Efficient Catalytic Sites Research Articles

Exploring complete catalytic cycle of methane oxidation to methanol on Cu2O2 stabilized within MIL-53(Al) framework: A combined DFT and microkinetic study

Although inspiration from copper-based natural enzymes has shown promise in improving catalyst design for methane-to-methanol (MTM) oxidation, high productivity, and selectivity under mild conditions remain a significant challenge. This study constructs the dinuclear copper (Cu2) species stabilized within the metal-organic framework (MOF), MIL-53(Al), containing Cu as efficient catalytic sites and explores the ability of different oxidants (O2, N2O, and H2O2) to oxidize Cu2 into the dicopper-oxo (Cu2O2) species using density functional theory (DFT) calculations. Our results indicate the kinetic and thermodynamic favorability of Cu2O2 species formation using O2 as an oxidant within the MIL-53(Al) framework. Furthermore, the thermal stability of Cu2O2/MIL-53(Al) has been verified via ab initio molecular dynamics (AIMD) calculations. The kinetics of the complete MTM oxidation cycle over Cu2O2/MIL-53(Al) have been studied using both DFT and microkinetic simulation methods. The present study predicts that the C-H activation on the Cu2O2/MIL-53(Al) has a low free energy barrier (0.77 eV) and that the high stability of CH3 and its very low free energy barrier in the C-O coupling step favors the methanol formation over the formaldehyde. More importantly, Cu2O2/MIL-53(Al) exhibits high methanol selectivity owing to the inhibition of CH3 dehydrogenation and low methanol desorption energy (0.21 eV). Microkinetic simulations confirm the methanol production under relatively mild reaction conditions (200–280 K and 1 bar). This work provides insights into the feasibility of selective MTM oxidation over this family of MOF under mild conditions.

Step-by-step transfer of photoexcited electron in donor-acceptor-catalyst configuration covalent triazine framework for efficient photoreduction CO2 to formic acid

Covalent triazine frameworks (CTFs) have great potential for photocatalysis. However, the electron-hole recombination and the lack of efficient catalytic sites constrain the activity and selectivity. Herein, a novel design strategy of donor–acceptor-catalyst (D-A-C) configuration is proposed. This configuration enables the photoexcited electron undergoes stepwise transfer from donor unit to acceptor unit and ultimately reaches catalytic center, effectively inhibiting electron-hole recombination. The proof-of-concept model CTF-TT-Ir, in which thieno[3,2-b]thiophene (TT) serves as the donor unit, triazine as the acceptor unit, and Cp*Ir(bpy) (Ir) as the built-in catalytic site, was prepared for the photocatalytic reduction of CO2 to HCOOH. The stepwise transfer of photoexcited electrons in the ternary structure has been demonstrated through the in-situ XPS measurements and the theoretical calculations. Photoluminescence and photocurrent tests have indicated CTF-TT-Ir exhibits superior charge separation efficiency. Without additional photosensitizer and co-catalyst, the photocatalytic HCOOH yield rate of CTF-TT-Ir reached 245 μmol g−1h−1 (selectivity of 97 %).

Cu Foil Modification By Ag Inkjet Printing for Improved Li Plating in Anode-Free Li Batteries

