Digital carbon neutrality: evidence of carbon emission reduction based on digital inclusive finance.

As a powerful engine for economic reform and curbing carbon emissions, digital inclusive finance provides solid support for achieving the goal of digital carbon neutrality. This study reveals the positive effect of digital inclusive finance on carbon emission reduction and the deeper reasons behind it by digging deeper into the panel data of 213 cities in China. The study adopts advanced empirical analysis methods to rigorously test the association between digital inclusive finance and carbon emissions. The results show that there is a strong positive correlation between the booming development of digital inclusive finance and the significant decline in carbon emissions. This finding remains solid after several rounds of robustness tests, which fully proves the reliability of the research results. Further mechanism analysis reveals the multiple paths of digital financial inclusion on carbon emission reduction. First, it promotes the optimization and upgrading of industrial structure by optimizing the allocation of financial resources, thus reducing the proportion of high-carbon emission industries. Second, digital inclusive finance attracts more foreign capital inflows and introduces advanced low-carbon technologies and management experience, further promoting the development of low-carbon economy. In addition, the study also found that the differences between different cities in terms of geographic location and city size have a significant impact on the carbon emission reduction effect of digital inclusive finance. In particular, the carbon emission reduction effect of digital inclusive finance is particularly significant in western regions, central cities, and first-tier cities. In response to these findings, this paper proposes a series of targeted policy recommendations. First, the financial service system should be further optimized to increase the coverage and penetration of digital inclusive finance, especially in less developed regions and small- and medium-sized cities. Second, regional policy synergies should be strengthened to form a strong synergy to promote the development of a low-carbon economy. In addition, it should guide capital flows to low-carbon industries and encourage enterprises to increase green technology research and development and application, while actively promoting low-carbon consumption concepts and guiding consumers to form green consumption habits. Through the implementation of these measures, it is expected that the potential of digital inclusive finance in the development of a low-carbon economy will be further stimulated, making a greater contribution to the realization of the goals of carbon peaking and carbon neutrality.

A Primary Report 166 Cases of Abdominal or Pelvic Neuroblastoma Surgery Utilizing the International Neuroblastoma Surgical Report Form (INSRF).

BACKGROUND AND AIMS: Surgery is pivotal in the management of neuroblastoma (NB), particularly in patients with Image-Defined Risk Factors (IDRFs). The International Neuroblastoma Surgical Report Form (INSRF) was introduced to enhance surgical reporting quality and analyze the defining role of extensive surgery in NB. This study reports our experience with INSRF and explores new criteria for evaluating the extent of surgical resection. METHODS: INSRF was deployed to critically analyze 166 patients with abdominal or pelvic NB who underwent surgery at our department between October 2021 and June 2023. Patient demographics, clinical characteristics, surgical datasets, and postoperative complications were described in detail. Receiver operating characteristic (ROC) curves were used to explore a new method to evaluate the extent of resection. A questionnaire was formulated to obtain attitudes/feedback and commentary from surgical oncologists with INSRF. RESULTS: 166 neuroblastoma patients with a median disease age 36.50 months. This study collated 320 INSRF reports. Among the 166 index cases, 137 were documented by two surgeons, with a concordance rate of 16.78%. Items with high inconsistency were (i) the extent of tumor resection (29.20%), (ii) renal vein involvement (25.55%), (iii) abdominal aorta encasement (16.79%), and (iv) mesenteric infiltration (17.52%). According to INSRF, the extent of resection was complete excision in 86 (51.81%) patients, minimal residual tumor < 5 cm3 in 67 (40.36%) patients, and incomplete excision > 5 cm3 in 13 (7.83%) patients. In ROC curve analysis, the number of vessels encased by tumors > 3 had a high predictive value in determining that a tumor could not be completely resected (AUC 0.916, sensitivity 0.838, specificity 0.826) using INSRF as the gold standard reference. The questionnaires showed that surgeons agreed that the extent of resection and tumor involvement of organ/vascular structures were important, while the definition and intervention(s) of intraoperative complications were less operational and understandable. CONCLUSIONS: INSRF has significant clinical application in neuroblastoma surgery. The extent of resection can be predicted based on the number of tumor-encased blood vessels. Supplementary information should be considered with the INSRF to aid practitioner reporting. Multicenter studies are needed to explore the defining role of INSRF in NB surgical management.

