Strain and Surface Engineering of Multicomponent Metallic Nanomaterials with Unconventional Phases.

Multicomponent metallic nanomaterials with unconventional phases show great prospects in electrochemical energy storage and conversion, owing to unique crystal structures and abundant structural effects. In this review, we emphasize the progress in the strain and surface engineering of these novel nanomaterials. We start with a brief introduction of the structural configurations of these materials, based on the interaction types between the components. Next, the fundamentals of strain, strain effect in relevant metallic nanomaterials with unconventional phases, and their formation mechanisms are discussed. Then the progress in surface engineering of these multicomponent metallic nanomaterials is demonstrated from the aspects of morphology control, crystallinity control, surface modification, and surface reconstruction. Moreover, the applications of the strain- and surface-engineered unconventional nanomaterials mainly in electrocatalysis are also introduced, where in addition to the catalytic performance, the structure-performance correlations are highlighted. Finally, the challenges and opportunities in this promising field are prospected.

A Biphasic Strategy to Synergistically Accelerate Activation and CO Spillover in Formic Acid Oxidation Catalysis.

Developing highly efficient and carbon monoxide (CO)-tolerant platinum (Pt) catalysts for the formic acid oxidation reaction (FAOR) is vital for direct formic acid fuel cells (DFAFCs), yet it is challenging due to the high energy barrier of direct intermediates (HCOO* and COOH*) as well as the CO poisoning issues associated with Pt alloy catalysts. Here we present a versatile biphasic strategy by creating a hexagonal/cubic crystalline-phase-synergistic PtPb/C (h/c-PtPb/C) catalyst to tackle the aforementioned issues. Detailed investigations reveal that h/c-PtPb/C can simultaneously facilitate the adsorption of direct intermediates while inhibiting CO adsorption, thereby significantly improving the activation and CO spillover. As a result, h/c-PtPb/C showcases an outstanding FAOR activity of 8.1 A mgPt-1, which is 64.5 times higher than that of commercial Pt/C and significantly surpasses monophasic PtPb. Moreover, the h/c-PtPb/C-based membrane electrode assembly exhibits an exceptional peak power density of 258.7 mW cm-2 for practical DFAFC applications.

Heterostructured Pt-PbS Nanobelt Achieves Remarkable Direct Formic Acid Oxidation Catalysis.

Developing efficient and CO-tolerant platinum (Pt)-based anodic catalysts is challenging for a direct formic acid fuel cell (DFAFC). Herein, we report heterostructured Pt-lead-sulfur (PtPbS)-based nanomaterials with gradual phase regulation as efficient formic acid oxidation reaction (FAOR) catalysts. The optimized Pt-PbS nanobelts (Pt-PbS NBs/C) display the mass and specific activities of 5.90 A mgPt-1 and 21.4 mA cm-2, 2.2/1.2, 1.5/1.1, and 36.9/79.3 times greater than those of PtPb-PbS NBs/C, Pt-PbSO4 NBs/C, and commercial Pt/C, respectively. Simultaneously, it exhibits a higher membrane electrode assembly (MEA) power density (183.5 mW cm-2) than commercial Pt/C (40.3 mW cm-2). This MEA stably operates at 0.4 V for 25 h, demonstrating a competitive potential of device application. The distinctive heterostructure endows the Pt-PbS NBs/C with optimized dehydrogenation steps and resisting the CO poisoning, thus presenting the remarkable FAOR performance. This work paves an effective avenue for creating high-performance anodic catalysts for fuel cells and beyond.

Amorphization Activated Multimetallic Pd Alloys for Boosting Oxygen Reduction Catalysis.

Amorphous nanomaterials have drawn extensive attention owing to their unique features, while amorphization on noble metal nanomaterials still remains formidably challenging. Herein, we demonstrate a universal strategy to synthesize amorphous Pd-based nanomaterials from unary to quinary metals through the introduction of phosphorus (P). The amorphous Pd-based nanoparticles (NPs) exhibit generally promoted oxygen reduction reaction (ORR) activity and durability compared with their crystalline counterparts. Significantly, the quinary P-PdCuNiInSn NPs, benefiting from the amorphous structure and multimetallic component effect, exhibit mass activities as high as 1.04 A mgPd-1 and negligible activity decays of 1.8% among the stability tests, which are much better than values for original Pd NPs (0.134 A mgPd-1 and 28.4%). Experimental and theoretical analyses collectively reveal that the synergy of P-induced amorphization and the expansion of metallic components can considerably lower the free energy changes in the rate-determined step, thereby explaining the positive correlation with the catalytic activity.

