Halogenated organic pollutants (HOPs), produced by extensively using halogenated compounds, damage the environment. The repurposing of HOPs offers a means of pollution abatement and reduces greenhouse gas emissions.The utility of HOPs, especially halogens in HOPs, is limited due to the challenge of direct chlorination of C–H bonds in HOPs.Recently, a research group led by Prof. CHEN Qingan from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS) has realized the reuse of HOPs. They developed a bromide-catalyzed chlorine transfer reaction, which utilized HOPs as halogen sources, thereby enabling the reuse of various HOPs. This study was published in Nature Chemistry.Repurposing of halogenated organic pollutants via alkyl bromide-catalysed transfer chlorination (Image by LIU Heng)The developed strategy realized the repurposing of HOPs via alkyl bromide-catalysed transfer chlorination. It enabled the chlorination of ketones and facilitated the chlorohydroxylation of olefins via the chlorine-transfer reaction.The researchers found that the reaction proceeded through a halogen-exchange process, facilitating chlorine transfer between distinct molecules. Therefore, they realized the diversified use of the brominated pollutant hexabromocyclododecane (HBCD).In addition, the researchers indicated that this strategy could repurpose a variety of chlorinated organic pollutants, including chlorinated paraffins (CPs), dichlorodiphenyltrichloroethane (DDT), chloromethyl polystyrene (CMPS) and poly(vinyl chloride) (PVC). The practical value of this reaction was further shown by synthesizing three pharmaceuticals and reusing PVC waste."Our study demonstrated that transfer chlorination could be facilitated by alkyl bromide catalysis, and the developed strategy will promote the development of transforming waste into value-added products," said Prof. CHEN.The research was supported by DICP, the Dalian Outstanding Young Scientific Talent, and the National Natural Science Foundation of China. (Text by LIU Heng)

Producing valuable multicarbon (C2+) chemicals and fuels like ethylene via catalytic conversion of carbon monoxide (CO) derived from coal, natural gas, and biomass is an important nonpetroleum route. The thermocatalytic CO conversion processes such as Fischer-Tropsch synthesis (FTS) suffer from substantial CO2 emission as well as the formation of undesired methane by-products.Renewable energy-driven CO electrolysis is an emerging catalytic CO conversion route. This reaction proceeds with water as a hydrogen source under ambient conditions and can electrochemically eliminate the formation of CO2 by applying a negative potential on CO molecules.Recently, a research team from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS) achieved high-rate electrosynthesis of C2+ chemicals and fuels via CO electrolysis.This study was published in Nature Communications on May 30.High-rate electrosynthesis of multicarbon chemicals and fuels from carbon monoxide (Image by LI Hefei)The researchers developed a Cu nanoparticle catalyst with high-density grain boundaries (GBs) via a facile wet-chemistry synthesis approach. In combination with advanced alkaline membrane electrode assembly electrolyzers developed by the team, they achieved a C2+ partial current density as high as 4.35 A cm-2 at a low cell voltage of 2.78 V, with a C2+ Faradaic efficiency of 87% and a notable C2+ yield as high as 85%.Operando Raman spectroscopy and density functional theory calculation results revealed that the abundant grain boundaries of Cu nanoparticles facilitate CO adsorption and C-C coupling, thus rationalizing the impressive C2+ production.A scale-up demonstration using the above Cu catalyst and an electrolyzer stack with five 100 cm2 membrane electrode assembly achieved high C2+ and ethylene formation rates of 118.9 mmol min-1 and 1.2 L min-1 at a total current of 400 A, respectively."This work demonstrates the great promise of CO electrolysis as a sustainable and practical route for the electrochemical synthesis of valuable C2+ chemicals," said Prof. GAO Dunfeng who is the author of this study. "Our work also highlights the significance of coupling catalyst design and device design in developing highly-efficient electrolysis technology," said Prof. WANG Guoxiong who is another author of this study.The above work was supported by the National Key R&D Program of China, the National Natural Science Foundation of China, the Liaoning Revitalization Talents Program, and the Youth Innovation Fund of DICP. (Text by GAO Dunfeng)

