Positive Onset Research Articles

Analysis of clinical characteristics and factors affecting treatment responses in patients with pyoderma gangrenosum: a multicenter study of 239 patients☆

BackgroundPyoderma Gangrenosum (PG) is a chronic disease characterized by recalcitrant skin ulcers. ObjectiveWe aimed to evaluate the demographic, clinical characteristics, treatments and factors affecting the treatment responses of patients with PG. MethodsWe performed a multicenter study of 12 tertiary care centers. We analyzed the data of the patients who were followed up with a diagnosis of PG between the years 2012‒2022 retrospectively. ResultsWe included a total of 239 patients of whom 143 were female and 96 were male, with an average age of 54.2 ± 17.4 years. The most common treatment was systemic steroids (n = 181, 75.7%). Among these patients, 50.8% (n = 92) used systemic steroids as the sole systemic agent, while 49.2% (n = 89) used at least one adjuvant immunosuppressive agent. The independent factors determined in regression analysis to influence response to systemic steroids positively were disease onset age ≥ 30-years, negative pathergy, absence of leukocytosis, negative wound culture, presence of a single lesion, and absence of upper extremity involvement. Biological agents were used in 18.4% (n = 44) of the patients in the present study. We also analyzed pathergy positive PG and early onset (onset age < 30) PG separately due to their distinct clinical features which were revealed during statistical analysis. Study limitationsRetrospective nature of the present study. ConclusionsAnalyses of the factors influencing treatment responses are addressed in this study. Also, we concluded that investigation for accompanying autoinflammatory diseases of pathergy positive PG and early onset PG is necessary and the patients in these two groups are more resistant to treatment, necessitating more complicated treatments.

Minimizing liquid/solid interfacial energy boosts Fe−N doping inside hollow carbon sphere for oxygen reduction in membrane-less direct formate fuel cell

Porous hollow carbon sphere (HCS) is an attractive catalyst support for oxygen reduction reaction (ORR) due to its large specific surface area for active site anchoring, porous and hollow structure for active site exposure and mass transfer. However, due to the high transfer resistance for exogenous heteroatoms into HCS, most of active sites are usually loaded on the outer surface of HCS, leading to the decrease of active site density and the aggregation of heteroatomic particles. In this work, we proposed that accompanied with the decrease of liquid/solid interfacial energy by changing solvent composition during impregnation, penetration of exogenous heteroatoms-containing solution was facilitated in HCS, resulting in increased density of uniformly-dispersed Fe−Nx active site by 58 %. Taking advantage of high-content and well-dispersed active site, structure-derived porosity for ion transfer and active site exposure, this HCS-derived catalyst (Fe-HCS@C2H5OH) exhibited positive onset and half-wave potentials of 0.953 V and 0.901 V (vs. RHE), as well as high power density of 20.17 ± 0.31 mW cm−2 when applied in membrane-less direct formate fuel cell cathode, surpassing those of commercial Pt/C and the state-of-the-art carbonaceous catalysts. This strategy of interfacial energy control provides a new stepping-stone for the synthesis of high-performance electrocatalysts.

Diagnostic and clinical utility of comprehensive multigene panel testing for patients with neuropathy.

Prior to next-generation sequencing (NGS), the evaluation of a patient with neuropathy typically consisted of screening for acquired causes, followed by clinical genetic testing of PMP22, MFN2, GJB1, and MPZ in patients with a positive family history and symptom onset prior to age 50. In this study, we examined the clinical utility of NGS in a large cohort of patients analyzed in a commercial laboratory. A cohort of 6849 adult patients underwent clinician-ordered peripheral neuropathy multigene panel testing ranging from 66 to 111 genes that included NGS and intragenic deletion/duplication analysis. A molecular diagnosis was identified for 8.4% of the cohort (n = 573/6849). Variants in PMP22, MFN2, GJB1, MPZ, and TTR accounted for 73.8% of molecular diagnoses. Results had potential clinical actionability for 398 (69.5%) patients. Our results suggest that 225/573 (39.3%) of molecular diagnoses and 113/398 (28.4%) of clinical interventions would have been missed if the testing approach had been restricted to older guidelines. Our results highlight the need for expanded genetic testing guidelines that account for the increased number of genes associated with hereditary neuropathy, address the overlap of acquired and hereditary neuropathy, and provide broader access to genetic diagnosis for patients.

