Accounts of Chemical Research最新文献

The direct oxidation of methane, which is the main component of natural gas, shale gas, methane clathrates, and biogas, to value-added products is an economically attractive and environmentally friendly alternative to strongly endothermic methane steam reforming to synthesis gas (CO/H₂). Among the different routes, the oxidative coupling of methane (OCM) to ethylene/ethane (C₂-hydrocarbons) is the most promising one. A key limiting factor is insufficiently high selectivity to C₂-hydrocarbons due to their overoxidation to carbon oxides (CO_x) at industrially relevant degrees of methane conversion. Although it is generally agreed that both selective and unselective reactions are initiated by oxygen species on the surface of catalysts, the kind, role, and origin of these species remain elusive, which hampers the tailored design of catalysts.

In this Account, we summarize our recent progress in understanding how product selectivity in the OCM reaction can be tuned by controlling the type of oxygen species through catalyst composition or reaction conditions. The combination of in situ time- and temperature-resolved catalyst characterization with transient kinetic methods, i.e., temporal analysis of products (TAP) and steady-state isotopic transient kinetic analysis (SSITKA), has been proven to be effective for understanding the origin and role of oxygen species involved in selective and unselective pathways. We also present strategies for regulating the concentrations of selective and unselective oxygen species. For the Mn-M(M = Na, K, Rb, or Cs)₂WO₄ system, the electronegativity of the alkali metal was found to influence the ability of the catalysts to form selective oxygen species from gas-phase oxygen. The binding strength of atomic oxygen species is a key parameter for hindering the oxidation of methane to CO_x over Gd₂O₃-based catalysts. This property can be adjusted by using a metal oxide promoter. The nature and concentration of different oxygen species can also be controlled through the use of steam or an alternative oxidizing agent, N₂O, and by performing the OCM reaction in a chemical looping mode, i.e., by alternating between CH₄- and air-containing feeds. Using steam in the latter option enabled us to largely enhance the productivity of C₂-hydrocarbons, thus making this technology more attractive for large-scale applications. The knowledge summarized in this Account is expected to present insights for further studies in the development of selective catalysts for various alkane oxidation reactions and in the optimization of reactor operation.

The remarkable complexity of life is supported by proteins, yet their functional diversity is constrained by the limited chemical alphabet of 20 canonical amino acids. Although nature partially overcomes this restriction through nongenetically encoded processes such as post-translational modifications or cofactors, these mechanisms are often difficult to predict, control and engineer. This limitation raises a fundamental question: can we programmably “chemically edit” proteins to generate new functions on demand? To address this challenge, our laboratory has been dedicated to advancing a “protein chemical editing” toolkit by integrating synthetic chemistry with protein engineering. This framework enables precise manipulation of proteins from individual residues to entire functional domains. We pursue two complementary strategies: genetic code expansion, which introduces unnatural amino acids (UAAs) as new chemical building blocks, and directed evolution platforms, which generate programmable protein-editing enzymes capable of rewriting protein sequences.

In this Account, we outline a multiscale approach for protein chemical editing, spanning atomic-level control of active sites with photocaged amino acids, refinement of catalytic pockets using noncanonical residues, covalent stabilization of protein–protein interfaces through designer electrophile warheads, and domain-level editing enabled by evolved proteases.

Prospectively, through the synergistic integration of chemical design, genetic encoding, and directed evolution, protein chemical editing unlocks a new level of control over biological function. This paradigm, which merges the precision of synthetic chemistry with the complexity of living systems, fundamentally transforms our capabilities from merely observing life to actively programming it, with profound implications for biomedicine and biotechnology.

ConspectusTraditional metal nanoparticles have been widely utilized as heterogeneous catalysts in both fundamental scientific research and industrial applications. Their catalytic performances are commonly statistical and represent averaged results from all of the nanoparticles due to their inherent size polydispersity and structure heterogeneity. Recently, metal clusters (1-2 nm) with precise compositions and well-defined structures have provided opportunities to precisely correlate the catalytic properties with the structure and composition of the clusters at the atomic level. Specifically, the distinct metal core, interface, and surface structures of these clusters render them ideal for exploring the contributions of the surface/interface/core of cluster-based catalysts to catalytic properties.In this Account, we introduce the correlation of the catalytic properties of clusters with their ligand, interface, and metal kernel, ultimately mapping out the key factors that dictate the catalytic activity and selectivity. We first preview atomically precise clusters and the structural characteristics of the surface, interface, and kernel. Then, we emphasize the modulation of catalytic properties of cluster catalysts through the ligand, interface, and core. (i) Surface ligand: An efficient surface modification via ligand exchange is able to not only remarkably enhance the catalytic activity but also effectively modulate the product selectivity. (ii) Metal-ligand interface and cluster-cluster interface: The metal-ligand interface can enable the catalytic sites to directly control the whole catalytic process through the synergy between the metal atom and the ligand. Additionally, the interfaces between the clusters and their surrounding environment can cooperatively tailor the catalytic activity and selectivity. (iii) Metal core: The one-atom variation in the cluster kernel composition can effectively tune the overall electronic structures of clusters, thereby indirectly improving their catalytic activities. Furthermore, the central atom within an open core can also act as the active site to directly participate in and facilitate the catalytic reaction. Ultimately, looking to the future of catalysis science, there are still many challenges, but atomically precise metal clusters deserve more future efforts to unravel fundamental catalysis. Therefore, we offer several perspectives on the future research of precise catalysis using atomically precise cluster catalysts. We anticipate that this Account can provide fundamental insight into the unique contributions of the surface/interface/core of heterogeneous catalysts to their overall catalytic performances. By learning these fundamental principles, we will ultimately be able to design high-performance catalysts for a variety of catalytic processes.

ConspectusThe global transition toward carbon neutrality is accelerating the integration of intermittent renewable energy sources, including solar and wind power, and creating a pressing demand for large-scale energy storage systems. Among available technologies, rechargeable metal batteries have emerged as promising candidates for high-energy storage systems (e.g., lithium metal batteries) or grid-scale energy storage (e.g., zinc metal batteries) due to their high energy density, environmental compatibility, and cost efficiency. However, their commercialization remains hindered by limited energy density in cathodes. While notable progress has been achieved in anode stabilization, the development of cathode materials continues to lag, significantly restricting the overall energy output of full cells. Conventional cathode materials, whether inorganic or organic, consistently face a trade-off between high capacity and cycling stability. Although organic electrodes offer advantages such as molecular tunability and sustainability, their performance is often undermined by low electronic conductivity and dissolution of reactive intermediates, resulting in unsatisfactory capacity and cycling durability for practical applications.In this Account, we integrate our research progress with relevant insights from the field to propose that using nitrogen (N) as a multifunctional species represents a powerful approach to addressing these limitations. We systematically analyze how three inherent properties of N, i.e., variable valence states, high electronegativity, and lone-pair electrons, can be strategically utilized to increase operating voltage and reaction kinetics, construct stable electrode-electrolyte interfaces, and enable efficient multi-electron transfer processes. By presenting tailored molecular systems from our studies, e.g., N-doped organic sulfur cathodes, bipyridine-based interfacial anchoring systems, and cooperative halogen fixation platforms, we clarify the essential structure-property-performance relationships and derive general design principles for N-enhanced organic cathodes.This Account seeks to reveal the role of nitrogen in electrochemical materials, transforming its perception from a passive constituent into an active design species that decisively influences electrochemical behavior. We expect the conceptual and practical framework outlined here to offer actionable guidance for the rational development of next-generation high-performance and sustainable energy storage systems.