Efficient and Durable Oxidation Removal of Formaldehyde over Layered Double Hydroxide Catalysts at Room Temperature.

Room temperature catalytic oxidation (RTCO) using non-noble metals has emerged as a highly promising technique for removal of formaldehyde (HCHO) under ambient conditions; however, non-noble catalysts still face the challenges related to poor water resistance and low stability under harsh conditions. In this study, we synthesized a series of layered double hydroxides (LDHs) incorporating various dual metals (MgAl, ZnAl, NiAl, NiFe, and NiTi) for formaldehyde oxidation at ambient temperature. Among the synthesized catalysts, the NiTi-LDH catalyst showed an HCHO removal efficiency and CO2 yield close to 100.0%, and exceptional water resistance and chemical stability on running 1300 min. The abundant hydroxyl groups in LDHs directly bonded with HCHO, leading to the production of CO2 and H2O, thus inhibiting the formation of CO, even in the absence of O2 and H2O. The coexistence of O2 effectively reduced the reaction barrier for H2O molecule dissociation, facilitating the formation of hydroxyl groups and their subsequent backfill on the catalyst surface. The mechanisms underlying the involvement and regeneration of hydroxyl groups in room temperature oxidation of formaldehyde were elucidated with the combined in situ DRIFTS, HCHO-TPD-MS, and DFT calculations. This work not only demonstrates the potential of LDH catalysts in environmental applications but also advances the understanding of the fundamental processes involved in room temperature oxidation of formaldehyde.

SP1/CTR1-mediated oxidative stress-induced cuproptosis in intervertebral disc degeneration.

Intervertebral disc degeneration (IDD) is an age-related disease and is responsible for low back pain. Oxidative stress-induced cell death plays a fundamental role in IDD pathogenesis. Cuproptosis is a recently discovered form of programmed cell death dependent on copper availability. Whether cuproptosis is involved in IDD progression remains unknown. Herein, we established in vitro and in vivo models to investigate cuproptosis in IDD and the mechanisms by which oxidative stress interacts with copper sensitivity in nucleus pulposus cells (NPCs). We found that ferredoxin-1 (FDX1) content increased in both rat and human degenerated discs. Sublethal oxidative stress on NPCs led to increased FDX1 expression, tricarboxylic acid (TCA) cycle-related proteins lipoylation and aggregation, and cell death in the presence of Cu2+ at physiological concentrations, while FDX1 knockdown inhibited cell death. Since copper homeostasis is involved in copper-induced cytotoxicity, we investigated the role of copper transport-related proteins, including importer (CTR1) and efflux pumps (ATPase transporter, ATP7A, and ATP7B). CTR1 and ATP7A content increased under oxidative stress, and blocking CTR1 reduced oxidative stress/copper-induced TCA-related protein aggregation and cell death. Moreover, oxidative stress promoted the expression of specific protein 1 (SP1) and SP1-mediated CTR1 transcription. SP1 inhibition decreased cell death rates, preserved disc hydration, and alleviated tissue degeneration. This suggests that oxidative stress upregulates FDX1 expression and copper flux through promoting SP1-mediated CTR1 transcription, leading to increased TCA cycle-related protein aggregation and cuproptosis. This study highlights the importance of cuproptosis in IDD progression and provides a promising therapeutic target for IDD treatment.

PGC1α-Inducing Senomorphic Nanotherapeutics Functionalized with NKG2D-Overexpressing Cell Membranes for Intervertebral Disc Degeneration.

Cellular senescence is a significant contributor to intervertebral disc aging and degeneration. However, the application of senotherapies, such as senomorphics targeting senescence markers and the senescence-associated secretory phenotype (SASP), remains limited due to challenges in precise delivery. Given that the natural killer group 2D (NKG2D) ligands are increased on the surface of senescent nucleus pulposus (NP) cells, the NKG2D-overexpressing NP cell membranes (NNPm) are constructed, which is expected to achieve a dual targeting effect toward senescent NP cells based on homologous membrane fusion and the NKG2D-mediated immunosurveillance mechanism. Then, mesoporous silica nanoparticles carrying a peroxisome proliferator-activated receptor-É£ coactivator 1α (PGC1α)inducer (SP) are coated with NNPm (SP@NNPm) and it is found that SP@NNPm selectively targets senescent NP cells, and the SP cores exhibit pH-responsive drug release. Moreover, SP@NNPm effectively induces PGC1α-mediated mitochondrial biogenesis and mitigates senescence-associated markers induced by oxidative stress and the SASP, thereby alleviating puncture-induced senescence and disc degeneration. This dual-targeting nanotherapeutic system represents a novel approach to delivery senomorphics for disc degeneration treatment.