Structuring Cu Membrane Electrode for Maximizing Ethylene Yield from CO2 Electroreduction.

Electrocatalytic ethylene (C2H4) evolution from CO2 reduction is an intriguing route to mitigate both the energy and environmental crises; however, to acquire industrially relevant high productivity and selectivity at low energy cost remains to be challenging. Membrane assembly electrode has shown great prospect and tailoring its architecture for maximizing C2H4 yield at minimum voltage with long-term stability becomes critical. Here a freestanding Cu membrane cathode is designed and constructed by electrochemically depositing mesoporous Cu film on Cu foam to simultaneously manage CO2, electron, water, and product transport, which shows an extraordinary C2H4 Faradaic efficiency of 85.6% with a full cell power conversion efficiency of 33% at a current density of 368 mA cm-2, heading the techno-economic viability for electrocatalytic C2H4 production.

Electrochemiluminescence Analysis of Multiple Glycans on Single Living Cell with a Closed Bipolar Electrode Array Chip.

The profiling of multiple glycans on a single cell is important for elucidating glycosylation mechanisms and accurately identifying disease states. Herein, we developed a closed bipolar electrode (BPE) array chip for live single-cell trapping and in situ galactose and sialic acid detection with the electrochemiluminescence (ECL) method. Methylene blue-DNA (MB-DNA) as well as biotin-DNA (Bio-DNA) codecorated AuNPs were prepared as nanoprobes, which were selectively labeled on the cell surface through chemoselective labeling techniques. The individual cell was captured and labeled in the microtrap of the cathodic chamber, under an appropriate potential, MB molecules on the cellular membrane underwent oxidation, triggering the reduction of [Ru(bpy)3]2+/TPA and consequently generating ECL signals in the anodic chamber. The abundance of MB groups on the single cell enabled selective monitoring of both sialic acid and galactosyl groups with high sensitivity using ECL. The sialic acid and galactosyl content per HepG2 cell were detected to be 0.66 and 0.82 fmol, respectively. Through comprehensive evaluation of these two types of glycans on a single cell, tumor cells, and normal cells could be effectively discriminated and the accuracy of single-cell heterogeneous analysis was improved. Additionally, dynamic monitoring of variations in galactosyl groups on the surface of the single cell was also achieved. This work introduced a straightforward and convenient approach for heterogeneity analysis among single cells.

Renal preservation in high-risk retroperitoneal neuroblastoma: Impact on survival and local progression.

BACKGROUND: Retroperitoneal neuroblastomas predominantly encroach upon critical structures, complicating surgical intervention and yielding elevated rates of surgery-associated complications. The kidney and renal vasculature represent the organs most susceptible to retroperitoneal neuroblastoma infiltration. Prior investigations have revealed high nephrectomy incidence and a paucity of renal-preserving surgical approaches. METHODS: A retrospective analysis was undertaken, examining patients with retroperitoneal neuroblastoma who underwent surgical procedures from January 2018 to December 2019 at Beijing Children's Hospital. RESULTS: The study encompassed 225 patients, presenting a median age of 37 months. Concomitant nephrectomy and tumor excision were performed in 11 (4.9%) patients, while 214 (95.1%) patients successfully preserved their kidneys during surgery. Among the patients who retained their kidneys, 8 (3.5%) experienced renal atrophy postoperatively. Predominant rationales for simultaneous nephrectomy included tumor invasion into the renal hilum (n = 9), markedly diminished function of the affected kidney (n = 2), and ureteral infiltration (n = 1). Subsequent to a median follow-up duration of 43 months, the outcomes demonstrated no considerable divergence in overall survival (OS) and event-free survival (EFS) between the nephrectomy and renal-preserving cohorts among high-risk (HR) neuroblastoma patients. Among the eight HR children who underwent nephrectomy, four experienced local recurrence. The nephrectomy cohort exhibited a significantly elevated cumulative incidence of local progression (CILP) relative to the renal-preserving group. CONCLUSION: In high-risk retroperitoneal neuroblastoma patients, nephrectomy does not enhance CILP, EFS, or OS. The guiding surgical tenet involves preserving the kidney while striving for gross total resection of the primary neoplasm, barring instances of severe deterioration of the affected renal function.