In Situ Imaging of GGT and HOBr-Triggered Atherosclerotic Plaque Rupture via Activating the RunX2/Col IV Signaling Pathway.

Calcification and abnormal collagen deposition within blood vessels constitute causative factors for atherosclerotic plaque rupture, and their occurrence is intimately linked with γ-glutamyltranspeptidase (GGT) and hypobromous acid (HOBr). However, the underlying regulatory mechanisms of GGT and HOBr in plaque rupture remain unclear. Hence, we developed a dual-responsive near-infrared (NIR) fluorescent probe (BOC-H) that effectively avoids spectral crosstalk for the in situ visualization of the fluctuations in GGT and HOBr levels during atherosclerotic plaque rupture. We found that both GGT and HOBr contents increase significantly in the calcification models of cells and animals. The overexpressed GGT participated in intracellular oxygen-promoting behavior, which obviously upregulated the expression of RunX2 and Col IV by facilitating H2O2 and HOBr secretion. This process triggered calcification and abnormal collagen deposition within the plaque, which raised the risk of plaque rupture. PM2.5-induced arteriosclerotic calcification models further verified the results that GGT and HOBr accelerate plaque rupture via activation of the RunX2/Col IV signaling pathway. Moreover, the assessment of GGT and HOBr in serum samples from patients with acute myocardial infarction further confirmed the co-regulation of GGT and HOBr in the plaque rupture. Together, our studies highlight the involvement of GGT and HOBr in driving plaque rupture and offer new targets for the prevention and treatment of acute cardiovascular disease.

Compressive Strain in Platinum-Iridium-Nickel Zigzag-Like Nanowire Boosts Hydrogen Catalysis.

Strain effect in the structurally defective materials can contribute to the catalysis optimization. However, it is challenging to achieve the performance improvement by strain modulation with the help of geometrical structure because strain is spatially dependent. Here, a new class of compressively strained platinum-iridium-metal zigzag-like nanowires (PtIrM ZNWs, M = nickel (Ni), cobalt (Co), iron (Fe), zinc (Zn) and gallium (Ga)) is reported as the efficient alkaline hydrogen evolution reaction (HER) and hydrogen oxidation reaction (HOR) catalysts. Particularly, the optimized PtIrNi ZNWs with 3% compressive strain (cs-PtIrNi ZNWs) can achieve the highest HER/HOR performances among all the catalysts investigate. Their HOR mass and specific activities are 3.2/14.4 and 2.6/32.7 times larger than those of PtIrNi NWs and commercial Pt/C, respectively. Simultaneously, they can exhibit the superior stability and high CO resistance for HOR. Further, experimental and theoretical studies collectively reveal that the compressive strain in cs-PtIrNi ZNWs effectively weakens the adsorption of hydroxyl intermediate and modulates the electronic structure, resulting in the weakened hydrogen binding energy (HBE) and moderate hydroxide binding energy (OHBE), beneficial for the improvement of HOR performance. This work highlights the importance of strain tuning in enhancing Pt-based nanomaterials for hydrogen catalysis and beyond.

Tuning Crystal Phase of Palladium-Selenium Nanowires for Enhanced Ethylene Glycol Electrocatalytic Oxidation.

