嵌入性组织中的政策企业家如何推动政策创新?——基于农业生产托管政策变迁的历时观察

过往研究关注政府组织、企业和行业协会等组织形式中政策企业家对于推动政策创新的影响。然而,嵌入性组织中的政策企业家未被相关研究所涉及。论文基于2000—2016年间山东省农业生产托管政策的变迁,揭示具有中国特色的嵌入性组织(即农村供销合作社)中政策企业家推动政策创新的过程与机制。研究发现,在政策企业家推动政策创新的过程中,其所处的组织结构发挥着重要影响作用。政策企业家能够基于嵌入性组织多元、多层级的网络制度关系,凭借其充分信息和制度合法性形成广泛的子系统行动者网络,进而通过协同各方和各层级的行动者来推动理念的实践与论证,在经历信念形成、利益赋予、联盟扩张和创新涌现四个阶段后,推动政策创新的实现。具有中国特色的嵌入性组织,过去往往因混合了政府、企业等不同组织性质而受到诸多批判。论文发现了嵌入性组织新的优势领域,即嵌入性组织促进了超出自身的更大范围的政策创新的产生。我国应加强嵌入性组织的改革与建设,提升嵌入性组织在各类公共政策中的参与程度,从而基于其充分的信息与制度合法性的优势来推动高质量的政策创新。

Probing the catalytic behavior of ZnO nanowire supported Pd_1 single-atom catalyst for selected reactions

We have dispersed individual Pd atoms onto ZnO nanowires(NWs)as single‐atom catalysts(SACs)and evaluated their catalytic performance for several selected catalytic reactions.The Pd1/ZnO SAC is highly active,stable,and selective towards CO2for steam reforming of methanol to produce hydrogen.This catalyst system is active for oxidation of CO and H2but performs poorly for preferential oxidation of CO in hydrogen‐rich stream primarily due to the strong competitive oxidation of H2on ZnO supported Pd1atoms.At ambient pressure,reverse water‐gas‐shift reaction occurs on the Pd1/ZnO SAC.This series of tests of catalytic reactions clearly demonstrate the importance of selecting the appropriate metal and support to develop SACs for catalytic transformation of molecules.

Synthesis of Pd Nanocrystals Enclosed by {100} Facets and with Sizes 〈10 nm for Application in CO Oxidation

The catalytic activity of noble-metal nanocrystals is mainly determined by their sizes and the facets exposed on the surface. For single crystals, it has been demonstrated that the Pd（100） surface is catalytically more active than both Pd（110） and Pd（111） surfaces for the CO oxidation reaction. Here we report the synthesis of Pd nanocrystals enclosed by {100} facets with controllable sizes in the range of 6-18 nm by manipulating the rate of reduction of the precursor. UV-vis spectroscopy studies indicate that the rate of reduction of Na2PdC14 can be controlled by adjusting the concentrations of Br- and C1- ions added to the reaction mixture. Pd nanocrystals with different sizes were immobilized on ZnO nanowires and evaluated as catalysts for CO oxidation. We found that the activity of this catalytic system for CO oxidation showed a strong dependence on the nanocrystal size. When the size of the Pd nanocrystals was reduced from 18 nm to 6 nm, the maximum conversion rate was significantly enhanced by a factor of -10 and the corresponding maximum conversion temperature was lowered by -80℃.

New Insights into the Growth Mechanism and Surface Structure of Palladium Nanocrystals

This paper presents a systematic study of the growth mechanism for Pd nanobars synthesized by reducing Na_(2)PdCl_(4) with L-ascorbic acid in an aqueous solution in the presence of bromide ions as a capping agent.Transmission electron microscopy(TEM)and high-resolution TEM analyses revealed that the growth at early stages of the synthesis was dominated by particle coalescence,followed by shape focusing via recrystallization and further growth via atomic addition.We also investigated the detailed surface structure of the nanobars using aberration-corrected scanning TEM and found that the exposed{100}surfaces contained several types of defects such as an adatom island,a vacancy pit,and atomic steps.Upon thermal annealing,the nanobars evolved into a more thermodynamically favored shape with enhanced truncation at the corners.

Nested Metal Catalysts:Metal Atoms and Clusters Stabilized by Confinement with Accessibility on Supports

Supported catalysts that are important in technology prominently include atomically dispersed metals and metal clusters.When the metals are noble,they are typically unstablesusceptible to sinteringespecially under reducing conditions.Embedding the metals in supports such as organic polymers,metal oxides,and zeolites confers stability on the metals but at the cost of catalytic activity associated with the lack of accessibility of metal bonding sites to reactants.An approach to stabilizing noble metal catalysts while maintaining their accessibility involves anchoring them in molecular-scale nests that are in or on supports.The nests include zeolite pore mouths,zeolite surface cups(half-cages),raft-like islands of oxophilic metals bonded to metal oxide supports,clusters of non-noble metals(e.g.,hosting noble metals as single-atom alloys),and nanoscale metal oxide islands that selectively bond to the catalytic metals,isolating them from the support.These examples illustrate a trend toward precision in the synthesis of solid catalysts,and the latter two classes of nested catalysts offer realistic prospects for economical large-scale application.