Activity For CO2 Reduction Research Articles

Silicalite-1 Zeolite Enables Graphitic Carbon Nitride High Selectivity toward CO2 Photoreduction

Carbon monoxide (CO) constitutes a pivotal chemical feedstock, extensively applied in diverse industrial processes such as the Fischer–Tropsch synthesis and the water-gas shift reaction, among others, underscoring its significant role in the chemical industry. Photocatalytic CO2 reduction to produce CO provides an appealing route to consume useless greenhouse gases to valuable chemical feedstock. Regarding the poor selectivity of photocatalytic CO2 conversion and the separation complexity for mixed products, integrating zeolite with semiconductor photocatalyst is first presented to achieve highly selective CO2 photoreduction. Herein, silicalite-1 zeolite with high surface area and excellent CO2 affinity is selected to construct a graphitic carbon nitride/silicalite-1 (CN/S-1) composite via a facile thermal polymerization procedure. The introduced S-1 zeolite enables extended visible light response, enhanced CO2 adsorption, promoted separation and transportation of photoexcited charge carriers for the as-synthesized CN/S-1 composite. The resulting CN/S-1 composite shows significantly improved photocatalytic CO2 reduction activity, yielding CO and CH4 of 452.8 and 11.63 μmol·h-1, respectively. The CO selectivity of the CN/S-1 composite achieves 97.5%, which is maximal so far among the CN-based photocatalysts. In-situ Fourier transformed infrared (in-situ FTIR) spectra characterization reveals the composite prefer to dissociate COOH* to CO upon the incorporation of S-1 zeolite rather than protonation into hydrogenation products.

Electrochemical CO2 reduction to syngas on copper mesh electrode: Alloying strategy for tuning syngas composition

Electrochemical CO2 reduction to synthetic fuels and commodity chemicals using renewable energy offers a promising approach to mitigate CO2 emissions and alleviate energy crisis. Copper-based catalysts show potential for electrochemical CO2 reduction applications, while they face the key challenges of high potential, sluggish kinetics, and poor selectivity. In this work, Cu-Zn, Cu-Co, Cu-Cd, and Cu-In bimetallic catalysts are synthesized via the electrodeposition method for electrochemical CO2 reduction to syngas with adjustable CO/H2 ratios. The bimetallic catalysts are characterized using various techniques to reveal their crystalline structures, morphologies, and elemental compositions. The structure-property-activity relationships of these catalysts are investigated to identify optimal candidates for electrochemical CO2 reduction applications. The findings reveal that the bare Cu mesh catalyst exhibits poor CO2 reduction activity, and the products are dominated by hydrogen evolution reaction (HER). The bimetallic catalysts exhibit improved CO2 reduction performance, with the Cu-Zn and Cu-Cd catalysts showing excellent activity, and the CO/H2 ratio in syngas can be tuned over a wide range by adjusting the applied potential. The Cu-Zn and Cu-Cd catalysts demonstrate outstanding performance with Faradic efficiencies of ∼90 % and ∼80 % towards syngas production with CO/H2 ratios of ∼2.0 and ∼1.5 at −0.81 and −1.01 V vs. RHE, respectively, making the produced syngas suitable for various industrial applications. Stability tests over 450 min show that the Cu-Zn and Cu-Cd catalysts maintain stable catalytic activity, syngas selectivity and CO/H2 ratio, making them robust candidates for syngas production. The results will provide valuable insights into the design of robust catalysts for electrochemical CO2 reduction, offering a promising path toward sustainable syngas production.

Influence of Copper Valence in CuOx/TiO2 Catalysts on the Selectivity of Carbon Dioxide Photocatalytic Reduction Products

The Cu cocatalyst supported on the surface of TiO2 photocatalysts has demonstrated unique activity and selectivity in photocatalytic CO2 reduction. The valence state of copper significantly influences the catalytic process; however, due to the inherent instability of copper’s valence states, the precise role of different valence states in CO2 reduction remains inadequately understood. In this study, CuOx/TiO2 catalysts were synthesized using an in situ growth reduction method, and we investigated the impact of various valence copper species on CO2 photocatalytic reduction. Our results indicate that Cu+ and Cu0 serve as primary active sites, with the selectivity for CH4 and CO products during CO2 photoreduction being closely related to their respective ratios on the catalyst surface. The adsorption and activation mechanisms of CO on both Cu+ and Cu0 surfaces are identified as critical factors determining product selectivity in photocatalytic processes. Furthermore, it is confirmed that Cu+ primarily facilitates CH4 production while Cu0 is responsible for generating CO. This study provides valuable insights into developing highly selective photocatalysts.