Exploring B‐site Doping in LaFeO3 Perovskites for Superior ORR Performance in Acidic and Alkaline Conditions

AbstractIn recent times, perovskite oxides have recognized to be an ideal alternative to platinum‐based oxygen reduction reaction (ORR) electrocatalysts due to their excellent stability, cost‐effectiveness, and tailorable properties. Herein, an ABO3 type LaFeO3 perovskite was doped at its B‐site to form electrochemically active LaFeB′O6 (B′=Cr, Zn, Co) by one‐pot hydrothermal synthesis process. Due to the synergistic effects of increased surface area and electrochemically active sites, Cr‐doped LaFeO3 largely improves the mass transfer kinetics for ORR in both conditions, alkaline (0.1 M KOH) and acidic (0.5 M H2SO4) with a positive onset Eon of 0.80 and 0.81 V (vs Ag/AgCl). Similarly, a half‐wave (E1/2) potential of 0.68 and 0.63 V (vs Ag/AgCl), which was comparable to the commercial 20 % Pt/C. Moreover, the La‐based perovskites were able to catalyze ORR with an electron transfer number (n)&gt;3.6 signifying the superior 4‐electron pathway. Doped and undoped LaFeO3 exhibited remarkable stability in the chronoamperometry studies with a relative current of 92–95 % sustained over 8 h. Additionally, the La‐based electrocatalysts was unaffected by the crossover effect of methanol in both acidic and basic conditions, contrary to the commercial 20 % Pt/C. The present work serves as a useful strategy to maximize the efficiency and reliability in perovskites for energy‐related electrocatalytic applications and for alternative fuel generation.

Gas-phase electrochemical CO2 reduction on silver-copper BTC MOF in a zero-gap membrane electrode assembly

Bimetallic AgCu-BTC MOFs, derived from Cu-BTC (HKUST-1), have been synthesized by fast co-precipitation method and evaluated for CO2 reduction reaction (CO2RR) using humidified CO2 gas in a zero-gap configuration. Three compositions with varying Ag content – AgCu-1 (9.4 at.%), AgCu-2 (12.5 at.%), and AgCu-3 (16.5 at.%) – were characterized by SEM-EDS, PXRD, FTIR, and XPS. These structural analyzes confirmed the formation of a low-crystalline AgCu-BTC MOF with Ag+1 ions coordinated to the BTC framework. Electrochemical tests (CV and LSV) revealed that AgCu-3 MOF, with the highest Ag content (16.5 at.%), exhibited a more positive onset potential at -0.65 V vs Ag/AgCl compared to HKUST-1 MOF, indicating enhanced CO2RR activity, owing to Ag incorporation. Constant potential (CP) experiments showed that AgCu-3 MOF predominantly produced CO and H2, achieving faradaic efficiency of approximately 65 % for CO production and 5 % for H2 production. Moreover, lowering the relative humidity (RH%) in the inlet CO2 gas stream from 80% to 20% increased CO production by 2-fold from 6.2 µmol s-1 cm-2 to 13 µmol s-1 cm-2, simultaneously suppressing the hydrogen evolution reaction (HER). This reduction in humidity resulted in an increased local concentration of CO2 at the catalyst site, leading to an enhanced CO2RR rate. However, substantial morphological changes have been observed in the AgCu-3 MOF after the CP experiment under humid CO2 reduction conditions.

Phenotyping chronic respiratory diseases with airways obstruction.