Microbial biosynthesis provides a feasible approach to sustainably produce advanced biofuels and biochemicals from renewable feedstocks. Methanol is an ideal feedstock for bio-manufacturing since it can be produced from CO2 through green energy, such as solar energy.Recently, A joint research group led by Prof. ZHOU Yongjin and Prof. ZHANG Lihua from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS) engineered and optimized Pichia pastoris for bioproduction of α-bisabolene from sole methanol with the aid of proteomics.This study was published in JACS Au on April 29.Engineering α-bisabolene production from sole methanol might provide a sustainable approach for advanced biofuel production (Imaged by GAO Linhui)The researchers extensively engineered industrial yeast Pichia pastoris for overproduction of bisabolene by optimizing isoprenoid biosynthetic pathway in Pichia pastoris cytosol and peroxisome. By quantitative proteomic analysis, they have identified that acetoacetyl-CoA thiolase was a bottleneck in the peroxisomal isoprenoid biosynthetic pathway. And they enhanced the expression of acetoacetyl-CoA thiolase to improve the α-bisabolene biosynthesis by 100%, which realized 1.1 g/L α-bisabolene production under fed-batch in shake-flask.This study provides a feasible approach for optimizing the metabolic pathway for overproduction of other chemicals from sole methanol in Pichia pastoris."Engineering α-bisabolene production from sole methanol might provide a sustainable approach for advanced biofuel production," Prof. ZHOU said. "We here clearly showed that proteomic analysis can help to optimize the biosynthetic pathway by identifying the pathway bottleneck," Prof. ZHANG said.

Plastics are one of the most produced synthetic materials and the largest commodities, making our lives convenient and facilitating industrial processes.The global production of plastics was reported to reach 9.2 billion tons in 2020, and it is still increasing every year. Among them, polyolefins, represented by polyethylene (PE) and polypropylene (PP), account for about 55% of the total plastics. However, only about 10% of plastic wastes were recycled due to their chemical inertness.Recently, a research group led by Prof. PAN Xiulian from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS) achieved the upcycling of polyolefin waste plastics and carbon dioxide (CO2) to aromatics with a high selectivity. This study was published in the journal of National Science Review.Scheme of upcycling polyolefin waste plastics and CO2 to aromatics (Image by DING Yi)Inspired by the concept of oxide-zeolite (OXZEO) bifunctional catalysts for syngas conversion and CO2 hydrogenation, the researchers designed a bifunctional catalyst composed of ZSM-5 zeolite and Pt/MnOx for combined upcycling of polyolefin plastics and CO2 neutralization. ZSM-5 catalyzed the cracking of polyolefins and aromatization, generating hydrogen simultaneously while Pt/MnOx catalyzed the reaction of hydrogen with CO2, consequently driving the reaction toward aromatization. CO2 acted not only as a hydrogen scavenger but also as a carbon source that was incorporated into the aromatic-products.With this bifunctional catalyst, the researchers proved that 1.0 kg polyolefin consumed 0.2 kg CO2, and 90% of the consumed CO2 was incorporated into the aromatic products. It yielded 0.63 kg aromatics, 0.28 kg liquefied petroleum gas (LPG) and naphtha, with monocyclic aromatics accounting for 87% and benzene, toluene, and xylene (BTX) accounting for 60% of the aromatics. By contrast, the conventional pyrolysis or hydrocracking processes produced only 0.33 kg aromatics at 300 °C and 1 MPa.Furthermore, the researchers indicated that this designed bifunctional catalyst enabled upcycling of different polyolefins, including polyethylene, polypropylene, and their plastic products in different forms."We not only achieved the selective production of high value-added aromatic hydrocarbons such as BTX from waste polyolefin plastics under mild conditions but also provided a new strategy for the utilization of CO2," said Prof. PAN.