Fabrication of Eu-doped 3D flower-like BiOBr photocatalyst for boosted photoreduction CO2 performance

Here, Eu-doped BiOBr photocatalysts were prepared by a one-step hydrothermal method using ethylene glycol as solvent and hexadecyl trimethyl ammonium bromide (CTAB) as Br source. The photocatalytic CO2 reduction performance of the samples under xenon lamp illumination was examined. The results indicate that Eu doped BiOBr exhibits a higher activity of photocatalytic CO2 reduction to CO/CH4 compared to the reference BiOBr. Moreover, The Eu doped BiOBr sample showed a remarkable stability in cycling experiments. This work provides a useful reference for optimizing design of 3D flower BiOBr photocatalyst to improve photocatalytic CO2 reduction efficiency.

Subtle Modifications in Interface Configurations of Iron/Cobalt Phthalocyanine-Based Electrocatalysts Determine Molecular CO2 Reduction Activities.

Strain engineering has emerged as a powerful approach in steering material properties. However, the mechanism and potential limitations remain poorly understood. Here we report that subtle changes in molecular configurations can profoundly affect, conducively or adversely, the catalytic selectivity and product turnover frequencies (TOFs) of CO2 reduction reaction. Specifically, introducing molecular curvature in cobalt tetraaminophthalocyanine improves the multielectron reduction activity by favorable *CO hydrogenation, attaining methanol Faradaic efficiency up to 52 %. In stark contrast, strained iron phthalocyanine exacerbates *CO poisoning, leading to decreased TOFCO by >50 % at -0.5 VRHE and a rapid current decay. The uniform dispersion is crucial for optimizing electron transfer, while activity is distinctly sensitive to the local atomic environment around the active sites. Specifically, local strain either enhances binding to intermediates or poisons the catalytic sites. Our comprehensive analysis elucidates the intricate relationship between molecular structure and activities, offering insights into designing efficient heterogeneous molecular interfaces.

B and P dual sites co-modified g-C3N4 p–n homojunction for photocatalytic CO2 reduction coupled with metronidazole oxidation

The limited active sites and sluggish reaction kinetics greatly restrict the photocatalytic redox activity for CO2 reduction coupled with metronidazole (MNZ) oxidation. Herein, the electron rich P and electron deficient B were synergistically anchored on graphitic carbon nitride for constructing BPCN p − n homojunction with isolated B and P redox dual − sites, which exhibits an excellent CO yield rate of 3.811 μmol g−1h−1 coupled with outstanding MNZ removal rate of 92.60 %. The improvement of photocatalytic redox performance was mainly attributed to two aspects: On the one hand, the construction of p − n homojunction effectively accelerated the separation and migration of carriers; On the other hand, the B and P redox dual − sites availably reduced the reaction energy barrier of CO2 reduction and MNZ oxidation, respectively. Besides, the dual − functional coupled reaction system realized the full utilization of photogenerated charges. This work not only offers new insight for designing efficient p − n homojunction with redox double sites, but also confirms the potential application for congenerous environment renovation and energy conversion.

Single-Atom-Layer Metallization of Plasmonic Semiconductor Surface for Selectively Enhancing IR-Driven Photocatalytic Reduction of CO2 into CH4.

