PtNi-W/C with Atomically Dispersed Tungsten Sites Toward Boosted ORR in Proton Exchange Membrane Fuel Cell Devices

The performance of proton exchange membrane fuel cells is heavily dependent on the microstructure of electrode catalyst especially at low catalyst loadings.This work shows a hybrid electrocatalyst consisting of PtNi-W alloy nanocrystals loaded on carbon surface with atomically dispersed W sites by a two-step straightforward method.Single-atomic W can be found on the carbon surface,which can form protonic acid sites and establish an extended proton transport network at the catalyst surface.When implemented in membrane electrode assembly as cathode at ultra-low loading of 0.05 mgPt cm^(−2),the peak power density of the cell is enhanced by 64.4%compared to that with the commercial Pt/C catalyst.The theoretical calculation suggests that the single-atomic W possesses a favorable energetics toward the formation of*OOH whereby the intermediates can be efficiently converted and further reduced to water,revealing a interfacial cascade catalysis facilitated by the single-atomic W.This work highlights a novel functional hybrid electrocatalyst design from the atomic level that enables to solve the bottle-neck issues at device level.

Surface Molecular Encapsulation with Cyclodextrin in Promoting the Activity and Stability of Fe Single-Atom Catalyst for Oxygen Reduction Reaction

Fe single-atom catalysts(Fe-SACs)have been extensively studied as a highly efficient electrocatalyst toward the oxygen reduction reaction(ORR).Nonetheless,they suffer from stability issue induced by dissolution of Fe metal center and the OH^(−)blocking.Herein,a surface molecular engineering strategy is developed by usingβ-cyclodextrins(CDs)as a localized molecular encapsulation.The CD-modified Fe-SAC(Fe-SNC-β-CD)shows obviously improved activity toward the ORR with 0.90 V,4.10 and 4.09 mA cm^(-2)for E_(1/2),J_(0)and Jk0.9,respectively.Meanwhile,the Fe-SNC-β-CD shows the excellent long-term stability against aggressive stress and the poisoning.It is confirmed through electrochemical investigation that modification ofβ-CD can,on one hand,regulate the atomic Fe coordination chemistry through the interaction between the CD and FeN_(x) moiety,while on the other mitigate the strong adsorption of OH^(−)and function as protective barrier against the poisoning molecules leading to enhanced ORR activity and stability for the Fe-SACs.The molecular encapsulation strategy demonstrates the uniqueness of post-pyrolysis surface molecular engineering for the design of single-atom catalyst.

Effects of Combined Inhalation of Budesonide,Formoterol,and Tiotropium Bromide on Arterial Blood Gas and Pulmonary Function Indexes in Patients with Chronic Obstructive Pulmonary Disease

Objective:To analyze the effect of combined inhalation of budesonide formoterol and tiotropium bromide on arterial blood gas and pulmonary function indexes in patients with chronic obstructive pulmonary disease(COPD).Methods:100 patients with COPD treated from January to December 2022 were selected as observation objects,and were divided into a control group(n=50,in which budesonide and formoterol were administered)and an experimental group(n=50,the treatment drug was budesonide formoterol combined with tiotropium bromide)according to the computer grouping method,and compared the treatment results.Results:(i)Before treatment,there was no difference in the partial pressure of carbon dioxide and partial pressure of oxygen between the control group and the experimental group(P>0.05);after treatment,the partial pressure of carbon dioxide and partial pressure of oxygen in the experimental group were higher than those in the control group,with significant differences(P<0.05).(ii)Before treatment,there was no difference in forced vital capacity(FVC),forced expiratory volume in one second(FEV1),FEV1/FVC between the control group and the experimental group(P>0.05);after treatment,the FVC,FEV1,and FEV1/FVC in the experimental group were significantly higher than those in the control group(P<0.05).(iii)There was no difference in the levels of CRP,IL-6,and TNF-αbetween the control group and the experimental group(P>0.05);after treatment,the levels of CRP,IL-6,and TNF-αin the experimental group were lower than those in the control group,with significant differences(P<0.05).(iv)Compared to the total incidence of adverse reactions in the control group(28.00%),the incidence of total adverse reactions in the experimental group was lower at 10.00%,and the difference was significant(P<0.05).Conclusion:The combined inhalation of budesonide and formoterol with tiotropium bromide has demonstrated a clear therapeutic efficacy and safety in treating chronic obstructive pulmonary disease.This treatment approach effectively enhances arterial blood gas levels and lung function,showing promising potential for widespread application.

Dual-metal single-atomic catalyst:The challenge in synthesis,characterization,and mechanistic investigation for electrocatalysis

Dual-metal single-atom catalysts(DACs),featuring high atomic utilization efficiency,excellent selectivity,and stability originating from the atomically dispersed nature,have emerged as a new frontier in heterogeneous electrocatalysis due to the synergistic effect between diversified metal active sites in promoting their catalytic activity.In this review,the recent progress and development on the syntheses,characterizations,theoretical uniqueness,and applications for various catalytic reactions and devices(oxygen reduction reaction,oxygen evolution reaction,hydrogen evolution reaction,CO_(2) reduction reaction,N2 reduction reaction,proton exchange membrane fuel cells)are summarized and reviewed.Specifically,the synergistic effect between the two metal centers and electronic structures of catalysts is systematically discussed.Moreover,the future challenges and prospects in developing practical DACs are proposed as a possible direction for further investigation.

Rational design of Fe-N-C electrocatalysts for oxygen reduction reaction:From nanoparticles to single atoms

As an alternative energy,hydrogen can be converted into electrical energy via direct electrochemical conversion in fuel cells.One important drawback of full cells is the sluggish oxygen reduction reaction(ORR)promoted by the high-loading of platinum-group-metal(PGM)electrocatalysts.Fe-N-C family has been received extensive attention because of its low cost,long service life and high oxygen reduction reaction activity in recent years.In order to further enhance the ORR activity,the synthesis method,morphology regulation and catalytic mechanism of the active sites in Fe-N-C catalysts are investigated.This paper reviews the research progress of Fe-N-C from nanoparticles to single atoms.The structure-activity relationship and catalytic mechanism of the catalyst are studied and discussed,which provide a guidance for rational design of the catalyst,so as to promote the more reasonable design of Fe-N-C materials.