CO Yield Research Articles

Photothermal-boosted S-scheme heterojunction of α-Fe2O3@NiOx for high-selective reduction of CO2 to CO

Self-heating photothermal catalysis, combining light promotion and thermal activation, offers unique advantages for CO2 conversion. The meticulous design of active sites and light-absorbing materials is crucial for high-performance photothermal catalysts. Herein, a S-Scheme heterostructure composed of NiOx subunits with abundant oxygen vacancies (Vo) bonded with α-Fe2O3 nanoplatelets has been fabricated for solar-driven photothermal catalytic CO2 reduction. Under continuous full-spectrum light irradiation (0.3 W·cm−2), the α-Fe2O3@NiOx hybrids exhibited a CO yield rate of 199.3 μmol∙g−1·h−1 in a gas–solid reaction models with near-unity selectivity. Additionally, the apparent quantum yield for CO production at 420 nm reaches 1.56 %. The prominent activity is attributed to three key factors: (1) The Vo-rich NiOx facilitates the accumulation of photogenerated electrons and activation of chemisorbed CO2. (2) The implemented S-Scheme heterostructures boost interfacial charge-transfer and provide spatially separated catalytic sites for efficient overall CO2 reduction. (3) The substantial photothermal effect of NiOx, which arises from nonradiative exciton recombination, induces local heating of the catalyst, thereby enhancing reaction kinetics. This work provides valuable insights into the utilization of a photothermal-photocatalytic S-Scheme heterojunction system for the photothermal catalytic CO2 reduction.

Oxygen-bridged Schottky junction in ZnO–Ni3ZnC0.7 promotes photocatalytic reduction of CO2 to CO: Steering charge flow and modulating electron density of active sites

Developing carbon dioxide (CO2) photocatalysts from transition metal carbides (TMCs) with abundant active sites, modulable electron cloud density, as well as low cost and high stability is of great significance for artificial photosynthesis. Building an efficient electron transfer channel between the photo-excitation site and the reaction-active site to extract and steer photo-induced electron flow is necessary but challenging for the highly selective conversion of CO2. In this study, we achieved an oxygen-bridged Schottky junction between ZnO and Ni3ZnC0.7 (denoted as Znoxide–O–ZnTMC) through a ligand-vacancy strategy of MOF. The ZnO–Ni3ZnC0.7 heterostructure integrates the photo-exciter (ZnO), high-speed electron transport channel (Znoxide–O–ZnTMC), and reaction-active species (Ni3ZnC0.7), where Znoxide–O–ZnTMC facilitates the transfer of excited electrons in ZnO to Ni3ZnC0.7. The Zn atoms in Ni3ZnC0.7 serve as electron-rich active sites, regulating the CO2 adsorption energy, promoting the transformation of *COOH to CO, and inhibiting H2 production. The ZnO–Ni3ZnC0.7 shows a high CO yield of 2674.80 μmol g–1h–1 with a selectivity of 93.40 % and an apparent quantum yield of 18.30 % (λ = 420 nm) with triethanolamine as a sacrificial agent. The CO production rate remains at 96.40 % after 18 h. Notably, ZnO–Ni3ZnC0.7 exhibits a high CO yield of 873.60 μmol g–1h–1 with a selectivity of 90.20 % in seawater.

The practical utility of nitrogen doped TiO2 as a photocatalyst for the oxidative removal of gaseous formaldehyde