Alcohol electrooxidation is pivotal for a sustainable energy economy. However, designing efficient electrocatalysts for this process is still a formidable challenge. Herein, palladium-selenium nanowires featuring distinct crystal phases: monoclinic Pd7Se2 and tetragonal Pd4.5Se for ethylene glycol electrooxidation reaction (EGOR) are synthesized. Notably, the supported monoclinic Pd7Se2 nanowires (m-Pd7Se2 NWs/C) exhibit superior EGOR activity, achieving a mass activity (MA) and specific activity (SA) of 10.4 A mgPd -1 (18.7 mA cm-2), which are 8.0 (6.7) and 10.4 (8.2) times versus the tetragonal Pd4.5Se and commercial Pd/C and surpass those reported in the literature. Furthermore, m-Pd7Se2 NWs/C displays robust catalytic activity for other alcohol electrooxidation. Comprehensive characterization and density functional theory (DFT) calculations reveal that the enhanced electrocatalytic performance is attributed to the increased formation of Pd0 on the high-index facets of the m-Pd7Se2 NWs, which lowers the energy barriers for the C─C bond dissociation in CHOHCHOH* and the CO* oxidation to CO2*. This study provides palladium-based alloy electrocatalysts exhibiting the highest mass activity reported to date for the electrooxidation of ethylene glycol, achieved through the crystalline phase engineering strategy.

Macrophages-derived exo-miR-4449 induced by Cryptococcus affects HUVEC permeability and promotes pyroptosis in BEAS-2B via the HIC1 pathway.

Macrophages have recently been discovered to assume a significant role in the progression of cryptococcosis. However, the potential involvement of macrophage-derived exosomes in the pathogenesis of cryptococcosis remains uncertain. In this study, we investigated the changes of microRNAs in macrophage exosomes (exo-miRNAs) in cryptococcal infections and the role of markedly altered exo-miRNAs in the modulation of Human Umbilical Vein Endothelial Cells (HUVEC) permeability and ROS accumulation and pyroptosis in Human Bronchial Epithelioid Cells (BEAS-2B). Techniques such as microarray analysis and real-time quantitative PCR were used to detect different exo-miRNAs and to screen for the most highly expressed exo-miRNAs. Then its mimics were transfected into HUVEC to study its effect on the monolayer permeability of HUVEC. Finally, the relationship between this exo-miRNAs and the ROS accumulation and pyroptosis was verified by bioinformatics analysis. The results showed that five exo-miRNAs were overexpressed and two exo-miRNAs were reduced, among which, exo-miR-4449 was expressed at the highest level. Exo-miR-4449 could be internalized by HUVEC and enhanced its monolayer permeability. Moreover, exo-miR-4449 was found to promote ROS accumulation and pyroptosis in BEAS-2B through HIC1 pathway. Thus, exo-miR-4449 plays an important role in the pathogenesis of cryptococcosis and holds promise as a significant biomarker for treatment.

Exploration of glutaredoxin-1 oxidative modification in carbon nanomaterial-induced hepatotoxicity.

Herein, we present toxicological assessments of carbon nanomaterials in HL-7702 cells, and it was found that reactive oxygen species (ROS) levels were elevated. Mass spectrometry results indicated that cysteine sulfhydryl of glutaredoxin-1 (GLRX1) was oxidized to sulfenic acids and sulfonic acids by excessive ROS, which broke the binding of GLRX1 to apoptosis signal-regulating kinase 1, causing the activation of the JNK/p38 signaling pathway and ultimately hepatocyte apoptosis. However, a lower level of ROS upregulated GLRX1 instead of sulfonation modification of its active sites. Highly expressed GLRX1 in turn enabled the removal of intracellular ROS, thereby exerting inconspicuous toxic effects on cells. Taken together, these findings emphasized that CNM-induced hepatotoxicity is attributable to oxidative modifications of GLRX1 arising from redox imbalance.

Correlation between a low serum free triiodothyronine level and mortality of severe pulmonary tuberculosis patients.