The rush in the development of new generation of lithium-ion batteries (LIB) is focused on enhancing the specific energy of batteries by employing innovative materials and manufacturing techniques. Anode-free lithium metal batteries (AFLBs) are an emerging technology that can almost double the specific energy of LIBs by eliminating the conventional graphite negative electrode or excess lithium metal 1. However, AFLBs are well-known to suffer of fast capacity decay due to the poor lithium plating and stripping efficiency process associated to the typical porous growth of Li during charge 2. Tuning the interfacial electrochemistry was widely demonstrated to be one the most performing key to enable efficient and smooth Li deposition. In this regards, functional coatings of metals as Sn, Al, Zn and Ag have been widely demonstrated to dramatically improve the quality of Li plating process respect to the neat Cu foil substrate, by forming lithium-rich alloys that provide minimum Li nucleation overpotentials 3. Inkjet printing (IJP) could be a viable technique for electrode fabrication in LIBs manufacturing, being a quick, easy and scalable technology able to deposit both thin film and patterned structures 4. However, very poor attention has been paid so far to the potentiality of IJP for Cu modification for improved Li plating in AFLBs.In this work, we employed a Fujifilm Dimatix inkjet printer to achieve “lithiophilic” coatings of Ag nanoparticles deposited on a Cu foil. In particular, potenziodynamic and galvanostatic electrochemical test were employed to investigate the effect of the Ag printed structures on the Li nucleation overpotential. Ex-situ morphological analysis by electron scanning microscopy (SEM) were usefully employed to investigate the surface evolution of the printed electrodes during lithium alloying and plating. In particular, the effect pf patterned Ag structured rather than fully coated Cu was investigated, revealing that patterning can provide more mechanically robust electrode and efficient catalytic sites for Li electrodeposition respect to fully coated inkjet printed electrodes. Bibliography L. Lin et al., Advanced Materials, 34, 2110323 (2022).L. Su and A. Manthiram, Small Structures, 3, 2200114 (2022).X. Gu, J. Dong, and C. Lai, Engineering Reports, 3, e12339 (2021).P. Viviani, E. Gibertini, F. Iervolino, M. Levi, and L. Magagnin, Journal of Manufacturing Processes, 72, 411–418 (2021).

Nickel single-atom catalysts on porous carbon nanosheets for high-performance lithium-selenium batteries

Lithium-selenium (Li–Se) batteries have attracted intensive attention due to the high theoretical volumetric capacity (3253 mA h cm−3) and high electrical conductivity (1 × 10−3 S m−1) of selenium. However, the shuttle effect, rapid capacity fading and sluggish electrochemical process of the lithium selenides limit its further application. Herein, a catalyst of nickel single atoms (SA)/nitrogen-doped porous carbon nanosheets (Ni-NC) has been constructed and applied as an ideal host for selenium cathode. Such a material allows the adsorption of lithium selenides while the Ni SA serves as efficient catalytic site for the conversion of these selenides during charge/discharge process, as the theoretical calculation results suggest that the Ni SA could enhance the binding energy of the carbon host towards the intermediates and improve the electron transfer. As expected, the Ni-NC/Se cathode exhibits a capacity of 495 mAh g−1 at 0.2 C and 311 mAh g−1 at 4 C and good cycling stability of 225 mAh g−1 after 1000 cycles at 4 C with a Coulombic efficiency of ∼100 %, significantly better than the pure carbon host without Ni SA sites.

An Unlocked Two-Dimensional Conductive Zn-MOF on Polymeric Carbon Nitride for Photocatalytic H2O2 Production.

Developing highly efficient catalytic sites for O2 reduction to H2O2, while ensuring the fast injection of energetic electrons into these sites, is crucial for artificial H2O2 photosynthesis but remains challenging. Herein, we report a strongly coupled hybrid photocatalyst comprising polymeric carbon nitride (CN) and a two-dimensional conductive Zn-containing metal-organic framework (Zn-MOF) (denoted as CN/Zn-MOF(lc)/400; lc, low crystallinity; 400, annealing temperature in oC), in which the catalytic capability of Zn-MOF(lc) for H2O2 production is unlocked by the annealing-induced effects. As revealed by experimental and theoretical calculation results, the Zn sites coordinated to four O (Zn-O4) in Zn-MOF(lc) are thermally activated to a relatively electron-rich state due to the annealing-induced local structure shrinkage, which favors the formation of a key *OOH intermediate of 2e- O2 reduction on these sites. Moreover, the annealing treatment facilitates the photoelectron migration from the CN photocatalyst to the Zn-MOF(lc) catalytic unit. As a result, the optimized catalyst exhibits dramatically enhanced H2O2 production activity and excellent stability under visible light irradiation.