This study reports the development of nitrogen-doped TiO2 (N–TiO2: N/Ti molar ratio = 1) photocatalyst with the enhanced photoelectronic properties for the phtocatalytic oxidation (PCO) of formaldehyde (FA). The N–TiO2 photocatalyst is coated with ceramic beads and placed in a packed-bed tube reactor to examine the PCO-based mineralization of FA vapor (100 - 500 ppm) under ultraviolet (UV)-A illumination (32 W light source) with the control of flow rate (100–500 mL min−1), O2 (0–21%), and relative humidity (RH: 0–100%). Accordingly, the N-TiO2 in dry conditions showcases 100% degradation of 100 ppm FA with high stability over 5 reuse cycles (compared to the P25 (75.9%) and bare TiO2 (69.2%)) at a flow rate of 100 mL min−1 and a 21 % O2 level (quantum yield = 1.72.E−02 molecules photon−1 and space-time yield = 3.44.E−03 molecules photon−1 mg−1). The superior performance of N–TiO2 may reflect the combination of N/O atoms in the crystal structure to enhance the photo-redox reactivities with the heightened valence band enegry and prolonged lifespan of charge carrier (1.34 ns) relative to 1.04 ns of P25 and 1 ns of pure (anatase) TiO2. The PCO efficiency of N–TiO2 increases by around 1.6 times in slightly humid conditions (74.6%: RH 20%) compared to dry conditions (47%: RH 0%) while the absence of oxygen (at 0% O2) reduces it significantly down to 13.6%. In situ diffuse reflectance infrared Fourier transform spectroscopy and electron paramagnetic resonance studies confirm the critical role of O2 and H2O vapor on the enhanced FA mineralization rate (CO2 yield = 91 %) through the generation of •O2-/•OH oxidative radicals. This study offers deep insights into the practical utility of N–TiO2 for the photocatalytic mineralization of aldehyde VOCs.

Contact-electro-catalytic CO2 reduction from ambient air

Traditional catalytic techniques often encounter obstacles in the search for sustainable solutions for converting CO2 into value-added products because of their high energy consumption and expensive catalysts. Here, we introduce a contact-electro-catalysis approach for CO2 reduction reaction, achieving a CO Faradaic efficiency of 96.24%. The contact-electro-catalysis is driven by a triboelectric nanogenerator consisting of electrospun polyvinylidene fluoride loaded with single Cu atoms-anchored polymeric carbon nitride (Cu-PCN) catalysts and quaternized cellulose nanofibers (CNF). Mechanistic investigation reveals that the single Cu atoms on Cu-PCN can effectively enrich electrons during contact electrification, facilitating electron transfer upon their contact with CO2 adsorbed on quaternized CNF. Furthermore, the strong adsorption of CO2 on quaternized CNF allows efficient CO2 capture at low concentrations, thus enabling the CO2 reduction reaction in the ambient air. Compared to the state-of-the-art air-based CO2 reduction technologies, contact-electro-catalysis achieves a superior CO yield of 33 μmol g−1 h−1. This technique provides a solution for reducing airborne CO2 emissions while advancing chemical sustainability strategy.

Local microenvironment modulation of zirconium-porphyrinic frameworks for CO2 reduction

Solar-powered photocatalysis offers a sustainable strategy to convert carbon dioxide into valuable fuels, which mitigates the energy crisis and the greenhouse effect. Nevertheless, exploring efficient, selective, stable, and environmentally friendly photocatalysts for CO2 reduction continues to meet a significant challenge. Herein, two iron-porphyrinic zirconium-based metal–organic frameworks, Zr6O4(OH)4(FeTCBPP)3 (MOF-526-H) and Zr6O4(OH)4(FeTCBPP-NH2)3 (MOF-526-NH2) were achieved by the integration of the light-harvesting sites and catalytic centers into one phase (FeTCBPP = iron 5,10,15,20-tetra[4-(4′-carboxyphenyl)phenyl]-porphyrin, FeTCBPP-NH2 = iron 5,10,15,20-tetra[4-(4′-carboxyphenyl)-2-aminophenyl]-porphyrin), which were employed as a couple of models for CO2 photoreduction. MOF-526-NH2 exhibited excellent CO2 reduction with a CO yield of 21.2 mmol·g−1 in the absence of any photosensitizer under visible light, which was 4-fold higher than that of MOF-526-H. Additionally, MOF-526-NH2 showed no significant reduction in CO production during the four rounds, indicating that MOF-526-NH2 possessed good stability. The presence of amino groups in MOF-526-NH2 played an important role in adjusting the micro-environment and electronic structure, which was beneficial to CO2 enrichment and light absorption, and thus improved CO2 photoreduction performance. Based on the density functional theory calculations, a possible mechanism of photocatalytic CO2 reduction over porphyrinic MOFs was proposed.

