Efficient CO2 Reduction Research Articles

Efficient photocatalytic CO2 and Cr(VI) reduction on carbon quantum dots/carbon nitride heterojunctions

Carbon quantum dots (CQDs), known for their exceptional optical properties, hold the potential to enhance light absorption, charges separation and transfer in semiconductor materials. However, using cheap medicinal materials as precursors in the field of photocatalysis to obtain CQDs has seldom concerned. In this study, we utilized biomass-derived CQDs from carbon-rich licorice powder to improve photocatalytic CO2 and Cr(VI) reduction in polymer carbon nitride (PCN). The CQDs/g-C3N4 heterojunctions were synthesized via a hydrothermal method, and the successful fabrication and integration of CQDs on g-C3N4 surfaces were confirmed through detailed characterization. The optimal sample with a licorice powder to PCN mass ratio of 0.05:1 ((50CQDs/CN) demonstrates a tripling in CO2 conversion efficiency under simulated sunlight compared to the reference PCN. Under visible light irradiation, the 50CQDs/CN also performs superior photocatalytic Cr (VI) removal efficiency, which is 2.48 times of that of the reference PCN. This significant boost is attributable to the successful construction of the CQDs/CN heterojunction and the abundance of functional groups on the CQDs surface, which provide more active sites, improve light absorption and increase charges migration rates. The stability of these new photocatalysts was confirmed through repeated photocatalytic cycles, indicating their potential for practical applications. Mechanistic studies reveal insights into the enhanced photocatalytic pathways and intermediate conversion processes. Our findings present a novel, efficient and sustainable route to fabricate g-C3N4-based photocatalysts, offering a promising strategy for further mitigate the greenhouse gas crisis and environmental pollution.

Monolithic Nitrogen-Doped Carbon Electrode with Hierarchical Porous Structure for Efficient Electrochemical CO2 Reduction.

N-doped carbon materials have garnered extensive development in electrochemical CO2 reduction due to their abundant sources, high structural plasticity, and excellent catalytic performance. However, the use of powder carbon materials for electrocatalytic reactions limits their current density and mechanical strength, which pose challenges for industrial applications. In this study, we synthesized a monolithic N-doped carbon electrode with high mechanical strength for efficient electrochemical reduction of CO2 to CO through a simple pyrolysis method, using phenolic resin as the precursor and ZIF-8 as the sacrificial template. At 900 °C, the decomposition of ZIF-8 and the volatilization of Zn atoms promote the formation of a hierarchical porous structure in the carbon matrix, characterized by macropores with extended mesoporous channels. Simultaneously, N active species derived from ZIF-8 are effectively generated around the pores and fully exposed. The efficient mass transfer facilitated by the hierarchical porous structure and high activity of exposed nitrogen species enables efficient conversion of CO2 to CO. When the ZIF-8 content is 30%, the catalyst achieves a Faradaic efficiency of 88.9% for CO at a low potential of -0.7 V (vs RHE), with a CO production rate of 244.05 μmol h-1 cm-2. After 50 h of potentiostatic electrolysis, the current density and FECO remain stable. This work not only provides a strategy for the synergistic effects of hierarchical porous structures and nitrogen doping but also offers an effective method to avoid using powder binders and prepare integrated, stable monolithic electrodes.

Integration of multi-strategy modifications in an Au cocatalyst-loaded 2D/2D BiVO4/P-doped g-C3N4 Z-scheme heterojunction for efficient photocatalytic CO2 reduction

Mimicking nature to fulfill the artificial conversion of CO2 and H2O into solar fuels is an appealing tactic to alleviate energy scarcity and environmental concerns. However, obstacles such as inferior charge separation and light absorption of semiconductors, complex water dissociation, and high CO2 activation energy barrier, immensely restrict photocatalytic CO2 reduction activity. Herein, multi-strategy modifications including element doping, 2D/2D Z-scheme heterojunction construction, and cocatalyst loading, were integrated into an Au-loaded BiVO4/P-doped g-C3N4 composite (Au-BVO/P-CN), which help the photocatalytic system to achieve superior visible light harvest, eminent charge separation, and robust redox capacity. The optimal Au-BVO/P-CN manifests eminent visible light photocatalytic CO2 reduction activity with a CO yield of 20.87 µmol g−1 h−1. The Z-scheme mechanism in Au-BVO/P-CN is verified by the improved photocatalytic CO2 reduction activity and free radical capture experiments. The progressively generated *COOH and *CO intermediatesprobed by in-situ infrared spectroscopy reveal the reason for high CO product selectivity. The synergistic benefits of multi-strategy modifications can inspire future photocatalyst design for efficient solar fuel production.

