Photoionization (PI) is an efficient ionization technique, hyphenating to Ion Mobility Spectrometry (IMS), which has been widely employed in various on-site analysis fields such as clinical diagnosis, food quality control, environmental pollutant monitoring, and national security. However, ion loss caused by ion recombination under atmospheric pressure leads to decreased sensitivity and linear dynamic range of PI-IMS.
　　Recently, a research group led by Prof. LI Haiyang from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS) conducted a study on the response profile of PI-IMS under different pressure conditions based on the independently developed PI-IMS.
　　The researchers quantitatively analyzed the factors causing ion loss, like ion recombination and space charge, to enhance the signal intensity and linear dynamic range of PI-IMS. Furthermore, they revealed factors influencing the PI-IMS response would also benefit the applications of other chemical ionization sources in IMS or mass spectrometry (MS). The study was published in Analytical Chemistry.
　　The variation trends of the optimal pressure (Poptimal) versus analyte concentration and the electric field (Image by XU Yiqian)
　　The researchers developed variable pressure PI-IMS to investigate the signal response of PI-IMS for toluene by varying its working pressure from 1 to 0.1 bar.
　　They found that ion recombination and space charge were the primary factors contributing to ion loss under high-pressure and low-pressure conditions. They derived a simplified theoretical equation taking ion recombination as the primary ion loss factor to link the optimal pressure with analyte concentration and electric field.
　　Compared to the ambient pressure, they found that PI-IMS at 0.4 bar provided a signal intensity increment of over 400% for 0.716 ppmv of toluene, and the linear dynamic range was also expanded over two times.
　　The above study was supported by the National Natural Sciences Foundation of China and the National Key Research and Development Program of China.

　　Direct methane conversion has advantages such as low energy consumption, less processes, and better economics. However, it is difficult to activate methane at room temperature due to the high dissociation energy of C-H bonds of methane. Additionally, the target products, such as methanol, acetic acid, and other oxygenates, are prone to over-oxidation, resulting in the generation of CO2. Therefore, the design of catalysts with high activity and selectivity is important.
　　Recently, a group led by Prof. ZHANG Tao, Prof. WANG Xiaodong, and Asso. Prof. HUANG Chuande from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS), in collaboration with Prof. CHANG Chunran's group from Xi'an Jiaotong University, have realized the efficient direct conversion of methane through single-atom catalysis at room temperature.
　　This study was published in Angewandte Chemie International Edition.
　　Direct methane conversion to acetic acid over CO-promoted Pd1-ZSM-5 single-atom catalyst (Image by XU Weibin)
　　The researchers proposed a strategy involving CO molecule modification to regulate the electronic structure of single-atom catalyst M1-ZSM-5 (M = Rh, Ru, Fe), which enhances the efficiency of direct methane conversion. They realized catalyzing methane conversion with H2O2 as an oxidant at room temperature (25℃), the turnover frequency (TOF) of Pd1-ZSM-5 reached 207 h-1 with nearly 100% selectivity towards oxygenates.
　　Combining experimental characterization with density functional theory (DFT) calculations, the researchers discovered that the C atom in the CO molecule tends to coordinate with the Pd1 single atom, transferring electrons from CO to the active oxygen center L-Pd1-O (L = CO), resulting in the reduce of the dissociation barrier of C-H bonds of methane, from 1.27 eV to 0.48 eV.
　　Moreover, this strategy exhibited good universality as TOF of the M1-ZSM-5 (M = Rh, Ru, Fe) series catalysts could be increased by 3.2 to 11.3 times through CO molecule modification.
　　"We have developed the electronically tunable molecular sieve-supported M1-O isolated active centers, providing a new method to achieve selective methane conversion to chemicals under mild conditions," said Prof. WANG.
　　This work was supported by the National Natural Science Foundation of China (NSFC), the Youth Innovation Promotion Association of CAS, and the NSFC Center for Single-Atom Catalysis.