Efficient harvesting and utilization of abundant infrared (IR) photons from sunlight is crucial for the industrial application of photocatalytic CO2 reduction. Plasmonic semiconductors have significant potential in absorbing low-energy IR photons to generate energetic hot electrons. However, modulating these hot electrons to selectively enhance the activity of CO2 reduction into CH4 remains a challenge. Herein, the study proposes a single-atom-layer (SAL) metallization strategy to enhance the generation of IR-driven hot electrons and facilitate their transfer from plasmonic semiconductors to CO2 for producing CH4. This strategy is demonstrated using a paradigmatic W18O49@W-Sn nanowire array (NWA), where Sn2+ ions are grafted onto exposed O atoms on the surface of plasmonic W18O49 to form a surface W-Sn SAL. The incorporation of Sn single atoms enhances plasmonic absorption in IR light for W18O49 NWA. The W-Sn SAL not only promotes CO2 adsorption and reduces its reaction activation energy barrier but also shifts the endoergic CO-protonation process toward an exoergic reaction pathway. Thus, the W18O49@W-Sn NWA exhibits >98% selectivity for IR-driven CO2 reduction to CH4 with an activity over 9.0 times higher than that of bare W18O49 NWA. This SAL metallization strategy can also be applied to other plasmonic semiconductors for selectively enhancing CO2-to-CH4 reduction reactions.

Novel Single Perovskite Material for Visible-Light Photocatalytic CO2 Reduction via Joint Experimental and DFT Study.

Developing advanced and economically viable technologies for the capture and utilization of carbon dioxide (CO2) is crucial for sustainable energy production from fossil fuels. Converting CO2 into valuable chemicals and fuels is a promising approach to mitigate atmospheric CO2 levels. Among various methods, photocatalytic reduction stands out for its potential to reduce emissions and produce useful products. Here, novel perovskite ZnMoFeO3 (ZMFO) nanosheets are presented as promising semiconductor photocatalysts for CO2 reduction. Experimental results show that ZMFO has a narrow bandgap, exceptional visible light response, large specific surface area, high crystallinity, and various surface-active sites, leading to an impressive photocatalytic CO2 reduction activity of 24.87 µmolg-1h-1 and strong stability. Theoretical calculations reveal that CO2 conversion into CO and CH4 on the ZMFO surface follows formaldehyde and carbine pathways. This study provides significant insights into designing innovative perovskite oxide-based photocatalysts for economical and efficient CO2 reduction systems.

Enhancing Internal Electric Field of Metal-Free Donor-Acceptor Conjugated Photocatalysts for Efficient Photocatalytic Degradation of Tetracycline and CO2 Reduction.

Constructing alternating donor-acceptor (D-A) units within g-C3N4 represents an effective strategy for enhancing photocatalytic performance through improved charge carrier separation while concurrently addressing energy shortages and facilitating wastewater remediation. Here, a series of D-A-type conjugated photocatalysts (CNBTC-X) are prepared using g-C3N4 as an acceptor unit and different masses of 5-bromo-2-thiophenecarboxaldehyde (BTC) as a donor unit by a one-step thermal polymerization. CNBTC-50 presents higher photocatalytic properties for CO2 reduction coupled with tetracycline (TC) removal than those of g-C3N4, CNBTC-10, CNBTC-30, and CNBTC-70. The introduction of the unique electron-donor-acceptor structure effectively drives the separation and transfer of photoinduced carriers while reducing the internal carrier transfer hindrance. Photocatalytic experiments reveal that the CNBTC-50 photocatalyst achieves up to 94.6% TC removal under visible light irradiation conditions. Compared with that of the pristine g-C3N4, the photocatalytic degradation reaction rate constant of CNBTC-50 is significantly increased by about 3.87 times. The study examines the influence of various reaction parameters on degradation activity, including catalyst concentration, pH, and TC concentration. Additionally, LC-MS is utilized to perform a comprehensive analysis of the intermediates and pathways involved in TC degradation. Furthermore, CNBTC-50 demonstrates remarkable photocatalytic CO2 reduction activity, achieving rates of 20.83 μmol g-1 h-1 (CO) and 9.36 μmol g-1 h-1 (CH4), which are 10.68 and 5.98 times more efficient than those of g-C3N4, respectively. This work aims to offer valuable guidance for the rational design of nonmetal D-A-structured catalysts and effectively integrates reaction systems to couple CO2 reduction with antibiotic removal.

Hydrogen- assisted synthesis of defective triazine/heptazine homostructured nanosheets for efficient CO2photoreduction.

