ABSTRACT
Electrolysis that reduces carbon dioxide (CO2) to useful chemicals can, in principle, contribute to a more sustainable and carbon-neutral future1-6. However, it remains challenging to develop this into a robust process because efficient conversion typically requires alkaline conditions in which CO2 precipitates as carbonate, and this limits carbon utilization and the stability of the system7-12. Strategies such as physical washing, pulsed operation and the use of dipolar membranes can partially alleviate these problems but do not fully resolve them11,13-15. CO2 electrolysis in acid electrolyte, where carbonate does not form, has therefore been explored as an ultimately more workable solution16-18. Herein we develop a proton-exchange membrane system that reduces CO2 to formic acid at a catalyst that is derived from waste lead-acid batteries and in which a lattice carbon activation mechanism contributes. When coupling CO2 reduction with hydrogen oxidation, formic acid is produced with over 93% Faradaic efficiency. The system is compatible with start-up/shut-down processes, achieves nearly 91% single-pass conversion efficiency for CO2 at a current density of 600 mA cm-2 and cell voltage of 2.2 V and is shown to operate continuously for more than 5,200 h. We expect that this exceptional performance, enabled by the use of a robust and efficient catalyst, stable three-phase interface and durable membrane, will help advance the development of carbon-neutral technologies.
ABSTRACT
The kinetics and pathway of most catalyzed reactions depend on the existence of interface, which makes the precise construction of highly active single-atom sites at the reaction interface a desirable goal. Herein, we propose a thermal printing strategy that not only arranges metal atoms at the silica and carbon layer interface but also stabilizes them by strong coordination. Just like the typesetting of Chinese characters on paper, this method relies on the controlled migration of movable nanoparticles between two contact substrates and the simultaneous emission of atoms from the nanoparticle surface at high temperatures. Observed by in situ transmission electron microscopy, a single Fe3O4 nanoparticle migrates from the core of a SiO2 sphere to the surface like a droplet at high temperatures, moves along the interface of SiO2 and the coated carbon layer, and releases metal atoms until it disappears completely. These detached atoms are then in situ trapped by nitrogen and sulfur defects in the carbon layer to generate Fe single-atom sites, exhibiting excellent activity for oxygen reduction reaction. Also, sites' densities can be regulated by controlling the size of Fe3O4 nanoparticle between the two surfaces. More importantly, this strategy is applicable to synthesize Mn, Co, Pt, Pd, Au single-atom sites, which provide a general route to arrange single-atom sites at the interface of different supports for various applications.
ABSTRACT
Terpenoids are the most diverse group of specialized metabolites with numerous applications. Their biosynthesis is based on the five-carbon isoprene building block and, as a result, almost all terpenoids isolated to date are based on backbones that contain multiples of five carbon atoms. Intrigued by the discovery of an unusual bacterial terpenoid with a 16-carbon skeleton, here we investigate whether the biosynthesis of 16-carbon terpenoids is more widespread than this single example. We mine bacterial genomic information and identify potential C16 biosynthetic clusters in more than 700 sequenced genomes. We study selected clusters using a yeast synthetic biology platform and reveal that the encoded synthases produce at least 47 different noncanonical terpenoids. By thorough chemical analysis, we explain the structures of 13 C16 metabolites, most of which possess intricate highly strained bi- and tricyclic backbones. Our results unveil the existence of an extensive class of terpenoids in bacteria.
