorganisms and nirS-type denitrifying bacteria, and urea and nitrification inhibitors were detrimental to the growth of Ensifer and Sinorhizobium in the nirK community. Nitrification and urease inhibitors can effectively slow down nitrification and greenhouse gas emissions, reduce N loss and improve soil quality by inhibiting the growth of ammonia-oxidizing microorganisms and denitrifying bacteria.

Synergistic role of Cu-C and Cu-N dual bonding of nanostructured g-C3N4/Cu2SnS3 photocatalysts for efficient CO2 conversion to CO

Herein, a 2D/0D g-C3N4/Cu2SnS3 heterostructure is successfully constructed via the facile calcination method, and its application to photocatalytic CO2 conversion is demonstrated for the first time. The fabricated g-C3N4/Cu2SnS3 nanocomposite is featured with its unique Cu-C and Cu-N dual chemical bond at the interface. The engineered g-C3N4/Cu2SnS3 nanocomposites record a superior CO production rate of 18.2 μmol∙g−1∙h−1 with an apparent quantum yield of 2.2% at 500 nm of light illumination, which is the highest among g-C3N4/ternary metal sulfide photocatalysts to the best of our knowledge. This notable improvement is attributed to the effective incorporation of Cu2SnS3 nanoparicles onto the surfaces of ultra-thin g-C3N4 and, the formation of Cu-N and Cu-C dual bonds at the interface. This helps not only the activation of interface defect-mediated Z-scheme conduction but also supplies highly reactive Cu sites in the Cu2SnS3 nanoparticles for efficient photocatalytic CO2 conversion.

Impact of phytosterol addition on fermentation progress and volatile compounds synthesis during alcoholic fermentation in synthetic and natural grape musts

Lipid nutrition is an important factor for yeast during alcoholic fermentation. Although recent research reports have revisited the role of sterols during alcoholic fermentation, our knowledge of lipids assimilation and volatile compound biogenesis remains partial. This study aimed to find out more about the impact of grape must phytosterol content on fermentative kinetics, nitrogen assimilation by yeast and fermentative aroma synthesis. To that end, experimental fermentations were performed in synthetic and Chardonnay musts supplemented with different phytosterol concentrations (0, 1, 3 and 5 mg/L). Sterols addition significantly increased the maximum CO2 production rate while reducing fermentation duration. This can be explained by higher nitrogen assimilation by yeast due to sterols, which leads to higher yeast growth and better viability at the end of the fermentation process. Regarding the aromatic profile, sterol addition also significantly increased acetate esters, ethyl esters, fusel alcohols and medium-chain fatty acids production. These new advances highlight the major role of phytosterols in fermentation control and wine aroma profile.

Synergistically boosting of CO2 photoreduction over Bi/BiOBr nanostructure via in-situ formation of oxygen vacancy and metallic Bi

Depositing metal on the surface of semiconductor has been deemed to be an valid tactics to heighten the reducing activity of photocatalyst. Herein, the Bi/BiOBr catalyst was prepared via NaBH4-assisted reduction reaction. The photocatalytic capacity of CO2 conversion for Bi/BiOBr was appraised. The optimal Bi/BiOBr exhibits that the production rates of CO and CH4 are 251.2 and 25.6 μmol g-1h−1 individually, being 12.3 and 8.9 times as high as original BiOBr. The excellent activity for Bi/BiOBr could be put down to the synergy of surface plasmon resonance (SPR) effect of metallic Bi and OVs in the surface of BiOBr. More importantly, the OVs on surface of BiOBr could be deemed as reactive locations for the adsorption of CO2 and H2O molecules. This work reveals the synergistic effect of in-situ formed OVs and metal nanoparticles of Bi on enhancing the photocatalytic activity.