Development of Ce-doped NH2-UiO-66(Zr) photocatalysts for efficient CO2 reduction in an aqueous system

A series of bimetallic NH2-UiO-66(Zr/Ce) catalysts with varying Zr/Ce molar ratios were synthesized using a straightforward solvothermal method. Among the tested samples, NH2-UiO-66(Zr/Ce1:1) demonstrated superior performance, attributed to its optimized electronic structure, enhanced CO2 adsorption capacity, and efficient separation of photogenerated electron-hole pairs, outperforming the NH2-UiO-66(Zr) variant. The NH2-UiO-66(Zr/Ce1:1) exhibited a bandgap of 2.67 eV, CO2 adsorption capacity of 65.85 cm3/g, and a photocurrent density of 0.43 μA·cm−2. This catalyst achieved achieving a CO production rate of 30.04 μmol·g−1·h−1, representing a 1.66-fold improvement over NH2-UiO-66(Zr), with CO selectivity increasing from 95.2 % to 97.2 %. The results underscore the efficacy of Zr/Ce bimetallic NH2-UiO-66 for CO2 reduction, highlighting the potential of structural modifications in NH2-UiO-66 to enhance photocatalytic performance. This study provides valuable insights into the design and development of advanced catalysts for efficient and sustainable CO2 reduction.

An Efficient Strategy for Tailoring Interfacial Charge Transfer Pathway on Semiconductor Photocatalysts: A Case of (BiFeO3)x(SrTiO3)1−x/Mn3O4

AbstractThe ability to generate heterostructures with a desirable charge transfer pathway is essential for achieving semiconductor photocatalysts with super photocatalytic activity. Herein, it is proposed to realize robust tailoring of effective charge transfer pathway in semiconductor‐based heterostructures via work function regulation, and elucidate the influence of the work function of the semiconductor on the charge transfer mechanism at the heterostructure interface. Specifically, taking type‐II heterostructure SrTiO3/Mn3O4 as an example, introducing BiFeO3 into SrTiO3 effectively regulate the work function of the (BiFeO3)x(SrTiO3)1−x/Mn3O4 (BxT1−x/Mn3O4) solid solution through optimizing the x value. Combined with in situ testing, the results show that the original type‐II heterojunction SrTiO3/Mn3O4 is converted into S‐scheme heterojunction (BiFeO3)0.3(SrTiO3)0.7/Mn3O4 when BiFeO3 is introduced. This increases the work function of the semiconductor, inducing the light‐generated carriers to be guided and separated by the generated built‐in electric field. Therefore, the implementation of this strategy can achieve efficient photocatalytic CO2 reduction. In contrast to pristine SrTiO3/Mn3O4, the (BiFeO3)0.3(SrTiO3)0.7/Mn3O4 heterostructure exhibits a 28‐fold enhancement of in electron consumption rate during photocatalytic CO2 reduction, and the reaction mechanism is suggested. In this study, a strategy for effectively converting interfacial charge transfer pathways in semiconductor photocatalysts is developed to enhance the photoconversion kinetics of CO2 and H2O.

