Oxygen Evolution Reaction in Energy Conversion and Storage: Design Strategies Under and Beyond the Energy Scaling Relationship

The oxygen evolution reaction(OER)is the essential module in energy conversion and storage devices such as electrolyzer,rechargeable metal–air batteries and regenerative fuel cells.The adsorption energy scaling relations between the reaction intermediates,however,impose a large intrinsic overpotential and sluggish reaction kinetics on OER catalysts.Developing advanced electrocatalysts with high activity and stability based on non-noble metal materials is still a grand challenge.Central to the rational design of novel and high-efficiency catalysts is the development and understanding of quantitative structure–activity relationships,which correlate the catalytic activities with structural and electronic descriptors.This paper comprehensively reviews the benchmark descriptors for OER electrolysis,aiming to give an in-depth understanding on the origins of the electrocatalytic activity of the OER and further contribute to building the theory of electrocatalysis.Meanwhile,the cutting-edge research frontiers for proposing new OER paradigms and crucial strategies to circumvent the scaling relationship are also summarized.Challenges,opportunities and perspectives are discussed,intending to shed some light on the rational design concepts and advance the development of more efficient catalysts for enhancing OER performance.

Variant Scaling Relationship for Mass-Density Across Tree-Dominated Communities

The past few decades have seen a resurgence of Interest in biological allometry. Specifically, a number of recent studies has suggested a -4/3 Invariant scaling relationship between mass and density that Is universally valid for tree-dominated communities, regardless of their phyietic affiliation or habitat. In the present study, we test this scaling relationship using a comprehensive forest biomass database, Including 1 266 plots of six blomes and 17 forest types across China. The present study shows that the scaling exponent of the massdensity relationship varies across different tree-dominated communities and habitats. This great variability In the scaling exponent makes any generalization unwarranted. Although Inappropriate regression methods can lead to flawed estimation of the scaling exponent, inconsistency of theoretical framework and empirical patterns may have undermined the validity of previous work.

Scaling relationships of elastic-perfectly plastic film/coating materials from small scale sharp indentation

The scaling relationships of elastic-perfectly plastic film/coating materials during sharp indentation have been obtained using dimensional analysis and finite-element modeling. Besides the bulk substrate materials, a wide range of film/coating materials with different ratios in term of the Young’s modulus and yield strength were examined, namely different values of Ef/Esand Yf/Es.Based on these scaling relationships, the substrate effects on indentation response and deformed surface profile of residual imprint are given. Furthermore, the scaling relationship among the work of indentation, reduced elastic modulus and hardness has been found. It is found that the ratio of the indentation hardness to measurement of substrate elastic modulus could be used to characterize the wear resistance of film/coating materials. In addition, a novel method to acquire the intrinsic hardness and elastic modulus of film/coating materials is proposed combined with the well-known 10% critical indentation depth rule, which avoids the error caused by estimating the contact area. This work could be contributed for characterizing the mechanical properties of film/coating materials at micro-and nanoscale.

Trans-scale surface wrinkling model and scaling relationship analysis of stiff film-compliant substrate structures

The self-assembly of surface-order structures based on the surface wrinkling of stiff film-compliant substrate structures(SFCS)is potentially useful in the fabrication of functional devices,the manufacture of superhydrophobic or self-cleaning surfaces,and so on.Due to the influence of the intrinsic characteristic length(g),the surface wrinkling behavior of SFCS at the micro scale is different from that at the macro scale.In this work,based on the strain gradient theory,a trans-scale surface wrinkling model for SFCS is established.First,the effectiveness of this model is verified by previous experiments.Then,based on the model and dimensional analysis,the effect of g on the surface wrinkling behavior is investigated,and the scaling relationship of surface wrinkling of SFCS at different scales is analyzed.The results show that the influence of g cannot be neglected when the film thickness decreases to the one comparable to g.At the micro scale,g will lead to the increase of the critical wrinkling wavelength and load.In addition,the scaling relationship of surface wrinkling at the micro scale will not follow the traditional one.Our study explains the underlying mechanism of the dissimilarity of surface wrinkling behaviors of SFCS at different scales and lays a theoretical foundation for the precise control of surface-order structures.