An Engineered Bionic Nanoparticle Sponge as a Cytokine Trap and Reactive Oxygen Species Scavenger to Relieve Disc Degeneration and Discogenic Pain.

The progressive worsening of disc degeneration and related nonspecific back pain are prominent clinical issues that cause a tremendous economic burden. Activation of reactive oxygen species (ROS) related inflammation is a primary pathophysiologic change in degenerative disc lesions. This pathological state is associated with M1 macrophages, apoptosis of nucleus pulposus cells (NPC), and the ingrowth of pain-related sensory nerves. To address the pathological issues of disc degeneration and discogenic pain, we developed MnO2@TMNP, a nanomaterial that encapsulated MnO2 nanoparticles with a TrkA-overexpressed macrophage cell membrane (TMNP). Consequently, this engineered nanomaterial showed high efficiency in binding various inflammatory factors and nerve growth factors, which inhibited inflammation-induced NPC apoptosis, matrix degradation, and nerve ingrowth. Furthermore, the macrophage cell membrane provided specific targeting to macrophages for the delivery of MnO2 nanoparticles. MnO2 nanoparticles in macrophages effectively scavenged intracellular ROS and prevented M1 polarization. Supportively, we found that MnO2@TMNP prevented disc inflammation and promoted matrix regeneration, leading to downregulated disc degenerative grades in the rat injured disc model. Both mechanical and thermal hyperalgesia were alleviated by MnO2@TMNP, which was attributed to the reduced calcitonin gene-related peptide (CGRP) and substance P expression in the dorsal root ganglion and the downregulated Glial Fibrillary Acidic Protein (GFAP) and Fos Proto-Oncogene (c-FOS) signaling in the spinal cord. We confirmed that the MnO2@TMNP nanomaterial alleviated the inflammatory immune microenvironment of intervertebral discs and the progression of disc degeneration, resulting in relieved discogenic pain.

Enzymatically Bioactive Nucleus Pulposus Matrix Hydrogel Microspheres for Exogenous Stem Cells Therapy and Endogenous Repair Strategy to Achieve Disc Regeneration.

Exogenous stem cell therapy and endogenous repair has shown great potential in intervertebral disc regeneration. However, limited nutrients and accumulation of lactate largely impair the survival and regenerative capacity of implanted stem cells and endogenous nucleus pulposus cells (NPCs). Herein, an injectable hydrogel microsphere (LMGDNPs) have been developed by immersing lactate oxidase (LOX)-manganese dioxide (MnO2 ) nanozyme (LM) into glucose-enriched decellularized nucleus pulposus hydrogel microspheres (GDNPs) through a microfluidic system. LMGDNPs showed a delayed release profile of LOX and satisfactory enzymatic capacity in consuming lactate. Mesenchymal stem cells (MSCs) plated on LMGDNPs exhibited better cell viability than cells on GelMA and decellularized nucleus pulposus microspheres (DNP) and showed a obviously increased NPCs phenotype. LMGDNPs prevented MSCs and NPCs death and promoted extracellular matrix synthesis by exhausting lactate. It is determined that LMGDNPs promoted NPCs autophagy by activating transforming growth factor ß2 overlapping transcript 1 (TGFB2-OT1), relying on the nanozyme. MSCs-loaded LMGDNPs largely preserved disc hydration and alleviated matrix degradation in vivo. Summarily, LMGDNPs promoted cell survival and matrix regeneration by providing a nutrient supply, exhausting lactate, and activating autophagy via TGFB2-OT1 and its downstream pathway and may serve as an ideal delivery system for exogenous stem cell therapy and endogenous repair.

Multifunctional annulus fibrosus matrix prevents disc-related pain via inhibiting neuroinflammation and sensitization.