Homostructure construction has been demonstrated to be an effective way for boosting the photocatalytic activity of polymeric carbon nitride. However, the contribution of the intrinsic activity of molecular fragments in the catalytic performance of homostructured carbon nitride is yet to be explored. In this paper, a facile hydrogen-assisted strategy was used to synthesize triazine/heptazine intermolecular homojunctions (g-C3N4(MU-H)) with an ultrathin and defective structure, via the co-pyrolysis of melamine and urea precursors. Experimental characterizations and theoretical calculations revealed the copolymerization of triazine- and heptazine-based carbon nitride generated a homostructured interface with a large build-in electric field for efficient separation of photogenerated carriers. Due to the synergestic effect between the homostructured interface and nitrogen vacancies, as-synethesized g-C3N4(MU-H) exhibited an outstanding activity for photocatalytic CO2 reduction, with a CO yield rate of 14.45 μmol h-1, which was 23.5 and 3.64 times higher than those of bulk g-C3N4 and g-C3N4(M-H) synthesized from a single precursor, respectively. This study provides a new avenue for optimizing the charge separation efficiency of CO2 photoreduction catalysts by constructing intramolecular homojunction.

Designing S-scheme heterojunction via in situ converting partial NH2-MIL-68 into defective In2O3 for photocatalytic CO2 reduction

Intrinsic characteristics of metal–organic frameworks (MOFs) make them become promising candidates for the application of photocatalytic CO2 reduction. However, their photocatalytic activities are still unsatisfactory due to serious recombination of photogenerated charge carriers and insufficient light absorption. S-scheme heterojunction has demonstrated high superiority in the separation of charge carriers due to its unique structure and interface interaction. Nevertheless, it is difficult to construct it in MOF-based photocatalysts because of high interface connection requirements. Herein, a NH2-MIL-68 (In-MOF) is chosen as the research object. S-scheme heterojunction (In2O3@In-MOF) with oxygen vacancies (OVs) is easily constructed via in situ converting partial In-MOF into defective In2O3. The in-situ derivatization strategy is similar to epitaxial crystal growth, which could avoid drastic changes in the morphology of epitaxial growth rh-In2O3 to ensure the high-quality interface connection. The S-scheme heterojunction not only enhances the separation efficiency of photogenerated charge carriers of In-MOF, but also maintains the high reduction power of its photogenerated electrons as well as expanding its light absorption capacity. Therefore, In2O3@In-MOF exhibits enhanced photocatalytic CO2 reduction activity compared to those of pure In-MOF and In2O3. This work may open a potential pathway for the S-scheme heterojunction designing in the field of photocatalytic CO2 reduction.

UV–visible-infrared light driven photothermal synergistic catalytic reduction of CO2 over Cs3Bi2Br9/MoS2 S-scheme photocatalyst

Photothermocatalytic CO2 reduction has been considered as a green and sustainable strategy for solar-to-fuel conversion, since it can utilize the solar energy to simultaneously provide heat input and produce photogenerated charge carriers. To this end, exploring photothermal catalysts with broad-band absorption, high photo-heat conversion and charge separation efficiency is highly desirable. In this work, an innovative Cs3Bi2Br9/MoS2 (CBB/MoS2) composite has been elaborately constructed to investigate the photothermocatalytic performance towards CO2 reduction. In this composite, MoS2 plays dual roles: with photoinduced self-heating effect, it can act as an extra heater to accelerate the catalytic reaction, and meanwhile serves as a cocatalyst to promote charge separation by forming S-scheme heterojunction with CBB. As expected, the developed CBB/MoS2 composite delivered outstanding photothermocatalytic activity for CO2 reduction without any extra heat input, with the CO production rate reaching 172.79 μmol g−1h−1. As confirmed by experimental tests and theoretical calculations, the superior photothermocatalytic CO2 reduction performance of CBB/MoS2 was attributed to the synergetic effect of high photo-thermo transformation efficiency and highly improved charge separation. The present work offers a potential strategy for developing highly-efficient photothermal catalysts used in artificial photosynthesis.