Efficient CO2 reduction to C2 products in a Ce-TiO2 photoanode-driven photoelectrocatalysis system using a Bnanometer Cu2O cathode

Excessive emission of CO2 into the atmosphere has caused significant environmental issues. Photoelectrocatalytic (PEC) reduction of CO2 is an effective method that combines the benefits of both photo- and electrocatalysis. This process effectively minimizes CO2 emissions, enhances the efficiency of CO2 reduction, and diminishes energy consumption during the reduction process. In this work, we have successfully developed a photoelectrochemical (PEC) system, integrating a Ce-doped TiO2 film as the photoanode and Cu2O as the dark cathode, in which the 4 % Ce-TiO2 film photoanode demonstrated the best performance. Electrochemical performance data revealed that the Cu2O catalysts, characterized by their octahedral geometry that optimally presents active sites for CO2 reduction, displayed superior activity in converting CO2. Through a straightforward hydrothermal synthesis, we crafted three-dimensional, flower-like TiO2 thin films. The strategic incorporation of cerium into the TiO2 matrix not only enhanced the material's crystallinity but also resulted in a uniform and compact morphology. This modification significantly narrowed the band gap of TiO2, thereby boosting its photocatalytic capabilities. In the system where a 4 % Ce-TiO2 thin film photoanode was used to drive the PEC reduction of CO2, the octahedral Cu2O catalyst demonstrated the highest selectivity for C2 products. This occurred at a reaction voltage of −1.4 V vs. RHE, resulting in a total Faraday efficiency of 67.33 %. Notably, this Faraday efficiency is double the one produced from the electrocatalytic (EC) system. This work demonstrates that the use of a 4 % Ce-TiO2 film as a photoanode is able to solve the photocorrosion problem of the Cu2O catalyst while employing a photovoltaic combination to enhance the selectivity to C2 products.

Precisely Constructing Molecular Junctions in Hydrogen-Bonded Organic Frameworks for Efficient Artificial Photosynthetic CO2 Reduction.

The development of artificial photocatalysts to convert CO2 into renewable fuels and H2O into O2 is a complex and crucial task in the field of photosynthesis research. The current challenge is to enhance photogenerated charge separation, as well as to increase the oxidation capability of materials. Herein, a molecular junction-type porphyrin-based crystalline photocatalyst (Ni-TCPP-TPyP) was successfully self-assembled by incorporating a nickel porphyrin complex as a reduction site and pyridyl porphyrin as an oxidation site via hydrogen bonding and π-π stacking interactions. The resulting material has a highly crystalline structure, and the formation of inherent molecular junctions can accelerate photogenerated charge separation and transport. Thus, Ni-TCPP-TPyP achieved an excellent CO production rate of 309.3 μmol g-1 h-1 (selectivity, ~100%) without the use of any sacrificial agents, which is more than ten times greater than that of single-component photocatalyst (Ni-TCPP) and greater than that of the most organic photocatalysts. The structure-function relationship was investigated by femtosecond transient absorption spectroscopy and density functional theory calculations. Our work provides new insight for designing efficient artificial photocatalysts, paving the way for the development of clean and renewable fuels through the conversion of CO2 using solar energy.

Bifunctional Au@UiO‐67‐bpy‐Cu Plasmonic Nanostructures for the Solar‐Driven CO2 Reduction to Methanol

AbstractPhotocatalytic CO2 reduction is gaining more interest as a sustainable route to produce methanol, a key starting material in the synthesis of many chemicals and a potential energy carrier. Here, metal‐organic frameworks (MOFs) are used as platforms to integrate plasmonic Au nanospheres and Cu active centers in joint bifunctional hybrid photocatalysts. The methodology followed in obtaining stable Au@UiO‐67‐bpy‐Cu MOFs is based on synthesizing Au@UiO‐67‐bypiridine (bpy) MOFs through a core‐shell procedure, and then modifying them with Cu ions after their coordination with the bpy ligands. This gains the final structure regular coverage of active metal centers that can be excited by the interaction with the plasmonic nanospheres. In the absence of Au, the system demonstrates selectivity toward the formation of methanol under hole scavenger‐free conditions owing to the excitation of the bpy‐Cu complex with visible light. The obtained yield duplicates upon Au nanospheres incorporation as a result of the injection of hot electrons, excited by surface‐mediated intraband processes, to the bpy‐Cu states, thus increasing their CO2 reduction efficiency. Additionally, the catalytic activity remains stable during four consecutive cycles.