Chronic low back pain mainly attributed to intervertebral disc (IVD) degeneration. Endogenous damage-associated molecular patterns (DAMPs) in the injured IVD, particularly mitochondria-derived nucleic acid molecules (CpG DNA), play a primary role in the inflammatory responses in macrophages. M1-type macrophages form a chronic inflammatory microenvironment by releasing pro-inflammatory factors and nerve growth factor (NGF) that induce nerve growth into the inner annulus fibrosus, resulting in persistent hyperalgesia. We fabricated an amphiphilic polycarbonate that naturally forms cationic nanoparticles (cNP) in aqueous solutions, with the hydrophobic core loaded with TrkA-IN-1, an antagonist against the NGF receptor (TrkA). The drug delivery nanoparticles were denoted as TI-cNP. TrkA-IN-1 and TI-cNP were added to the decellularized annulus fibrosus matrix (DAF) hydrogel to form hybrid hydrogels, denoted as TI-DAF and TI-cNP-DAF, respectively. As a result, TrkA-IN-1 showed a delayed release profile both in TI-DAF and TI-cNP-DAF. Each mole of cNP could bind approximately 3 mol of CpG DNA to inhibit inflammation. cNP-DAF and TI-cNP-DAF significantly inhibited the M1 phenotype induced by CpG DNA. TI-DAF and TI-cNP-DAF reduced neurite branching and axon length, and inhibited the expression of neurogenic mediators (CGRP and substance P) in the presence of NGF. Besides, TI-cNP-DAF relieved mechanical hyperalgesia, reduced CGRP and substance P expression in the dorsal root ganglion, and downregulated GFAP and c-FOS signaling in the spinal cord in the rat disc herniation model. Summarily, TI-cNP-DAF, a novel composite IVD hydrogel, efficiently mediated the inflammatory environment, inhibited nerve ingrowth and sensitization, and could be clinically applied for treating discogenic pain. STATEMENT OF SIGNIFICANCE: Discogenic lower back pain, related to intervertebral disc degeneration (IDD), imposes a tremendous health and economic burden globally. M1-type macrophages release pro-inflammatory factors and nerve growth factor (NGF) that induce nerve growth into the inner annulus fibrosus, resulting in persistent hyperalgesia and discogenic pain. Reconstructing matrix integrity and modulating the inflammatory microenvironment are promising strategies for preventing the ingrowth and activation of neurites. The TI-cNP-DAF hydrogel recovers tissue integrity, alleviates inflammation, and delivers the TrkA antagonist to inhibit the activity of NGF, thus restraining hyperinnervation and nociceptive input. Due to its simple production process, injectability, and acellular strategy, the hydrogel is operable and holds great potential for treating discogenic lower back pain.

Hsa_circ_0007031 promotes the proliferation and migration of osteosarcoma cells by sponging miR-196a-5p to regulate the HOXB6.

Circular RNAs (circRNAs), a subclass of noncoding RNAs, have been demonstrated to play an essential role in osteosarcoma (OS) development. However, there is still a significant gap in investigating its biological functions and underlying molecular mechanisms, and novel targets of circRNAs have yet to be fully explored. Herein, we found that hsa_circ_0007031 is noticeably raised in OS clinical tissues and cell lines. Hsa_circ_0007031 accelerates OS cell proliferation and migration in vitro and tumor growth and metastasis in vivo and is strongly linked with the stemness of cancer stem cells in OS. Mechanistically, hsa_circ_0007031 shares miRNA response elements with Homeobox B6 (HOXB6), which is identified as a novel pro-tumorigenic gene of OS. Hsa_circ_0007031 competitively binds to miR-196a-5p to prevent miR-196a-5p from lowering the level of HOXB6, which modulates chemokines of cytokine-cytokine receptor interaction signaling pathway and finally promotes OS malignant behavior. In summary, our data unveiled that hsa_circ_0007031/miR-196a-5p/HOXB6 axis-mediated cytokine-cytokine receptor interaction facilitates the progression of OS and maintains the properties of tumor stem cells, which could be a promising therapeutic target for OS.

Highly Enhanced Photocatalytic NO Removal and Inhibited Peroxyacetyl Nitrate Formation in Synergistic Acetaldehyde Degradation.