BACKGROUND: This study aimed to assess the relationship between a low serum free triiodothyronine (FT3) level and the mortality of severe pulmonary tuberculosis (TB) patients. METHODS: We performed a retrospective study and reviewed the medical records of patients with severe pulmonary TB between January 2016 and June 2022. The patient demographics, Acute Physiology and Chronic Health Evaluation (APACHE) II score, survival or death at 28 and 90 days after hospital admission, and serum FT3 level were recorded. Bivariate regression analysis was performed to study the relationship between mortality and the FT3 level. The Kaplan-Meier method and the log-rank test were used to compare the survival rates between patients with different serum FT3 levels. RESULTS: Our study included 495 severe pulmonary TB patients, with 383 (77.4%) patients having a low serum FT3 level. The low-serum FT3 group had high 28-day and 90-day mortalities. The patients who had died by 28 or 90 days after hospital admission had a low FT3 level. Survival analysis showed that the patients with a low serum FT3 level had a low probability of survival at 28 days and at 90 days after hospital admission. CONCLUSION: The serum FT3 level was correlated with the 28-day and 90-day mortalities in patients with severe pulmonary TB. The serum FT3 level should be monitored in these patients to help manage their disease.

Sensitivity of Botrytis cinerea from Vineyards to Boscalid, Isofetamid, and Pydiflumetofen in Shandong Province, China.

Succinate dehydrogenase inhibitor (SDHI) fungicides are the most commonly and effectively used class of fungicides for controlling gray mold. Among them, only boscalid has been registered in China for controlling grape gray mold, whereas isofetamid and pydiflumetofen are two new SDHI fungicides that have demonstrated high efficacy against various fungal diseases. However, the sensitivity of Botrytis cinerea isolates from vineyards in China to these three fungicides is currently unknown. In this study, the sensitivity of 55 B. cinerea isolates from vineyards to boscalid, isofetamid, and pydiflumetofen was determined, with the effective concentrations for inhibiting 50% of spore germination (EC50) values ranging from 1.10 to 393, 0.0300 to 42.0, and 0.0990 to 25.5 µg ml-1, respectively. The resistance frequencies for boscalid, isofetamid, and pydiflumetofen were 60.0, 7.2, and 12.8%, respectively. Three mutations (H272R, H272Y, and P225F) were detected in the SdhB subunit, with H272R being the most prevalent (75.7%), followed by H272Y (16.2%) and P225F (8.1%). All three mutations are associated with resistance to boscalid, and of them, H272R mutants exhibited high resistance. Only P225F and H272Y mutants exhibited resistance to isofetamid and pydiflumetofen, respectively. A weakly positive cross-resistance relationship was observed between boscalid and pydiflumetofen (r = 0.38, P < 0.05). Additionally, the H272R mutants showed no significant fitness costs, whereas the remaining mutants exhibited reduced mycelial growth (P225F) and sporulation (H272Y and P225F). These results suggest that isofetamid and pydiflumetofen are effective fungicides against B. cinerea in vineyards, but appropriate rotation strategies must be implemented to reduce the selection of existing SDHI-resistant isolates.

Patient Characteristics Associated with Concurrent Klebsiella pneumoniae Infection and Severe Pulmonary Tuberculosis.

BACKGROUND: This study aims to investigate the clinical characteristics associated with concurrent Klebsiella pneu-moniae (K. pneumoniae) infection in hospitalized patients with severe pulmonary tuberculosis. METHODS: A retrospective study was conducted on hospitalized severe pulmonary tuberculosis patients between January 2019 and December 2020. Among the 487 patients with severe pulmonary tuberculosis, a positive sputum culture for K. pneumoniae was reported in 76 patients (15.6%, 61 males and 15 females). RESULTS: Among these patients, 27 (35.5%) and 49 (64.5%) patients were with and without K. pneumoniae infection, respectively. Compared to patients without K. pneumoniae infection, patients with K. pneumoniae infection had higher mortality (16.3% vs. 40.7%, p = 0.02), and lower inhibitory/cytotoxic CD8 count (24.2 ± 9.9 vs. 17.8 ± 8.0, p = 0.02), complement C4 (0.3 ± 0.1 vs. 0.2 ± 0.1, p = 0.01), and retinol-binding protein level (32.2 ± 22.2 vs. 22.4 ± 11.8, p = 0.02). Furthermore, the acute Physiology and Chronic Health Evaluation II score was associated with the K. pneumoniae infection in severe pulmonary tuberculosis patients. CONCLUSIONS: It can be concluded that a significant number of severe pulmonary tuberculosis patients can have concurrent K. pneumoniae infection. Immunity, nutritional status, and disease severity are associated with the concurrent infection of K. pneumoniae in these patients.