<sec id="st1"><title>BACKGROUND</title>Given the high prevalence of asthma-chronic obstructive pulmonary disease overlap (ACO) in Vietnam, there is an urgent need to establish a simplified strategy for categorising patients as either having asthma or chronic obstructive pulmonary disease (COPD). This classification would streamline the application of treatment recommendations outlined by the Global Initiative for Asthma (GINA) and the Global Initiative for Chronic Obstructive Lung Disease (GOLD).</sec><sec id="st2"><title>METHODS</title>Patients with obstructive lung function were classified as having COPD, asthma, or ACO based on GINA/GOLD guidelines. We hypothesised that ACO-like asthma (ACO-A) would present with positive skin prick tests (SPTs) or early onset of symptoms without a history of tuberculosis (TB), while those with ACO-like COPD (ACO-B) would exhibit negative SPTs and late onset of symptoms and/or a history of TB.</sec><sec id="st3"><title>RESULTS</title>Among 235 patients, the prevalence of asthma, ACO-A, ACO-B, and COPD was respectively 21%, 22%, 17%, and 40%. Allergic history, rhinitis, and childhood asthma were associated with ACO-A, while high cumulative smoking was correlated with ACO-B. Socio-economic and demographic parameters, medical history, clinical features, smoking habits, lung function, and para-clinical investigations significantly differed between "all asthma" (i.e., individuals with asthma combined with ACO-A) and "all COPD" (i.e., individuals with COPD combined with ACO-B).</sec><sec id="st4"><title>CONCLUSION</title>Based on SPTs, history of TB, and onset age, ACO patients may be defined as people with asthma or COPD.</sec>.

Enhanced activity and durability of Pt nanoclusters catalyst by using nitrogen-doped carbon layer coated carbon nanotubes as anchors and nanowires for ORR

Platinum-based catalysts remain the top choice for oxygen reduction reaction (ORR) in fuel cells. However, their activity and durability in the acidic medium are still under improvement. In this work, the Pt nanoclusters anchored the nitrogen-doped carbon nanotubes (Pt-NCNTs) have been synthesized by using a series process of pyrrole coating on the CNTs and subsequent pyrolysis to the chemical immersion reduction of Pt ions. The inner CNTs of Pt-NCNTs function as the nanowires offering a high-speed pathway for electron transport, and the Pt nanoclusters increases the active sites. The theoretical calculation demonstrates that the local structural defects and the uneven charge distribution induced by nitrogen-containing functional groups and porous structure are favorable to capture Pt ions for the nucleation of Pt nanoclusters. Compared with the commercial 40 wt% Pt/C (0.94 and 0.80 V), the Pt-NCNTs-1000 with Pt loading amount of 33.0 wt% owns the more positive onset potential and half-wave potential of 0.97 and 0.81 V in the sulfuric acid medium. Meanwhile, the strong attachment of Pt nanoclusters on the nitrogen-doped porous carbon layer results in a stable interface to effectively prevent the metallic species from migration and agglomeration during the electrode reactions. Therefore, the ORR current of Pt-NCNTs-1000 retained 84.3% of the initial value after 50000 s operation superior to the commercial Pt/C (64.6%).

Surprising Route to a Monoazaporphyrin and Full Characterization of Its Complexes with Five Different 3d Metals.

In the search for mild agents for the oxidative cyclization of tetrapyrromethane to the corresponding corrole, we discovered a route that leads to a monoazaporphyrin with three meso-CF3 groups. Optimization studies that allowed access to appreciable amounts of this new macrocycle paved the way for the preparation of its cobalt, copper, nickel, zinc, and iron complexes. All complexes were fully characterized by various spectroscopic methods and X-ray crystallography. Their photophysical and electrochemical properties were determined and compared to those of analogous porphyrins in order to deduce the effect of the peripheral N atom. Considering the global efforts for designing efficient alternatives to platinum group metal (PGM) catalysts, they were also absorbed onto a porous carbon electrode material and studied as electrocatalysts for the oxygen reduction reaction (ORR). The cobalt complex was found to be operative at a quite positive catalytic onset potential and with good selectivity for the desirable 4-electrons/4-protons pathway.

Characterizing brain tau and cognitive decline along the amyloid timeline in Alzheimer's disease.