The Reduced Barrier for the Photogenerated Charge Migration on Covalent Triazine‐Based Frameworks for Boosting Photocatalytic CO2 Reduction Into Syngas

AbstractPhotocatalytic CO2 reduction together with hydrogen generation is a promising approach to generate syngas, the photogenerated electron migration from photosensitizers to the catalytic active sites is the rate‐determining step. Herein, an integrative strategy is presented by covalently grafting metal complexes into donor–acceptor covalent triazine‐based frameworks. The catalytic active sites are integrated with the photosensitizer units by covalent linkages to form an extended π‐conjugated framework, which significantly reduces the energy barrier for the migration of the photogenerated charge carriers, resulting in high activity and durability in photocatalytic CO2 reduction into syngas under visible light irradiation. The CO and H2 evolution amounts in 1.5 h are 1086 and 1042 µmol g−1, respectively, which greatly surpass those in the host‐guest counterparts. Furthermore, selective adsorption for CO2 over N2 renders this photocatalytic system to be effective for syngas production from the simulated flue gas. This study provides new approaches to construct the integrative photocatalytic systems for solar‐to‐chemical energy conversion.

Enhanced Charge Transfer in Poly(Heptazine Imide) Synergistically Induced by Donor-Acceptor Motifs and Ohmic Junctions for Efficient Photocatalytic CO2 Reduction.

Poly(heptazine imide) (PHI) has received widely interest in the photocatalytic CO2 reduction due to its good crystallinity and complete in-plane structure. However, its poor photo-induced carrier separation and migration efficiency and insufficient active sites results in undesirable photocatalytic CO2 reduction performance. Herein, we designed and constructed a novel ohmic junction photocatalyst by integrating melamine edge-modified PHI (mel-PHI) with extended π-conjugated system with TiN (TiN/mel-PHI) for enhancing the photocatalytic CO2 reduction activity. Strikingly, the photocayalytic CO2 reduction yield of the optimal TiN/mel-PHI is 62.64 µmol·g-1·h-1, which is 5.6 and 2.8 times higher than PHI (11.26 µmol·g-1·h-1) and mel-PHI (22.32 µmol·g-1·h-1), respectively. The superior photocatalytic CO2 reduction activity is attributed not only to the formation of D-A structure by the introduction of melamine, which extends the π-conjugation system, alters the electronic structure of PHI, and accelerates the charge separation and migration, but also to the induced internal electric field by ohmic junction further enhances the charge separation and migration efficiency. Meanwhile, the synergistic effect of mel-PHI and TiN enriched the electron number of TiN, reducing the CO2 reduction potential. This work highlights the synergistic enhancement of charge transfer between D-A motifs and ohmic junctions, confirming their potential in optimizing photocatalysts.

Potassium and Boron Co-Doping of g-C3N4 Tuned CO2 Reduction Mechanism for Enhanced Photocatalytic Performance: A First-Principles Investigation.

Graphitic phase carbon nitride (g-C3N4, abbreviated as CN) can be used as a photocatalyst to reduce the concentration of atmospheric carbon dioxide. However, there is still potential for improvement in the small band gap and carrier migration properties of intrinsic materials. K-B co-doped CN (KBCN) was investigated as a promising photocatalyst for carbon dioxide reduction via the Density Functional Theory (DFT) method. The electronic and optical properties of CN and KBCN indicate that doping K and B can improve the catalytic performance of CN by promoting charge migration and separation. In terms of the Gibbs free energy change, the CO2 reduction reaction catalysed by KBCN results in CH3OH, and its optimal pathway is CO2 → *CO2 → *COOH → CO → *OCH → HCHO → *OCH3 → CH3OH. Compared with CN, the doping elements K and B shift the rate-determining step from CO2 → *CO2 to *CO2 → *COOH. The K and B elements co-doping tuned the charge distribution between the catalyst and the adsorbate and reduced the Gibbs free energy of the rate-determining step from 1.571 to 0.861 eV, suggesting that the CO2 reduction activity of KBCN is superior to that of CN. Our work provides useful insights for the design of metallic-nonmetallic co-doped CN for photocatalytic CO2 reduction (CO2PR) reactions.