Effect of ceria morphology on hydrogen production via methane steam reforming for membrane reformer

AbstractHydrogen is a potential energy carrier in comparison to conventional fuels due to its high energy content. Methane is an attractive source for ‘on‐site’ production of hydrogen by using membrane reformer due to its low cost. However, such reformers are not well studied and high temperature operation of steam methane reforming (SMR) makes the integration with membrane separation difficult. Further, the main product of SMR is CO and H2 in which CO has an inhibition effect on the membrane separation process. Therefore, it is vital to synthesize a low temperature and low CO selective catalyst for a suitable integration with membrane reformer. Nickel‐based catalyst is widely used for SMR due to its low cost and high catalytic activity. CeO2 is a favoured support as it mobilizes the lattice oxygen and reduces the coke formation and CO selectivity. Though several studies are reported on CeO2 based support, the effect of CeO2 surface morphology is not studied for SMR. In the current work, Ni/CeO2 of different shapes (nanocube and nanorod) are synthesized. The complete characterization of the support was performed. The effect of support shape, calcination temperature, and reduction temperature on SMR activity is found at different operating temperatures. For each condition conversion, CO, CO2 selectivity, and hydrogen yield are calculated. The results show the CeO2 morphology has a considerable effect on conversion, CO selectivity, and hydrogen yield. It is found that ceria nanocube calcined at 550°C provides better performance at high temperature.

Advancing hydrogen generation: Kinetic insights and process refinement for sorption-enhanced steam gasification of biomass utilizing waste carbide slag

Sorption enhanced steam gasification of biomass (SESGB) presents a promising approach for producing high-purity H2 with potential for zero or negative carbon emissions. This study investigated the effects of gasification temperature, CaO to carbon in biomass molar ratio [CaO/C], and steam flow on the SESGB process, employing carbide slag (CS) and its modifications, CSSi2 (mass ratio of CS to SiO2 is 98:2) and CSCG5 (mass ratio of CS to coal gangue (CG) is 95:5), as CaO-based sorbents. The investigation included non-isothermal and isothermal gasification experiments and kinetic analyses using corn cob (CC) in a macro-weight thermogravimetric setup, alongside a fixed-bed pyrolysis-gasification system to assess operational parameter effects on gas product. The results suggested that CO2 capture by CaO reduced the mass loss during the main gasification as the [CaO/C] increased. The appropriate temperature for SESGB process should be selected between 550 and 700 °C at atmospheric pressure. The appropriate amount of sorbent or steam could facilitate the gasification reaction, but excessive addition led to adverse effects. Operational parameters influenced the apparent activation energy (Ea) by affecting various gasification reactions. For each test, Ea at the char gasification stage was significantly higher than that at the rapid pyrolysis stage. The addition of CS notably increased H2 concentration and yield, while sharply reducing CO2 levels. H2 concentration initially rose and then fell with greater steam flow, peaking at 76.11 vol% for a steam flow of 1.0 g/min. H2 yield peaked at 298 mL/g biomass with a steam flow of 1.5 g/min, a gasification temperature of 600 °C and a [CaO/C] of 1.0. Increasing gasification temperature remarkably boosted the H2 and CO2 yields. Optimal conditions for the SESGB using CS as a sorbent, determined via response surface methodology (RSM), include a gasification temperature of 666 °C, a [CaO/C] of 1.99, and a steam flow of 0.5 g/min, under which H2 and CO2 yields were 464 and 48 mL/g biomass, respectively. CSSi2 and CSCG5 demonstrated excellent cyclic H2 production stability, maintaining H2 yields around 440 mL/g biomass and low CO2 yields (∼60 mL/g biomass) across five cycles. The study results offer new insights for the high-value utilization of agroforestry biomass and the reduction and resource utilization of industrial waste.