The coexistence of NO and CH3CHO in the air is considered to produce secondary peroxyacetyl nitrate (PAN) under sunlight irradiation, threatening the ecological environment and public health. Herein, we provide a simple strategy for the photocatalytic removal of NO and acetaldehyde (CH3CHO) on Sr2Sb2O7. In comparison with the single removal, the nearly complete removal of NO is reached by deep oxidation to NO3- with the assistance of CH3CHO. The underlying mechanism is revealed by GC-MS, in situ DRIFTS, and density functional theory calculations. The intermediates •CH3 from CH3CHO and NO2- from NO tend to bond and further oxidize to CH3ONO2, thus promoting NO removal. CH3NO2 and CH3ONO2 are the key products instead of PAN on Sr2Sb2O7 from the synergistic degradation of NO and CH3CHO. This work brings new insights into reaction pathway regulation for promoting performance and suppressing byproducts during synergistic air pollutant removal.

Extracellular Vesicle-Conjugated Functional Matrix Hydrogels Prevent Senescence by Exosomal miR-3594-5p-Targeted HIPK2/p53 Pathway for Disc Regeneration.

Nucleus pulposus stem cells (NPSCs) senescence plays a critical role in the progression of intervertebral disc degeneration (IDD). Stem cell-derived extracellular vesicles (EV) alleviate cellular senescence. Whereas, the underlying mechanism remains unclear. Low stability largely limited the administration of EV in vivo. RGD, an arginine-glycine-aspartic acid tripeptide, strongly binds integrins expressed on the EV membranes, allowing RGD to anchor EV and prolong their bioavailability. An RGD-complexed nucleus pulposus matrix hydrogel (RGD-DNP) is developed to enhance the therapeutic effects of small EV (sEV). RGD-DNP prolonged sEV retention in vitro and ex vivo. sEV-RGD-DNP promoted NPSCs migration, decreased the number of SA-ß-gal-positive cells, alleviated cell cycle arrest, and reduced p16, p21, and p53 activation. Small RNA-seq showed that miR-3594-5p is enriched in sEV, and targets the homeodomain-interacting protein kinase 2 (HIPK2)/p53 pathway. The HIPK2 knockdown rescues the impaired therapeutic effects of sEV with downregulated miR-3594-5p. RGD-DNP conjugate with lower amounts of sEV achieved similar disc regeneration with free sEV of higher concentrations in DNP. In conclusion, sEV-RGD-DNP increases sEV bioavailability and relieves NPSCs senescence by targeting the HIPK2/p53 pathway, thereby alleviating IDD. This work achieves better regenerative effects with fewer sEV and consolidates the theoretical basis for sEV application for IDD treatment.

Animal models of cancer metastasis to the bone.

Cancer metastasis is a major cause of mortality from several tumors, including those of the breast, prostate, and the thyroid gland. Since bone tissue is one of the most common sites of metastasis, the treatment of bone metastases is crucial for the cure of cancer. Hence, disease models must be developed to understand the process of bone metastasis in order to devise therapies for it. Several translational models of different bone metastatic tumors have been developed, including animal models, cell line injection models, bone implant models, and patient-derived xenograft models. However, a compendium on different bone metastatic cancers is currently not available. Here, we have compiled several animal models derived from current experiments on bone metastasis, mostly involving breast and prostate cancer, to improve the development of preclinical models and promote the treatment of bone metastasis.

Amorphous SnO2 decorated ZnSn(OH)6 promotes interfacial hydroxyl polarization for deep photocatalytic toluene mineralization.

Surface hydroxyl groups play a decisive role in the generation of hydroxyl radicals with stronger oxidizing ability, which is indispensable in photocatalytic VOCs removal, especially under the condition of low humidity. In this work, non-noble amorphous SnO2 decorated ZnSn(OH)6 (ZSH) was synthesized by an in-situ method. The charge transport, reactant activation and hydroxyl polarization are enhanced through decoration of amorphous SnO2 on ZSH. Combined with the designed experiment, in-situ EPR, DTF calculation and in-situ DRIFTS, the role and mechanism of interfacial hydroxyl polarization are revealed on SnO2 decorated ZnSn(OH)6. Compared with pristine ZSH and noble-metal modified ZSH, the toluene degradation rate of amorphous SnO2 decorated ZSH is increased by 13.0 and 3.8 times, and the toluene mineralization rate is increased by 5.2 and 2.2 times. The ZSH-24 sample maintains a high toluene degradation activity after 6 cyclic utilization without catalyst deactivation. This work emphasizes the role of non-noble metal and the origin of hydroxyl group polarization on ZnSn(OH)6 for photocatalytic VOCs mineralization.