Recent longitudinal PET imaging studies have established methods to estimate the age at which amyloid becomes abnormal at the level of the individual. Here we recontextualized amyloid levels into the temporal domain to better understand the downstream Alzheimer's disease processes of tau neurofibrillary tangle (NFT) accumulation and cognitive decline. This cohort study included a total of 601 individuals from the Wisconsin Registry for Alzheimer's Prevention and Wisconsin Alzheimer's Disease Research Center that underwent amyloid and tau PET, longitudinal neuropsychological assessments and met clinical criteria for three clinical diagnosis groups: cognitively unimpaired (n = 537); mild cognitive impairment (n = 48); or dementia (n = 16). Cortical 11C-Pittsburgh compound B (PiB) distribution volume ratio (DVR) and sampled iterative local approximation were used to estimate amyloid positive (A+; global PiB DVR > 1.16 equivalent to 17.1 centiloids) onset age and years of A+ duration at tau PET (i.e. amyloid chronicity). Tau PET burden was quantified using 18F-MK-6240 standardized uptake value ratios (70-90 min, inferior cerebellar grey matter reference region). Whole-brain and region-specific approaches were used to examine tau PET binding along the amyloid timeline and across the Alzheimer's disease clinical continuum. Voxel-wise 18F-MK-6240 analyses revealed that with each decade of A+, the spatial extent of measurable tau spread (i.e. progressed) from regions associated with early to late NFT tau stages. Regional analyses indicated that tau burden in the entorhinal cortex was detectable, on average, within 10 years of A+ onset. Additionally, the entorhinal cortex was the region most sensitive to early amyloid pathology and clinical impairment in this predominantly preclinical sample. Among initially cognitively unimpaired (n = 472) individuals with longitudinal cognitive follow-up, mixed effects models showed significant linear and non-linear interactions of A+ duration and entorhinal tau on cognitive decline, suggesting a synergistic effect whereby greater A+ duration, together with a higher entorhinal tau burden, increases the likelihood of cognitive decline beyond their separable effects. Overall, the amyloid time framework enabled a spatiotemporal characterization of tau deposition patterns across the Alzheimer's disease continuum. This approach, which examined cross-sectional tau PET data along the amyloid timeline to make longitudinal disease course inferences, demonstrated that A+ duration explains a considerable amount of variability in the magnitude and topography of tau spread, which largely recapitulated NFT staging observed in human neuropathological studies. By anchoring disease progression to the onset of amyloid, this study provides a temporal disease context, which may help inform disease prognosis and timing windows for anti-amyloid therapies.

Selectivity-Enhanced Electroreduction of CO2 to CO at Novel Ru-Linked-GO Nanohybrids: the Role of Nanoarchitecture.

Recently, global-scale efforts have been conducted for the electroreduction of CO2 as a potentially beneficial pathway for the conversion of greenhouse gases to useful chemicals and renewable fuels. This study focuses on the development of selective and sustainable electrocatalysts for the reduction of aqueous CO2 to CO. A RuIIcomplex [Ru(tptz)(ACN)Cl2] (RCMP) (tptz = 2,4,6-tris(2-pyridyl)-1,3,5-triazine, ACN = acetonitrile) was prepared as a molecular electrocatalyst for the CO2 reduction reaction in an aqueous solution. Density functional theory-calculated frontier molecular orbitals suggested that the tptz ligand plays a key role in dictating the electrocatalytic reactions. The RCMP electrocatalyst was grafted onto the graphene oxide (GO) surface both noncovalently (GO/RCMP) and covalently (GO-RCMP). The field emission scanning electron microscopy and elemental distribution analyses revealed the homogeneous distribution of the complex onto the GO sheet. The photoluminescence spectra confirmed accelerated charge-transfer in both nanohybrids. Compared to the bare complex, the GO-RCMP and GO/RCMP nanohybrids showed enhanced electrocatalytic activity, achieving >95% and 90% Faradaic efficiencies for CO production at more positive onset potentials, respectively. The GO-RCMP nanohybrid demonstrated outstanding electrocatalytic activity with a current of ∼84 μA. The study offers a perspective on outer- and inner-sphere electron-transfer mechanisms for electrochemical energy conversion systems.