Oxygen vacancy-mediated Mn2O3 catalyst with high efficiency and stability for toluene oxidation

Oxygen vacancy engineering in transition metal oxides is an effective strategy for improving catalytic performance. Herein, defect-enriched Mn2O3 catalysts were constructed by controlling the calcination temperature. The high content of oxygen vacancies and accompanying Mn4+ ions were generated in Mn2O3 catalysts calcined at low temperature, which could greatly improve the low-temperature reducibility and migration of surface oxygen species. DFT theoretical calculations further confirmed that molecular oxygen and toluene were easily adsorbed over defective α-Mn2O3 (222) facets with an energy of −0.29 and −0.48 eV, respectively, and corresponding OO bond length is stretched to 1.43 Å, resulting in the highly reactive oxygen species. Mn2O3-300 catalyst with abundant oxygen vacancies exhibited the highest specific reaction rate and lowest activation energy. Furthermore, the optimized catalyst possessed the outstanding stability, water tolerance and CO2 yield. In comparison with the fresh Mn2O3-300 catalyst, the physical structure and surface property of the used catalyst remained almost unchanged regardless of whether undergoing the stability test at consecutive catalytic runs as well as high temperature, and water resistance test. In situ DRIFTS spectra further elucidated that introducing the water vapor had little effect on the reaction intermediates, indicating the excellent durability of the defect-enriched catalyst.

Reaction synergy of bimetallic catalysts on ZSM-5 support in tailoring plastic pyrolysis for hydrogen and value-added product production

Hydrogen, viz. a green energy carrier, is poised to considerably contribute to the empowerment of a sustainable society. By valorizing plastics, catalytic pyrolysis was envisaged as a promising route to produce green hydrogen and value-added product here. Firstly, the screening of optimal catalyst support (from activated carbon and four zeolites: M-zeolite, B-zeolite, Y-zeolite, ZSM-5) was executed by studying catalytic polypropylene (PP) pyrolysis over supported Ni catalysts. In view of the highest H2 yield (19.2 mmol/gPP) of Ni/ZSM-5, ZSM-5 was put forth as the optimal catalyst support. Then, the identification of optimal active metal (from Ni, Fe, Co, FeNi, FeCo, and NiCo) was performed by running the catalytic PP pyrolysis over ZSM-5 supported catalysts. For catalytic PP pyrolysis, NiCo/ZSM-5 was the optimal catalyst with the highest H2 yield (28.7 mmol/gPP), while the resulting pyrolysis oil demonstrated potential for use as jet fuel. From catalytic pyrolysis of various plastics over NiCo/ZSM-5, polystyrene gave the highest H2 composition (83.2 vol%) of pyrolysis gas and high composition (52.8 area%) of benzocyclobutene (useful chemicals for semiconductor and microelectronics fields) in pyrolysis oil. Lastly, the catalytic mechanism was discussed based on the results, revealing NiCo's remarkable enhancement in H2 yield to 28.7 mmol/g, which surpassed the individual yields of Ni (19.2 mmol/g) and Co (10.2 mmol/g), thereby underscoring the synergistic effect of NiCo. This study supports the recycling of plastics waste into hydrogen energy and valuable products, contributing to environmental pollution mitigation.

Identification of intrinsic vacancies and polarization effect on ternary halo‐sulfur‐bismuth compounds for efficient CO2 photoreduction under near‐infrared light irradiation