An Unlocked Two‐Dimensional Conductive Zn‐MOF on Polymeric Carbon Nitride for Photocatalytic H2O2 Production

AbstractDeveloping highly efficient catalytic sites for O2 reduction to H2O2, while ensuring the fast injection of energetic electrons into these sites, is crucial for artificial H2O2 photosynthesis but remains challenging. Herein, we report a strongly coupled hybrid photocatalyst comprising polymeric carbon nitride (CN) and a two‐dimensional conductive Zn‐containing metal–organic framework (Zn‐MOF) (denoted as CN/Zn‐MOF(lc)/400; lc, low crystallinity; 400, annealing temperature in °C), in which the catalytic capability of Zn‐MOF(lc) for H2O2 production is unlocked by the annealing‐induced effects. As revealed by experimental and theoretical calculation results, the Zn sites coordinated to four O (Zn‐O4) in Zn‐MOF(lc) are thermally activated to a relatively electron‐rich state due to the annealing‐induced local structure shrinkage, which favors the formation of a key *OOH intermediate of 2e− O2 reduction on these sites. Moreover, the annealing treatment facilitates the photoelectron migration from the CN photocatalyst to the Zn‐MOF(lc) catalytic unit. As a result, the optimized catalyst exhibits dramatically enhanced H2O2 production activity and excellent stability under visible light irradiation.

A layered metal‐organic framework with acidic sites as a multiphase catalyst for Knoevenagel condensation

AbstractA layered metal‐organic framework Zn‐TPN was designed and fabricated by solvothermal reaction. The crystal structure was a lamellar structure, and the unique coordination pattern provided Lewis acid sites that could be employed as efficient catalytic sites. Zn‐TPN displayed a satisfactory catalytic effect for Knoevenagel condensation of malononitrile and benzaldehyde. At 75 °C, the conversion rate reached 96.96 % basing on the acidic sites after 1 hour, and it showed ideal catalytic activities for Knoevenagel condensation containing various aldehydes. Zn‐TPN could be utilized as a promising heterogeneous catalyst for Knoevenagel condensation.

Bridging Au nanoclusters with ultrathin LDH nanosheets via ligands for enhanced charge transfer in photocatalytic CO2 reduction

Au nanoclusters (NCs) bring new opportunities for constructing visible-light photocatalysts for solar-driven CO2 conversion, whereas the agglomeration under illumination and lack of catalytic sites severely hinder their application. One promising approach to address the limitations is the confinement of Au NCs on a heterogeneous substrate with efficient catalytic sites, in which a concomitant bottleneck originates from the electron transfer between Au NCs and catalytic sites determining the charge transfer dynamics. Herein, we develop an effective strategy for grafting Au NCs onto ultrathin layered double hydroxide (LDH) nanosheets via engineering bridging ligands. The bridging ligands function as both surface anchors and electron mediators, which confine and stabilize Au NCs on LDH, as well as facilitate electron transfer from Au NCs to catalytic sites. As a result, the durability and efficiency for photocatalytic CO2 reduction is significantly enhanced. This work provides a fresh hint for stabilizing ultrasmall nanoclusters and facilitating the electron transfer between light-harvesting nanoclusters and catalytic sites through bridging ligands.

In-situ formation of electron-deficient Pd sites on AuPd alloy nanoparticles under irradiation enabled efficient photocatalytic Heck reaction