Subject(s)
Bacteria , Terpenes , Terpenes/metabolism , Bacteria/genetics , Bacteria/metabolism , Saccharomyces cerevisiae/genetics , Synthetic Biology/methodsABSTRACT
Proton-exchange-membrane fuel cells (PEMFCs) are attractive next-generation power sources for use in vehicles and other applications1, with development efforts focusing on improving the catalyst system of the fuel cell. One problem is catalyst poisoning by impurity gases such as carbon monoxide (CO), which typically comprises about one per cent of hydrogen fuel2-4. A possible solution is on-board hydrogen purification, which involves preferential oxidation of CO in hydrogen (PROX)3-7. However, this approach is challenging8-15 because the catalyst needs to be active and selective towards CO oxidation over a broad range of low temperatures so that CO is efficiently removed (to below 50 parts per million) during continuous PEMFC operation (at about 353 kelvin) and, in the case of automotive fuel cells, during frequent cold-start periods. Here we show that atomically dispersed iron hydroxide, selectively deposited on silica-supported platinum (Pt) nanoparticles, enables complete and 100 per cent selective CO removal through the PROX reaction over the broad temperature range of 198 to 380 kelvin. We find that the mass-specific activity of this system is about 30 times higher than that of more conventional catalysts consisting of Pt on iron oxide supports. In situ X-ray absorption fine-structure measurements reveal that most of the iron hydroxide exists as Fe1(OH)x clusters anchored on the Pt nanoparticles, with density functional theory calculations indicating that Fe1(OH)x-Pt single interfacial sites can readily react with CO and facilitate oxygen activation. These findings suggest that in addition to strategies that target oxide-supported precious-metal nanoparticles or isolated metal atoms, the deposition of isolated transition-metal complexes offers new ways of designing highly active metal catalysts.
ABSTRACT
Electrocatalytic reduction of nitrate to ammonia (NO3RR) is gaining attention for low carbon emissions and environmental protection. However, low ammonia production rate and poor selectivity have remained major challenges in this multi-proton coupling process. Herein, we report a facile strategy toward a novel Fe-based hybrid structure composed of Fe single atoms and Fe3C atomic clusters that demonstrates outstanding performance for synergistic electrocatalytic NO3RR. By operando synchrotron Fourier transform infrared spectroscopy and theoretical computation, we clarify that Fe single atoms serve as the active site for NO3RR, while Fe3C clusters facilitate H2O dissociation to provide protons (*H) for continued hydrogenation reactions. As a result, the Fe-based electrocatalyst exhibits ammonia Faradaic efficiency of nearly 100%, with a corresponding production rate of 24768 µg h-1 cm-2 at -0.4 V vs RHE, exceeding most reported metal-based catalysts. This research provides valuable guidance toward multi-step reactions.
ABSTRACT
Rational design of well-defined active sites is crucial for promoting sluggish oxygen reduction reactions. Herein, leveraging the surfactant-oriented and solvent-ligand effects, we develop a facile self-assembly strategy to construct a core-shell catalyst comprising a high-index Pt shell encapsulating a PtCu3 intermetallic core with efficient oxygen-reduction performance. Without undergoing a high-temperature route, the ordered PtCu3 is directly fabricated through the accelerated reduction of Cu2+, followed by the deposition of the remaining Pt precursor onto its surface, forming high-index steps oriented by the steric hindrance of surfactant. This approach results in a high half-wave potential of 0.911 V versus reversible hydrogen electrode, with negligible deactivation even after 15000-cycle operation. Operando spectroscopies identify that this core-shell catalyst facilitates the conversion of oxygen-involving intermediates and ensures antidissolution ability. Theoretical investigations rationalize that this improvement is attributed to reinforced electronic interactions around high-index Pt, stabilizing the binding strength of rate-determining OHads species.
ABSTRACT
Understanding the characteristics of interfacial hydroxyl (OH) at the solid/liquid electrochemical interface is crucial for deciphering synergistic catalysis. However, it remains challenging to elucidate the influences of spatial distance between interfacial OH and neighboring reactants on reaction kinetics at the atomic level. Herein, we visualize the distance-dependent synergistic interaction in heterogeneous dual-site catalysis by using ex-situ infrared nanospectroscopy and in situ infrared spectroscopy techniques. These spectroscopic techniques achieve direct identification of the spatial distribution of synergistic species and reveal that OH facilitates the reactant deprotonation process depending on site distances in dual-site catalysts. Via modulating Ir-Co pair distances, we find that the dynamic equilibrium between generation and consumption of OH accounts for high-efficiency synergism at the optimized distance of 7.9 Å. At farther or shorter distances, spatial inaccessibility and resistance of OH with intermediates lead to OH accumulation, thereby diminishing the synergistic effect. Hence, a volcano-shaped curve has been established between the spatial distance and mass activity using formic acid oxidation as the probe reaction. This notion could also be extended to oxophilic metals, like Ir-Ru pairs, where volcano curves and dynamic equilibrium further evidence the universal significance of spatial distances.