AbstractTernary halo‐sulfur bismuth compound Bi19X3S27 (X = Cl, Br, I) with distinct electronic structure and full‐spectrum light‐harvesting properties show great application potential in the CO2 photoreduction field. However, the relationship between photocatalytic CO2 reduction performance and the function of halogens in Bi19X3S27 is still poorly understood. Herein, a series of Bi19X3S27 nanorod photocatalysts with intrinsic X and S dual vacancies were developed, which showed significant near‐infrared (NIR) light responses. The types and concentrations of intrinsic vacancies were confirmed and quantified by positron annihilation spectrometry and electron spin resonance spectroscopy. Experimental results showed that Br atoms and intrinsic vacancies (dual Br‐S) in Bi19Br3S27 could greatly enhance the internal polarized electric field and improve the transfer and separation of photogenerated carriers compared with Bi19Cl3S27 and Bi19I3S27. Theoretical calculations revealed that Br atoms in Bi19Br3S27 could facilitate CO2 adsorption and activation and decrease the formation energy of reactive hydrogen. Among Bi19X3S27 nanorods, Bi19Br3S27 nanorods revealed the highest CO2 photoreduction activity with CO yield rate of 28.68 and 2.28 μmol gcatalyst−1 h−1 with full‐spectrum and NIR lights, respectively. This work presents an atomic understanding of the intrinsic vacancies and halogen‐mediated CO2 photoreduction mechanism.

Investigation of the co-pyrolysis characteristics and gas emission properties of spent bleaching earth and biomass in a thermogravimetric analyser and a fixed bed reactor

The co-pyrolysis of spent bleaching earth (SBE) for adsorption decolorization and biomass can promote the resource utilization of industrial waste. The thermal behaviour and kinetics during the co-pyrolysis of SBE with sawdust (SD) were comparatively evaluated with thermogravimetric analysis at different mixing ratios and heat rates. Activation energies corresponding to the different conversion rates were determined by the distributed activation energy model (DAEM). The pyrolysis yield and evolved gases were measured by a fixed bed pyrolysis system. The results demonstrated that as SBE increased, the activation energy during the initial stage of pyrolysis clearly decreased. The fixed bed isothermal pyrolysis experiment showed that the increase in SBE had a significant effect on the gas production components, resulting in a decrease in CO and CO2 yields and an increase in alkane content. At 800°C, the addition of 30 % SBE had the highest H2 yield, indicating that SBE is a valuable additive.

The role of ceria in promoting Ni catalysts supported on phosphate‐modified zirconia for the partial oxidation of methane

AbstractThe catalytic partial oxidation of methane (POM) is aimed at the mitigation of CH4 (a highly potent greenhouse gas) from the environment and the synthesis of syngas with a high H2/CO ratio. Herein, to enhance the POM reaction, Ni‐supported phosphate‐modified‐zirconia were synthesized with promotor “Ce” to achieve high H2/CO ratio (2.4–3.2). The catalysts were characterized by surface area and porosity, X‐ray diffraction, RAMAN, temperature‐programmed experiments (TPR, CO2‐TPD, and TPO), and TEM. Increasing the ceria addition over 10Ni/PO4 + ZrO2 resulted in lower crystallinity, higher dispersion of active sites, and enhanced the surface area of catalyst. The unique and prominent reducibility and basicity of NiO‐species and surface oxide ions, respectively, are particularly notable at 4 wt.% ceria loading. At a reaction temperature of 600°C, the highest concentration of active sites and a unique concentration of moderate strength basic sites can be achieved with 4 wt.% ceria loading over 10Ni/PO4 + ZrO2. This leads to 44% conversion of CH4, 36% yield of H2, 35% yield of CO2, and H2/CO ratio of 3.16 for the POM reaction. The cyclic H2TPR‐O2TPO‐H2TPR experiment confirms the reorganization of the active site towards high temperature under oxidizing gas O2 and reducing gas H2 gas stream during the POM reaction.

Study on the preparation of CdS/TiO2 corn straw biochar composite materials for photocatalytic reduction of CO2 and collaborative H2 production.