Tailoring the local catalytic microenvironment of metal centers NH2 groups to enhance the CO2RR performance of Ni based catalysts

Efficient catalytic reduction of the main greenhouse gas CO2 into high value-added chemicals is an important measure to alleviate the greenhouse effect and energy depletion. Metal nitrogen (M-N4) macrocyclic complexes have attracted increasing attention in the field of electrocatalytic CO2 reduction (CO2RR) due to the precise adjustment of the catalytic active site according to the requirements and the flexible modification of the external ligand structure. Nevertheless, the poor activity and low selectivity of reduction products restrict their widespread application in electrocatalytic CO2RR. Herein, a combination of nanoscale and molecular level method has been developed to construct easily obtainable 4NH2-NiPc/NH2-CNT hybrid material, in which amino groups are connected to provide electrons toward the central Ni-N4 site to promote the electrocatalytic CO2RR catalytic activity. As a result, the catalyst 4NH2-NiPc/NH2-CNT mainly produces CO in the electrocatalytic CO2RR, which exhibits a Faradaic efficiency of CO (FECO) higher than 92 % within a wide overpotential range of −0.70 to −0.95 V vs. RHE, and provides excellent stability with a current density of 12 mA cm−2 at −0.80 V vs. RHE. In addition, 4NH2-NiPc/NH2-CNT reaches its maximum FECO value of 96 % at −0.8 V vs. RHE, which is approximately 3.1 times that of the original unmodified NiPc/CNT, demonstrating excellent promotion of electrochemical performance. Similarly, compared to NiPc/CNT without amino modification, the current density of 4NH2-NiPc/NH2-CNT exceeds it by more than twice. The research results indicate that promoting role of electron substituted amino groups in catalysis dispersion and electronic environment coordination. This study proposes a promising strategy of introducing amino groups into molecular catalysts and hybridizing with carbon nanotube to enhance the electrocatalytic conversion of CO2 to deep reduction products.

Maximizing CO2 Reduction Efficiency: Surface‐Regulated Highly Porous Ag‐Cu Alloy Aerogel Inserted With Multi‐Wall Carbon Nanotube Achieving Nearly Complete CO Selectivity

AbstractThe electrochemical reduction of CO2 (eCO2RR) holds promise in mitigating atmospheric greenhouse gas levels but is hindered by low reaction kinetics, high energy barriers, and poor selectivity. To address these challenges, we developed a novel series of cost‐effective AgCu‐containing metal‐aerogel catalysts with high electrochemical surface areas (ECSA) using a top‐down reduction approach. The Ag85Cu15 aerogel, with an ECSA of 27.41 cm2, achieved a Faraday efficiency (FE%) of 89.3 % for CO production at −0.9 V vs. RHE. Increasing the Cu content to over 50 % in the aerogel matrix produced small amounts of C2H4, with a maximum FE% of 12.9 % at −1.0 V vs. RHE. To further enhance CO2 reduction efficiency, multi‐walled carbon nanotubes (CNT) were incorporated into the Ag85Cu15 alloy aerogel via a hydrothermal treatment. The highly dispersed CNTs within the aerogel matrix increased the ECSA to 57.00 cm2 by forming a well‐defined porous structure through van‐der Waals interactions, improving CO selectivity, and achieving a FE% of 98.6 % at −0.7 V vs. RHE and a partial current density of 9.6 mA/cm2 in an H‐cell. 86 % of the initial FECO% was maintained during an 18 h test with continuous electrolysis.

Ru Single Atom Dispersed Cu Nanoparticle with Dual Sites Enables Outstanding Photocatalytic CO2 Reduction.