ABSTRACT
The electrochemical reduction reaction of carbon dioxide (CO2RR) into valuable products offers notable economic benefits and contributes to environmental sustainability. However, precisely controlling the reaction pathways and selectively converting key intermediates pose considerable challenges. In this study, our theoretical calculations reveal that the active sites with different states of copper atoms (1-3-5-7-9) play a pivotal role in the adsorption behavior of the *CHO critical intermediate. This behavior dictates the subsequent hydrogenation and coupling steps, ultimately influencing the formation of the desired products. Consequently, we designed two model electrocatalysts comprising Cu single atoms and particles supported on CeO2. This design enables controlled *CHO intermediate transformation through either hydrogenation with *H or coupling with *CO, leading to a highly selective CO2RR. Notably, our selective control strategy tunes the Faradaic efficiency from 61.1% for ethylene (C2H4) to 61.2% for methane (CH4). Additionally, the catalyst demonstrated a high current density and remarkable stability, exceeding 500 h of operation. This work not only provides efficient catalysts for selective CO2RR but also offers valuable insights into tailoring surface chemistry and designing catalysts for precise control over catalytic processes to achieve targeted product generation in CO2RR technology.
ABSTRACT
Electrosynthesis has emerged as an enticing solution for hydrogen peroxide (H2O2) production. However, efficient H2O2 generation encounters challenges related to the robust gas-liquid-solid interface within electrochemical reactors. In this work, we introduce an effective hydrophobic coating modified by iron (Fe) sites to optimize the reaction microenvironment. This modification aims to mitigate radical corrosion through Fe(II)/Fe(III) redox chemistry, reinforcing the reaction microenvironment at the three-phase interface. Consequently, we achieved a remarkable yield of up to 336.1 mmol h-1 with sustained catalyst operation for an extensive duration of 230 h at 200 mA cm-2 without causing damage to the reaction interface. Additionally, the Faradaic efficiency of H2O2 exceeded 90% across a broad range of test current densities. This surface redox chemistry approach for manipulating the reaction microenvironment not only advances long-term H2O2 electrosynthesis but also holds promise for other gas-starvation electrochemical reactions.
ABSTRACT
Taxol is a potent drug used in various cancer treatments. Its complex structure has prompted extensive research into its biosynthesis. However, certain critical steps, such as the formation of the oxetane ring, which is essential for its activity, have remained unclear. Previous proposals suggested that oxetane formation follows the acetylation of taxadien-5α-ol. Here, we proposed that the oxetane ring is formed by cytochrome P450-mediated oxidation events that occur prior to C5 acetylation. To test this hypothesis, we analyzed the genomic and transcriptomic information for Taxus species to identify cytochrome P450 candidates and employed two independent systems, yeast (Saccharomyces cerevisiae) and plant (Nicotiana benthamiana), for their characterization. We revealed that a single enzyme, CYP725A4, catalyzes two successive epoxidation events, leading to the formation of the oxetane ring. We further showed that both taxa-4(5)-11(12)-diene (endotaxadiene) and taxa-4(20)-11(12)-diene (exotaxadiene) are precursors to the key intermediate, taxologenic oxetane, indicating the potential existence of multiple routes in the Taxol pathway. Thus, we unveiled a long-elusive step in Taxol biosynthesis.
