Coevolution Research Articles

F− doped Bi2MoO6 nanosheets for photoreduction of CO2 with H2O

The issue of excessive CO2 emissions has emerged as a significant global challenge. Photocatalytic technology holds great promise for controlling CO2 emissions. In this paper, two-dimensional Bi2MoO6 nanosheets were prepared by the hydrothermal method and modified by CTAB and F- doping to impart specific morphological characteristics and an energy band structure. The results showed that F-2D BMO with a doping amount of 1.5 wt% exhibited the highest photocatalytic efficiency. The CO evolution rate can be increased from 1.8 μmol/g/h to 5.6 μmol/g/h, with the CO generation selectivity increasing from 52.94 % to 87.50 %. This enhancement can be attributed to the replacement of original lattice O2– by the doped F-, which altered the lattice parameters and energy band structure of the catalyst. Consequently, the band gap was reduced and the conduction band potential became more negative, rendering it more suitable for CO production. Additionally, the improved separation rate of photogenerated carriers, reduced complexation rate, and enhanced generation and transfer of active species all contribute to the enhanced photocatalytic CO2 reduction performance of the catalysts. Therefore, this study highlights the potential benefits and significance of using F- doped Bi2MoO6 nanosheets for addressing concerns regarding CO2 emission concerns and promoting sustainable energy solutions.

Early Nitrogen Budget of the Martian Atmosphere and Its Evolution

AbstractIn 1976, Viking measured a 14N/15N ratio of 170 ± 15 in the Martian atmosphere, and in 2012, MSL measured a ratio of 173 ± 11. This type of enrichment of the heavier isotope can only be explained by a significant loss of N to space, with the lighter isotope escaping more efficiently. A quantitative understanding of this nitrogen evolution of the Martian atmosphere requires analyzing all of the sources, sinks and exchanges of N2. We employ the processes of sputtering, photochemical escape by dissociative recombination and photodissociation, volcanic outgassing and impact processes to understand the evolution of N2 through time. We use a forward time‐marching model starting at initial abundance at 4 Gya to calculate the N2 abundance and 15N/14N enrichment over the history of Mars. We also incorporate a simultaneous CO2 evolution, which decays in either a power‐law or linear function to the present‐day value of 6 mbar. We constrain the simulated evolutionary tracks to the present day N2 abundance and 15N/14N ratio of the Martian atmosphere to explore the initial conditions of the early atmosphere. Our model indicates a modal value of 120 mbar of initial N2 pressure, with an upper limit of 3.6 bars, for an initial CO2 pressure of 1 bar. This modal value is in good agreement with the N2 budget of Earth's atmosphere when scaled to the mass of Mars, which amounts to ∼110 mbar.

Photocatalytic CO2 reduction integrated with biomass selective oxidation via single-atom Ru and P dual sites on carbon nitride

Photocatalytic biorefinery integrated with CO2 reduction to co-produce value-added chemicals and fuels is significant but challenging. Herein, a novel photocatalyst with dual active sites is constructed, in which Ru single atoms coordinated with N2O2 on phosphorus-doped carbon nitride (Ru1N2O2@PCNx) via a pre-assembled pyrolysis strategy. Ru1N2O2@PCN1.0 catalyst exhibits an exceptional performance in both CO2 reduction and biorefinery processes, originating from the high photon-to-electron conversion rate. It achieves an extraordinary CO2 reduction and biorefinery, with 100.1 μmol g−1 h−1 evolution of CO and 91.2% yield of lactic acid. Furthermore, the as-prepared Ru1N2O2@PCN1.0 is successfully used in biomass-derived monosaccharides and xylan systems, validating the universality for broad applications. Experimental and theoretical analysis indicates that doping P in CN by replacing a corner C atom facilitates charge transfer/separation. Additionally, the introduction of Ru-N2O2 coordination regulates the electronic structure of CN and reduces the reaction energy barrier.