Cu-based catalysts are promising candidates for CO2 reduction owing to the favorable energetics of Cu sites for CO2 adsorption and transformation. However, CO2 reduction involving insurmountable activation barriers and various byproducts remains a significant challenge to achieve high activity and selectivity. Herein, a photocatalyst constructed with single-Ru-site-on-Cu-nanoparticle on Bi4Ti3O12 exhibits exceptional activity and selectivity for CO2 conversion to CO. The experimental and theoretical results consistently reveal that the Ru-Cu dual sites allow the rapid transfer of photogenerated carriers for closely interacting with CO2 molecules. Importantly, the Ru-Cu dual sites exhibit extremely strong CO2 adsorption ability, and the Gibbs free energy of the rate-determining step (*CO2 to *COOH) has been significantly reduced, synergistically enhancing the entire CO2 conversion process. The optimal BTOCu2Ru0.5 photocatalyst manifests a high performance for selective reduction of CO2 to CO, yielding 10.84 μmol over 15 mg of photocatalyst in 4 h (180.67 μmol·g-1·h-1) under a 300 W Xe lamp without any photosensitizer and sacrificial reagent, outperforming all bismuth-based materials and being one of the best photocatalysts ever reported under similar reaction conditions. This work presents a strategy for the rational design of multiple metal sites toward efficient photocatalytic reduction of CO2.

Microenvironment modulation of Fe-porphyrinic metal–organic frameworks for CO2 photoreduction

Photocatalytic CO2 reduction to fuels and chemicals is a promising pathway towards carbon resource recovery. Herein, three isomorphic Fe-porphyrinic MOFs, Zr6O4(OH)4(Fe-TCPP)3 (MOF-525, Fe-TCPP = iron 5,10,15,20-tetra(4-carboxyphenyl)-porphyrin), Zr6O4(OH)4(Fe-TCPP-NO2)3 (MOF-525-NO2, Fe-TCPP-NO2 = iron 5,10,15,20-tetra(2-nitro-4-carboxyphenyl)-porphyrin), and Zr6O4(OH)4(Fe-TCBPP-NO2)3 (MOF-526-NO2, Fe-TCBPP-NO2 = iron 5,10,15,20-tetra[4-(4′-carboxyphenyl)-2-nitrophenyl]-porphyrin) were synthesized and employed as photocatalysts for CO2 reduction. Among them, MOF-525-NO2 exhibited the highest catalytic activity with CO and H2 yields of 10.36 and 0.46 mmol·g−1 without any photosensitizer under visible light. Mechanism investigations suggested that the micro-environments of these MOFs were adjusted by introducing porphyrinic fragments with different lengths and functional groups, resulting in stronger CO2 affinity, faster photocurrent response, and efficient photogenerated electron-hole separation and transfer, which finally promoted the efficiency for photocatalytic CO2 reduction.

Disentangling the efficient photocatalytic reduction of CO2 by a stable UiO-66-NH2/Cs2AgBiBr6 catalyst

The compelling global warming crisis as well as extraterrestrial artificial light synthesis craves photocatalytic reduction of CO2 into fuels and value-added chemicals, for which efficient and robust catalysts with high selectivity and conversion rate is a prerequisite but hitherto a rarity. Herein we create a lead-free double metal perovskite of Cs2AgBiBr6, coupling with mesoporous/microporous UiO-66-NH2 MOF to form type-II heterojunctions for efficient photocatalytic reduction of CO2 with a high CO selectivity of 95 % at an electron consumption rate of 33 μmol g−1 h−1 (13.4 μmol g−1 h−1 for CO and 0.72 μmol g−1 h−1 for CH4). Multilayered mesoporous MOF particles manifest higher catalytic activity than their microporous counterparts due to the highly open mesoporous channels and larger pore volume of the former. Femtosecond transient absorption in combination with in situ infrared spectroscopic measurements disentangle the underlying mechanism accounting for the high product selectivity: the ultrafast electron transfer of 12.3 ps from Cs2AgBiBr6 to UiO-66-NH2-2 enables efficient charge separation; primary *COOH intermediates and rapid CO desorption from Bi-based photocatalyst lead to dominant CO product. Moreover, the MOF crystals maintain stability after γ-rays irradiation equivalent of over 45-year accumulation in a typical earth orbit, hinting their promising potential in extraterrestrial artificial light synthesis.

Photocatalytic CO2 Reduction to Solar Fuels by a Chemically Stable Bimetallic Porphyrin-Based Framework.