Tuning Redistribution of CuOx Nanoparticles on TiO2 Support.

Nanoparticles exhibit unique catalytic performance, depending on their nanoscale size. However, controlling the particle size of the supported catalysts is still challenging. Here, we present a method for tunable redistribution of CuOx nanoparticles on rutile TiO2 support by physically adding pristine TiO2. The redistribution is driven by the work function difference (WFD) between the TiO2 support and the TiO2 additive, both of which exhibit distinct values, as determined through Kelvin probe force microscopy and electron binding energy analysis. Addition of TiO2 with lower work function (rutile) promotes electron transfer toward the CuOx/TiO2 composite, resulting in nanoparticle aggregation, while addition of TiO2 with higher work function (anatase) results in smaller CuOx on TiO2. The increase in particle size and electron density of CuOx, driven by the addition of rutile TiO2, promoted the complete conversion of nitrobenzene (100%) within 5 h. This is 2.7 times that of dispersed and degraded CuOx driven by mixing with anatase TiO2 (36.9%).

Strong Metal-Support Interaction Facilitated Multicomponent Alloy Formation on Metal Oxide Support.

Multicomponent alloy (MA) contains a nearly infinite number of unprecedented active sites through entropy stabilization, which is a desired platform for exploring high-performance catalysts. However, MA catalysts are usually synthesized under severe conditions, which induce support structure collapse and further deteriorate the synergy between MA and support. We propose that a strong metal-support interaction (SMSI) could facilitate the formation of MA by establishing a tunnel of oxygen vacancy for metal atom transport under low reduction temperature (400-600 °C), which exemplifies the holistic design of MA catalysts without deactivating supports. PtPdCoFe MA is readily synthesized on anatase TiO2 with the help of SMSI, which exhibits good catalytic activity and stability for methane combustion. This strategy demonstrates excellent universality on various supports and multicomponent alloy compositions. Our work not only reports a holistic synthesis strategy for MA synthesis by synergizing unique properties of reducible oxides and the mixing entropy of alloy but also offers a new insight that SMSI plays a vigorous role in the formation of alloy NPs on reducible oxides.

Pediatric adrenocortical carcinoma: clinical features and application of neoadjuvant chemotherapy.

OBJECTIVE: To summarize the clinical characteristics of children with adrenocortical carcinoma (ACC) and preliminarily explore the indications for and efficacy of neoadjuvant chemotherapy in certain patients. METHODS: The data of 49 children with adrenocortical tumors (ACT) in the past 15 years were retrospectively analyzed, and after pathology assessment using Weiss system grading, 40 children diagnosed with ACC were included. Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 and three-dimensional (3D) reconstruction of contrast-enhanced computed tomography data were used to evaluate the response to neoadjuvant chemotherapy. RESULTS: Forty patients (17 males, 23 females) with ACC were enrolled. Abnormal hormone levels were common in children with ACC (n = 31), and in terms of clinical presentation, sexual precocity was the most common (n = 14, 35.0%), followed by Cushing's syndrome (n = 12, 30.0%). Seven of 40 children received neoadjuvant chemotherapy due to a maximum lesion diameter greater than 10 cm (n = 4), invasion of surrounding tissues (n = 2), intravenous tumor thrombus (n = 2), and/or distant metastasis (n = 2); 2 patients achieved partial response, and 5 had stable disease according to the RECIST 1.1 standard. Furthermore, 3D tumor volume reconstruction was performed in 5 children before and after neoadjuvant chemotherapy. Tumor volumes were significantly reduced in all 5 children, with a median volume reduction of 270 (interquartile range, IQR 83, 293) (range: 49-413) ml. After surgery with/without chemotherapy, the 5-year overall survival rate for all children was 90.0% (95% CI-confidence interval 80.0-100.0%), and the 5-year event-free survival rate was 81.5% (95% CI 68.0-97.7%). CONCLUSION: In the diagnosis and treatment of pediatric ACC, a comprehensive endocrine evaluation is necessary to facilitate early diagnosis. Surgery and chemotherapy are important components of ACC treatment, and neoadjuvant chemotherapy should be considered for children with ACC who meet certain criteria, such as a large tumor, distant metastases, or poor general condition.

