编译 | 未玖

Science, 10 MAY 2024, VOL 384, ISSUE 6696

《科学》2024年5月10日，第384卷，6696期

天文学Astronomy

Isotopic evidence of long-lived volcanism on Io

木卫一长期火山活动的同位素证据

▲ 作者：KATHERINE DE KLEER, ERY C. HUGHES, FRANCIS NIMMO, JOHN EILER, AMY E. HOFMANN, STATIA LUSZCZ-COOK, ET AL.

▲ 链接：

https://www.science.org/doi/10.1126/science.adj0625

▲ 摘要：

木卫一上有大量的火山活动，由潮汐加热驱动。木卫一挥发性化学元素（包括硫和氯）的同位素组成反映了其放气和质量损失的历史，从而记录了演化信息。

研究组利用对木卫一大气层的亚毫米观测来测量气态二氧化硫和一氧化硫中的硫同位素，以及气态氯化钠和氯化钾中的氯同位素。

结果发现34S/32S = 0.0595±0.0038（相当于δ34S = +347±86‰），与太阳系的平均值相比高度富集，这表明木卫一已经损失了94~99%的可用硫。测量还发现37Cl/35Cl = 0.403±0.028（δ37Cl = +263±88‰），表明氯也同样富集。

这些结果表明，木卫一在其大部分（或全部）历史中都有火山活动，早期可能有更高的放气率和质量损失率。

▲ Abstract：

Jupiter’s moon Io hosts extensive volcanism, driven by tidal heating. The isotopic composition of Io’s inventory of volatile chemical elements, including sulfur and chlorine, reflects its outgassing and mass-loss history and thus records information about its evolution. We used submillimeter observations of Io’s atmosphere to measure sulfur isotopes in gaseous sulfur dioxide and sulfur monoxide, and chlorine isotopes in gaseous sodium chloride and potassium chloride. We find 34S/32S = 0.0595 ± 0.0038 (equivalent to δ34S = +347 ± 86‰), which is highly enriched compared to average Solar System values and indicates that Io has lost 94 to 99% of its available sulfur. Our measurement of 37Cl/35Cl = 0.403 ± 0.028 (δ37Cl = +263 ± 88‰) shows that chlorine is similarly enriched. These results indicate that Io has been volcanically active for most (or all) of its history, with potentially higher outgassing and mass-loss rates at earlier times.

材料科学Materials Science

Catalog of topological phonon materials

拓扑声子材料目录

▲ 作者：YUANFENG XU, M. G. VERGNIORY, DA-SHUAI MA, JUAN L. MA?ES, ZHI-DA SONG, B. ANDREI BERNEVIG, ET AL.

▲ 链接：

https://www.science.org/doi/10.1126/science.adf8458

▲ 摘要：

声子在固态系统的许多特性中起着至关重要的作用，人们期望拓扑声子可导致丰富和非常规的物理特性。

在现有声子材料数据库的基础上，研究组汇编了1万多种三维晶体材料的拓扑声子带目录。利用拓扑量子化学计算了声子数据库中材料的每组孤立声子带的能带表示、兼容关系和能带拓扑。

此外还计算了所有拓扑平凡带的实空间不变量，并将其分类为原子能带或受阻原子能带。研究组已选择了1000多种“理想”的非平凡声子材料用于未来实验分析。这些数据集将被用于建立拓扑声子数据库。

▲ Abstract：

Phonons play a crucial role in many properties of solid-state systems, and it is expected that topological phonons may lead to rich and unconventional physics. On the basis of the existing phonon materials databases, we have compiled a catalog of topological phonon bands for more than 10,000 three-dimensional crystalline materials. Using topological quantum chemistry, we calculated the band representations, compatibility relations, and band topologies of each isolated set of phonon bands for the materials in the phonon databases. Additionally, we calculated the real-space invariants for all the topologically trivial bands and classified them as atomic or obstructed atomic bands. We have selected more than 1000 “ideal” nontrivial phonon materials to motivate future experiments. The datasets were used to build the Topological Phonon Database.