A thermal synthesis method was employed in this work to prepare CdS/TiO2 corn straw biochar photocatalytic composite materials suitable for synergistic hydrogen production with the photocatalytic reduction of CO2. The structure and synergistic reaction of these composite materials were characterized by its photogenerated electron transfer process. Compared with pure TiO2, the energy band gap of the optimal CdS/TiO2 corn straw biochar composite material was reduced to 2.89eV. The heterostructure coupling between TiO2 and CdS in the biochar accelerated the transfer of photogenerated electrons and reduced the recombination rate of photogenerated electrons and holes. Under visible light irradiation, the photocatalytic H2 yield of this CdS/TiO2 corn straw-derived biochar composite material was 1200µmol·h-1·g-1, the CO yield was 150µmol·h-1·g-1, and the CH4 yield was 55µmol·h-1·g-1. The key to this synergistic reaction is the formation of heterojunctions between CdS and TiO2 as well as the rapid oxidation of holes in the composite material caused by the doping of biochar.

WO3/BiOBr S-Scheme Heterojunction Photocatalyst for Enhanced Photocatalytic CO2 Reduction.

The photocatalytic CO2 reduction strategy driven by visible light is a practical way to solve the energy crisis. However, limited by the fast recombination of photogenerated electrons and holes in photocatalysts, photocatalytic efficiency is still low. Herein, a WO3/BiOBr S-scheme heterojunction was formed by combining WO3 with BiOBr, which facilitated the transfer and separation of photoinduced electrons and holes and enhanced the photocatalytic CO2 reaction. The optimized WO3/BiOBr heterostructures exhibited best activity for photocatalytic CO2 reduction without any sacrificial reagents, and the CO yield reached 17.14 μmol g-1 after reaction for 4 h, which was 1.56 times greater than that of BiOBr. The photocatalytic stability of WO3/BiOBr was also improved.

Cu infiltrated Ni-YSZ cathode in CO2 (+H2) stream: Reverse water gas shift vs. CO2 electrolysis

Ni-Yttria Stabilized Zirconia (Ni-YSZ) cermet electrode is known to perform in CO2 (+H2) stream. Introducing H2 in CO2 containing streams enables thermochemical reverse water gas shift reaction (rWGS: CO2 + H2 → CO + H2O) at open circuit. Without the application of any bias, the rWGS responds positively to an increase in temperature and concentrations of CO2 and H2. Application of bias results in enhancement in CO yield above the rWGS baseline value. With bias, both CO2 and H2O electrolysis are enabled. The infiltration of Cu on the Ni-YSZ backbone results in significant improvement of the reaction kinetics and increases H2 and CO production. Impedance analysis indicates that the kinetic limitation originates from reaction steps with slower time constants with Ni{Cu}x-YSZ outperforming Ni-YSZ in this aspect. Cu infiltration suppresses particle coarsening typically observed in Ni-YSZ.

Pulsed laser induced plasma and thermal effects on molybdenum carbide for dry reforming of methane

Dry reforming of methane (DRM) is a highly endothermic process, with its development hindered by the harsh thermocatalytic conditions required. We propose an innovative DRM approach utilizing a 16 W pulsed laser in combination with a cost-effective Mo2C catalyst, enabling DRM under milder conditions. The pulsed laser serves a dual function by inducing localized high temperatures and generating *CH plasma on the Mo2C surface. This activates CH4 and CO2, significantly accelerating the DRM reaction. Notably, the laser directly generates *CH plasma from CH4 through thermionic emission and cascade ionization, bypassing the traditional step-by-step dehydrogenation process and eliminating the rate-limiting step of methane cracking. This method maintains a carbon-oxygen balanced environment, thus preventing the deactivation of the Mo2C catalyst due to CO2 oxidation. The laser-catalytic DRM achieves high yields of H2 (14300.8 mmol h−1 g−1) and CO (14949.9 mmol h−1 g−1) with satisfactory energy efficiency (0.98 mmol kJ−1), providing a promising alternative for high-energy-consuming catalytic systems.