Subject(s)
Cytochrome P-450 Enzyme System , Taxus , Cytochrome P-450 Enzyme System/metabolism , Paclitaxel/metabolism , Ethers, Cyclic , Catalysis , Taxus/genetics , Taxus/metabolismABSTRACT
Iron-nitrogen-carbon (Fe-N-C) catalysts, although the most active platinum-free option for the cathodic oxygen reduction reaction (ORR), suffer from poor durability due to the Fe leaching and consequent Fenton effect, limiting their practical application in low-temperature fuel cells. This work demonstrates an integrated catalyst of a platinum-iron (PtFe) alloy planted in an Fe-N-C matrix (PtFe/Fe-N-C) to address this challenge. This novel catalyst exhibits both high-efficiency activity and stability, as evidenced by its impressive half-wave potential (E1/2) of 0.93 V versus reversible hydrogen electrode (vs RHE) and minimal 7 mV decay even after 50,000 potential cycles. Remarkably, it exhibits a very low hydrogen peroxide (H2O2) yield (0.07%) at 0.6 V and maintains this performance with negligible change after 10,000 potential cycles. Fuel cells assembled with this cathode PtFe/Fe-N-C catalyst show exceptional durability, with only 8 mV voltage loss at 0.8 A cm-2 after 30,000 cycles and ignorable current degradation at a voltage of 0.6 V over 85 h. Comprehensive in situ experiments and theoretical calculations reveal that oxygen species spillover from Fe-N-C to PtFe alloy not only inhibits H2O2 production but also eliminates harmful oxygenated radicals. This work paves the way for the design of highly efficient and stable ORR catalysts and has significant implications for the development of next-generation fuel cells.
ABSTRACT
BACKGROUND AND PURPOSE: Interstitial lung disease (ILD) represents a significant complication of rheumatoid arthritis (RA) that lacks effective treatment options. This study aimed to investigate the intrinsic mechanism by which resveratrol attenuates rheumatoid arthritis complicated with interstitial lung disease through the AKT/TMEM175 pathway. METHODS: We established an arthritis model by combining chicken type II collagen and complete Freund's adjuvant. Resveratrol treatment was administered via tube feeding for 10 days. Pathological changes in both the joints and lungs were evaluated using HE and Masson staining techniques. Protein expression of TGF-ß1, AKT, and TMEM175 was examined in lung tissue. MRC-5 cells were stimulated using IL-1ß in combination with TGF-ß1 as an in vitro model of RA-ILD, and agonists of AKT, metabolic inhibitors, and SiRNA of TMEM175 were used to explore the regulation and mechanism of action of resveratrol RA-ILD. RESULTS: Resveratrol mitigates fibrosis in rheumatoid arthritis-associated interstitial lung disease and reduces oxidative stress and inflammation in RA-ILD. Furthermore, resveratrol restored cellular autophagy. When combined with the in vitro model, it was further demonstrated that resveratrol could suppress TGF-ß1 expression, and reduce AKT metamorphic activation, consequently inhibiting the opening of AKT/MEM175 ion channels. This, in turn, lowers lysosomal pH and enhances the fusion of autophagosomes with lysosomes, ultimately ameliorating the progression of RA-ILD. CONCLUSION: In this study, we demonstrated that resveratrol restores autophagic flux through the AKT/MEM175 pathway to attenuate inflammation as well as fibrosis in RA-ILD by combining in vivo and in vitro experiments. It further provides a theoretical basis for the selection of therapeutic targets for RA-ILD.