Coordination engineering and electronic structure modulation of FeNi dual-single-atoms encapsulated in N, P-codoped 3D hierarchically porous carbon electrocatalyst for synergistically boosting oxygen reduction reaction

With the increasing energy and environmental issues in recent years, it is vital to explore inexpensive and highly activated oxidation reduction reaction (ORR) catalysts for next generation energy storage and conversion devices such as zinc-air batteries. Herein, FeNi dual-single-atoms were efficiently encapsulated into N,P-codoped 3D hierarchically porous carbon (FeNi DSAs/N,P-PC) by a simple one-step pyrolysis. The resulting FeNi DSAs/N,P-PC catalyst exhibited the better ORR activity with the positive onset potential (Eonset = 1.02 V) and half-wave potential (E1/2 = 0.88 V) over commercial Pt/C, and performed well in the assembled zinc-air batteries (peak power density of 124.73 mW cm−2,and long-term charge/discharge stable cycling for 330 h). The XAFS analysis clearly displayed the coordination structure and interactions of the FeNi dual atoms. The DFT calculations show that P-O bonds have great influence on the electronic structure of the FeNi dual atoms. And Ni site can effectively modulate the electronic structure of the Fe site to promote charge transfer and further reduce the energy barrier of the rate-limiting step. This strategy provides a viable strategy for development of low-cost high-performance transition metal diatomic catalysts suitable for energy conversion and storage devices.

Association between intraoperative fluid management and post-operative acute kidney injury: A single-center observational study

Background: Post-operative acute kidney injury (AKI) poses significant risks. Identifying intraoperative determinants is crucial for enhancing patient outcomes and tailoring surgical interventions. Aims and Objectives: This study aimed to investigate the onset of post-operative AKI in patients subjected to various surgical interventions and identify potential intra-operative determinants. Materials and Methods: In this observational investigation conducted at our institution, 100 patients who underwent diverse surgical procedures were included in the study. AKI diagnosis was based on the kidney disease: improving global outcomes guidelines. The parameters assessed encompassed patient demographics, intraoperative fluid management, surgical and anesthetic durations, and post-operative AKI incidence. Determinants of AKI were identified using multivariate logistic regression. Results: The cohort comprised 58% males, with a mean age of 65±12 years. Key comorbidities included hypertension (42%), diabetes mellitus (28%), chronic kidney disease (15%), and cardiovascular disease (20%). Intraoperatively, the average fluid volume administered was 2.5 ± 0.8 L. Fluid management primarily included balanced crystalloids (70%), followed by normal saline (20%), and colloids (10%). Anesthesia was maintained for an average of 3.5 ± 1.2 h. Post-surgery, 15% of the patients developed AKI. A detailed evaluation revealed a strong association between positive intraoperative fluid balance and AKI onset. The statistical analysis pinpointed elevated intraoperative fluid balance (odds ratio: 5.89; 95% confidence interval [CI]: 1.72–20.15; P=0.004) and extended anesthesia duration (odds ratio: 2.12; 95% CI: 1.01–4.47; P=0.046) as significant predictors. Conclusion: AKI onset post-surgery is closely tied to intraoperative factors, notably fluid balance, and anesthesia duration. This underscores the importance of personalized fluid management and vigilant post-operative renal function monitoring to mitigate AKI risks.

Enhanced electrocatalytic activity of palladium electrocatalysts supported on corncob biochar for ethanol oxidation reaction in alkaline medium