Porphyrin-based photocatalysts have emerged as promising candidates for facilitating carbon dioxide (CO2) reduction due to their exceptional light-harvesting properties. However, their performance is hindered by complex synthesis procedures, limited structural stability, inadequate CO2 activation capabilities, and a lack of comprehensive structure-property relationships. This study investigates the performance of a porphyrin-based bimetallic framework, [Cu(TPP)Cu2Mo3O11] (TPP = tetrapyridylporphyrin), termed MoCu-1 for photocatalytic CO2 reduction. In addition to its straightforward one-pot synthesis method, the framework shows remarkable chemical stability, particularly notable in alkaline reaction conditions, making it a compelling option for sustainable catalytic applications. By harnessing the superior photoabsorption properties of the porphyrin linker and the abundance of catalytic sites provided by the bimetallic structure, this framework exhibits the potential for enhancing CO2 reduction efficiency. MoCu-1 demonstrates excellent activity in converting CO2 into CO, achieving a maximum yield of 3.21 mmol g-1 with a selectivity of ∼93%. We unravel the intricate interplay of structural features and catalytic activity through systematic characterization techniques and an in situ diffuse reflectance Fourier transform study, which provided insights into the mechanism governing CO2 conversion and was supported by density functional theory calculations. This work contributes to advancing our understanding of photocatalytic processes and offers guidance for designing robust materials for CO2 utilization in renewable energy applications.

Metrics for quantifying the efficiency of atmospheric CO2 reduction by marine carbon dioxide removal (mCDR)

Abstract Marine carbon dioxide removal (mCDR) is gaining interest as a tool to meet global climate goals. Because the response of the ocean–atmosphere system to mCDR takes years to centuries, modeling is required to assess the impact of mCDR on atmospheric CO2 reduction. Here, we use a coupled ocean–atmosphere model to quantify the atmospheric CO2 reduction in response to a CDR perturbation. We define two metrics to characterize the atmospheric CO2 response to both instantaneous ocean alkalinity enhancement (OAE) and direct air capture (DAC): the cumulative additionality (α) measures the reduction in atmospheric CO2 relative to the magnitude of the CDR perturbation, while the relative efficiency (ϵ) quantifies the cumulative additionality of mCDR relative to that of DAC. For DAC, α is 100% immediately following CDR deployment, but declines to roughly 50% by 100 years post-deployment as the ocean degasses CO2 in response to the removal of carbon from the atmosphere. For instantaneous OAE, α is zero initially and reaches a maximum of 40%–90% several years to decades later, depending on regional CO2 equilibration rates and ocean circulation processes. The global mean ϵ approaches 100% after 40 years, showing that instantaneous OAE is nearly as effective as DAC after several decades. However, there are significant geographic variations, with ϵ approaching 100% most rapidly in the low latitudes while ϵ stays well under 100% for decades to centuries near deep and intermediate water formation sites. These metrics provide a quantitative framework for evaluating sequestration timescales and carbon market valuation that can be applied to any mCDR strategy.

Chemically bonded to construct S-scheme CNQDs/Bi2WO6 heterostructure: The Bi-N bonds as interfacial electronic channel boosting the efficient photocatalytic CO2 reduction under simulated sunlight

Photoinduced carrier separation efficiency plays a crucial role in determining the photocatalytic activity of photocatalysts, but it remains a challenge to accurately and efficiently control charge separation. Hence, we successfully prepared S-scheme CNQDs/Bi2WO6 heterostructure via a simple hydrothermal method. The theoretical calculations demonstrate that Bi-N bonds at the interface between CNQDs and Bi2WO6 serve as an electron transfer channel to facilitate charge transfer at the atomic level, which plays a vital role in driving the photoreduction of CO2 to CO. Interestingly, S-scheme heterostructure not only remains strong reducing ability of CNQDs, but also significantly reduces the energy barrier of *CO2 *COOH and release the product CO easily. The CO yield of the CNQDs/Bi2WO6 sample (26.24 µmol/g) was 11 times higher than that of the pure Bi2WO6 (2.43 µmol/g) without any sacrificial agents under 300 W xenon lamp. This work highlights the critical role of chemical bonding interfaces in the design of efficient S-scheme heterostructure photocatalysts.

The Reconstruction of Bi2Te4O11 Nanorods for Efficient and pH-universal Electrochemical CO2 Reduction.