The odd-number cyclo[13]carbon and its dimer, cyclo[26]carbon

奇数环[13]碳及其二聚体环[26]碳

▲ 作者：FLORIAN ALBRECHT, IGOR RON?EVI?, YUEZE GAO, FABIAN PASCHKE, ALBERTO BAIARDI, IVANO TAVERNELLI, ET AL.

▲ 链接：

https://www.science.org/doi/10.1126/science.ado1399

▲ 摘要：

N个碳原子的分子环（环[N]碳，或CN）是测试量子化学理论方法的优秀基准系统，也是其他富碳材料有价值的前体。奇数—N环碳迄今为止一直难以捉摸，预计比偶数—N环碳更不稳定。

研究组报道了用扫描探针显微镜尖端操纵十氯芴在表面合成环[13]碳，C13。通过实验和理论模拟表征了C13的性质。C13采用三重态基态和扭结几何结构的开壳构型，根据分子环境的不同表现出不同程度的扭曲和卡宾局域化。

此外，研究组制备并表征了C13二聚体，即环[26]碳，证明了环碳及其前体作为碳同素异形体构建块的潜力。

▲ Abstract：

Molecular rings of N carbon atoms (cyclo[N]carbons, or CN) are excellent benchmarking systems for testing quantum chemical theoretical methods and valuable precursors to other carbon-rich materials. Odd-N cyclocarbons, which have been elusive to date, are predicted to be even less stable than even-N cyclocarbons. We report the on-surface synthesis of cyclo[13]carbon, C13, by manipulation of decachlorofluorene with a scanning probe microscope tip. We elucidated the properties of C13 by experiment and theoretical modeling. C13 adopts an open-shell configuration with a triplet ground state and a kinked geometry, which shows different extents of distortion and carbene localization depending on the molecular environment. Moreover, we prepared and characterized the C13 dimer, cyclo[26]carbon, demonstrating the potential of cyclocarbons and their precursors as building blocks for carbon allotropes.

化学Chemistry

Atomically dispersed hexavalent iridium oxide from MnO2 reduction for oxygen evolution catalysis

MnO2还原的原子分散六价氧化铱助力析氧催化

▲ 作者：AILONG LI, SHUANG KONG, KIYOHIRO ADACHI, HIDESHI OOKA, KAZUNA FUSHIMI, QIKE JIANG, ET AL.

▲ 链接：

https://www.science.org/doi/10.1126/science.adg5193

▲ 摘要：

人们预测六价氧化铱（IrVI）在酸中的析氧反应中比其他氧化铱更具活性、更稳定；然而其实验实现仍颇具挑战性。

研究组报道了用于质子交换膜（PEM）水电解的原子分散IrVI氧化物（IrVI-ado）的合成、表征和应用。用氧化锰（MnO2）氧化取代六氯铱酸钾（K2IrCl6）配体，合成了IrVI-ado。

IrVI-ado的质量比活度（1.7×105 A/gIr）和周转率（1.5×108）超过了基准铱氧化物，PEM操作期间的原位X射线分析表明，IrVI在电流密度高达2.3 A/cm2时仍具备耐久性。IrVI-ado的高活性和稳定性显示了其作为PEM电解阳极材料的前景。

▲ Abstract：

Hexavalent iridium (IrVI) oxide is predicted to be more active and stable than any other iridium oxide for the oxygen evolution reaction in acid; however, its experimental realization remains challenging. In this work, we report the synthesis, characterization, and application of atomically dispersed IrVI oxide (IrVI-ado) for proton exchange membrane (PEM) water electrolysis. The IrVI-ado was synthesized by oxidatively substituting the ligands of potassium hexachloroiridate(IV) (K2IrCl6) with manganese oxide (MnO2). The mass-specific activity (1.7 × 105 amperes per gram of iridium) and turnover number (1.5 × 108) exceeded those of benchmark iridium oxides, and in situ x-ray analysis during PEM operations manifested the durability of IrVI at current densities up to 2.3 amperes per square centimeter. The high activity and stability of IrVI-ado showcase its promise as an anode material for PEM electrolysis.