Confined catalysis has been regarded as an important strategy to modulate chemical reactions and enhance catalytic performance. Previous studies demonstrated that the applications of confinement effect in catalysis are in enclosed nanospace. However, whether an open space had this effect is still unclear.Recently, a research group led by Prof. BAO Xinhe and FU Qiang from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS) revealed the interface confinement effect on open space in In2O3-TiO2 catalyst during reverse water gas shift (RWGS) reaction. This study was published in the Journal of the American Chemical Society.Confinement-induced indium oxide nanolayers formed on TiO2 for enhanced CO2 hydrogenation reaction (Image by WANG Jianyang)The researchers physically mixed In2O3 and TiO2 to obtain an In2O3-TiO2 catalyst for the RWGS reaction. They verified that the open surface of TiO2 could create a confined environment for In2O3, which drove the spontaneous transformation of free In2O3 nanoparticles into In oxide nanolayers (InOx) covering onto the TiO2 surface during RWGS.Besides, the researchers found that the formed InOx nanolayers were easy to create surface oxygen vacancies but were against over reduction to metallic In in the H2-rich atmospheres, resulting in enhanced activity and stability compared with the pure In2O3 catalyst. They identified that the formation of interfacial In-O-Ti bonding drove the In2O3 dispersion and stabilized the metastable InOx layer.Therefore, the researchers demonstrated that the InOx overlayers with distinct chemistry from their free counterparts could be confined on various oxide surfaces, and the important confinement effect at oxide/oxide interfaces."The interface confinement effect plays an important role in many oxide/oxide catalysts, which can be used to enhance the catalytic performance," said Prof. FU.This work was supported by the National Key R&D Program of China, the National Natural Science Foundation of China, and the Photon Science Center for Carbon Neutrality.

　　Aqueous Zn batteries are considered as safe and low-cost alternatives to commercial Li-ion batteries.
　　However, water molecules in the aqueous electrolytes tend to undergo a phase transition from a disordered state to an ordered ice by forming extra hydrogen bonds. Furthermore, the electrostatic interaction between cations and anions in the electrolyte is strengthened at low temperatures, resulting in the undesired solidification of the aqueous electrolytes at low temperatures.
　　Consequently, the electrolyte freezing hampers the mobility of ions and impairs the low-temperature (particularly below -30 ℃) electrochemical activity of aqueous Zn batteries.
　　Recently, a research group led by Prof. WU Zhong-Shuai from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS), in collaboration with Prof. Sang-Young Lee from Yonsei University and Prof. Sang Kyu Kwak from Korea University, have developed a soft-acidic/hard-basic zwitterion for low-temperature anode-free Zn ion batteries. This study was published in Energy & Environmental Science.
　　Schematic depicting the roles of soft-acidic/hard-basic 2-(trimethylazaniumyl)acetate in enabling the low-temperature aqueous electrolyte and the cyclability of the anode-free Cu||Znxa-V2O5@Graphene pouch cell (115 × 95 mm2 in size) and its photograph (inset) (Image by WANG Xiao)
　　The researchers have proposed a new electrolyte design using zwitterions based on the hard and soft acids and based principle to restructure aqueous electrolytes.
　　They found that the incorporation of a soft-acidic/hard-basic zwitterion into an aqueous electrolyte could disrupt the hydrogen bonds of water molecules, weakening of zinc-trifluoromethanesulfonate (Zn2+ - OTf-) interactions, and resulting in the destabilization of the Zn2+ solvation sheath. Therefore, this electrolyte could enhance the anti-freezing phenomena with a solid–liquid transition temperature of -95 ℃ and Zn2+ desolvation kinetics.
　　By using this electrolyte, the researchers developed an anode-free full cell (Cu||Znxa-V2O5@graphene) which exhibited high energy and power densities (142 W h kg-1 at 50 mA g-1 and 230 W kg-1 at 2 A g-1) with stable cyclability at -40 ℃. It was comparable to low-temperature Li–metal batteries.
　　The above study was supported by the National Natural Sciences Foundation of China, and the DICP Innovation Foundation.

