Promoting role of Ru species on Ir-Fe/BN catalyst in 1,2-diols hydrogenolysis to secondary alcohols

Noble metal-based-bimetallic catalysts have been highly investigated and applied in wide applications including biomass transformation via regioselective C−O hydrogenolysis while further modification especially with noble metal is highly promising yet still under investigation.Herein,Ru was found as an effective modifier among the screened noble metals(Ru,Pt,Rh,Pd,Au,and Ag)for Ir-Fe/BN(Ir=5 wt%,Fe/Ir=0.25)catalyst in terminal C−O hydrogenolysis of 1,2-butanediol(1,2-BuD)to 2-butanol(2-BuOH).Only trace amount of Ru(up to 0.5 wt%)was effective in terms of high 2-BuOH selectivity(>60%)and activity(about twice).Larger amount of Ru species(3 wt%)highly enhanced the activity but gave low selectivity to 2-BuOH with by-products of terminal C−C bond scission.Optimized catalyst(Ru(0.5)-Ir-Fe/BN)was reusable at least 4 times and gave moderate 2-BuOH yield(47%)in hydrogenolysis of 1,2-BuD.The promoting effect of Ru addition(0.5 wt%)to Ir-Fe/BN on hydrogenolysis of various alcohols was also confirmed.Combining catalytic tests with various characterizations,the promotion mechanism of Ru species in trimetallic catalysts was clarified.The Ru species in Ru(0.5)-Ir-Fe/BN form alloy with Ir and are enriched at the interface with BN surface,and direct interaction between Ru and Fe was not necessary in Ru-Ir-Fe alloy.The interface of Ir and Fe on the surface of Ir-Fe alloy may work as active sites for 1,2-diols to secondary alcohols via direct C−O hydrogenolysis,in which Ru-modified Ir activates H_(2) to form hydride-like species.The activity of Ru species in C−C bond cleavage was highly suppressed due to the direct interaction with Ir species and less exposed to substrate.Larger loading amount of Ru species(3 wt%)led to the formation Ru-rich trimetallic alloy,which further works as active sites for C−C bond scission.

Structures of Stoichiometric Sodium Oxide Cluster Cations Studied by Ion Mobility Mass Spectrometry

Structures of stable compositions of sodium oxide cluster cations (NanOm+,n≤11) have been investigated by ion mobility mass spectrometry. Stoichiometric compositions series, Na(Na2O)(n-1)/2^+(n=3, 5, 7, 9, and 11), were observed as stable composition series, and NaO(Na2O)(n-1)/2^+ series (n=5, 7, 9, and 11) were observed as secondary stable series in the mass spectra. To assign the structures of these cluster ion series, collision cross sections between the ions and helium buffer gas were determined experimentally from the ion mobility measurements. Theoretical collision cross sections were also calculated for optimized structures of these compositions. Finally, the structures of Na(Na2O)(n-1)/2^+ and NaO(Na2O)(n-1)/2^+ were assigned to those having similar structural frames for each n except for n=9. All bonds in the assigned structures of Na(Na2O)(n-1)/2^+ were between sodium and oxygen. On the other hand, there was one O-O bond in addition to Na-O bonds in NaO(Na2O)(n-1)/2^+. This result indicates that NaO(Na2O)(n-1)/2^+ have a peroxide ion (O22-) as a substitute for an oxide ion (O2-) of Na(Na2O)(n-1)/2^+. As a result, both stable series, Na(Na2O)(n-1)/2^+ and NaO(Na2O)(n-1)/2^+, are closed-shell compositions. These closed-shell characteristics have a strong influence on the stability of sodium oxide cluster cations.

Effect of Sulfate Adlayer on Formic Acid Oxidation on Pd(111) Electrode

The kinetics of formic acid oxidation (FAO) on Pd(111) in 0.1 mol/L H2SO4+0.1 mol/L HCOOH with and without addition of Na2SO4 is studied using cyclic voltammetry and potential step method, which is compared with that in 0.1 mol/L HClO4. It is found that adsorbed sulfate has significant inhibition effect on FAO kinetics. After addition of 0.05 mol/L or 0.1 mol/L Na2SO4, FAO current in the negative-going scan is found to be significantly smaller than that at the same potential in the positive-going scan. We speculate that at potentials positive of the phase transition potential for the (SO4*ad)m+[(H2O)n-H3O+] or(SO4*ad)m+[Na+(H2O)n-H3O+] adlayer, the adlayer structure probably becomes denser and more stable with the increase of potential or with the addition of Na2SO4. The formation of connected adlayer network greatly enhance the stability of the adlayer, and the insertion of positive-charged H+ or Na+ into the adlayer network further reduces the electrostatic repulsion between partially charged sulfates. As a result, the destruction/desorption of compact sulfate adlayer becomes more difficult, which leaves much less free sites on the surface for FAO, and thus FAO kinetics at higher potentials and in the subsequent negative-going potential scan is significantly inhibited.

