A research group led by Assoc. Prof. LUO Nengchao and Prof. WANG Feng from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences realized selective control of photocatalytic coupling reaction of alcohols.
　　This study was published in Journal of the American Chemical Society on Oct. 10.
　　Radicals are common intermediates in photocatalytic conversions, with open-shell electronic structures. They are highly active and readily adsorb on the surface of semiconductors strongly, resulting in a variety of reactions. Solution can influence the product selectivity and quantum yield of the photocatalytic reaction.
　　Steering the reaction paths of αHRs toward C-C bond coupling by forming hydrogen bonds (Image by MU Junju and GAO Zhuyan)
　　In this work, the researchers found that adding 5 vol% water to ethanol solution could increase the selectivity of 2,3-butanediol generated by photocatalytic coupling of ethanol from 37% to 57%, with a reaction rate 2.4 times of the original.
　　Using radical trapping experiments, deuterium experiments, DFT calculations, and molecular dynamics simulations, they found that the introduction of a small amount of water enabled the intermediate α-hydroxyethyl radical (αHR) to form hydrogen bonds with solvent molecules both on the catalyst surface and in bulk solution. With the help of hydrogen bonding, αHR tended to desorb from the catalyst surface and was stabilized in solution, avoiding the predominant oxidation of αHR to acetaldehyde and reverse reaction between αHRs and H· that recoverd ethanol.
　　"Our study revealed that non-chemical bonding interactions can steer the reaction paths of radicals for selective photocatalysis," said LUO.
　　This work was supported by the Ministry of Science and Technology of the People's Republic of China, the National Natural Science Foundation of China, the Liaoning Revitalization Talents Program, the Fundamental Research Funds for the Central Universities, the Joint Fund of the Yulin University and the Dalian National Laboratory for Clean Energy, and by Dalian Institute of Chemical Physics, CAS. (Text by GAO Zhuyan)

　　A research team led by Prof. WU Zhong-Shuai from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences has developed all-3D printed Li metal batteries (LMBs) with robust cycle stability and ultrahigh areal energy density.
　　The LMBs take a porous and conductive Ti3C2Tx MXene skeleton for dendrite-free and stable Li metal anode and multi-dimensionally conductive LiFePO4 (LFP) lattice as ultra-thick cathode.
　　This study was published in Energy Storage Materials on Oct. 19.
　　LMBs are considered as a class of high-energy-density systems beyond current state-of-the-art lithium-ion batteries. Nevertheless, the uncontrollable dendrite growth and huge volume change of Li metal anodes have raised poor cycle life.
　　Schematic illustration of the fabrication process of 3D printed LMBs (Image by MA Jiaxin and ZHENG Shuanghao)
　　In this study, the researchers reported an all-3D printing approach for constructing ultrahigh-performance LMBs. The LMBs were comprised of a dendrite-free Li metal anode with porous MXene lattices to regulate local current distribution, which homogenized the lithium nucleation, and a 3D conductive porous LFP framework cathode to achieve fast ion/electron transfer channels.
　　Due to the abundance of Li nucleation sites and large pore volume in the MXene lattices, the 3D printed MXene scaffolds prevented the infinite volume change and dendritic formation of Li anodes.
　　Furthermore, by pairing ultra-thick LFP cathodes lattices with high-efficiency electron and ion networks, the all-3D printed LFP||MXene@Li LMBs delivered unprecedented areal capacity (25.3 mAh/cm2) and energy density (81.6 mWh/cm2) under an ultrahigh mass loading of 171 mg/cm2, exceeding all reported 3D printed batteries so far.
　　This work was supported by the National Natural Science Foundation of China, the Strategic Priority Research Program of CAS, and Dalian National Laboratory for Clean Energy of CAS. (Text by MA Jiaxin and ZHENG Shuanghao)