Evaluating the clinical efficacy and limitations of indocyanine green fluorescence-guided surgery in childhood hepatoblastoma: A retrospective study.

BACKGROUND: Indocyanine green (ICG) fluorescence guided surgery has been used to treat childhood hepatoblastoma (HB), but the advantages and disadvantages of this technique have not been fully discussed. The purpose of this study is to summarize the experience and to explore the clinical value of this technique for children with HB. METHODS: 45 children with HB who underwent ICG fluorescence guided surgery (n = 22) and general surgery (n = 23) in our center from January 2020 to December 2022 were enrolled retrospectively. RESULTS: All the liver tumors in the ICG group showed hyperfluorescence, including total and partial fluorescent types. With the help of ICG navigation, minimally invasive surgery was performed in 3 cases. 18.2 % of cases with tumors could not be accurately identified under white light, but could be identified by fluorescence imaging. The fluorescent cutting lines of 59.1 % of cases were consistent with the safe cutting lines. In 36.4 % of cases, the fluorescence boundary was not clear because of tumor necrosis. In 36.4 % of cases, the fluorescence could not be detected on the inner edge of the tumors because of the depth. A total of 29 ICG (+) suspicious lesions were found during the operations, of which 5 were true positive lesions. CONCLUSION: ICG fluorescence guided surgery is safe and feasible in children with HB. This technique is helpful for locating tumors, determining margin and finding small lesions with negative imaging, especially in minimally invasive surgery. However, preoperative chemotherapy, tumor necrosis, tumor depth, and ICG administration impact the effect of fluorescence imaging.

Synergistic ROS generation and directional overloading of endogenous calcium induce mitochondrial dysfunction in living cells.

Taking advantage of endogenous Ca2+ to upregulate intramitochondrial Ca2+ level has become a powerful mean for mitochondrial dysfunction-mediated tumor therapy. However, the Ca2+ entered into mitochondria is limited ascribing to the uncontrollability and non-selectivity of endogenous Ca2+ transport. It remains a great challenge to make the maximum use of endogenous Ca2+ to ensure sufficient Ca2+ overloading in mitochondria. Herein, we smartly fabricate an intracellular Ca2+ directional transport channel to selectively transport endogenous Ca2+ from endoplasmic reticulum (ER) to mitochondria based on cascade release nanoplatform ABT-199@liposomes/doxorubicin@FeIII-tannic acid (ABT@Lip/DOX@Fe-TA). In tumor acidic microenvironment, Fe3+ ions are firstly released and reduced by tannic acid (TA) to Fe2+ for ROS generation. Subsequently, under the NIR light irradiation, the released ABT-199 molecules combine with ROS contribute to the formation of IP3R-Grp75-VDAC1 channel between ER and mitochondria, thus Ca2+ ions are directionally delivered and intramitochondrial Ca2+ level is significantly upregulated. The synergetic ROS generation and mitochondrial Ca2+ overloading effectively intensifies mitochondrial dysfunction, thereby achieving efficient tumor inhibition. This work presents a new insight and promising avenue for endogenous Ca2+-involved tumor therapies.