Identification of Candidate MicroRNA-mRNA Subnetwork for Predicting the Osteosarcoma Progression by Bioinformatics Analysis.

Osteosarcoma (OS) is the pretty common primary cancer of the bone among the malignancies in adolescents. A single molecular component or a limited number of molecules is insufficient as a predictive biomarker of OS progression. Hence, it is necessary to find novel network biomarkers to improve the prediction and therapeutic effect for OS. Here, we identified 230 DE-miRNAs and 821 DE-mRNAs through two miRNA expression-profiling datasets and three mRNA expression-profiling datasets. We found that hsa-miR-494 is closely linked with the survival of OS patients. In addition, we analyzed GO and KEGG enrichment for targets of hsa-miR-494-5p and hsa-miR-494-3p through R programming. And five mRNAs were predicted as common targets of hsa-miR-494-5p and hsa-miR-494-3p. We further revealed that upregulated TRPS1 was strongly correlated with poor outcomes in OS patients through the survival analysis based on the TARGET database. The qRT-PCR study verified that the expression of hsa-miR-494-5p and hsa-miR-494-3p was declined considerably, while TRPS1 was notably raised in OS cells when compared to the osteoblasts. Thus, we generated a new regulatory subnetwork of key miRNAs and target mRNAs using Cytoscape software. These results indicate that the novel miRNA-mRNA subnetwork composed of hsa-miR-494-5p, hsa-miR-494-3p, and TRPS1 might be a characteristic molecule for assessing the prognostic value of OS patients.

Template-Sacrificing Synthesis of Well-Defined Asymmetrically Coordinated Single-Atom Catalysts for Highly Efficient CO2 Electrocatalytic Reduction.

Although various single-atom catalysts have been designed, atomically engineering their coordination environment remains a great challenge. Herein, a one-pot template-sacrificing pyrolysis approach is developed to synthesize well-defined Ni-N4-O catalytic sites on highly porous graphitic carbon for electrocatalytic CO2 reduction to CO with high Faradaic efficiency (maximum of 97.2%) in a wide potential window (-0.56 to -1.06 V vs RHE) and with high stability. In-depth experimental and theoretical studies reveal that the axial Ni-O coordination introduces asymmetry to the catalytic center, leading to lower Gibbs free energy for the rate-limiting step, strengthened binding with *COOH, and a weaker association with *CO. The present results demonstrate the successful atomic-level coordination environment engineering of high-surface-area porous graphitic carbon-supported Ni single-atom catalysts (SACs), and the demonstrated method can be applied to synthesize an array of SACs (metal-N4-O) for various catalysis applications.

Metal-organic framework derived carbon-supported bimetallic copper-nickel alloy electrocatalysts for highly selective nitrate reduction to ammonia.

Developing electrocatalysts for efficient reduction of nitrate contaminant to value-added ammonia as energy carrier is a pivotal part for restoring the nitrogen cycle. However, the selectivity of ammonia is far from satisfaction, often suffering from accumulation of toxic nitrite byproduct. Herein, a series of CuNi alloy nanoparticles embedded in nitrogen-doped carbon matrix (CuNi/NC) with hierarchical pores were fabricated by pyrolysis of bimetallic metal-organic frameworks (MOFs). The catalysts exhibited excellent selectivity (94.4%) and faradaic efficiency (79.6%) for nitrate reduction to ammonia, greatly outperforming the performance of monometallic Cu/NC (selectivity of 60.8% and faradaic efficiency of 60.6%). Impressively, the introduction of nickel distinctly suppressed the production of toxic byproduct of nitrite. Online differential electrochemical mass spectrometry (DEMS) and in situ surface-enhanced infrared absorption spectroscopy (SEIRAS) tests were utilized to reveal the key intermediates and the reaction pathway. Density functional theory (DFT) calculations demonstrated that the introducing of nickel into copper lattice modified both the electronic and geometric structures of the catalysts. The copper and nickel sites in the CuNi alloy catalysts operate synergistically to facilitate the hydrogenation of NO2* to HNO2* and suppress the hydrogen evolution reaction, boosting the selective formation of ammonia. This work could provide a new synthetic route for bimetallic catalysts and mechanistic understanding for nitrate to ammonia reaction.