Association between maternal blood lipids and neonatal hypoglycaemia in pregnancy with gestational diabetes mellitus: a cohort study.

BACKGROUND: Gestational diabetes mellitus (GDM) prevalence is on the rise globally. Offspring of diabetic mothers face increased risk of neonatal hypoglycaemia (NH), and women with GDM have abnormal lipid profiles. However, there is no consensus on the link between maternal blood lipids and NH in infants from mothers with GDM. This study aimed to explore how maternal blood lipids affect NH. METHODS: A retrospective cohort study was conducted at the First Affiliated Hospital of Sun Yat-sen University. Information on participants' baseline characteristics and maternal metabolic profiles of glucose and lipids was collected. Significant variables from the univariate analysis were included in logistic regression, which was used to construct the predictive model for NH. A nomogram was constructed for visualizing the model and assessed using the area under the receiver operating characteristic (ROC) curve (AUC). RESULTS: Neonatal capillary blood glucose (CBG) decreased rapidly in the first hour after birth, increased gradually from the first to the second hour, and then remained stable. In the NH group, 86.11% (502/583) of hypoglycaemia cases occurred within the first two hours after birth. Multivariate logistic regression suggested that the lipid indices of maternal apoprotein B/apoprotein A1 (Apo-B/Apo-A1) (odds ratio (OR) = 1.36, 95% confidence intervals (CIs): 1.049-1.764, P = 0.02) and apoprotein E (Apo-E) (OR = 1.014, 95% CIs: 1.004-1.024, P = 0.004) were positively associated with NH in neonates from mothers with GDM. Triglycerides (TGs) (OR = 0.883, 95% CIs: 0.788-0.986, P = 0.028) were inversely associated with NH. Maternal glycated haemoglobin (HbA1c), age, twin pregnancy and caesarean delivery also had predictive value of NH. The AUC of the nomogram derived from these factors for the prediction model of NH was 0.657 (95% CIs: 0.630-0.684). CONCLUSIONS: The present study revealed that the Apo-B/Apo-A1 and Apo-E levels were associated with an increased risk of NH. A nomogram was developed to forecast the risk of NH in babies born to mothers with GDM, incorporating maternal blood lipids, HbA1c, age, twin pregnancy, and caesarean section. The trajectory of glycaemia for neonates indicates the need for intensive CBG monitoring within 2 h of birth for neonates from mothers with GDM.

Highly Selective CO2 Electroreduction to C2+ Products over Cu2O-Decorated 2D Metal-Organic Frameworks with Rich Heterogeneous Interfaces.

The electroreduction of carbon dioxide into high-value-added products is an effective approach to alleviating the energy crisis and pollution issues. However, there are still significant challenges for multicarbon (C2+) product production due to the lack of efficient catalysts with high selectivity. Herein, a Cu-rich electrocatalyst, where Cu2O nanoparticles are decorated on two-dimensional (2D) Cu-BDC metal-organic frameworks (MOFs) with abundant heterogeneous interfaces, is synthesized for highly selective CO2 electroreduction into C2+ products. A high C2+ Faradaic efficiency of 72.1% in an H-type cell and 58.2% in a flow cell are obtained, respectively. The heterogeneous interfaces of Cu2O/Cu-BDC can optimize the adsorption energy of reaction intermediates during CO2 electroreduction. An in situ infrared spectroscopy study indicates that the constructed interfaces can maintain the particular distribution of Cu valence states, where the C-C coupling is promoted to efficiently produce C2+ products owing to the stabilization of *CHO and *COH intermediates.

Nanotip-Induced Electric Field for Hydrogen Catalysis.