Recently, a research group led by Prof. LI Haiyang and Prof. HUA Lei from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS) has discovered a new phenomenon in pressure-driven switching of photoionization channel using a home-built time-of-flight mass spectrometer (TOFMS).The study was published in Analytical Chemistry on Mar. 29.Pressure-driven switching from photoelectron impact ionization-chemical ionization (PEI-CI) to Penning ionization (Image by YU Yi)Vacuum ultraviolet photoionization (VUV-PI) is a soft ionization technique operating under pressures ranging from vacuum to ambient pressure. VUV-PI has played an essential role in direct sampling mass spectrometry.In this study, the researchers have studied new ionization processes initiated by photoelectrons through the inclusion of a radio frequency (RF) electric field at different pressures. After deducting the contribution of single photoionization (SPI), they discovered that the signal intensity of 1 ppmv toluene (C7H8+) in Ar was approximately 5-fold higher than that in N2.The researchers further investigated mixed gases with different ionization energies (IEs) and excitation energies. They revealed that metastable species were involved in the enhancement process. Reactant ions were produced by photoelectron impact ionization (PEI), which further triggered ion-molecule reactions, i.e., chemical ionization (CI). Metastable species were produced by photoelectron impact excitation (PEE), which further triggered Penning ionization (PenI).Moreover, they indicated that analytes with IEs above 10.6 eV, such as CO2 (IE = 13.78 eV) and CHCl3 (IE = 11.37 eV), could be sensitively ionized by PenI with a sensitivity comparable to SPI. Except for the contribution of SPI, the dominant ionization process was switched from PEI-CI to PenI when the pressure was elevated from 50 to 500 Pa, as the electron energy gradually decreased and was only able to produce metastable states based on the kinetic energy balance equation of electrons."This study is helpful to develop new selective and sensitive VUV-PI sources and understand the ionization mechanism in other discharge ionization sources," said Prof. LI."The sensitivity of PenI could be further enhanced by employing VUV lamps with higher photon flux or photocathode material with higher quantum efficiency, which will result in higher density of photoelectron and produce more metastable atoms/molecules. High-pressure PenI initiated by photoelectron exhibits advantages of selectivity and sensitivity, which shows broad application prospects in the analysis of complicated samples," Prof. LI added.This work was supported by the National Natural Science Foundation of China, the Scientific Instrument Developing Project of CAS, and the Innovation Research Foundation of DICP.

Traditional non-aqueous lithium-ion batteries have a high energy density, but their safety is compromised due to the flammable organic electrolytes they utilize.Aqueous batteries use water as the solvent for electrolytes, significantly enhancing the safety of the batteries. However, due to the limited solubility of the electrolyte and low battery voltage, aqueous batteries typically have a lower energy density. This means that the amount of electricity stored per unit volume of aqueous battery is relatively low.In a new study published in Nature Energy, a research group led by Prof. LI Xianfeng from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS), in collaboration with Prof. FU Qiang's group also from DICP, developed a multi-electron transfer cathode based on bromine and iodine, realizing a specific capacity of more than 840 Ah/L, and achieving an energy density of up to 1200 Wh/L based on catholyte in full battery testing.To improve the energy density of aqueous batteries, researchers used a mixed halogen solution of iodide ions (I-) and bromide ions (Br-) as the electrolyte. They developed a multi-electron transfer reaction, transferring I- to iodine element (I2) and then to iodate (IO3-). During the charging process, I- were oxidized to IO3- on the positive side, and the generated H+ were conducted to the negative side in the form of supporting electrolyte. During the discharge process, H+ were conducted from the positive side, and IO3- were reduced to I-.The developed multi-electron transfer cathode had a specific capacity of 840 Ah/L. Combining the cathode with metallic Cd to form a full battery, researchers achieved an energy density up to 1200 Wh/L based on the developed catholyte.Besides, researchers confirmed that Br- added to the electrolyte could generate polar iodine bromide (IBr) during the charging process, which facilitated the reaction with H2O to form IO3-. During the discharge, IO3- could oxidize Br- to Br2 and participated in the electrochemical reaction to realize reversible and rapid discharge of IO3-. Therefore, the bromide intermediate formed during the charge and discharge process optimized the reaction process, effectively improving the kinetic and reversibility of the electrochemical reaction.Prof. FU's group proved the multi-electron transfer process through in-situ optical microscopy, Raman spectroscopy and so on."This study provides a new idea for the design of high-energy-density aqueous batteries, and may expand the aqueous batteries application in power batteries field," said Prof. LI.