Analysis and identification of m6A RNA methylation regulators in metastatic osteosarcoma.

Osteosarcoma (OS) is characterized by rapid growth and early metastasis. However, its mechanism remains unclear. N6-methyladenosine (m6A) modification and its regulatory factors play essential roles in most cancers, including OS. In this study, we screened out 21 m6A modifiers using the Therapeutically Applicable Research to Generate Effective Treatments (TARGET) database, followed by the identification of the critical m6A methylation modifiers. The results revealed that the expression levels of three m6A methylation regulators, namely RBM15, METTL3, and LRPPRC, were associated with the low survival rate of patients with OS. We further studied the independent prognostic factors by performing univariate and multivariate Cox analyses and found that metastasis was an independent prognostic factor for patients with OS. Furthermore, we found for the first time that RBM15 was specific for metastatic OS rather than non-metastatic OS. Moreover, the significant overexpression of RBM15 was validated in metastatic OS cell lines and in actual human clinical specimens. We also revealed that RBM15 promoted the invasion, migration, and metastasis of OS cells through loss-functional and gain-functional experiments and an animal metastatic model. In conclusion, RBM15 has a high correlation with OS metastasis formation and the decreased survival rate of patients with OS, and this may serve as a useful biomarker for predicting metastasis and prognosis of patients with OS.

Anti-inflammatory and immunomodulatory effects of the extracellular vesicles derived from human umbilical cord mesenchymal stem cells on osteoarthritis via M2 macrophages.

Osteoarthritis (OA) is a degenerative illness that greatly impacts the life quality of patients. Currently, the therapeutic approaches for OA are very limited in clinical. The extracellular vesicles (EVs) derived from different mesenchymal stem cells displayed a prominent therapeutic effect on OA. But most EVs have limited resources and the risks of host rejection, immunological response, and etc. Human umbilical cord mesenchymal stem cells (hUCMSCs) hold the advantages of easy availability, minimal immune rejection, and excellent immunomodulatory effects, although hUCMSCs-EVs have seldom been applied in OA. Herein, we investigated the potential immunomodulatory and anti-inflammatory effects of hUCMSCs-EVs on the treatment of OA. In our results, the treatment of hUCMSCs-EVs promoted the polarization of M2-type macrophages and the expression of anti-inflammation-related cytokines (IL-10). Notably, the supernate of M2 macrophages induced by hUCMSCs-EVs inhibited the level of inflammation-associated factors in OA chondrocytes caused by IL-1ß. Further, injection of hUCMSCs-EVs in the articular lumen ameliorated progression of OA and exerted chondroprotective potential based on the OA joint model created by the surgical transection of the anterior cruciate ligament (ACLT). In addition, we found five highly enriched miRNAs in hUCMSCs-EVs, including has-miR-122-5p, has-miR-148a-3p, has-miR-486-5p, has-miR-let-7a-5p, and has-miR-100-5p by High-throughput sequencing of miRNAs, with targeted genes mainly enriched in the PI3K-Akt signaling pathway. Furthermore, we also detected the protein abundance of hUCMSCs-EVs using liquidation chromatography with tandem quadrupole mass spectrometry (LC-MS/MS) analysis. Thus, our study indicates that hUCMSCs-EVs can alleviate cartilage degradation during the OA progression, mechanically may through delivering key proteins and modulating the PI3K-Akt signaling pathway mediated by miRNAs to promote polarization of M2 macrophage, exhibiting potent immunomodulatory potential. The current findings suggest that hUCMSCs-EVs might serve as a new reagent for the therapy of OA.

Promote the activation and ring opening of intermediates for stable photocatalytic toluene degradation over Zn-Ti-LDH.

Improving the selectivity of photocatalysis and reducing the generation of toxic by-products are the two key challenges for the development of highly efficient and stable photocatalysts. In this work, it was revealed that Zn-Ti-layered double hydroxide (ZT-LDH) photocatalyst, which generated less intermediates, showed better toluene degradation efficiency (removal ratio, 75.2%) and stability, compared with P25 (removal ratio, 10.9%). During the photocatalytic toluene degradation, benzaldehyde and benzoic acid were the main intermediates existed in the gas phase and on the surface of the catalyst, respectively. By combining experiments with theoretical calculation, it was found that the hydrogen atoms on the hydroxyl groups in the LDH would selectively attract the oxygen atoms in the carbon-oxygen double bond of the two major intermediates, facilitating their adsorption and activation on ZT-LDH. Besides, the surface electronic structure of ZT-LDH was demonstrated to facilitate the ring-opening reaction of the two major intermediates, eventually maintaining high activity and stability. This work could provide new molecular perspectives for understanding the photocatalytic reactions in VOCs degradation and developing efficient and stable photocatalysts.