Plasmonic metal nanoparticles have emerged as important candidates for photocatalysis. Numerous studies have shown that coupling of a plasmonic component (such as Au) as the light energy harvester with a catalytically active metal component (such as Pd) to form hybrid or alloy structures could achieve enhanced catalytic performance. However, the microscopic mechanism relative to the multicomponent plasmonic photocatalysis is still elusive. Here, we find that the electron-deficient Pd sites (Pdδ+) on AuPd alloy nanoparticle were formed under visible light irradiation, which play a decisive role in the AuPd alloy nanoparticle photocatalysis. The in-situ formed Pdδ+ under irradiation offers ideal platform for the catalytic reaction which is comparable to that under thermal heating conditions (>100 °C). The AuPd alloy nanoparticles show excellent conversion and selectivity for visible-light-driven Heck cross-coupling reaction under ambient conditions. The combination of experimental and density functional theory results suggest that the photocatalytic Heck reaction proceeds via a new radical-based single-electron transfer pathway on the AuPd alloy, and the in-situ formed Pdδ+ sites ideally provided efficient catalytic sites for the activation of reactant with much lower activation energy barrier under irradiation. The present work sheds light on the new mechanistic understandings of bimetallic plasmonic photocatalysis.

Cationic MOF-Based Cu/Mo Bimetal Doped Multifunctional Carbon Nanofibers As Efficient Catalyst for High Sulfur Loading Lithium-Sulfur Batteries

High sulfur loading is the key to achieve high energy density promised by lithium-sulfur (Li-S) batteries. However, serious problems such as low sulfur utilization, poor rate performance and cycle stability have been exposed during the scaling up of the sulfur loading for freestanding cathodes. To address these issues, the adsorption/catalytic ability of high sulfur loading cathode toward polysulfides must be improved. Herein, based on excellent properties of cationic MOFs, we proposed that Cu-Mo bimetallic nanoparticles embedded in multifunctional freestanding nitrogen-doped porous carbon nanofiber (Cu-Mo@NPCN) with efficient catalytic sites and high sulfur loading capacity could be prepared by facile transition metal-based anion exchange of cationic MOFs. And the sulfur embedded in Cu-Mo@NPCN was directly used as freestanding sulfur cathodes, enabling a high areal capacity, good rate performance, and cycling stability even under high sulfur loading. The freestanding Cu-Mo@NPCN/10.3S achieves high areal capacity of 9.3 mA h cm-2 and volumetric capacity of 1163 mA h cm-3 at 0.2 C with a sulfur loading of 10.3 mg cm-2. This work provides new insights into freestanding sulfur cathode engineering for high-performance Li-S batteries and would advance the development of cationic MOF-derived bimetallic catalysts in various energy storage technologies. Figure 1

Cu-Mo Bimetal Modulated Multifunctional Carbon Nanofibers Promoting the Polysulfides Conversion for High-Sulfur-Loading Lithium-Sulfur Batteries.

High sulfur loading is essential for achieving high energy density lithium-sulfur (Li-S) batteries. However, serious issues such as low sulfur utilization, poor cycling stability, and sluggish rate performance have been exposed when increasing the sulfur loading for freestanding cathodes. To solve these problems, the adsorption/catalytic ability of high-sulfur-loading cathode toward polysulfides must be improved. Herein, based on excellent properties of cationic MOFs, we proposed that Cu-Mo bimetallic nanoparticles embedded in multifunctional freestanding nitrogen-doped porous carbon nanofibers (Cu-Mo@NPCN) with efficient catalytic sites could be prepared by facile MoO42- anion exchange of cationic MOFs. And, the sulfur embedded in Cu-Mo@NPCN was directly used as self-supporting electrodes, enabling a high areal capacity, good rate performance, and decent cycling stability even under high sulfur loading. The freestanding Cu-Mo@NPCN/10.3S cathode achieves a high volumetric capacity of 1163 mA h cm-3 and a decent areal capacity of 9.3 mA h cm-2 at 0.2 C with a sulfur loading of 10.3 mg cm-2. This work provides an innovative approach for engineering a freestanding sulfur cathode and would forward the development of cationic MOF-derived bimetallic catalysts in various energy storage systems.