　　A research group led by Prof. GUO Jianping and Prof. CHEN Ping from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences, in collaboration with Prof. WU An'an from Xiamen University, revealed how lithium hydride mediated hydrogenolysis of anilines to arenes.
　　This study was published in Journal of the American Chemical Society on Sep. 15.
　　Lithium hydride mediated transition metal-free hydrogenolysis of anilines to arenes (Image by CAI Yongli)
　　C-N bonds are ubiquitous in organic and biomacromolecules. The activation of C-N bonds is involved in many important chemical processes. Because of the high C-N bond dissociation energy, the intense coordinating ability, and the inferior leaving ability of the NH2 group, the cleavage of C-N bond, specially the sp2C-N bond remains challenging.
　　The researchers proposed a lithium hydride (LiH)-mediated chemical looping process for the hydrogenolysis of aniline, which decoupled the overall hydrodenitrogenation (HDN) reaction into a set of separated steps.
　　In the first step of the loop, LiH deprotonated aniline to form a lithium anilide and H2. The lithium anilide was then exposed to dihydrogen at elevated temperatures to produce benzene and lithium amide (LiNH2) in the second step. And in the last step, the LiH was regenerated by the hydrogenation of LiNH2 in a flow of H2, closing the chemical cycle.
　　They found that benzene was the dominant denitrogenated product in this process, which was in sharp contrast to those of transition metals. This led to the complete hydrogenation of aromatic rings. Therefore, they achieved a highly denitrogenated product formation rate under lower temperatures and pressures, which was comparable to the catalytic rate of transition metal catalysts.
　　The computational studies revealed that the cleavage of C-N bond was facilitated via a LiH-mediated pathway, in which the hydride (H-) of LiH functioned as a nucleophile to attack the α-sp2C atom and Li cation interacted with the distorted aromatic ring by a cation-π interaction.
　　"This work provides a new strategy for C-N bond activation and may help the design and development of new materials or catalysts for the HDN as well as other important chemical transformations," said Prof. GUO. (Text by CAI Yongli)

　　A joint research team led by Prof. PAN Xiulian, Prof. BAO Xinhe and Prof. HOU Guangjin from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS) revealed the reaction mechanism of ketene transformation to gasoline on the zeotype H-SAPO-11.
　　The study was published in Journal of the American Chemical Society on Oct. 3.
　　In 2016, the team proposed a new catalyst concept based on metal oxide-zeolite bifunctional catalysts and ketene intermediate was detected by highly sensitive synchrotron-based vacuum ultraviolet photoionization mass spectrometry during syngas conversion.
　　Further studies demonstrated that ketene can be converted to mixed light olefins over SAPO-34 and transformed to ethene over the eight-membered ring side pocket acid sites of mordenite. Although ketene has also been identified as an important intermediate in other zeolite-catalyzed C1 chemistry, its transformation mechanism is not well understood.
　　Chemistry of ketene transformation to gasoline catalyzed by H SAPO-11(Image by ZHANG Yang and GAO Pan)
　　In this study, the researchers studied ketene conversion over H-SAPO-11 employing kinetic analyses, in situ infrared spectroscopy, and solid-state nuclear magnetic resonance spectroscopy.
　　They found that ketene transformed to butene on the acid sites via either acetyl species following an acetic acid ketonization pathway or acetoacetyl species with keto-enol tautomerism following an acetoacetic acid decarboxylation pathway in the presence of water.
　　"Our study revealed experimentally for the first time on the reaction network of catalytic ketene conversion over zeotypes and may benefit the further understanding of C1 chemistry," said Prof. PAN. 
　　This work was supported by the Ministry of Science and Technology of China, the National Natural Science Foundation of China, the Liaoning Revitalization Talents Program, the China National Postdoctoral International Exchange Program, the China National Postdoctoral Program for Innovative Talents, and the China Postdoctoral Science Foundation. (Text by ZHANG Yang and GAO Pan)