AbstractIn this study, palladium particles supported on carbon black (Vulcan XC‐72) (Pd/C) and corncob biochar (Pd/CB800, Pd/CB900, and Pd/CB1000) were successfully synthesized using borohydride reduction. The biochar support was obtained from corncob waste via pyrolysis from 800 to 1000°C. Scanning electron microscopy with energy dispersive x‐ray (SEM–EDX) revealed successful deposition of Pd metal particles on the carbon support materials. X‐ray diffraction (XRD) analysis confirmed the crystalline structures of Pd, and the crystallite size was found to be smallest in Pd/CB900. The electrocatalytic activity of the Pd electrocatalyst composites towards ethanol oxidation reaction (EOR) in an alkaline medium was investigated using cyclic voltammetry (CV). CV analysis has shown that Pd/CB900 gave the least positive onset potential (Eonset = −0.587 ± 0.0065 V), highest electrochemically active surface area (EASA = 31.51 ± 2.24 m2·g−1), and highest anodic peak current density (If = 20.77 mA·cm−2) compared with Pd/CB800, Pd/CB1000, and Pd/C. Furthermore, the Tafel plot and chronoamperometry have shown that Pd/CB900 exhibited faster kinetics (Tafel slope = 297.6 ± 4.62 mV·dec−1) and durability (% current retention = 50.64 ± 2.99%) than Pd/C towards EOR in an alkaline medium. This study highlights the simple and straightforward synthesis of the anode electrocatalyst material for direct ethanol fuel cell application.

Development of Dual N, S‐Heteroatom Doped Hollow Carbon Spheres as an Alternative Electrocatalyst for Oxygen Reduction Reaction in Alkaline Medium

AbstractHollow heteroatom‐doped mesoporous carbons were found to be an efficient non‐noble metal catalyst to enhance the oxygen reduction reaction (ORR) in fuel cells. Here, we use dopamine hydrochloride (DHC) and dibenzyl disulfide (DBS) as the nitrogen and sulfur precursors to infiltrate N and S into the HCS in a single‐step process. Dibenzyl disulfide is less explored in literature as a sulfur dopant. Due to its high sulfur content and high boiling point, dibenzyl disulfide acts as an excellent sulfur dopant and can withstand the carbonization process. Among them, NSMHCS‐0.2 obtained by adding 0.2 g of dibenzyl disulfide at 31 h intervals to the polydopamine (PDA) loaded silica leads to the ideal N, S dual hetero‐atom doping in NSMHCS. Notably, it has a high shell thickness (45 nm), high BET surface area (637 m2 g−1), high pyridinic nitrogen (13.54 %), and thiophene sulfur (89.8 %) concentration. Such property tuning paved the way to reach a high positive onset potential (0.86 V vs RHE) and a limiting current density of 3.64 mA cm−2 at 0.4 V vs RHE. Additionally, NSMHCS‐0.2 has shown superior methanol tolerance and strong electrochemical stability when compared to Pt/C 20 %.

Oxygen reduction mediated by tetrapyridylalkylamine Cu(II) complexes with diimines

Oxygen reduction reaction (ORR) is important in artificial energy conversion systems such as fuel cells. However, it is kinetically sluggish. It is thereby highly desirable to develop ORR catalysts to improve the efficiency of energy conversion. In this work, three copper(II) complexes based on the hexadentate tetrapyridylalkylamine N,N,N’,N’-tetrakis(2-pyridyl-methyl)-1,4-butanediamine (tpbn), namely [Cu2(tpbn)(CH3OH)4(ClO4)2](ClO4)2 (Cu-tpbn), [Cu2(tpbn)(bpy)2](ClO4)4.2CH3COCH3 (Cu-tpbn-bpy, bpy = 2,2′-bipyridine), and [Cu2(tpbn)(Me2bpy)2](ClO4)4.3CH3CN (Cu-tpbn-Me2bpy, Me2bpy = 4,4′-dimethyl-2,2′-bipyridine), were prepared and their catalytic properties for ORR studied. All three complexes were homogeneous electrocatalysts for ORR in neutral phosphate buffer solutions. The ORR mediated by Cu-tpbn-Me2bpy had the most positive onset potential of 0.461 V vs RHE. In the applied potential window of -0.19 – 0.50 V vs RHE, Cu-tpbn boosted the stepwise four-electron ORR to mainly produce H2O, whereas Cu-tpbn-bpy and Cu-tpbn-Me2bpy mediated the ORR to mainly generate H2O2. The rate constants for the ORR to H2O promoted by Cu-tpbn, Cu-tpbn-bpy and Cu-tpbn-Me2bpy were 1.2 × 103 s−1, 3.2 × 10 s−1 and 7.8 × 10 s−1, respectively. The foot-of-the-wave analysis showed that the turnover frequencies for the reduction of O2 to H2O2 mediated by Cu-tpbn, Cu-tpbn-bpy and Cu-tpbn-Me2bpy were 1.5 × 104 s−1, 7.5 × 10 s−1 and 2.7 × 102 s−1, respectively. Meanwhile, complexes Cu-tpbn-bpy and Cu-tpbn-Me2bpy were more stable than Cu-tpbn. This work unveiled that the catalytic activity and the product selectivity of the ORR were greatly associated with the denticity, the steric effect and the electronic property of the organic ligands.