Local electric field induced by the lightning-rod effect attracts great attention for regulating the local microenvironment and electronic properties of active sites. Nevertheless, local electric-field-assisted applications are mainly limited to metals with strong surface plasmonic resonance properties (e.g., Au, Ag, and Cu). Herein, we fabricate RuCu snow-like nanosheets (SNSs) with high-curvature nanotips for enhancing the hydrogen oxidation reaction (HOR) and hydrogen evolution reaction (HER). Theoretical simulations show that RuCu SNSs can induce a strong local electric field around the sharp nanotips, which favors the accumulation of OH- for HOR and H+ for HER. Cu incorporation can modulate the binding strength of OH* and H*, leading to significantly enhanced HOR and HER performance. Impressively, the mass activity of RuCu SNSs for alkaline HOR is 31.3 times higher than that of RuCu nanocrystals without sharp tips. Besides, the required overpotential for reaching 10 mA cm-2 during HER over RuCu SNSs is 14.0 mV.

Emerging two dimensional metastable-phase oxides: insights and prospects in synthesis and catalysis.

Since the discovery of graphene, the development of new two-dimensional (2D) materials has received considerable interest. Recently, as a newly emerging member of the 2D family, 2D metastable-phase oxides that combine the unique advantages of metal oxides, 2D structures, and metastable-phase materials have shown enormous potential in various catalytic reactions. In this review, the potential of various 2D materials to form a metastable-phase is predicted. The advantages of 2D metastable-phase oxides for advanced applications, reliable methods of synthesizing 2D metastable-phase oxides, and the application of these oxides in different catalytic reactions are presented. Finally, the challenges associated with 2D metastable-phase oxides and future perspectives are discussed.

Highly Selective Synthesis of Monoclinic-Phased Platinum-Tellurium Nanotrepang for Direct Formic Acid Oxidation Catalysis.

Designing efficient formic acid oxidation reaction (FAOR) catalysts with remarkable membrane electrode assembly (MEA) performance in a direct formic acid fuel cell (DFAFC) medium is significant yet challenging. Herein, we report that the monoclinic-phased platinum-tellurium nanotrepang (m-PtTe NT) can be adopted as a highly active, selective, and stable FAOR catalyst with a desirable direct reaction pathway. The m-PtTe NT exhibits the high specific and mass activities of 6.78 mA cm-2 and 3.2 A mgPt-1, respectively, which are 35.7/22.9, 2.8/2.6, and 3.9/2.9 times higher than those of commercial Pt/C, rhombohedral-phased Pt2Te3 NT (r-Pt2Te3 NT), and trigonal-phased PtTe2 NT (t-PtTe2 NT), respectively. Simultaneously, the highest reaction tendency for the direct FAOR pathway and the best tolerance to poisonous CO intermediate can also be realized by m-PtTe NT. More importantly, even in a single-cell medium, the m-PtTe NT can display a much higher MEA power density (171.4 mW cm-2) and stability (53.2% voltage loss after 5660 s) than those of commercial Pt/C, demonstrating the great potential in operating DFAFC device. The in-situ Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy jointly demonstrate that the unique nanostructure of m-PtTe NT can effectively optimize dehydrogenation steps and inhibit the CO intermediate adsorption, as well as promote the oxidation of noxious CO intermediate, thus achieving the great improvement of FAOR activity, poisoning tolerance, and stability. Density functional theory calculations further reveal that the direct pathway is the most favorable on m-PtTe NT than r-Pt2Te3 NT and t-PtTe2 NT. The higher activation energy to produce CO and the relatively weaker binding with CO of m-PtTe NT result in the better CO tolerance. This work achieves remarkable FAOR and MEA performances of advanced Pt-based anodic catalysts for DFAFCs via a phase engineering strategy.

Sub-Monolayer SbOx on PtPb/Pt Nanoplate Boosts Direct Formic Acid Oxidation Catalysis.

To promote the commercialization of direct formic acid fuel cell (DFAFC), it is vital to explore new types of direct formic acid oxidation (FAOR) catalysts with high activity and direct pathway. Here, we report the synthesis of intermetallic platinum-lead/platinum nanoplates inlaid with sub-monolayer antimony oxide surface (PtPb/Pt@sub-SbOx NPs) for efficient catalytic applications in FAOR. Impressively, they can achieve the remarkable FAOR specific and mass activities of 28.7 mA cm-2 and 7.2 A mgPt-1, which are 151 and 60 times higher than those of the state-of-the-art commercial Pt/C, respectively. Furthermore, the X-ray photoelectron spectroscopy and X-ray absorption spectroscopy results collectively reveal the optimization of the local coordination environment by the surface sub-monolayer SbOx, along with the electron transfer from Pb and Sb to Pt, driving the predominant dehydrogenation process. The sub-monolayer SbOx on the surface can effectively attenuate the CO generation, largely improving the FAOR performance of PtPb/Pt@sub-SbOx NPs. This work develops a class of high-performance Pt-based anodic catalyst for DFAFC via constructing the unique intermetallic core/sub-monolayer shell structure.