The Implications of Population Decline and Fiscal Austerity on Public Nature:Insights From the Evolution of Urban Park Management System in Japan

Facing challenges of population decline and fiscal austerity,Japan has implemented a series of initiatives to promote public-private partnerships(PPP)to ensure the sustainability of urban parks and revitalize urban spaces.These initiatives,while alleviating the government’s financial burdens on parks,have also raised concerns about the potential erosion of publicness and public interests resulted from the commercialization of public assets.This paper reviews the evolution of Japan’s urban park management system after World War II—including three phases of being purely public goods,initiating marketization,and diversifying management entities.The functions of parks have continuously enriched,and the construction,management,and operational modes have shifted from government-led towards multi-stakeholder participation,along with expanded funding sources.By examining the PPP types,driving forces,implementation mechanisms and challenges in urban park management,this paper points out that,in different eras and social contexts,the Japanese government has kept adjusting its role to maximize public interests.This has proactively updated the implications of publicness in infrastructure like urban parks,from a post-war opposite of publicness versus privateness on ownership,to the participation of private capital for a higher efficiency,and finally to a community for a stronger regional competitiveness.The reforms of urban park management system in Japan offer significant lessons and insights for urban infrastructure management in other countries and regions.

Removal Arsenic(V)Efficiency and Characteristics Using Modified Basic Oxygen Furnace Slag in Aqueous Solution

Basic oxygen furnace(BOF) slag, the solid waste produced in the steelmaking process, is reused in industry, agriculture and environmental treatment. However, as an adsorbent for wastewater, the removal effect of BOF slag on anionic pollutants needs to be improved. In this study, acid and alkali were used to modify BOF slag,and the removal efficiency and mechanism of arsenic(V) with modified BOF slag in solution were studied. The effects of the As(V) initial concentration, solution pH and reaction time on the removal efficiency were determined by batch experiments, and the removal mechanism of As(V) using modified BOF slag was studied by an adsorption kinetic model and isothermal adsorption model and the Fourier transform infrared spectroscopy(FTIR) and X-ray photoelectron spectroscopy(XPS) spectral analysis. The results showed that the slag modified by 15% sulfuric acid had the best removal effect on As(V), while the removal effect of As(V) by alkali-modified slag was not ideal. The removal rate of As(V) by acid-modified slag increased with the increase in the initial concentration, decreased slowly with the increase in pH and reached equilibrium in 180 min. The adsorption kinetic model and isothermal adsorption model of As(V) by acid-modified BOF slag showed that the chemical adsorption was the limiting step.The FTIR and XPS analysis results showed that the silicate and ferrite in the acid-modified slag could remove As(V)in the solution by ion exchange to form an arsenate precipitate. Therefore, modified BOF slag can be used as a potential adsorbent for large scale arsenic polluted waterbody to realize the ecological utilization of industrial solid waste.

苏东坡《表忠观碑》刻石考

在宋代,章惇、蔡京执政后开始全面打压旧法党。直到宣和末年,朝廷禁止有人持有东坡的诗文,并摧毁了他所写的书作和碑文。苏东坡四十三岁所作《表忠观碑》也在不久之后被毁掉。从表忠观的迁移重修及重刻等问题来看,可知该碑的来龙去脉较为复杂。

致国语审议会委员的公开信——关于当用汉字表、常用汉字表的问题

作者与作品简介制定当用汉字表和现代假名遣,已近四十年了。其间为日语书写方式造成许多混乱。八十二岁的原东大教授、法国文学家市原丰太有鉴于此,从维护日本的纯正面貌出发,以书信形式给《文艺春秋》1985年新年特别号上撰写了一篇题为《致国语审议会委员的公开信》的文章。文中谈到战后日语经过国语审议会审定而发展的一些情况,认为限制汉字规定的当用汉字和以现代假名遣取代历史假名遣是留给后代子孙最坏的遗产,要求撤销。这里摘录有关限制汉字一段,略加删改,附以注译。全文用历史假名遣撰写。未做改动。