Boosting the oxygen reduction activity of non-metallic catalysts via geometric and electronic engineering through nitrogen and chlorine dual-doping.

The development of heteroatom dual-doped porous carbon frameworks with uniform doping is highly desirable for achieving highly efficient oxygen reduction reaction (ORR) activity, due to their tunable chemical and electronic structures. Herein, porous covalent triazine-based frameworks (CTFs) incorporating nitrogen/chorine dual-doped porous carbon networks were fabricated by selecting 1,3-bis(4-cyanophenyl) imidazolium chloride as a building block, in a facile and controllable way via a bottom-up strategy. The resulting nitrogen/chorine dual-doped catalyst CCTF-700 exhibits excellent ORR performance with a more positive onset and half-wave potential (0.85 V vs. RHE), higher diffusion-limited current density and significantly improved stability in comparison with the benchmark commercial 20 wt% Pt/C catalyst. It is worth mentioning that CCTF-700 shows one of the best ORR performances among all the reported metal-free electrocatalysts under alkaline conditions. This work paves the way for a controllable and reliable strategy to craft highly efficient heteroatom dual-doped carbon catalysts for energy conversion.

The N-anchoring effect in NH2-functionalized MOF-derived iron-carbon nanomaterials for oxygen reduction.

The incorporation of an iron source into NH2-MOF-5, followed by thermal decomposition, yields a porous metal-carbon catalyst (MOF5A-Fe@NC). This catalyst possesses significant N content, a high degree of graphitization, and abundant Fe-Nx sites, which contribute to enhanced oxygen reduction. Specifically, the obtained MOF5A-Fe@NC demonstrates a positive onset potential (0.972 V), a substantial limiting current density (4.815 mA cm-2), and a small Tafel slope (58.7 mV dec-1), and maintains a high current retention of 96.3% after 10 hours.

Nanowires-based MnO2-Ru/rGO: An efficient oxygen reduction reaction electrocatalyst

Oxygen Reduction Reaction (ORR) for clean energy is hindered by expensive Pt-based electrocatalysts, prompting efforts to replace it with alternative electrocatalysts. Thus, we started by synthesizing MnO2 nanowires through a hydrothermal approach, followed by the growth of ruthenium nanoparticles (Ru NPs) without surface modification, using just 2.0 wt% of the noble metal (MnO2-Ru). However, to further enhance the electrocatalyst's performance and reduce costs, we combined different ratios of reduced graphene oxide (rGO) with the electrocatalyst. X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, and energy dispersive X-ray spectroscopy were employed to characterize the chemical composition and morphological properties of MnO2-Ru. These analyses identified the presence of the compounds during synthesis and confirmed the deposition of Ru NPs on the surface of MnO2 nanowires. The optimized MnO2-Ru/rGO demonstrated superior ORR activity than rGO, MnO2, and MnO2-Ru individually, with more positive onset potential (−0.054 V) and half-wave potential of −0.173 V. Notably, MnO2-Ru/rGO reduced oxygen via the four-electron transfer pathway. Furthermore, the higher stability and excellent methanol tolerance of MnO2-Ru/rGO compared to the commercial 20 wt% Pt/C indicates its suitability for fuel cells, maintaining approximately 70 % of its initial current after 8000 s.