Electrocatalytic methane oxidation to formate on magnesium based metal-organic frameworks

The electrochemical methane oxidation reaction is a potential approach for upgrading the nature-abundant methane (CH4) into value-added chemicals, while the activity and selectivity have remained substantially low due to the extremely inert chemical property of CH4. Inspired by the methane mono-oxygenase in nature, we demonstrated Mg-substituted metal–organic frameworks (Mg-MOF-74) containing a uniform distribution of Mg-oxo-Mg nodes as efficient catalytic sites. Compared to MgNi-MOF-74 and Mg(OH)2 without the Mg-oxo-Mg nodes, the Mg-MOF-74 presented a much enhanced CH4 electrooxidation performance, with a unique selectivity of producing formate. The maximum Faradaic efficiency of all liquid products reached 10.9% at 1.60 V versus reversible hydrogen electrode (RHE), corresponding to the peak production rate of 126.6 μmol·h−1·g−1.

Bimetallic Metal–Organic Frameworks MIL-53(xAl–yFe) as Efficient Catalysts for H2S Selective Oxidation

Catalytic oxidation of H2S is a crucial green pathway that can fully convert H2S into value-added elemental S for commercial use. However, achieving high catalytic stability and S selectivity by traditional-metal-based catalysts still remain a major challenge. Herein, a facile one-step solvothermal strategy is designed for the fabrication of bimetallic MIL-53(xAl-yFe) catalysts. The as-synthesized MIL-53(1Al-5Fe) possesses ample coordinatively unsaturated metal sites, which served as efficient catalytic sites for the selective oxidation of H2S. As a result, the representative MIL-53(1Al-5Fe) achieves a S yield of nearly 100% at 100-160 °C with almost no obvious decrease of catalytic stability in the run of 30 h. Under the defined reaction conditions, the bimetallic metal-organic frameworks are obviously superior to MIL-53(Al) (49.3%) and MIL-53(Fe) (70.5%) in S yield. This study suggests that the introduction of elemental Al into MIL-53(xAl-yFe) could effectively modulate the electronic properties and spatial configuration of the catalysts, further conducing the adsorption and activation of H2S and thus accelerating the dissociation of H2S into a key intermediate S* and improving their catalytic performance.

ZnSe Nanorods-CsSnCl3 Perovskite Heterojunction Composite for Photocatalytic CO2 Reduction.

Utilizing sunlight to convert CO2 into chemical fuels could simultaneously address the greenhouse effect and fossil fuel crisis. ZnSe nanocrystals are promising candidates for photocatalysis because of their low toxicity and excellent photoelectric properties. However, pristine ZnSe generally has low catalytic activities due to serious charge recombination and the lack of efficient catalytic sites for CO2 reduction. Herein, a ZnSe nanorods-CsSnCl3 perovskite (ZnSe-CsSnCl3) type II heterojunction composite is designed and prepared for photocatalytic CO2 reduction. The ZnSe-CsSnCl3 type II heterojunction composite exhibits enhanced photocatalytic activity for CO2 reduction with respect to pristine ZnSe nanorods. The experimental characterizations and theoretical calculations reveal that the efficient charge separation and lowered free energy of CO2 reduction facilitate the CO2 conversion on the ZnSe-CsSnCl3 heterojunction composite. This work presents a type II heterojunction composite photocatalyst based on ecofriendly metal chalcogenides and metal halide perovskites. Our study has also promoted the understanding of the CO2 reduction mechanisms on perovskite nanocrystals, which could be valuable for the development of metal halide perovskite photocatalysts.

Non-metal boron atoms on a CuB12 monolayer as efficient catalytic sites for urea production.