Methanol-to-olefins (MTO) conversion, one of the most important reactions in C1 chemistry, has proven to be the most successful non-petrochemical industrialized route for producing light olefins.Establishing a comprehensive understanding of the dynamical multiscale diffusion and reaction process is crucial for zeolite shape-selective catalysis and is urgently demanded in academia and industry, especially for zeolite-catalyzed MTO conversion.So far, diffusion and reaction for MTO and DTO (dimethyl ether-to-olefins) have been usually studied separately and focused on a single scale. The dynamic autocatalysis of MTO further complicates the reaction and diffusion in MTO reactions. It is challenging but imperative to unravel the dynamical interactive effect of diffusion and reaction within the time-dependent MTO zeolite materials at multiple scales.Recently, a research group led by Profs. LIU Zhongmin and Prof. WEI Yingxu from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS) disclosed the dynamical multiscale cross-talk behaviors and mechanisms among time-dependent material, diffusion, and reaction for SAPO-34 catalyzed methanol and dimethyl ether conversions, at multiple scales, from the scale of molecules to single catalyst crystal and catalyst ensemble.The study was published in the National Science Review on August 04.Multiscale reaction and deactivation model of MTO and DTO reactions over SAPO-34, from the catalyst-bed scale to the catalyst-crystal and CHA-cavity scale (Image by LIN Shanfan)In this study, the researchers found that even being performed in the same zeolite material and possessing very close hydrocarbon pool mechanisms, the dynamical proceeding of the DTO reaction (relative to MTO) was distinctly regulated by the cross-talk of diffusion – reaction - material.On one side, due to the confined-organics modification, cavity type SAPO-34 material was dynamically evolved in time with the autocatalytic MTO reaction running from the initiation to decay. On the other side, the time-dependent material, in turn, creates the catalysis with the dynamical evolution of diffusion and reaction.Such dynamical cross-talk among time-dependent material, diffusion, and reaction occurred from the catalyst-bed scale to the catalyst crystal and CHA-cavity scale, and eventually resulted in the spatiotemporal heterogeneity in carbonaceous species distribution at multiple scales, revealing the root of heterogeneous catalytic efficiency, shape-selective catalysis (especially reactant shape-selective catalysis) and deactivation mode.The multiscale cross-talk behaviors and mechanisms originate from the reactant shape-selectivity of zeolite materials in the dynamical reaction procedure of MTO and DTO. Compared with methanol, mass transfer of DME is constrained over SAPO-34, since its external surface permeation and inter-cavity hopping are hindered due to the higher energy barrier of surface permeability and intracrystalline diffusivity. The constrained mass transfer of DME elongates the reaction zone of DTO over the catalyst bed but also engenders the lower local chemical potential of the reactant, thereby generating moderate reaction kinetic and less heavy coke in the local catalyst microenvironment.Such cross-talk of diffusion—reaction—material occurring at microscale in the CHA cavity triggers the cross-talk behaviors at multiple scales: (i) enabling the inner part of the catalyst crystal still accessible to quite a part of DME at the late reaction stage, sustaining the turnover of DME with high capacity, and (ii) eventually leading to a relatively moderate and homogenous reaction and deactivation mode, and higher catalyst utilization efficiency. In contrast, methanol conversion exhibits a layer-by-layer inhomogeneous reaction and deactivation mode and meanwhile, the higher local chemical potential of methanol enables the intensified rection and deactivation localized in the outer part of the catalyst crystal, working as the main efficient zone. The characteristics of the DTO reaction presented in this work, moderately evolved reaction kinetics and depressed coke deposition, imply the possibility of realizing the long-term operation of fixed-bed DTO process.Zeolite catalysis not only reflects the reaction characteristics of heterogeneous catalysis, but also provides enhanced, moderate or suppressed local reaction kinetics through the special catalytic microenvironment, which lead to the heterogeneity of diffusion and reaction at multiple scales, thereby realizing efficient and shape-selective catalysis. For the specific dynamic reaction catalyzed by zeolite material, achieving the best spatiotemporal cooperation of material, diffusion and reaction is the most critical strategy for the optimized catalyst development and process application.

　　Lithium-oxygen (Li-O2) battery is one of the most promising batteries due to its high theoretical energy density. However, the poor catalytic performance of its air-cathode impeded its commercialization.
　　Recently, a joint research group led by Prof. BAO Xinhe and Prof. WU Zhong-Shuai from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS) has fabricated two-dimensional (2D) Mn3O4 nanosheets with dominant crystal planes on graphene (Mn3O4 NS/G) as efficient oxygen catalysts Li-O2 batteries, achieving ultrahigh capacity and long-term stability.This study was published in ACS Catalysis on Oct. 7.
　　Schematic diagram of structure, cycling performance and working mechanism of 2D Mn3O4 NS/G (Image by LI Yuejiao)Designing oxygen catalysts with well-defined shapes and high-activity crystal facets can effectively regulate the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) at the three-phase interfaces, but it is still remains challenging.The researchers indicated that the Mn3O4 NS/G with the (101) facets and enriched oxygen vacancies offered a lower charge overpotential of 0.86 V than that of Mn3O4 nanoparticles on graphene (1.15 V).Moreover, Mn3O4 NS/G cathode exhibited long-term stability over 1,300 hours and ultrahigh specific capacity up to 35,583 mAh/g at 200 mA/g, outperforming most Mn-based oxides for Li-O2 batteries reported.Both the experimental and theoretical results proved the lower adsorption energy of Mn3O4 (101) for the discharge product Li2O2 in comparison with Mn3O4 (211), manifesting the easier decomposition of Li2O2 during the charging process. "This work may provide clues for engineering Mn-based materials with defined crystal facet for high-performance Li-O2 batteries," said Prof. WU.The above work was supported by the National Natural Science Foundation of China, and Dalian National Laboratory for Clean Energy of CAS. (Text by LI Yuejiao)