Ammonia is the feedstock for nitrogen fertilizers and thus vital to the sustainable development of society.
　　Industrial ammonia synthesis catalyzed by Fe or Ru is carried out under high temperature and high pressure with enormous CO2 emission. The development of efficient catalyst enabling ammonia synthesis under mild condition is important.
　　Recently, a joint research team led by Prof. CHEN Ping from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS) and Prof. Tejs Vegge from Technical University of Denmark (DTU) has found that ternary complex hydrides of ruthenium and alkali (alkaline earth) metals (i.e., Li4RuH6 and Ba2RuH6) performed well in catalyzing ammonia synthesis under mild condition.
　　This study was published in Nature Catalysis on Nov. 18.
　　Ternary ruthenium complex hydrides for ammonia synthesis via the associative mechanism (Image by WANG Qianru and Jaysree Pan)
　　They found that the key to achieve efficient ammonia synthesis under mild condition was the unique configuration and function mechanism of the ternary complex hydride center, which was different from the conventional Ru based catalysts.
　　In ternary hydride catalytic system, N2 underwent non-dissociative activation over the electron-rich [RuH6] anionic centers through the involvement of hydridic hydrogens in mediating electron and proton transfers and Li or Ba cations in stabilizing NxHy species, leading to ammonia production with superior kinetics.
　　Hence, the synergistic engagement of all the components of the ternary complex hydrides enabled a reaction path with a narrow energy span, and thus favored ammonia production under mild conditions.
　　"This work opens an avenue for the design and development of efficient catalysts to tackle the conversion of kinetically stable molecules," said Prof. CHEN.
　　The study was supported by the National Natural Science Foundation of China, the Youth Innovation Promotion Association of CAS, and K. C. Wong Education Foundation. (Text by WANG Qianru) 

　　A research group led by Prof. JIN Shengye from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences revealed an ultrafast and high-yield polaronic exciton dissociation mechanism in two-dimensional (2D) perovskites.
　　This study was published in Journal of the American Chemical Society on Nov. 3.  
　　2D perovskites are a class of naturally formed quantum well (QW) materials. The exciton binding energy in 2D perovskite is much larger (up to hundreds of meV) than that in their 3D counterparts due to strong quantum and dielectric confinement.
　　Therefore, it is commonly believed that the photogenerated charge carriers in 2D perovskites are mainly exist in the form of excitons, which are difficult to dissociate into free carriers at room temperature.
　　Polaronic exciton dissociation equilibrium in 2D perovskites (Image by SUN Qi, ZHAO Chunyi and TIAN Wenming)
　　In this study, by using femtosecond photoluminescence up-conversion (PL-UC) and transient absorption (TA) spectroscopy, the researchers for the first time directly and dynamically observed the ultrafast (< 1.4 ps) and highly efficient (> 80%) exciton dissociation in 2D perovskites (n ≥ 2). This confirmed that free-carriers were the dominant carrier species in 2D perovskites under room temperature, which is conflict with previous thought.
　　Moreover, they proposed a polaron-induced exciton dissociation mechanism, where the exciton-polarons were readily formed by strong exciton-phonon coupling as in 3D perovskites, and the polaronic screening effect led to a prominent reduction in binding energy for efficient exciton dissociation.
　　The researchers demonstrated that the exciton dissociation into free-carriers was a major factor limiting the photoluminescence quantum yield of 2D perovskites by introducing additional nonradiative carrier loss.
　　"This work reveals a common exciton dissociation property in this class of 2D materials and provides a guideline for the design and rational utilization of 2D perovskites in optical and optoelectronic applications," said Prof. JIN.
　　This study was supported by the Ministry of Science and Technology of China, the National Natural Science Foundation of China and the Youth Innovation Promotion Association of CAS. (Text by SUN Qi, ZHAO Chunyi and TIAN Wenming)

　　Syngas is an important feedstock for modern chemical industries and can be directly used as fuel. Carbon monoxide (CO) is its main component. Direct conversion of widespread renewable biomass resources into CO can help to achieve sustainable development.
　　Conventionally, bio-syngas is mainly produced through thermal-chemical processes such as pyrolysis, steam reforming or aqueous reforming, which require high temperature and consume a lot of energy.
　　Recently, a research team led by Prof. WANG Feng from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences, in collaboration with Prof. WANG Min from Dalian University of Technology, developed a new method to directly convert bio-polyols into CO.
　　The results were published in Chem on Nov. 16.
　　Oxygen-controlled photo-reforming of biopolyols (Image by ZHOU Hongru)
　　The researchers developed a photocatalytic oxidative reforming process to directly convert the bio-polyols into CO under ambient conditions, using a Z-scheme CdS@g-C3N4 catalysts with core-shell structure.
　　The particular catalyst structure facilitated the adsorption and activation of dioxygen on the surface of catalyst and thus promoted the production of hydroxyl radicals and enhanced the CO production rate.
　　They found that the regulation of the molar ratio of O2 and substrates not only accelerated the reaction rates but also prevented the over oxidation of substrates to CO2.
　　Under natural sunlight irradiation, this system could still stably catalyze the production of CO from glycerol.
　　"This work provides new ideas for the effective utilization of biomass resources," said Prof. WANG. (Text by ZHOU Hongru) 