An electrocatalytic C–N coupling reaction to convert CO2 and N2 into urea under mild conditions has been proposed to be a promising alternative experimentally, but the development of highly stable, low-cost and high-performance non-metal catalytic sites remains rare and challenging. Herein, a global-minimum CuB12 monolayer with superior stability has been identified based on first-principles computations, and the most significant finding is that the CuB12 monolayer possesses the best catalytic activity among the reported urea catalysts thermodynamically and kinetically. All possible reaction pathways to form urea (NH2CONH2) starting from the CO2 molecule and N2 molecule, including the CO2 pathway, OCOH pathway, CO pathway, NCON pathway and mixed pathway, as well as the kinetic energy barriers of six possible C–N coupling reactions are systematically investigated. Non-metal B atoms at the midpoint of the edges of the squares act as excellent catalytic sites with a limiting potential of urea production of 0.23 V through the CO2 pathway and OCOH pathway and the lowest kinetic energy barrier of C–N bond formation (0.54 eV) through the reaction *CO + *NHNH → *NHCONH. Therefore, this study not only identifies the first non-metal B catalytic sites for urea formation, but also perfects the reaction mechanism to convert CO2 and N2 into urea, which could provide great guiding significance to explore other high-performance urea catalysts.

Single Al atom anchored on defective MoS2: An efficient catalytic site for reduction of greenhouse N2O gas by CO or C2H4 molecules

Single-atom catalysts have gained a lot of interest recently due to their remarkable catalytic activity in a number of chemical processes. Using density functional theory calculations, we investigate an Al-atom doped MoS2 (Al-MoS2) as a potential catalyst for the reduction of nitrous oxide (N2O) by CO or C2H4 molecules. The reduction of N2O over Al-MoS2 is achieved in two steps. N2O is first decomposed on the Al atom to form the Al-O* active site, and then CO or C2H4 interacts with the Al-O* site to generate CO2 or ethylene oxide. The elimination of the O* by a CO molecule on the Al atom requires a negligible activation barrier (0.05 eV), which is lower than previously obtained for noble metals. The adsorbed O* species on Al-MoS2 need a barrier of 0.36 eV to oxidize ethylene, which seems to be overcome at low temperatures. Since the adsorption energy of an O2 molecule is smaller than that of a N2O, N2O is expected to dominantly occupy the active site of Al-MoS2 catalyst. Nonetheless, it is found that the introduction of an O2 molecule increases the activation energies required for the removal of O* by CO and C2H4, and therefore prologs the reaction times.

Reticular chemistry approach to explore the catalytic CO2-epoxide cycloaddition reaction over tetrahedral coordination Lewis acidic sites in a Rutile-type Zinc-phosphonocarboxylate framework

The problem with metal–organic frameworks (MOFs) as CO2-epoxide cycloaddition catalysts is the ambiguous catalytic sites. No system can precisely modify the structures and thus optimize the catalytic performance. Reticular chemistry is recognized as an efficient approach to systematically control the chemical and structural features as well as the properties of porous, crystalline materials. In this work, a Zn-phosphonocarboxylate framework (ZnPC-2) was employed as a prototype structure to investigate the structure–property relationship (SPR). ZnPC-2 is a porous rutile-type framework constructed by 6-connected Zn3(PO3)2(CO2)4 secondary building unit (Zn3-SBU) and tritopic 5-phosphonobenzene-1,3-dicarboxylic acid (H4pbdc). ZnPC-2 showed the ability to catalyze the CO2 cycloaddition reactions and Zn3-SBU was proved as efficient catalytic site. Guided by reticular chemistry, a series of iso-reticular frameworks, including Hpyr@ZnPC-2 (Hpyr = protonated pyrrolidine, Hpyr is fixed by hydrogen bonding interactions to participate the channel into segments); MZnPC-2 (M = Mg, Mn, Fe, Co, Cu; Zn(II) atoms on Zn3-SBU were partially replaced by M) and ZnPC-2-im (im = imidazole, im coordinates to the apical Zn(II) on Zn3-SBU), were designed and successfully synthesized to explore the precise active site. The catalytic performances over these iso-structures together with density functional theory calculations revealed that the dynamical transformation of the apical Zn (II) on Zn3-SBU from tetrahedral geometry to five coordinated model played the pivotal role during the catalytic process.