Copper‐Sulfur‐Nitrogen Cluster Providing a Local Proton for Efficient Carbon Dioxide Photoreduction

AbstractAtomically precise Cu clusters are highly desirable as catalysts for CO2 reduction reaction (CO2RR), and they provide an appropriate model platform for elaborating their structure–activity relationship. However, an efficient overall photocatalytic CO2RR with H2O using assembled Cu‐cluster aggregates as single component photocatalyst has not been reported. Herein, we report a stable crystalline Cu−S−N cluster photocatalyst with local protonated N−H groups (denoted as Cu6−NH). The catalyst exhibits suitable photocatalytic redox potentials, high structural stability, active catalytic species, and a narrow band gap, which account for its outstanding photocatalytic CO2RR performance under visible light, with ≈100 % selectivity for CO evolution. Remarkably, systematic isostructural Cu‐cluster control experiments, in situ infrared spectroscopy, and density functional theory calculations revealed that the protonated pyrimidine N atoms in the Cu6−NH cluster act as a proton relay station, providing a local proton during the photocatalytic CO2RR. This efficiently lowers the energy barrier for the formation of the *COOH intermediate, which is the rate‐limiting step, efficiently enhancing the photocatalytic performance. This work lays the foundation for the development of atomically precise metal‐cluster‐based photocatalysts.

Copper-Sulfur-Nitrogen Cluster Providing a Local Proton for Efficient Carbon Dioxide Photoreduction.

Atomically precise Cu clusters are highly desirable as catalysts for CO2 reduction reaction (CO2 RR), and they provide an appropriate model platform for elaborating their structure-activity relationship. However, an efficient overall photocatalytic CO2 RR with H2 O using assembled Cu-cluster aggregates as single component photocatalyst has not been reported. Herein, we report a stable crystalline Cu-S-N cluster photocatalyst with local protonated N-H groups (denoted as Cu6 -NH). The catalyst exhibits suitable photocatalytic redox potentials, high structural stability, active catalytic species, and a narrow band gap, which account for its outstanding photocatalytic CO2 RR performance under visible light, with ≈100 % selectivity for CO evolution. Remarkably, systematic isostructural Cu-cluster control experiments, in situ infrared spectroscopy, and density functional theory calculations revealed that the protonated pyrimidine N atoms in the Cu6 -NH cluster act as a proton relay station, providing a local proton during the photocatalytic CO2 RR. This efficiently lowers the energy barrier for the formation of the *COOH intermediate, which is the rate-limiting step, efficiently enhancing the photocatalytic performance. This work lays the foundation for the development of atomically precise metal-cluster-based photocatalysts.

Structural Determination and Hierarchical Evolution of Transition Metal Clusters Based on an Improved Self-Adaptive Differential Evolution with Neighborhood Search Algorithm.

Determining the optimal structures and clarifying the corresponding hierarchical evolution of transition metal clusters are of fundamental importance for their applications. The global optimization of clusters containing a large number of atoms, however, is a vastly challenging task encountered in many fields of physics and chemistry. In this work, a high-efficiency self-adaptive differential evolution with neighborhood search (SaNSDE) algorithm, which introduced an optimized cross-operation and an improved Basin Hopping module, was employed to search the lowest-energy structures of CoN, PtN, and FeN (N = 3-200) clusters. The performance of the SaNSDE algorithm was first evaluated by comparing our results with the parallel results collected in the Cambridge Cluster Database (CCD). Subsequently, different analytical methods were introduced to investigate the structural and energetic properties of these clusters systematically, and special attention was paid to elucidating the structural evolution with cluster size by exploring their overall shape, atomic arrangement, structural similarity, and growth pattern. By comparison with those results listed in the CCD, 13 lower-energy structures of FeN clusters were discovered. Moreover, our results reveal that the clusters of three metals had different magic numbers with superior stable structures, most of which possessed high symmetry. The structural evolution of Co, Pt, and Fe clusters could be, respectively, considered as predominantly closed-shell icosahedral, Marks decahedral, and disordered icosahedral-ring growth. Further, the formation of shell structures was discovered, and the clusters with hcp-, fcc-, and bcc-like configurations were ascertained. Nevertheless, the growth of the clusters was not simply atom-to-atom piling up on a given cluster despite gradual saturation of the coordination number toward its bulk limit. Our work identifies the general growth trends for such a wide region of cluster sizes, which would be unbearably expensive in first-principles calculations, and advances the development of global optimization algorithms for the structural prediction of clusters.