　　Long cycle life and high safety are required for energy storage devices (ESDs) in their large-scale applications. Therefore, it's important to explore both the operating and failure mechanisms of ESDs.
　　Previous characterization techniques such as X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray spectroscopy and topography, and nuclear magnetic resonance (NMR) were based on bulk regions of electrodes or electrolytes, and they overlooked the critical surface/interface behaviors that govern the operation and failure in ESDs.
　　Recently, a research team led by Prof. FU Qiang from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS) revealed the atmosphere-dependent relaxation and failure mechanisms of ESDs by in situ surface science methodology.
　　The results were published in Journal of the American Chemical Society on Oct. 13th.
　　Relaxation in anhydrous atmospheres and failure in hydrous atmospheres have been visualized by in situ surface science methodology over an Al/graphite model battery (Image by ZHANG Guohui and WANG Chao)
　　The researchers visualized atmosphere-dependent relaxation and failure processes in ESDs by in situ Raman, X-Ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS).
　　They found that for aluminum ion battery (AIB), the relaxation effects of the graphite electrode in anhydrous atmospheres were manifested by recoverable stage-structure change and electronic relaxation. The mechanisms could be described as the redistribution of the anion/cation pairs within graphite electrode by in situ XPS.
　　Once exposure to hydrous atmospheres, H2O molecules from ambient could intercalate into the graphite electrode and hydrolysis reactions could be induced between newly intercalated H2O and ions. After H2O intercalation and hydrolysis, the failure behaviors of the graphite electrode happened as shown by the stage-structure degradation and electronic decoupling.
　　"We have developed the atmosphere-, temperature- and potential- controlled operando/in situ surface/interface techniques and well-defined model devices," said Prof. FU. "Such methods can be extended to explore the relaxation and failure mechanisms of more ESDs, such as metal-ion secondary batteries/supercapacitors, and the interface reactions in metal-gas batteries".
　　This work was supported by the National Natural Science Foundation of China, the National Key R&D Program of China, the Strategic Priority Research Program of CAS, and the DICP&QIBEBT funding. (Text by ZHANG Guohui and WANG Chao)

Charge transfer is a key step in photosynthesis, biological signal transduction, and conversion of various energy sources. The theoretical framework for charge transfer was established by Rudolph Marcus in the 1950s. It predicts the existence of a so-called "Marcus inverted region", where the transfer rate decreases with increasing reaction exothermicity (or driving force).Low-dimensional semiconductor materials are attracting enormous attention because of their strong potential for optoelectronic and energy-related applications. To date, however, it remains unclear whether Marcus theory is applicable to the charge transfer behavior of these materials.Recently, a research group led by Prof. WU Kaifeng from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Science (CAS) observed the Marcus inverted region of charge transfer from low-dimensional semiconductor materials.This study was published in Nature Communications on Nov. 3.Marcus inverted region is observed by measuring charge transfer from single-charge states of quantum dots and nanoplatelets (Image by WANG Junhui)The researchers built a unique model system using zero-dimensional quantum dots or two-dimensional nanoplatelets and surface-adsorbed molecules that allows for measuring charge transfer from transiently-populated, single-charge states.Combined with the capability of tuning the electron transfer driving forces through the quantum confinement effect, this measurement allowed to probe the fundamental energetics dependence of electron transfer, and to reveal a Marcus inverted region for these low-dimensional semiconductor materials."This is the first observation of a Marcus inverted region for low-dimensional semiconductor materials," said Prof. WU. "It may benefit energy conversion applications of these materials."The study was supported by the National Natural Science Foundation of China, the Strategic Pilot Science and Technology Project of CAS, the Ministry of Science and Technology of China and the Youth Innovation Promotion Association CAS. (Text by WANG Junhui)

　　Vibrationally excited molecular hydrogen is an essential species for determining the chemical composition in the interstellar medium.
　　Vibrational excited interstellar H2 has been detected in shock-heated gas and in photodissociation regions (PDRs) near hot stars, which was formed by collisions and fluorescence excitation in PDRs.
　　Recently, a research group led by Prof. YUAN Kaijun and Prof. YANG Xueming from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS) demonstrated vibrationally excited H2 production from the water photochemistry using the Dalian Coherent Light Source. This process represents a further source of vibrationally excited H2 observed in the interstellar medium.
　　Their findings were published in Nature Communications on Nov. 2.
　　Dalian Coherent Light Source revealing vibrationally excited molecular hydrogen production from the water photochemistry (Image by CHANG Yao)
　　The experimental results indicated that all of the H2 fragments identified in the O(1S) + H2(X1Σg+) channel following vacuum ultraviolet photodissociation of H2O in the wavelength range of λ=~100-112 nm were vibrationally excited. In particular, more than 90% of H2(X) fragments populated in a single vibrational state v=3 at λ~112.81 nm.
　　The estimated cross section for forming H2(v>0) fragments at λ~107.5 nm was determined to be ~3.2×10-18 cm2.
　　The abundance of the water molecules and vacuum ultraviolet photons in the interstellar space suggested that the contributions of these H2(v>0) sources from water photochemistry could be significant and thus should be recognized in appropriate interstellar chemistry models.
　　This research was supported by the Strategic Priority Research Program of CAS, Chemical Dynamics Research Center, and the National Natural Science Foundation of China. (Text by CHANG Yao)