Surgical treatment of postoperative intractable bile leakage after liver tumor surgery in children.

Aim: To summarize systematically our six-year experience in the surgical treatment of postoperative bile leakage after liver tumor surgery in children, and explore its reoperation approach and treatment effect. Methods: The clinical data of 6 patients with postoperative bile leakage cured by surgery from January 2016 to January 2022 were reviewed retrospectively. Results: Among the six pediatric patients with postoperative bile leakage cured by surgery, four were male (67%) and two were female (33%). All patients underwent complex segmentectomy. The median time to bile leakage was 14 days (range, 10 to 32), and the daily drainage volume was stable from 170 ml to 530 ml per day. After conservative treatment failed, four patients received biliary-enteric anastomosis (patients 1, 3, 4, and 6), and two patients received bilio-cholecyst anastomosis (patients 2 and 5). All six patients were successfully treated with reoperation, and five patients were alive and without recurrence, while one patient was lost to follow-up due to abandoned treatment. Conclusion: Our study suggests that surgery is a reliable and effective treatment for postoperative intractable bile leakage in children undergoing complex segmentectomy. Bilioenteric anastomosis is the most common technique for bile leakage, and bilio-cholecyst anastomosis is a feasible and effective surgical approach. These findings have important implications for the management of postoperative complications in pediatric patients undergoing complex segmentectomy.

Clinical application of indocyanine green fluorescence imaging navigation for pediatric renal cancer.

Background: Indocyanine Green (ICG) fluorescence imaging has been widely used in the surgical treatment of adult renal cancers, but its application in pediatric renal cancers has rarely been reported. This study aims to summarize the experience of ICG fluorescence imaging in pediatric renal cancers and explores its safety and feasibility. Methods: The clinical features, surgical information, ICG administration regimen, near infrared radiography data in vivo and ex vivo and pathological results of children with renal cancers using ICG navigation were analyzed and summarized. Results: There were 7 cases of renal cancer, including 4 cases of Wilms tumor (WT), 1 case of malignant rhabdoid tumor of the kidney (MRTK) and 2 cases of renal cell carcinoma (RCC). By intraoperative intravenous injection of ICG from 2.5 to 5 mg (0.05-0.67 mg/kg), the tumors were visualized in 6 cases in vivo or ex vivo, and the tumor visualization failed in 1 case due to renal artery embolization before operation. By injecting 5 mg ICG into the normal renal tissue during the operation, 3 patients achieved fluorescent localization of sentinel lymph nodes. No ICG-related adverse reactions were found in any of the patients during or after operation. Conclusions: ICG fluorescence imaging is safe and feasible for renal cancers in children. Intraoperative administration can achieve tumor and sentinel lymph node visualization which will facilitate the development of nephron sparing surgery (NSS). However, the technique is affected by ICG dose, anatomical conditions around the tumor, and renal blood flow. A proper dose of ICG and the complete removal of perirenal fat are helpful for the fluorescence imaging of the tumor. It has potential in the operation of renal cancer in children.

Safety and feasibility of laparoscopic resection of abdominal neuroblastoma without image-defined risk factors: a single-center experience.

OBJECTIVE: To explore the criteria, safety and efficacy of laparoscopic surgery in pediatric neuroblastoma (NB). METHODS: A retrospective study of 87 patients with NB without image-defined risk factors (IDRFs) between December 2016 and January 2021 at Beijing Children's Hospital was conducted. Patients were divided into two groups according to the surgical procedure. RESULTS: Between the 87 patients, there were 54 (62.07%) cases in the open surgery group and 33 (37.93%) cases in the laparoscopic surgery group. There were no significant differences between the two groups regarding demographic characteristics, genomic and biological features, operating time or postoperative complications. However, in terms of intraoperative bleeding (p = 0.013) and the time to start postoperative feeding after surgery (p = 0.002), the laparoscopic group was obviously better than the open group. Furthermore, there was no significant difference in the prognosis between the two groups, and no recurrence or death was observed. CONCLUSION: For children with localized NB who have no IDRFs, laparoscopic surgery could be performed safely and effectively. Surgeons who are skilled in this can help children reduce surgical injuries, speed up postoperative recovery, and obtain the same prognosis as open surgery.