Goat manure waste and palm oil mill effluent, viable crude oil degradation substrates: A thermodynamic and composting investigation studies

The composting and thermodynamic processes of crude oil (CO) degradation using the compost of goat manure origin (CGMO) and compost of palm oil mill effluent origin (CPOMEO) were studied. Microbial activity was investigated using the carbon dioxide (CO₂) evolution test. The physiochemical properties of the composts and that of the treated CO-contaminated soil (COCS) were also investigated. In particular, CGMO significantly improve CO degradation with the highest CO₂ evolution rate of 45 mg/g compared to the CPOMEO and the control. The CO degradation rates of 85.7 %, 71.4 %, and 14 % corresponded to the first-order CO degradation rate constants of 0.743 day−1, 0.689 day−1, and 0.136 day−1 for CGMO, CPOMEO, and control, respectively. The Fourier transforms infrared (FTIR) spectral pattern for both composts revealed adsorption bands that were identifiable with polysaccharides, potassium, and nitrogen, whereas the scanning electron microscope and energy dispersive spectrophotometry (SEMEDX) of CPOMEO indicated carbon and oxygen as the sole compositions. The negative ΔG and ΔH values indicated the spontaneity and exothermic nature of the CO composting process, respectively.

From Ru to RuAl intermetallic/Ru heterojunction: Enabling high reversibility of the CO2 redox reaction in Li–CO2 battery based on lowered interface thermodynamic energy barrier

The impenetrable thermodynamic barrier of the Li2CO3 decomposition reaction has been the challenge to achieve high reversibility of Li–CO2 batteries. Ruthenium-based nanomaterials represent one class of promising cathode catalysts, but are still challenged by the limited catalytic activity for reducing the thermodynamic energy barrier of the decomposition of Li2CO3. Herein, we clarify that the intrinsic catalytic activity of Ru can be distinctly enhanced by screening RuAl intermetallic and interpenetrating‑phase trimodal porous RuAl/Ru heterojunction (NP-RuAl/Ru). The NP-RuAl/Ru with multilevel pore channels is straightforwardly made through driving the phase and microstructure reconstruction upon controllable dealloying of partial Al from a Ru–Al master alloy. Density functional theory simulations disclose that the RuAl/Ru interface can dramatically lower the Gibbs free energy of the Li-dissociation related intermediate steps in the CO2 evolution process owing to the intrinsically high catalytic activity of RuAl intermetallic and strong interface coupling. The multilevel network skeleton with rich nano-interfaces provides high density of active sites, the fluent pathway for both the electron and mass transportation, as well as ample space for discharge product uptaking. In situ differential electrochemical mass spectrometry demonstrates that the molar ratio of evolved-CO2 to transferred-electrons in the charging process is ∼0.73 closing to the theoretical value of 0.75, attesting the high reversibility of the CO2 redox reaction over NP-RuAl/Ru in Li–CO2 battery. The well-crafted NP-RuAl/Ru catalyst delivers a lower voltage gap stabilized at ∼1.25 V for 1400 h (nearly two months) at 200 mA g–1. Such “the phase and structure reconstruction” protocol in the light of dealloying unveils a new paradigm to build the highly efficient intermetallic-based electrocatalysts incorporated with non-precious metals for Li–CO2 batteries and other energy-related applications.

Insight into the Dynamic Evolution of Co3Mo3N Bimetallic Nitride Surface during Ammonia Synthesis

Insight into the Dynamic Evolution of Co₃Mo₃N Bimetallic Nitride Surface during Ammonia Synthesis

Boosting CO2 Photoreduction via Regulating Charge Transfer Ability in a One‐Dimensional Covalent Organic Framework

AbstractTwo‐dimensional (2D) imine‐based covalent organic frameworks (COFs) hold potential for photocatalytic CO2 reduction. However, high energy barrier of imine linkage impede the in‐plane photoelectron transfer process, resulting in inadequate efficiency of CO2 photoreduction. Herein, we present a dimensionality induced local electronic modulation strategy through the construction of one‐dimensional (1D) pyrene‐based covalent organic frameworks (PyTTA‐COF). The dual‐chain‐like edge architectures of 1D PyTTA‐COF enable the stabilization of aromatic backbones, thus reducing energy loss during exciton dissociation and thermal relaxation, which provides energetic photoelectron to traverse the energy barrier of imine linkages. As a result, the 1D PyTTA‐COF exhibits significantly enhanced CO2 photoreduction activity under visible‐light irradiation when coordinated with metal cobalt ion, yielding a remarkable CO evolution of 1003 μmol g−1 over an 8‐hour period, which surpasses that of the corresponding 2D counterpart by a factor of 59. These findings present a valuable approach to address in‐plane charge transfer limitations in imine‐based COFs.