Treatment preferences in men with erectile dysfunction： an open label study in Korean men switching from sildenafil citrate to tadalafil

To evaluate patient preferences for sildenafil citrate or tadalafil （PDE-5 inhibitors available for the treatment of erectile dysfunction [ED]） and assess potential reasons for these preferences. Methods： This open-label study was conducted on Korean men taking sildenafil, at least 6 weeks prior to study entry, for ED. Following screening, patients continued sildenafil treatment for 4 weeks, then after a 1-week washout period, switched to tadalafil for 8 weeks. Patients then continued with their treatment of choice during an extension phase. Psychosocial factors （time concern, spontaneity, sexual self-confidence） were evaluated using Psychological and Interpersonal Relation- ship Scales （PAIRS）, while timing of dose to sexual attempt patterns were assessed from patient diaries. Results： The present study enrolled 160 Korean men （mean age 55 years） with prior median sildenafil use of 585 days. During the extension phase, 73.7% of patients elected to take tadalafil, whereas 26.3% chose sildenafil （P 〈 0.001）. After switching from sildenafil to tadalafil, mean PAIRS time concern scores decreased from 2.54 to 2.42 （P = 0.002）, with no statistically significant differences observed between the sildenafil and tadalafil assessment phases in sexual spontaneity and self-confidence scores. Sexual attempts made 〉 4 h to 〈 36 h post-dose occurred in 4.5% of patients during the sildenafil assessment phase compared with 17.5% during the tadalafil assessment phase. Conclusion： After experiencing both sildenafil and tadalafil, the majority of patients exhibited a preference for tadalafil. This preference might be influenced by psychosocial factors, such as decreased time concerns, and a broader window of opportunity available for sexual activity.

Shoot-level biomass allocation is affected by shoot type in Fagus sylvatica

Aims The present study aims(i)to examine if recently reported interspecific shoot-level biomass allocational trade-offs,i.e.isometric trade-offs between leaf mass(LM)and stem mass(SM)and between leaf size and leaf number,hold intraspecifically and(ii)to explore whether those scaling relationships are independent of shoot type(i.e.long vs.short shoots).Methods In order to address our questions,we used Fagus sylvatica saplings growing under a broad light range that were sampled in theWestern Carpathians Mountains(Slovakia).Important Findings We found that:(i)intraspecific shoot-level biomass allocational trade-offs differ from those reported interspecifically and that(ii)long and short shoots differ in biomass allocation scaling coefficients.Allometric relationships with slopes statistically smaller than 1.0 or higher than -1.0,were found between SM and LM and between mean leafing intensity and individual leaf mass,respectively,in long shoots.In contrast,isometric scaling was found in short shoots.This suggests that leaf mass in short shoots is unaffected by shoot stem mass,in contrast to long shoots.Short shoots also had a larger fraction of biomass allocated to leaves.Beech shoots,as has been observed in other shoot dimorphic species,are specialized,with short shoots specializing in carbon gain and long shoots in space acquisition.A greater shift in LM than in SM among species during speciation shifting from allometric intraspecific relationships to an isometric interspecific scaling relationship between those traits could explain the discrepancies between the outputs of the present intraspecific study and others similar studies.This study draws attention to the importance of considering shoot types in future studies dealing with allocation rules in species with dimorphic shoots.

Mechanism investigation and catalyst screening of high-temperature reverse water gas shift reaction

Reverse water gas shift(RWGS)catalysis,a prominent technology for converting CO2 to CO,is emerging to meet the growing demand of global environment.However,the fundamental understanding of the reaction mechanism is hindered by the complex nature of the reaction.Herein,microkinetic modeling of RWGS on different metals(i.e.,Co,Ru,Fe,Ni,Cu,Rh,Pd,and Pt)was performed based on the DFT results to provide the mechanistic insights and achieve the catalyst screening.Adsorption energies of the carbon-based species and the oxygen-based species can be correlated to the adsorption energy of carbon and oxygen,respectively.Moreover,oxygen adsorption energy is an excellent descriptor for the barrier of CO2 and CO direct dissociation and the difference in reaction barrier between CO2(or CO)dissociation and hydrogenation.The reaction mechanism varies on various metals.Direct CO2 dissociation is the dominating route on Co,Fe,Ru,Rh,Cu,and Ni,while it competes with the COOH-mediated path on Pt and Pd surface.The eights metals can be divided into two groups based on the degree of rate control analysis for CO production,where CO–O bond cleavage is rate relevant on Pt,Pd,and Cu,and OH–H binding is rate-controlling on Co,Fe,Ru,Ni,and Rh.Both CO-direct dissociation and hydrogen-assisted route to CH4 contribute to the methane formation on Co,Fe,Pt,Pd,Ru,and Rh,despite the significant barrier difference between the two routes.Besides,the specific rate-relevant transition states and intermediates are suggested for methane formation,and thus,the selectivity can be tuned by adjusting the energy.The descriptor(C-and O-formation energy)based microkinetic modeling proposed that the activity trend is Rh~Ni>Pt~Pd>Cu>Co>Ru>Fe,where Fe,Co,Ru,and Ni tends to be oxidized.The predicted activity trend is well consistent with those obtained experimentally.The interpolation concept of adsorption energy was used to identify bimetallic materials for highly active catalysts for RWGS.