Subject(s)
Arthritis, Rheumatoid , Fibrosis , Inflammation , Lung Diseases, Interstitial , Potassium Channels , Proto-Oncogene Proteins c-akt , Resveratrol , Signal Transduction , Animals , Arthritis, Rheumatoid/complications , Arthritis, Rheumatoid/drug therapy , Arthritis, Rheumatoid/pathology , Autophagy/drug effects , Cell Line , Inflammation/pathology , Inflammation/drug therapy , Lung/pathology , Lung/drug effects , Lung Diseases, Interstitial/drug therapy , Lung Diseases, Interstitial/complications , Lung Diseases, Interstitial/pathology , Lung Diseases, Interstitial/metabolism , Membrane Proteins/metabolism , Oxidative Stress/drug effects , Proto-Oncogene Proteins c-akt/drug effects , Proto-Oncogene Proteins c-akt/metabolism , Resveratrol/pharmacology , Resveratrol/therapeutic use , Signal Transduction/drug effects , Transforming Growth Factor beta1/metabolism , Mice , Potassium Channels/drug effects , Potassium Channels/metabolismABSTRACT
Gastroesophageal reflux disease (GERD) is a prevalent chronic ailment, and present therapeutic approaches are not always effective. This study aimed to find new drug targets for GERD and Barrett's esophagus (BE). We obtained genetic instruments for GERD, BE, and 2004 plasma proteins from recently published genome-wide association studies (GWAS), and Mendelian randomization (MR) was employed to explore potential drug targets. We further winnowed down MR-prioritized proteins through replication, reverse causality testing, colocalization analysis, phenotype scanning, and Phenome-wide MR. Furthermore, we constructed a protein-protein interaction network, unveiling potential associations among candidate proteins. Simultaneously, we acquired mRNA expression quantitative trait loci (eQTL) data from another GWAS encompassing four different tissues to identify additional drug targets. Meanwhile, we searched drug databases to evaluate these targets. Under Bonferroni correction (P < 4.8 × 10-5), we identified 11 plasma proteins significantly associated with GERD. Among these, 7 are protective proteins (MSP, GPX1, ERBB3, BT3A3, ANTR2, CCM2, and DECR2), while 4 are detrimental proteins (TMEM106B, DUSP13, C1-INH, and LINGO1). Ultimately, C1-INH and DECR2 successfully passed the screening process and exhibited similar directional causal effects on BE. Further analysis of eQTLs highlighted 4 potential drug targets, including EDEM3, PBX3, MEIS1-AS3, and NME7. The search of drug databases further supported our conclusions. Our study indicated that the plasma proteins C1-INH and DECR2, along with 4 genes (EDEM3, PBX3, MEIS1-AS3, and NME7), may represent potential drug targets for GERD and BE, warranting further investigation.
Subject(s)
Barrett Esophagus , Gastroesophageal Reflux , Genome-Wide Association Study , Mendelian Randomization Analysis , Quantitative Trait Loci , Humans , Barrett Esophagus/genetics , Barrett Esophagus/drug therapy , Barrett Esophagus/pathology , Gastroesophageal Reflux/genetics , Gastroesophageal Reflux/drug therapy , Genetic Predisposition to Disease , Protein Interaction Maps/genetics , Polymorphism, Single NucleotideABSTRACT
Plant lignocellulosic biomass, i.e. secondary cell walls of plants, is a vital alternative source for bioenergy. However, the acetylation of xylan in secondary cell walls impedes the conversion of biomass to biofuels. Previous studies have shown that REDUCED WALL ACETYLATION (RWA) proteins are directly involved in the acetylation of xylan but the regulatory mechanism of RWAs is not fully understood. In this study, we demonstrate that overexpression of a Populus trichocarpa PtRWA-C gene increases the level of xylan acetylation and increases the lignin content and S/G ratio, ultimately yielding poplar woody biomass with reduced saccharification efficiency. Furthermore, through gene coexpression network and expression quantitative trait loci (eQTL) analysis, we found that PtRWA-C was regulated not only by the secondary cell wall hierarchical regulatory network but also by an AP2 family transcription factor HARDY (HRD). Specifically, HRD activates PtRWA-C expression by directly binding to the PtRWA-C promoter, which is also the cis-eQTL for PtRWA-C. Taken together, our findings provide insights into the functional roles of PtRWA-C in xylan acetylation and consequently saccharification and shed light on synthetic biology approaches to manipulate this gene and alter cell wall properties. These findings have substantial implications for genetic engineering of woody species, which could be used as a sustainable source of biofuels, valuable biochemicals, and biomaterials.