Boosting CO2 Photoreduction via Regulating Charge Transfer Ability in a One-Dimensional Covalent Organic Framework.

Two-dimensional (2D) imine-based covalent organic frameworks (COFs) hold potential for photocatalytic CO2 reduction. However, high energy barrier of imine linkage impede the in-plane photoelectron transfer process, resulting in inadequate efficiency of CO2 photoreduction. Herein, we present a dimensionality induced local electronic modulation strategy through the construction of one-dimensional (1D) pyrene-based covalent organic frameworks (PyTTA-COF). The dual-chain-like edge architectures of 1D PyTTA-COF enable the stabilization of aromatic backbones, thus reducing energy loss during exciton dissociation and thermal relaxation, which provides energetic photoelectron to traverse the energy barrier of imine linkages. As a result, the 1D PyTTA-COF exhibits significantly enhanced CO2 photoreduction activity under visible-light irradiation when coordinated with metal cobalt ion, yielding a remarkable CO evolution of 1003 μmol g-1 over an 8-hour period, which surpasses that of the corresponding 2D counterpart by a factor of 59. These findings present a valuable approach to address in-plane charge transfer limitations in imine-based COFs.

Halogenated Functional Electrolyte Additive for Li-CO2 Batteries.

In recent years, functional electrolyte additives have been widely studied during the CO2 evolution reaction (CO2ER) and CO2 reduction reaction (CO2RR) processes for Li-CO2 batteries. Owing to different concerns, functions of these additives are also multiple and limited. In this work, the multiple impacts of functional electrolyte additives for Li-CO2 batteries are discussed. N-phenylpyrrolidine (PPD) and 1-(3-bromophenyl) pyrrole (Br-PPD) are investigated as additives successively. First, the corresponding charging potential during the CO2ER process can be reduced to 3.65 V with PPD; then the Li||Li symmetric cells with Br-PPD possess a superior long-term cycling of 800 h benefited from a stable solid electrolyte interphase (SEI) on the surface of a Li metal by using a Li anode protected with bromine functional groups. In Br-PPD-based Li-CO2 cells, the charging potential can be maintained at 3.70 V for 120 cycles even with a Super P cathode. In this work, the relationship between the structural properties of organic molecules and their electrochemical applications is discussed and investigated. This is essential for the targeted design and preparation of additives in rechargeable batteries.

Mechanical energy-driven triboelectric plasma catalytic CO2 reduction over oxygen-vacancy-introduced In2O3 nanoparticles

As the single electron transfer of CO2 to CO2− ions is the critical step in the CO2 activation, it is very important to develop appropriate strategies to construct efficient catalytic systems. Herein, we constructed a coupled catalytic system consisting of mechanical-energy-driven triboelectric plasma and indium oxide rich in oxygen vacancies to achieve CO2 reduction to CO at room temperature and atmospheric pressure. At the discharge distance of 0.6 mm, the indium oxide with more oxygen vacancies exhibited an optimal catalytic activity of 0.20 mmol·g−1·h−1 for CO evolution rate, and the conversion efficiency from electrical to chemical energy was 10.8 %. Electron paramagnetic resonance experiments showed that a large amount of CO2− ions were generated in the triboelectric plasma. The introduction of oxygen vacancies could increase the density of states near the Fermi level of indium oxide catalysts, stabilize highly active CO2− ions, and reduce the energy barrier of CO2− decomposition.

Atomically dispersed Au confined by oxygen vacancies in Au-θ-Al2O3/Au/PCN hybrid for boosting photocatalytic CO2 reduction driven by multiple built-in electric fields