Platinum-Lead-Bismuth/Platinum-Bismuth Core/Shell Nanoplate Achieves Complete Dehydrogenation Pathway for Direct Formic Acid Oxidation Catalysis.

Designing platinum (Pt)-based formic acid oxidation reaction (FAOR) catalysts with high performance and high selectivity of direct dehydrogenation pathway for direct formic acid fuel cell (DFAFC) is desirable yet challenging. Herein, we report a new class of surface-uneven PtPbBi/PtBi core/shell nanoplates (PtPbBi/PtBi NPs) as the highly active and selective FAOR catalysts, even in the complicated membrane electrode assembly (MEA) medium. They can achieve unprecedented specific and mass activities of 25.1 mA cm-2 and 7.4 A mgPt-1 for FAOR, 156 and 62 times higher than those of commercial Pt/C, respectively, which is the highest for a FAOR catalyst by far. Simultaneously, they show highly weak adsorption of CO and high dehydrogenation pathway selectivity in the FAOR test. More importantly, the PtPbBi/PtBi NPs can reach the power density of 161.5 mW cm-2, along with a stable discharge performance (45.8% decay of power density at 0.4 V for 10 h), demonstrating great potential in a single DFAFC device. The in situ Fourier transform infrared spectroscopy (FTIR) and X-ray absorption spectroscopy (XAS) results collectively reveal a local electron interaction between PtPbBi and PtBi. In addition, the high-tolerance PtBi shell can effectively inhibit the production/adsorption of CO, resulting in the complete presence of the dehydrogenation pathway for FAOR. This work demonstrates an efficient Pt-based FAOR catalyst with 100% direct reaction selectivity, which is of great significance for driving the commercialization of DFAFC.

Defective ZnIn2S4 Nanosheets for Visible-Light and Sacrificial-Agent-Free H2O2 Photosynthesis via O2/H2O Redox.

H2O2 photosynthesis has attracted great interest in harvesting and converting solar energy to chemical energy. Nevertheless, the high-efficiency process of H2O2 photosynthesis is driven by the low H2O2 productivity due to the recombination of photogenerated electron-hole pairs, especially in the absence of a sacrificial agent. In this work, we demonstrate that ultrathin ZnIn2S4 nanosheets with S vacancies (Sv-ZIS) can serve as highly efficient catalysts for H2O2 photosynthesis via O2/H2O redox. Mechanism studies confirm that Sv in ZIS can extend the lifetimes of photogenerated carriers and suppress their recombination, which triggers the O2 reduction and H2O oxidation to H2O2 through radical initiation. Theoretical calculations suggest that the formation of Sv can strongly change the coordination structure of ZIS, modulating the adsorption abilities to intermediates and avoiding the overoxidation of H2O to O2 during O2/H2O redox, synergistically promoting 2e- O2 reduction and 2e- H2O oxidation for ultrahigh H2O2 productivity. The optimal catalyst displays a H2O2 productivity of 1706.4 µmol g-1 h-1 under visible-light irradiation without a sacrificial agent, which is ∼29 times higher than that of pristine ZIS (59.4 µmol g-1 h-1) and even much higher than those of reported photocatalysts. Impressively, the apparent quantum efficiency is up to 9.9% at 420 nm, and the solar-to-chemical conversion efficiency reaches ∼0.81%, significantly higher than the value for natural synthetic plants (∼0.10%). This work provides a facile strategy to separate the photogenerated electron-hole pairs of ZIS for H2O2 photosynthesis, which may promote fundamental research on solar energy harvest and conversion.