Metal-free, light assisted integrated CO2 reduction coupled with selective oxidation of alcohols under visible light irradiation

An integrated CO2 photoreduction to CO by photo-induced electrons coupled with selective oxidation of aromatic alcohols to carbonyl compounds by photo-generated holes using metal-free anthraquinone (AQ) as an organo-photocatalyst under visible illumination is described. The maximum conversion of benzyl alcohol to benzaldehyde was 65.6% with a selectivity of 98 %, accompanied with the CO yield in gaseous phase 8.67 μmol h−1 g.−1 DFT calculations indicated that initial binding of benzyl alcohol with AQ formed an intermediate IM1 that subsequently interacted with CO2 to give CO2 anion with a free energy change of 0.24 eV. Further, the reduction of CO2 accompanied with the oxidation of benzyl alcohol provided CO and benzaldehyde, respectively along with the release of a water molecule. This concerted metal-free photocatalytic system offers the efficient use of electron-hole pairs for organic synthesis coupled with the CO2 conversion in a cost-effective and sustainable manner.

Disruption Symmetric Crystal Structure Favoring Photocatalytic CO2 Reduction: Reduced *COOH Formation Energy Barrier on Al Doped CuS/TiO2

AbstractHow to break the C═O bond and reduce the energy barrier of *COOH formation is the key to triggering the photocatalytic CO2 reduction (PCR) reaction and subsequent proton‐electron processes, which is as important as overcoming high recombination rate of photocarriers. In order to solve this issue, the symmetric structure of CuS/TiO2 is destroyed by S vacancy and Al doping (denoted as Al‐CuS/TiO2), which significantly expands the electron localization range and promotes the cis‐coordination splitting of Cu 3d orbits. The experimental results show that the CO yield selectivity of ≈90.68% and yield of ≈335.68 µmol·g−1·h−1 on Al‐CuS/TiO2. The redistribution of Cu electron states in specific d/s/p orbitals increases the adsorption of CO2 and reduces the reaction energy barrier of *COOH intermediates, while effectively breaking the C═O bond. Doped Al atoms also serve as adsorption sites for H2O molecules, effectively interleaving the competition with photocatalytic CO2 reduction at the Cu sites is effectively staggered. This study provides a new approach to reduce the energy barrier of *COOH formation and to accelerate the photocarrier migration by destroying local symmetry to adjust the crystal structure, which is important for further improving the activity and selectivity of PCR.

Syntheses of heterometallic organic frameworks catalysts via multicomponent postmodification: For improving CO2 photoreduction efficiency

To enhance the economic viability of photocatalytic materials for carbon capture and conversion, the challenge of employing expensive photosensitizer must be overcome. This study aims to improve the visible light utilization with zirconium-based metal–organic frameworks (Zr-MOFs) by employing a multi-component post-synthetic modification (PSM) strategy. An economical photosensitiser and copper ions are introduced into MOF 808 to enhance its photoreduction properties. Notably, the PSM of MOF 808 shows the highest CO yield up to 236.5 μmol g−1 h−1 with aHCOOH production of 993.6 μmol g−1 h−1 under non-noble metal, and its mechanistic insight for CO2 reaction is discussed in detail. The research results have important reference value for the potential application of photocatalytic metal–organic frameworks.

Efficient synthesis of CO and H2O2 via nanosecond pulsed CO2 bubble discharge

In the context of escalating global efforts to mitigate carbon emissions and explore sustainable energy resources, the transformation of CO2 into valuable chemicals and fuels via plasma technology has garnered significant attention. This study demonstrated a new pathway of CO2 conversion into CO and H2O2 via the bubble-enabled gas-liquid discharge driven by a nanosecond pulse. Results showed that the increased discharge frequency and larger pulse widths could enhance CO2 conversion rates and H2O2 yields, albeit potentially at the cost of reduced energy efficiency. Conversely, the rising time of pulse showed negligible impact on the process, whereas varying gas flow rates significantly altered CO and H2O2 yields, underscoring the nuanced influence of these parameters on the efficiency and selectivity of conversion processes. Through illuminating the dynamics of bubble discharge-assisted CO2 transformation, this study contributes to the broader understanding of gas-liquid discharge driven by nanosecond pulse, underlining its potential for addressing environmental and energy challenges.