Water-Induced Switching in Selectivity and Steric Control of Activity in Photochemical CO2 Reduction Catalyzed by RhCp*(bpy) Derivatives.

Photocatalytic reduction of CO2 to formic acid (HCOOH) was investigated in either organic or aqueous/organic media by employing three water-soluble [RhIIICp*(LH2)Cl]+ (LH2 = n,n'-dihydroxy-2,2'-bipyridine; n = 4, 5, or 6) in the presence of [Ru(bpy)3]2+, 1,3-dimethyl-2-phenyl-2,3-dihydro-1H-benzo[d]imidazole (BIH) and triethanolamine (TEOA). Through studying the electron-donating effects of two hydroxyl groups introduced into the bipyridyl ligand, we found that the substituent positions greatly affect both the catalytic efficiency and selectivity in CO2 reduction. More importantly, the HCOOH selectivity shows a dramatic increase from 14 to 83% upon switching the solvent media from pure organic to an aqueous/organic mixture, where the H2 selectivity shows a reverse phenomenon. The enhanced HCOOH selectivity and the drastic decrease in the H2 yield are well rationalized by the fact that the catalytic CO2 hydrogenation is not only driven photochemically via the attack of RhIII(H)Cp*(LH2-·) on CO2 but also partly bypassed by a dark H2 addition reaction yielding [RhIII(H)Cp*(L)]- from [RhIIICp*(L)Cl]+, which was also separately investigated under dark conditions. A combination of experimental and theoretical approaches was made to clarify the pKa values of catalyst intermediates together with the abundant species responsible for the major catalytic processes. Our DFT studies unveil that the exceptionally large structural strain given by the steric contacts between the 6,6'-dihydroxyl groups and the Cp* moiety plays a significant role in bringing about an outstanding catalytic performance of the 6,6'-substituted derivative. The intrinsic reaction coordinate calculations were carried out to clarify the mechanism of hydride transfer steps leading to generating formate together with the heterolytic H2 cleavage steps leading to afford the key hydridorhodium intermediates. This study represents the first report on the water-induced high selectivity in CO2-to-HCOOH conversion, shedding new light on the strategy to control the efficiency and selectivity in the catalysis of CO2 reduction.

Pb-N Chemically Anchors CsPbBr3 on 1D Porous Tubular g-C3N4 for Enhanced Photocatalytic CO2 Reduction.

Halide perovskite CsPbBr3 (CPB) quantum dots (QDs) are considered as a promising candidate for solar-driven CO2 conversion for their unique optoelectronic properties and suitable band structure. However, the CO2 conversion efficiency of pristine CsPbBr3 quantum dots is severely limited due to their rapid electron-hole pair recombination and insufficient active sites. In this study, by immobilizing CPB QDs onto one-dimensional (1D) porous tubular g-C3N4 (TCN), an effective 0D/1D CPB@TCN heterojunction photocatalyst for CO2 reduction is fabricated. Density functional theory (DFT) calculations combined with experimental studies demonstrate that CPB QDs are uniformly anchored on the surface of TCN through Pb-N chemical bonding, resulting in efficient separation and transfer of photogenerated carriers in CPB@TCN photocatalysts. The resultant CPB@TCN photocatalysts exhibit significantly enhanced photocatalytic activity for CO2 reduction with the highest conversion rate of 22.62 μmol·g-1·h-1, which is 5.33-times higher than that of pristine CPB QDs. This work unveils the interfacial bonding mechanism of CPB@TCN heterojunction through Pb-N chemical bond, which provides new insights for the development perovskite-based heterojunction photocatalysts.

Amyloid-Like Protein-Modified Carbon Nitride as a Bioinspired Material for Enhanced Photocatalytic CO2 Reduction.