Van der waals heterostructures by single cobalt sites-anchored graphene and g-C3N4 nanosheets for photocatalytic syngas production with tunable CO/H2 ratio

Graphitic carbon nitride (g-C3N4) is an appealing visible-light photocatalyst for CO2 reduction; however, the high recombination rate of photogenerated electron–hole pairs as well as lack of efficient active sites severely restrict its photocatalytic activity. In this work, reduced graphene oxide (rGO) coordinated with single Co sites is integrated with the g-C3N4 to form van der Waals heterostructures, which offers an ideal interface for efficient charge separation and transfer as well as provide catalytically active sites for photocatalytic CO2 reduction. In such van der Waals heterostructures, the π-π interaction formed at the interfacial of graphene and g-C3N4 can greatly expedite the transfer of photoinduced electrons from light-harvesting g-C3N4 to isolated Co catalytic sites whose coordination environment has been resolved by X-ray absorption near edge structure (XANES) spectroscopy. As a result, the two-dimensional van der Waals heterostructures (Co-rGO/C3N4) exhibit the remarkably enhanced photocatalytic efficiency for CO2 reduction to CO with a TON of 66 as compared with pristine g-C3N4. Remarkably, the ratio of CO/H2 in the produced syngas can be readily tuned ranging from 1:30 to 2:3 by adjusting the content of graphene. This work provides an up-and-coming strategy, which simultaneously improves charge transfer dynamics and creates highly efficient catalytic sites on van der Waals heterostructures, toward the design of efficient and tunable photocatalytic CO2 reduction systems.

Selective Se doping of NiFe2O4 on an active NiOOH scaffold for efficient and robust water oxidation

There remains a challenge in designing electrocatalysts for water oxidation to create highly efficient catalytic sites for the oxygen evolution reaction (OER) while maintaining their robustness at large outputs. Herein, an etching-assisted synthesis approach was developed to integrate highly active NiFe2O4 nanoparticles with a robust and active NiOOH scaffold directly on commercial stainless steel. A precise selenization strategy was then introduced to achieve selective Se doping of NiFe2O4 to further enhance its intrinsic OER activity while maintaining a three-dimensional NiOOH nanosheet array as a robust scaffold for prompt mass transfer and gas evolution. The resulting NiFe2O4−xSex/NiOOH electrode exhibited superior electrocatalytic activity with low overpotentials of 153 and 259 mV to deliver benchmark current densities of 10 and 500 mA cm−2, respectively. More importantly, the catalyst exhibited remarkable durability at a stable current output of 100 mA cm−2 for hundreds of hours. These findings may open up opportunities for exploring efficient and robust electrocatalysts for scalable hydrogen production with practical materials.

Coupling CsPbBr3 Quantum Dots with Covalent Triazine Frameworks for Visible-Light-Driven CO2 Reduction.

Photocatalytic reduction of CO2 into value-added chemical fuels is an appealing approach to address energy crisis and global warming. CsPbBr3 quantum dots (QDs) are good candidates for CO2 reduction because of their excellent photoelectric properties, including high molar extinction coefficient, low exciton binding energy, and defect tolerance. However, the pristine CsPbBr3 QDs generally have low photocatalytic performance mainly due to dominant charge recombination and lack of efficient catalytic sites for CO2 adsorption/activation. Herein, we report a new photocatalytic system, in which CsPbBr3 QDs are coupled with covalent triazine frameworks (CTFs) for visible-light-driven CO2 reduction. In this hybrid photocatalytic system, the robust triazine rings and periodical pore structures of CTFs promote the charge separation in CsPbBr3 and endow them with strong CO2 adsorption/activation capacity. The resulting photocatalytic system exhibits excellent photocatalytic activity towards CO2 reduction. This work presents a new photocatalytic system based on CTFs and perovskite QDs for visible-light-driven CO2 reduction, which highlights the potential of perovskite-based photocatalysts for solar fuel applications.