Subject(s)
Populus , Populus/genetics , Populus/metabolism , Xylans/metabolism , Acetylation , Biomass , Biofuels/analysis , Plants/metabolism , Cell Wall/metabolism , Lignin/metabolismABSTRACT
Although a large number of existing studies have confirmed that people with vitiligo are prone to mental disorders, these observational studies may be subject to confounding factors and reverse causality, so the true causal relationship is inconclusive. We conducted a bidirectional Mendelian randomization (MR) analysis to assess the causality between vitiligo and mental disorders, namely depression, anxiety, insomnia, schizophrenia, bipolar disorder, obsessive-compulsive disorder (OCD) and attention-deficit hyperactivity disorder (ADHD). Summary statistics from large available genome-wide association study (GWAS) datasets for generalized vitiligo (n = 44 266), depression (n = 173 005), anxiety (n = 17 310), insomnia (n = 386 988), schizophrenia (n = 130 644), bipolar disorder (n = 413 466), OCD (n = 9725) and ADHD (n = 225 534) were utilized. Inverse-variance weighted (IVW), MR-Egger and weighted median were employed to estimate causal effects. Sensitivity analysis and MR Pleiotropy Residual Sum and Outliers (MR PRESSO) were conducted to assess heterogeneity and pleiotropy, ensuring the robustness of the results. Additionally, we corrected for estimating bias that might be brought on by sample overlap using MRlap. In our findings, none of the rigorous bidirectional MR analyses uncovered a significant causal association. Even after applying the MRlap correction, the effect sizes remained statistically nonsignificant, thereby reinforcing the conclusions drawn via IVW. In summary, our genetic-level investigation did not reveal a causal link between generalized vitiligo and mental disorders.
Subject(s)
Mental Disorders , Sleep Initiation and Maintenance Disorders , Vitiligo , Humans , Vitiligo/genetics , Genome-Wide Association Study , Mendelian Randomization Analysis , Mental Disorders/geneticsABSTRACT
Mitosis entails global and dramatic alterations, such as higher-order chromatin organization disruption, concomitant with global transcription downregulation. Cells reliably re-establishing gene expression patterns upon mitotic exit and maintaining cellular identities remain poorly understood. Previous studies indicated that certain transcription factors (TFs) remain associated with individual loci during mitosis and serve as mitotic bookmarkers. However, it is unclear which regulatory factors remain bound to the compacted mitotic chromosomes. We developed formaldehyde-assisted isolation of regulatory elements-coupled mass spectrometry (FAIRE-MS) that combines FAIRE-based open chromatin-associated protein pull-down and mass spectrometry (MS) to quantify the open chromatin-associated proteome during the interphase and mitosis. We identified 189 interphase and mitosis maintained (IM) regulatory factors using FAIRE-MS and found intrinsically disordered proteins and regions (IDP(R)s) are highly enriched, which plays a crucial role in liquid-liquid phase separation (LLPS) and chromatin organization during the cell cycle. Notably, in these IDP(R)s, we identified mitotic bookmarkers, such as CEBPB, HMGB1, and TFAP2A, and several factors, including MAX, HMGB3, hnRNP A2/B1, FUS, hnRNP D, and TIAL1, which are at least partially bound to the mitotic chromosome. Furthermore, it will be essential to study whether these IDP(R)s through LLPS helps cells transit from mitosis to the G1 phase during the cell cycle.