Tumor-Background Ratio is an effective method to identify tumors and false-positive nodules in indocyanine-green navigation surgery for pediatric liver cancer.

Background: Indocyanine green (ICG) navigation surgery has been used for hepatoblastoma (HB) in children but the technique has been reported for using in other childhood liver cancers were rare. This article summarizes the application experience of ICG in HB and other childhood liver cancers in children and explores the role of fluorescence intensity measurement in identifying tumors. Methods: To summarize the clinical experience of children with liver cancer treated by ICG navigation surgery. The tumor and its surrounding tissue were photographed by near infrared during the operation. The fluorescence intensity of tumors, ICG (+) lesions and the normal liver was measured, and the Tumor-Background Ratio (TBR) was calculated. Results: A total of 11 children with liver cancer were injected intravenously with ICG 1 day before operation. With the help of ICG fluorescence navigation, there was no residual tumor at the surgical margin for all the children. Total fluorescence was seen in 2 cases, rim fluorescence in 2 cases, and partial fluorescence in 7 cases. 19 ICG false-positive nodules were found on the resection stump or residual liver tissue in 5 cases, and the TBR value of tumors was higher than that of false- positive nodules. 10 children have survived without disease. Conclusion: ICG navigation surgery is safe and feasible for liver cancer in children, which can enhance the visualization of the tumor during operation and provide more information about the location and boundaries of the tumor. This technique also has limitations, which can be affected by chemotherapy, tumor location, ICG administration regimen, and equipment. TBR is an effective method to identify tumor and non-cancerous lesions.

Electron-Level Mechanistic Insights into Ce Doping for Enhanced Efficiency Degradation of Bisphenol A under Visible Light Irradiation.

Bismuth oxybromide (BiOBr), with its special layered structure, is known to have potential as a visible-light-driven photocatalyst. However, the rapid recombination and short lifetime of the photogenerated carriers of BiOBr restrict its photocatalytic efficiency for the degradation of organic pollutants. Given the similar ionic size of Ce and Bi, Ce atoms might be easily introduced into the crystal of BiOBr to tailor its band structure. In this study, Ce doped BiOBr (Ce-BiOBr) samples with different percentages of Ce contents were prepared via a hydrothermal method. The intrinsic photocatalytic efficiency of Ce0.2-BiOBr for the degradation of bisphenol A (BPA) was 3.66 times higher than that of pristine BiOBr under visible light irradiation. The mechanism of Ce-doping modification for the enhanced photocatalytic performance was demonstrated based on a series of experiments and DFT calculation. The narrowed bandgap, the enhanced charge separation efficiency and Ce-doping energy level contributed to the remarkable photocatalytic performance of Ce-BiOBr.

Targeted killing of tumor cells based on isoelectric point suitable nanoceria-rod with high oxygen vacancies.

Nanozymes have great potential applications in tumor treatment due to their good stability, high biocompatibility, easy preparation and versatility. However, it remains a challenge to design highly active nanozymes with tumor cell targeting. Herein, three nanoceria structures (nanoceria-rod; nanoceria polyhedra, abbreviated as nanoceria-poly.; and nanoceria-cube) with different surface oxygen vacancy concentrations are designed. Among them, nanoceria-rod shows the highest enzyme activity and tumor cell toxicity because of its highest concentration of oxygen vacancies on the surface. Further study shows that nanoceria-rod can selectively enter tumor cells because nanoceria-rod with a suitable isoelectric point (IEP) remains positively charged in the acidic microenvironment of the tumor but negatively charged in the physiological microenvironment of normal cells. Nanoceria-rod distributes in lysosomes and phagosomes to produce reactive oxygen species (ROS) in tumor cells. Finally, the mitochondrial membrane potential (MMP) was reduced, which caused cell apoptosis. This study provides an interesting new tumor-targeting therapy method, which could also be extended to other drug nanocarriers and diagnostic imaging nanomaterials for tumors.