Scalable decarboxylative trifluoromethylation by ion-shielding heterogeneous photoelectrocatalysis

离子屏蔽非均相光电催化助力可扩展脱羧三氟甲基化

▲ 作者：YIXIN CHEN, YUCHEN HE, YONG GAO, JIAKUN XUE, WEI QU, JUN XUAN AND YIMING MO

▲ 链接：

https://www.science.org/doi/10.1126/science.adm8902

▲ 摘要：

电化学为增值精细化学品提供了可持续的合成途径，但通常受到电极和不同于靶位点的氧化还原敏感功能性之间竞争电子转移的限制。

研究组描述了一种离子屏蔽的非均相光电催化策略，以施加传质限制，从而逆转了热力学决定的电子转移顺序。使用三氟乙酸盐（一种廉价但相对惰性的三氟甲基（CF3）源）展示了该策略可实现敏感（杂）芳烃的脱羧三氟甲基化。

由三氟乙酸根阴离子静电吸附在正钼掺杂的三氧化钨（WO3）光阳极上形成的离子屏蔽层，可防止基底和光生空穴之间无益的电子转移。通过利用光电化学流动电池实现稳健的光阳极稳定性（约380小时）、良好的基底范围，以及100克合成的可扩展能力，充分证明了该策略的实用性。

▲ Abstract：

Electrochemistry offers a sustainable synthesis route to value-added fine chemicals but is often constrained by competing electron transfer between the electrode and redox-sensitive functionalities distinct from the target site. Here, we describe an ion-shielding heterogeneous photoelectrocatalysis strategy to impose mass-transfer limitations that invert the thermodynamically determined order of electron transfer. This strategy is showcased to enable decarboxylative trifluoromethylation of sensitive (hetero)arenes by using trifluoroacetate, an inexpensive yet relatively inert trifluoromethyl group (CF3) source. An ion-shielding layer, formed by trifluoroacetate anions electrostatically adsorbed on a positive molybdenum-doped tungsten trioxide (WO3) photoanode, prevents undesired electron transfer between substrates and photogenerated holes. The practicality of the developed method was demonstrated with robust photoanode stability (approximately 380 hours), a good substrate scope, and scaling capability to achieve 100-gram synthesis by using photoelectrochemical flow cells.

地球科学Earth Science

A diminished North Atlantic nutrient stream during Younger Dryas climate reversal

新仙女木期气候逆转期间北大西洋营养流减少

▲ 作者：JEAN LYNCH-STIEGLITZ, TYLER D. VOLLMER, SHANNON G. VALLEY, ERIC BLACKMON, SIFAN GU AND THOMAS M. MARCHITTO

▲ 链接：

https://www.science.org/doi/10.1126/science.adi5543

▲ 摘要：

北大西洋的高生物生产力由通过墨西哥湾流（营养流）向该地区平流供应的营养物质所刺激。有人提出，预计未来大西洋经向翻转环流（AMOC）的下降将导致营养物质供应减少，从而导致生产力下降。

研究组分析了标志着从末次冰期过渡的新仙女木期气候逆转期间营养流是如何变化的。在AMOC减弱期间，佛罗里达海峡的墨西哥湾流营养物质含量下降，氧含量增加。营养流的减少伴随着北大西洋高纬度地区生物生产力的下降，这支持了理论和建模研究中所假设的联系。

▲ Abstract：

The high rate of biological productivity in the North Atlantic is stimulated by the advective supply of nutrients into the region via the Gulf Stream (nutrient stream). It has been proposed that the projected future decline in the Atlantic Meridional Overturning Circulation (AMOC) will cause a reduction in nutrient supply and resulting productivity. In this work, we examine how the nutrient stream changed over the Younger Dryas climate reversal that marked the transition out of the last ice age. Gulf Stream nutrient content decreased, and oxygen content increased at the Florida Straits during this time of weakened AMOC. The decreased nutrient stream was accompanied by a reduction in biological productivity at higher latitudes in the North Atlantic, which supports the link postulated in theoretical and modeling studies.