A new Au-θ-Al2O3/Au/PCN hybrid is fabricated by the collaborative design strategy of active site and assembled structure, which achieves highly efficient photocatalytic CO2 reduction (CO2R) performance. The energy band structure of PCN is adjusted significantly owing to the strong coupling effect of Au-θ-Al2O3/Au nanosheets intercalated in PCN nanosheets. The result brings about up-shift of CB, VB and Fermi energy level overall and decrease of bandgap, which is in favor of harvesting visible light, exciting VB electrons and increasing reduction ability. In addition, the multiple built-in electric fields are induced by electron diffusion effect between structural units, due to the tight interface contact in the Au-θ-Al2O3/Au/PCN hybrid, which can effectively promote the separation of photoinduced charge carriers. Furthermore, the atomically dispersed Au atoms confined by the oxygen vacancies in Au-θ-Al2O3/Au can provide the plenty of effective active sites for CO2R reaction, and meanwhile, the localized surface plasmon resonance (LSPR) effect induced by Au nanoparticles on Au-θ-Al2O3/Au can improve the visible light response and produce abundant hot electrons to contribute to CO2R reaction. As a consequence, the average CO evolution rate of over the optimizing 10 %-Au-θ-Al2O3/Au/PCN hybrid (7.76 μmol g-1h−1) reaches up to 3.53 times than that of PCN (2.20 μmol g-1h−1) in the CO2R reaction, and maintains basically stable operation within 7 cycles of running, suggesting the superior activity and recyclability.

Amide Covalent Bonding Engineering in Heterojunction for Efficient Solar-Driven CO2 Reduction.

Inefficient charge separation and slow interfacial reaction dynamics significantly hamper the efficiency of photocatalytic CO2 reduction. Herein, a facile EDC/NHS-assisted linking strategy was developed to enhance charge separation in heterojunction photocatalysts. Using this approach, we successfully synthesized amide-bonded carbon quantum dot-g-C3N4 (CQD-CN) heterojunction photocatalysts. The formation of amide covalent bonds between CN and CQDs in the CN-CQD facilitates efficient carrier migration, CO2 adsorption, and activation. Exploiting these advantages, the CN-CQD photocatalysts exhibit high selectivity with CO and CH4 evolution rates of 79.2 and 2.7 μmol g-1 h-1, respectively. These rates are about 1.7 and 3.6 times higher than those of CN@CQD and bulk CN, respectively. Importantly, the CN-CQD photocatalysts demonstrate exceptional stability, even after 12 h of continuous testing. The presence of the COOH* signal is identified as a crucial intermediate species in the conversion of CO2 to CO. This study presents a covalent bonding engineering strategy for developing high-performance heterojunction photocatalysts for efficient solar-driven reduction of CO2.

The ocean carbon sinks and climate change.

The oceans act as major carbon dioxide sinks, greatly influencing global climate. Knowing how these sinks evolve would advance our understanding of climate dynamics. We construct a conceptual box model for the oceans to predict the temporal and spatial evolution of CO2 of each ocean, and the time-evolution of their salinities. Surface currents, deep water flows, freshwater influx, and major fluvial contributions are considered, as also the effect of changing temperature with time. We uncover the strongest carbon uptake to be from the Southern Ocean, followed by the Atlantic. The North Atlantic evolves into the most saline ocean with time and increasing temperatures. The Amazon River is found to have significant effects on CO2 sequestration trends. An alternative flow scenario of the Amazon is investigated, giving interesting insights into the global climate in the Miocene epoch.

Soil health indicator responses to three years of cover crop and crop rotation in a northern semi-arid region, the Canadian prairies

Increasing crop diversity via cover cropping is considered a powerful strategy to improve soil health; thus, a better understanding of the impacts on soil is crucial. In northern semi-arid regions, cover cropping can be agronomically challenging due to growing condition limitations, and the paucity of cover crop data only exacerbates this challenge. Still, farmers are interested in adopting cover crops to reach their soil health goals. Our study addressed this gap by 1) comparing rotations with versus without cover crops; and 2) comparing different rotational treatments of perennial alfalfa, two-year ‘short’ rotations, to four-year ‘long’ rotations with and without cover crops. After three years, soil health indicators were measured at four sites across the Canadian prairies, including wet aggregate stability (WAS), soil pH, electronic conductivity (EC), evolved soil CO2, soil active C, soil organic carbon (SOC), total carbon (C), N2O production, inorganic N, soil protein, potential mineralized N (PMN), and total N. During a dry period which limited cover crop growth, the cover crops had limited impact on soil health indicators, except for a reduction in spring soil nitrate-N levels at two of the four sites. Surprisingly, the crop phase of the rotation had more differences on soil health indicators than the inclusion of cover crops, but the inconsistency of the changes made it difficult to draw clear patterns. Most notably, soil health indicators (and especially soil CO2) responded to crop rotation treatment. The perennial treatment produced 4.57–8.74 µg g-1 24 hr-1; whereas other rotation treatments respired 25–28%, 44–45%, 22–28%, and 35–36% less CO2. Overall, early indicators of soil health change tended to be related to dynamics of soil inorganic N cycling and CO2 evolution. Our results suggest that a longer-term period of cover cropping and greater biomass accumulation will be needed to substantially impact soil health in this semi-arid environment. Implementing more ‘perennialized’ crop rotations will benefit the early indicators of soil health change in a short timeframe.