The electrochemical CO2 reduction reaction (CO2RR) to generate chemical fuels such as formate presents a promising route to a carbon-neutral future. However, its practical application is hindered by the competing CO production and hydrogen evolution reaction (HER), as well as the lack of pH-universal catalysts. Here, Te-modified Bi nanorods (Te-Bi NRs) were synthesized through in situ reconstruction of Bi2Te4O11 NRs under the CO2RR condition. Our study illustrates that the complex reconstruction process of Bi2Te4O11 NRs during CO2RR could be decoupled into three distinct steps, i.e., the destruction of Bi2Te4O11, the formation of Te/Bi phases, and the dissolution of Te. The thus-obtained Te-Bi NRs exhibit remarkably high performance in CO2RR towards formate production, showing high activity, selectivity, and stability across all pH conditions (acidic, neutral, and alkaline). In a flow cell reactor under neutral, alkaline, or acidic conditions, the catalysts achieved HCOOH Faradaic efficiencies of up to 94.3 %, 96.4 %, and 91.0 %, respectively, at a high current density of 300 mA cm-2. Density functional theory calculations, along with operando spectral measurements, reveal that Te manipulates the Bi sites to an electron-deficient state, enhancing the adsorption strength of the *OCHO intermediate, and significantly suppressing the competing HER and CO production. This study highlights the substantial influence of catalyst reconstruction under operational conditions and offers insights into designing highly active and stable electrocatalysts towards CO2RR.

Encapsulating Halide Perovskite Quantum Dots in Metal–Organic Frameworks for Efficient Photocatalytic CO2 Reduction

Halide perovskite has shown great potential in photocatalysis owing to its diversity, suitable energy band alignment, rapid charge transfer, and excellent optical properties. However, poor stability, especially under humid conditions, hinders their practical application in photocatalysis. In this work, we report the encapsulation of inorganic–organic hybrid perovskite QDs into MIL-101(Cr) through an in situ growth strategy to prepare a series of MAPbBr3@MIL-101(Cr) (MA = CH3NH3+) composites. The perovskite precursors, i.e., MABr and PbBr2, were successively introduced into the pores of MOF, where the perovskite quantum dots were self-assembled in the confined environment. In photocatalytic CO2 reduction, 11%MAPbBr3@MIL-101(Cr) composite displayed the best performance among the composites with a total CO and CH4 yield of 875 μmol g−1 in 9 h, which was 8 times higher than that of the pure MAPbBr3. Such high gas production efficiency could be maintained for 78 h at least without structural and morphologic decomposition. The remarkable stability and catalytic activity of composites are mainly due to the synergistic effect and improved electron transfer between MAPbBr3 and MIL-101(Cr). Moreover, these composites revealed a novel mechanism, showing switched CH4 selectivity with the controlling of the perovskite location and contents. Those with perovskites encapsulated in the mesopores of MIL-101(Cr) were more preferential for CO production, while those with perovskites encapsulated in both meso- and micropores could produce CH4 dominantly.

Facile and scalable synthesis of N-doped carbon based Ni electrocatalyst for efficient CO2 reduction to CO

Electrochemical reduction of CO2 into valuable chemical products could be realized by reasonable design of effective electrocatalysts with atomically dispersed active sites, but the task presents challenges for chemistry because of the lack of facile and scalable synthetic route. Therefore nitrogen-doped porous carbon supported Ni electrocatalyst is presented via a facile synthetic method. In the first step, commercial carbon black was oxidized by HNO3 to generate organic group followed by absorption of Ni ions. Secondly, calcination under NH3 atmosphere led to N doped carbon based Ni catalyst which exhibited excellent catalytic performance with approximate 95 % Faradaic efficiency for CO, which is helpful for chemists to reasonable design and scalable preparation of economical and efficient catalysts.

Chalcogen heteroatoms doped nickel-nitrogen-carbon single-atom catalysts with asymmetric coordination for efficient electrochemical CO2 reduction

Chalcogen heteroatoms doped nickel-nitrogen-carbon single-atom catalysts with asymmetric coordination for efficient electrochemical CO2 reduction