　　Chemical reactions are usually accompanied by thermal effects, inevitably resulting in temperature change in the reaction system. Therefore, temperature is an important parameter in reactions, which can affect chemical thermodynamics and reaction kinetics.
　　Precise measurement of the temperature near or at active sites inside a single catalyst particle during catalysis is important for establishing the reaction mechanism and developing the microscopic reaction kinetics.
　　Recently, a research team led by Prof. YE Mao and Prof. LIU Zhongmin from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS) has developed a three-dimensional spatiotemporal-resolved technique for the measurement of temperature distribution inside a single industrial zeolite-catalyst particle.
　　This study was published in the Journal of the American Chemical Society on Feb. 9.
　　Confocal up-conversion luminescence technique for the spatiotemporal measurements of temperature within individual catalyst particles (Image by GAO Mingbin)
　　The size of zeolite catalyst particles used in typical industrial processes is generally tens to hundreds of microns. However, the currently used thermocouples and infrared thermal imaging can only measure the surface temperature of the catalyst, and the spatial resolution is in millimeters.
　　To solve this problem, the researchers developed an imaging method with a spatial resolution of 800 nm, realizing the dynamic measurement of the three-dimensional spatiotemporal distribution of temperature inside the industrial zeolite catalyst particle during the methanol-to-olefins (MTO) reactions.
　　They developed this up-conversion confocal microscopic imaging technique by implanting the up-conversion nano-thermometer with high-temperature resistance into industrial zeolite catalyst particles using a microfluidic chip.
　　Furthermore, the researchers developed multimodal imaging techniques, i.e., confocal fluorescence and confocal infrared microscopy, and investigated the effects of zeolite contents and particle size on the spatiotemporal distribution of temperature inside the catalyst particles. They have revealed the utilization of active sites and the evolutions of reaction intermediates during MTO reactions affected by heterogeneous temperature distribution.
　　"This technique provides a new path to understand the heat transfer in catalyst particles toward rational design and optimization of industrial catalysts and catalysis," said Prof. YE.
　　This work was supported by the National Natural Science Foundation of China and the Strategic Priority Research Program of CAS.

　　Converting carbon dioxide (CO2) from industrial point sources to chemicals and fuels utilizing renewable energy can help to tackle the climate crisis. CO2 electrolysis is one of the promising route. 
　　Previous studies were generally performed with pure or highly concentrated CO2 feeds, while the CO2 concentration in flue gas from the combustion of fossil fuels was very low, typically from 5% to 15%. The energy and capital costs associated with capturing and purifying CO2 from flue gas point sources are very high. The direct utilization of industrial flue gas bypassing the capture and purification steps for producing pure CO2 feeds is still challenging.
　　Recently, a research team led by Profs. WANG Guoxiong and GAO Dunfeng from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS), in collaboration with Prof. AN Qingda from the Dalian Polytechnic University, have proposed a molecular enhancement strategy for direct electrolysis of dilute CO2 to CO.
　　This study was published in ACS Energy Letters on Feb. 9.
　　Molecularly enhanced direct electrolysis of dilute CO2 to CO (Image by CHEN Bingyu)
　　To deal with the unfavorable mass transport, reaction thermodynamics, and kinetics of direct electrolysis of dilute CO2, the researchers constructed reaction microenvironment surrounding catalytically active sites by molecularly modifying CoPc electrodes with a poly(4-vinylpyridine) (P4VP) molecule. The formed reaction microenvironment effectively integrated the capture and conversion of CO2 from dilute feed streams.
　　With a home-made alkaline membrane electrode assembly (MEA) electrolyzer, the researchers obtained a remarkable CO partial current density of 252 mA cm-2 with a CO Faradaic efficiency of 90% under the dilute feed with a typical CO2 concentration (10%) in flue gas, which was 2.24-fold higher than that of bare CoPc electrode.
　　Physicochemical and electrochemical structural characterization results indicated that the abundant pyridine groups of the P4VP modifier improved sequentially the physical adsorption and chemical activation of CO2 over Co sites of CoPc catalysts, resulting in the impressive performance for direct electrolysis of dilute CO2 to CO. 
　　This molecular enhancement strategy, with further precise control in catalyst structures and reaction microenvironments, will hold great promise in the direct electrolysis of industrial flue gas and the selective production of multicarbon chemicals such as ethylene.
　　"This work highlights the great promise of the molecular enhancement strategy for direct utilization of dilute CO2 stream from industrial flue gas," said Prof. GAO.
　　The above work was supported by the National Key R&D Program of China, the National Natural Science Foundation of China, the Collaborative Innovation Center of Chemistry for Energy Materials, the Liaoning Revitalization Talents Program, and the Youth Innovation Fund of DICP.