Multi-scale dynamic mathematical model of CO2 and fly ash mineralization

The multi-scale structural characteristics of micro-nano pores of fly ash are the core factors affecting the mechanisms of physical transport and chemical reaction of CO2. The existing theoretical models of mineralization do not take such characteristics into account. it is difficult to describe the mechanisms of physical transport and chemical reaction of CO2. In order to address this scientific problem, a theoretical model of multi-scale structures of pore series is established. A mathematical dynamic model of multi-scale internal diffusion-mineralization is also established for accurately describing the concentration variation law in physical transport and chemical reaction processes of CO2 in micro-nano pores of fly ash under natural static conditions. The model is simulated to analyze the key parameters affecting the transport-mineralization reaction rate in the evolutionary mechanism of CO2. The simulated results showed that if the initial apparent diffusion-mineralization coefficient is reduced by 100 times, the concentration of CO2 at the center of the particles is reduced by 25 order in magnitude. The attenuation coefficient is reduced by 2 order in magnitude and the concentration of CO2 at the center of the particles is changed by 9 order in magnitude. These findings indicate that the initial apparent diffusion-mineralization coefficient and attenuation coefficient are the factors affecting the diffusion-mineralization reaction in the evolution of CO2. The reason for the phenomenon of multi-scale evolution and mechanism of diffusion mineralization reaction of CO2 in the micro-nano pores of fly ash is revealed.

Modulating Bidirectional Catalytic Activity Through a RuNi Nanoalloy on Facile Candle Soot Carbon Towards Efficient Lithium‐CO2Mars Batteries

AbstractLithium‐CO2 batteries have been at the forefront of reducing CO2 emissions and addressing the present energy crisis. As the Martian atmosphere is 95 % CO2, this battery technology is ideal as a stand‐alone energy storage device on the planet. However, challenges such as low reversibility, high charging voltages, and poor cycling life restrict its practicability. The current study addresses these by increasing the reversibility of the active reaction sites on the cathode via a synergistic interaction between the RuNi nanoparticle catalyst and candle soot carbon (CSC). This helps the system achieve a full discharge capacity of 15207 mAh g−1 at a high current density of 200 mA g−1 with 99.3 % coulombic efficiency and an efficient cycling life of over 100 cycles at a higher current density of 500 mA g−1 for a limited capacity of 500 mAh g−1. Further, combining ex‐situ physical characterizations and density functional theory helps understand the underlying mechanism for improving the bidirectional CO2 reduction and evolution activities during discharging and charging. The study, thus using a bimetallic catalyst and carbon, provides an approach for a single solution towards addressing the dual challenges of regulating CO2 emissions on Earth and providing a constant energy source on Mars.

Enhancing biomass oxidation with carbon nitride nanosheets ring inserted on C. I. Pigment Yellow 53 photocatalysts for simultaneous CO and lactic acid production

Synchronously producing gas–liquid products from biomass conversion is an effective solution for addressing global energy depletion and environmental pollution. Here, we designed an efficient photocatalyst (CNs@PY53-x) to co-produce CO and lactic acid from biomass-derived sugars. Carbon nitride nanosheets were incorporated onto the surface of PY53 using an ultrasonic-assisted self-assembly coupled with evaporation-drying strategy. The CNs@PY53-x exhibited broader visible light absorption, stronger photocurrent density, and faster separation rate of photogenerated carriers as compared with CNs or PY53. The photocatalytic performance of CNs@PY53-x correlated well with its photoelectric characterization, achieving an CO evolution rate of 371.56 μmol g−1h−1 and a lactic acid yield of 86.9% in the xylose-alkaline system. Furthermore, CNs@PY53-2 demonstrated favorable applicability with various biomass-based sugars. Poisoning experiments, coupled with electron spin resonance (ESR) characterization, revealed that the superoxide radical (O2−) was the primary oxidation active species during this process. This work presents a new strategy for synchronously producing gas–liquid products during biomass conversion.