Insight into atomically dispersed porous M-N-C single-site catalysts for electrochemical CO2 reduction.

Transition metal single-site catalysts have unique activities for electrochemical CO2 reduction. However, the exact active center and reaction mechanism remain unclear due to a number of challenges in the controllable synthesis of single-atom catalysts (SACs) and defects in metal supports. Here we combine both experimental and theoretical calculations to systematically explore the mechanistic reaction path of selected transition metal single sites on nitrogen-doped porous carbon. Facile pyrolysis was employed to prepare a fullerene type carbon with 0.35 nm interlayer distances to support the family of M-N-C (M = Ni, Fe, Co and Cu). Experimentally, Ni and Fe outperform the other metals with high faradaic efficiency up to >97% and 86.8%, respectively. The theoretical calculations reveal that Ni-N-C exhibits optimum activity for CO2 reduction to CO at a higher overpotential because of the moderate *CO binding energy at the Ni site, which accommodates *COOH formation and *CO desorption. Furthermore, the strong binding energy of *CO on the Fe site enables the catalyst to reduce CO2 beyond CO. A remarkable current density of 17.6 mA cm-2 has been achieved with the Ni-N-C catalyst and a record of 5.74 s-1 TOF has been realized at -0.8 V vs. RHE for the Ni-N-C catalyst.

Delocalized electron effect on single metal sites in ultrathin conjugated microporous polymer nanosheets for boosting CO2 cycloaddition.

CO2 cycloaddition with epoxides at low temperature and pressure has been broadly recognized as an ambitious but challenging goal, which requires the catalysts to have precisely controlled Lewis acid sites. Here, we demonstrate that both stereochemical environment and oxidation state of single cobalt active sites in cobalt tetraaminophthalocyanine [CoPc(NH2)4] are finely tuned via molecular engineering with 2,5-di-tert-butyl-1,4-benzoquinone (DTBBQ). Notably, DTBBQ incorporation not only enables formation of 5-nm-thick conjugated microporous polymer (CMP) nanosheets due to the steric hindrance effect of tert-butyl groups but also makes isolated cobalt sites with high oxidation state due to the presence of delocalized electron-withdrawing effect of alkene groups in DTBBQ via conjugated skeleton. Notably, when used as heterogeneous catalysts for CO2 cycloaddition with different epoxides, single cobalt active sites on the ultrathin CMP nanosheets exhibit unprecedentedly high activity and excellent stability under mild reaction conditions.

Metalation of Catechol-Functionalized Defective Covalent Organic Frameworks for Lewis Acid Catalysis.

Covalent organic frameworks (COFs) have emerged as a fascinating crystalline porous material and are widely used in the field of catalysis. However, developing simple approaches to fabricate conjugated COFs with specific functional groups remains a significant challenge. In this study, the construction of defective COF-LZU1 with Lewis acid sites embedded into the frameworks is fulfilled by a facile solvent-assisted ligand exchange method. A monodentate ligand, protocatechualdehyde, is successfully introduced into the skeleton of COF-LZU1, which endows the defects in the structure of COF-LZU1 via replacement of the original coordinated benzene-1,3,5-tricarbaldehyde ligand. As-synthesized defective COF-LZU1 decorated with protocatechualdehyde is rich of free hydroxy groups for chelating with active metal ions. Specifically, after combining with Fe3+ , the defective COF-LZU1 shows excellent activity in catalytic alcoholysis of epoxides under mild conditions. The method reported here will open up the opportunity to incorporate different functional groups into COFs and enrich the strategies for creating new types of porous catalysts.