Modification of g-C3N4 with metal-free biomaterials through an environmentally friendly, low-energy, facile, and rapid single-step method is desired for the preparation of photocatalysts with efficient activity and high selectivity of CO2 reduction but remains a great challenge. Herein, we develop a phase-transitioned protein modification strategy for photocatalysts through superfast amyloid-like protein assembly on surfaces using a one-step sequential coating method. Metal-free carbon nitride/protein heterojunction composite photocatalysts (the phase-transitioned lysozyme (PTL), phase-transitioned bovine serum albumin (PTB), and phase-transitioned ovalbumin (PTO)-coated carbon nitride@SiO2 (CN@SiO2) and bioinspired carbon nitride hollow nanospheres (CN-HS) obtained by etching of CN@SiO2) are prepared using lysozyme, bovine serum albumin, and ovalbumin. The insulator-semiconductor heterojunctions formed at the protein-carbon nitride interface promote the migration and separation of photogenerated charges. The exposed hydrophobic alkyl and aryl groups of the surface-modified protein enable the formation of a CO2-aqueous solution-photocatalyst three-phase interface on the catalyst surface and the exposed -NH2 groups provide sites for CO2 adsorption, which effectively increases CO2 mass transfer and its adsorption as well as hydrophobicity, promoting CO2 reduction and inhibiting hydrogen production. Therefore, protein modification effectively improves the CO2 reduction activity and CO selectivity. For instance, compared to CN-HS, the CO yield of the PTL-modified CN-HS (1346.5 μmol g-1) increased by 24.5 times and the CO selectivity reached 90.5%. These findings represent a critical advancement in the surface modification of carbon nitride for CO2 reduction and the design of bioinspired materials for various applications.

Structurally Asymmetric Ni-O-Mn Node in Metal-Organic Layers on Carbon Nitride Support for CO2 Photoreduction.

The Jahn-Teller (J-T) effect-induced lattice distortion presents an advantageous approach to tailor the electronic structure and CO2 adsorption properties of catalytic centers, consequently conferring desirable photocatalytic CO2 reduction activity and selectivity. Nevertheless, achieving precise J-T distortion control over catalytic sites to enhance CO2 adsorption/activation and target-product desorption remains a formidable challenge. In this work, we successfully induced J-T lattice distortion in neighboring Ni sites by exchanging high-spin Mn2+ into Ni-O-Ni nodes. EXAFS results and DFT simulations revealed that the highly asymmetric Ni-O-Mn nodes induced structural contraction (shortened Ni-O bonds) in the adjacent Ni-O lattice. The magnetic hysteresis loop (M-H) confirmed that the introduction of Mn2+ increased the number of spin electrons, thereby increasing the magnetization intensity. The spin mismatch between photogenerated electrons and holes suppressed charge recombination. Significantly, the d orbitals of the Ni sites in the Ni-O-Mn nodes exhibited strong orbital hybridization with the p orbitals of CO2, as evidenced by the enhanced d-p orbital overlap, facilitating rapid CO2 adsorption and activation. Consequently, the sample featuring lattice-mismatched Ni-O-Mn nodes exhibited an 8.79-fold enhancement in CO production rate compared to the Ni-O-Ni nodes, in the absence of cocatalysts and sacrificial reagents.

TM@MoSSe (TM = Ni, Fe) as novel electrocatalysts for reduction of CO2 to CO: A DFT study

It is crucial to develop highly efficient, selective and low-overpotential electrocatalysts for CO2 reduction. This paper proposes an efficient iron and nickel single-atom catalyst using Janus MoSSe as the substrate to reduce CO2 to CO by using DFT calculations. The adsorption of a single TM atom like Fe, Co, Ni, Ru, Rh, Pd, Os, Ir and Pt on Janus MoSSe monolayer results in a decrease in band gap, which may accelerate the catalytic CO2 reduction. The excellent catalytic activity of Fe@MoSSe and Ni@MoSSe is owing to the high d-band center and hence the strong TM-CO2 bonding. The asymmetric structure of Janus MoSSe creates the local built-in electric field, which further increases by about 8% or 0.8% after the adsorption of single Ni or Fe atom so as to afford the better electrocatalytic performances for reduction of CO2 to CO in both TM modified systems. So, this work proposes the catalysts Fe@MoSSe and Ni@MoSSe with good selectivity and activity for CO2 reduction by revealing their underlying mechanisms, and Janus MoSSe may be used as a potential substrate material for CO2 reduction catalysts.