Subject(s)
Chromatin , Proteome , Proteome/genetics , Chromatin/genetics , Chromosomes , Transcription Factors/genetics , Transcription Factors/metabolism , Mitosis , Mass SpectrometryABSTRACT
BACKGROUND: Obesity is associated with extensive white adipose tissue (WAT) expansion and remodeling. Healthy WAT expansion contributes to the maintenance of energy balance in the liver, thereby ameliorating obesity-related hepatic steatosis. Tissue-resident mesenchymal stromal cell populations, including PDGFRß + perivascular cells, are increasingly recognized pivotal as determinants of the manner in which WAT expands. However, the full array of regulatory factors controlling WAT stromal cell functions remains to be fully elucidated. Hypoxia-inducible factors (HIFs) are critical regulators in WAT stromal cell populations such as adipocyte precursor cells (APCs). It is revealed that HIF1α activation within PDGFRß + stromal cells results in the suppression of de novo adipogenesis and the promotion of a pro-fibrogenic cellular program in obese animals. However, the role of HIF2α in PDGFRß + cells remains undetermined in vivo. METHODS: New genetic models were employed in which HIF1α (encoded by the Hif1a gene) and HIF2α (encoded by the Epas1 gene) are selectively inactivated in PDGFRß + cells in an inducible manner using tamoxifen (TAM). With these models, both in vitro and in vivo functional analysis of PDGFRß + cells lacking HIF proteins were performed. Additionally, comprehensive metabolic phenotyping in diet-induced mouse models were performed to investigate the roles of PDGFRß + cell HIF proteins in WAT remodeling, liver energy balance and systemic metabolism. RESULTS: Unlike HIF1α inactivation, the new findings in this study suggest that inducible ablation of HIF2α in PDGFRß + cells does not cause apparent effects on WAT expansion induced by obesogenic diet. The adipogenic ability of PDGFRß + APCs is not significantly altered by genetic HIF2α ablation. Moreover, no difference of key parameters associated with healthy WAT remodeling such as improvements of WAT insulin sensitivity, reduction in metabolic inflammation, as well as changes in liver fat accumulation or systemic glucose metabolism, is detected in PDGFRß + cell Epas1-deficient mice. CONCLUSION: The new findings in this study support that, in contrast to HIF1α, PDGFRß + cell HIF2α appears dispensable for WAT metabolic remodeling and the resulting effects on liver metabolic homeostasis in diet-induced obesity, underscoring the isoform-specific roles of HIFα proteins in the regulation of adipose tissue biology.
Subject(s)
Adipose Tissue, White , Basic Helix-Loop-Helix Transcription Factors , Obesity , Animals , Mice , Adipose Tissue/metabolism , Adipose Tissue, White/metabolism , Lipids , Liver/metabolism , Mice, Inbred C57BL , Mice, Obese , Obesity/metabolism , Basic Helix-Loop-Helix Transcription Factors/metabolismABSTRACT
Modifying the atomic and electronic structure of platinum-based alloy to enhance its activity and anti-CO poisoning ability is a vital issue in hydrogen oxidation reaction (HOR). However, the role of foreign modifier metal and the underlying ligand effect is not fully understood. Here, we propose that the ligand effect of single-atom Cu can dynamically modulate the d-band center of Pt-based alloy for boosting HOR performance. By in situ X-ray absorption spectroscopy, our research has identified that the potential-driven structural rearrangement into high-coordination Cu-Pt/Pd intensifies the ligand effect in Pt-Cu-Pd, leading to enhanced HOR performance. Thereby, modulating the d-band structure leads to near-optimal hydrogen/hydroxyl binding energies and reduced CO adsorption energies for promoting the HOR kinetics and the CO-tolerant capability. Accordingly, PtPdCu1/C exhibits excellent CO tolerance even at 1,000 ppm impurity.
ABSTRACT
Rational design of efficient methanol oxidation reaction (MOR) catalyst that undergo non-CO pathway is essential to resolve the long-standing poisoning issue. However, it remains a huge challenge due to the rather difficulty in maximizing the non-CO pathway by the selective coupling between the key *CHO and *OH intermediates. Here, we report a high-performance electrocatalyst of patchy atomic-layer Pt epitaxial growth on CeO2 nanocube (Pt ALs/CeO2) with maximum electronic metal-support interaction for enhancing the coupling selectively. The small-size monolayer material achieves an optimal geometrical distance between edge Pt-O-Ce sites and *OH absorbed on CeO2, which well restrains the dehydrogenation of *CHO, resulting in the non-CO pathway. Meanwhile, the *CHO/*CO intermediate generated at inner Pt-O-Ce sites can migrate to edge, inducing the subsequent coupling reaction, thus avoiding poisoning while promoting reaction efficiency. Consequently, Pt ALs/CeO2 exhibits exceptionally catalytic stability with negligible degradation even under 1000â s pure CO poisoning operation and high mass activity (14.87â A/mgPt), enabling it one of the best-performing alkali-stable MOR catalysts.