The Crystal Plane is not the Key Factor for CO2 -to-Methane Electrosynthesis on Reconstructed Cu2 O Microparticles.

Cu2 O microparticles with controllable crystal planes and relatively high stability have been recognized as a good platform to understand the mechanism of the electrocatalytic CO2 reduction reaction (CO2 RR). Herein, we demonstrate that the in situ generated Cu2 O/Cu interface plays a key role in determining the selectivity of methane formation, rather than the initial crystal plane of the reconstructed Cu2 O microparticles. Experimental results indicate that the methane evolution is dominated on all three different crystal planes with similar Tafel slopes and long-term stabilities. Density functional theory (DFT) calculations further reveal that *CO is protonated via a similar bridge configuration at the Cu2 O/Cu interface, regardless of the initial crystal planes of Cu2 O. The Gibbs free energy changes (ΔG) of *CHO on different reconstructed Cu2 O planes are close and more negative than that of *OCCOH, indicating the methane formation is more favorable than ethylene on all Cu2 O crystal planes.

Crystal-Structure-Dependent Photocatalytic Redox Activity and Reaction Pathways over Ga2O3 Polymorphs.

Differentiated crystal structures generally affect the surface physicochemical properties of catalysts, causing variety in catalytic activity between polymorphs. However, the underlying mechanism has not been completely revealed, especially the influence of surface physicochemical properties on photocatalytic redox activity and the reaction mechanism. In this work, we reveal the mechanism of surface redox properties on different crystal forms of gallium oxide from a molecular level. α-Ga2O3 and ß-Ga2O3 exhibit a slight difference in catalytic oxidation of organic pollutants due to comprehensive influencing factors, including their valence band position, reactive oxygen species, and pore structure properties related to the adsorption-reaction-desorption process. But the catalytic reduction ability of CO2 is obviously different due to the large differences of interaction between the surface of crystal structures and CO2 molecules, which are critical to determine the catalytic performance and reaction pathways. The enhanced adsorption and activation of CO2 on the α-Ga2O3 surface could promote the reduction reaction efficiency. Moreover, the large energy barrier of CH2* formation on ß-Ga2O3 makes the formation of methane (CH4) relatively difficult compared to that on α-Ga2O3. The yield rate of CH4 (1.8 µmol·g-1·h-1) on α-Ga2O3 is three times better than that on ß-Ga2O3 (CH4: 0.6 µmol·g-1·h-1). The current findings can offer novel insights into the understanding of crystal-structure-dependent photocatalytic performances and the design of new catalysts applied in energy conversion and environmental purification by crystal structure-tuning.

Identification of deactivation-resistant origin of In(OH)3 for efficient and durable photodegradation of benzene, toluene and their mixtures.

Aromatic hydrocarbon is a representative type of VOCs, which causes adverse effects to human health. The degradation stability of aromatic hydrocarbon is of vital importance to commercializing a photocatalyst for its practical application. The most commonly used titanium dioxide photocatalyst (P25) was deactivated rapidly in the photocatalytic VOCs degradation process. In this work, the indium hydroxide (In(OH)3) photocatalyst was developed, which exhibited not only higher efficient activity but also ultra-stable stability for degradation of benzene, toluene and their mixtures. The origin of the activity difference between two catalysts was investigated by combined experimental and theoretical ways. Based on in situ DRIFTS and GC-MS, it was revealed that benzoic acid and carbonaceous byproducts were specifically formed and accumulated on P25, which were responsible for deactivation of photocatalyst. In contrast, as revealed by both DFT calculations and experimental results, the reaction pathway with byproducts blocking the active sites can be thermodynamically avoided on In(OH)3. This rendered high durability to In(OH)3 photocatalyst in degradations of aromatic pollutants. The elucidation of deactivation-resistant effect and reaction mechanism as an ideal photocatalyst for practical usage were provided.