Ball-Milled P-CuGaO2 Particles As a Semitransparent Scaffolding Material for Dye-Sensitized Molecular Photocathodes

Dye-sensitized photocathodes using a metal complex as a photosensitizer are attractive candidates for catalytic material conversion reactions such as H2 evolution and CO2 reduction (Figure A). Band position, conductivity, and morphology of the p-type semiconductor scaffold electrode significantly affect the electron injection into the metal complex and the subsequent reaction process. Consequently, the properties of the semiconductor material can be one of the important factors the catalytic activity of the photocathodes.We have previously reported p-type semiconductor CuGaO2 for the scaffold materials that exhibits a higher photocurrent and a positive onset potential compared to the conventionally used NiO, when combined with a Ru-tris-bipyridine-type photosensitizer[1]. Owing to the thermophysical property of CuGaO2, the typical solid-state synthesis of CuGaO2 particles needs high-temperature calcination with around 1373 K under an inert atmosphere, resulting in the large particle size of several microns and the limited conductivity and small surface area. Therefore, the photocathode activity is still insufficient. Other processes such as solvothermal synthesis have been reported, but it is still difficult to control the particle size, shape and chemical state.In this study, we examined the ball milling to synthesize nano-sized fine CuGaO2 particles and to prepare a semitransparent scaffold electrode for dye-sensitized photoelectrochemical reaction. Planetary ball milling has been reported as the means to obtain fine semiconductor particles[2], while it is necessary to adjust the processing conditions and perform detailed analysis because there is a possibility of damaging the semiconductor and impairing its physical properties.The XRD pattern, UV-visible absorption spectrum, XPS, and XAFS measurements of the ball-milled CuGaO2 particles revealed that there was no obvious deterioration due to the treatment.The SEM image of the ball-milled CuGaO2 electrode implied that the particles, which have been miniaturized about less than several hundred nm by the treatment, formed a dense layer, showing the semi-transparency of the electrode (Figure B). Detailed observation also proved that the ball-milled particles keep the crystal habit. The photocathode with ball-milled CuGaO2 modified with Ru-tris-bipyridine-type complex exhibited a reduction current by photoexcitation of the photosensitizer, and the current value exceeded those of the photocathodes using an untreated CuGaO2 electrode and a NiO electrode under the same conditions. The results suggest that the the miniaturization improved the characteristics of the photocathodes. The current study showed a way to mass-produce high-performance semiconductor scaffold electrodes by a simple ball-milling process.[1] H. Kumagai, O. Ishitani, et al., Chem. Sci. 2017, 8, 4242.; C. Windle, H. Kumagai, R. Abe, O. Ishitani, V. Artero, et al., J. Am. Chem. Soc., 2019, 141, 9593. [2] K. Okuno, H. Kumagai, H. Kato, et al., Sustain. Energy Fuels, 2022,6, 1698. Figure 1

Atomic regulation strategies of dual-metal single-atom catalytic sites supported on 3D N-doped carbon nanotube aerogels for boosting oxygen reduction and zinc-air battery

Dual-metal single-atom catalysts (DSAs) exhibit excellent electrocatalytic properties, holding great promise in energy conversion and storage fields. Their rational design and synthesis are realized by optimizing the types of supporting substrate or regulating the coordination microenvironment. Herein, FeCo DSAs supported on N-doped carbon nanotube aerogels (FeCo DSAs/N-CNAs) were facilely fabricated by a glucose-assisted atomic regulation pyrolysis approach. The morphology and structure were characterized by a series of techniques. The influences of the pyrolysis temperature and types of the metal precursors were carefully investigated, coupled by elaborating the formation mechanism. The resulting FeCo DSAs/N-CNAs catalyst shows a positive onset potential (Eonset = 1.075 V) and half-wave potential (E1/2 = 0.907 V) for oxygen reduction reaction (ORR) in a 0.1 M KOH solution, outperforming those of commercial Pt/C. The obtained catalyst is further exploited for establishing rechargeable Zn-air battery, which shows a larger peak power density of 86.7 mW cm−2 and a longer cycle stability over 144 h. These findings identify low-cost FeCo DSAs/N-CNAs as promising electrocatalysts for advanced rechargeable Zn-air batteries.