Nitrogen is essential to all forms of life. The formidable strength of the N≡N triple bond makes N2 fixation into biologically available forms extremely difficult.
　　At present, the activation and conversion of nitrogen mainly rely on Haber-Bosch process. However, the process has significant drawbacks such as requirement of harsh reaction conditions, high energy consumption, and large CO2 emissions.
　　Recently, Prof. CHEN Ping's group from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences, together with their collaborators Prof. Yang Shao-Horn from the Massachusetts Institute of Technology, Prof. IB Chorkendorff from the Technical University of Denmark, Prof. Ifan E. L. Stephens from the Imperial College London, Prof. Andrew J. Medford from the Georgia Institute of Technology, published a primer in Nature Reviews Methods Primers to discuss research techniques and methods in the field of nitrogen reduction and oxidation.
　　New methods of sustainable N2 activation and conversion, such as low-temperature and low-pressure thermal catalysis and (photo)electrocatalysis, have been pursued, but progress has been hindered by the lack of rigor and reproducibility in the collection and analysis of results.
　　"We want to give a guidance on techniques and methods in the field of nitrogen reduction and oxidation," said Prof. CHEN.
　　A general protocol for N2 reduction and oxidation experiments (Image by ZHANG Xilun)
　　The researchers reviewed the historic development of N2 activation, and analyzed its importance and challenges combined with theoretical calculations.
　　Then, they provided a holistic step by step protocol applicable to all nitrogen-transformation reactions, including the introduction of experimental set-up, detection methods of the products, possible sources of the contaminants, catalytic performance evaluation, analysis of the experimental results, and theoretical calculations. They compared and analyzed the state-of-the-art results from different catalytic reactions following the protocol's framework.
　　This Primer covers various common pitfalls in the field, best practices to improve reproducibility and cost-efficient methods to carry out rigorous experimentation.
　　"The future research of nitrogen activation and conversion requires rigorous experimentation and standardization to prevent false positives from appearing in the literature, which would enable advancing towards practical technologies for the activation of N2," said Prof. CHEN. (Text by ZHANG Xilun)

　　Benzylamines, one type of N-functionalized aromatics, are widely used as precursors of pharmaceuticals and synthetic dyes. Catalytic conversion of lignin into value-added N-containing chemicals such as benzylamines is significant to bring the biorefinery concept into reality.
　　Recently, Prof. LI Changzhi and Prof. ZHANG Tao's group from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences designed a new strategy for direct transformation of lignin β-O-4 model compounds, the most abundant segment in lignin, into benzylamines.
　　This study was published in Angew. Chem. Int. Ed. on July 23.
　　Sustainable production of benzylamines from lignin (Image by LI Changzhi)
　　This proposed strategy involved dehydrogenation of Cα-OH, hydrogenolysis of the Cβ-O bond and reductive amination in the presence of Pd/C catalyst. Experimental data suggested that the dehydrogenation reaction proceeded over the other two reactions and secondary amines served as both reducing agents and amine sources in the transformation.
　　Based on the above findings, the researchers demonstrated the feasibility for the production of bio-based amines from lignin in a two-step process. First, the lignin-oil was obtained through mild depolymerization of lignin catalyzed by a binuclear rhodium complex. Then, direct conversion of lignin-oil with pyrrolidine occurred over Pd/C, producing major four benzylamines.
　　This work represents a first example of synthesis of benzylamines from lignin and provides a new opportunity for the sustainable synthesis of heteroatom functionalized chemicals from renewable biomass.
　　This study was supported by National Key R&D Program of China, the National Natural Science Foundation of China, and the Royal Society International Collaboration Award. (Text by LI Changzhi)

　　Higher alcohols (C2+OH), important intermediates for fine chemicals, are mainly produced via petrochemical route, which is energy-intensive and environmentally unfriendly.
　　Recently, a research team led by Prof. SUN Jian and Prof. GE Qingjie from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS) proposed a monometallic iron catalyst with Na and S co-modification for higher alcohols synthesis from CO2 hydrogenation.
　　This study was published in Applied Catalysis B: Environmental on July 28.
　　Iron is a well-known candidate catalyst for CO2 conversion. However, the strong ability for CO dissociation of the monometallic iron catalyst decreases the efficiency of higher alcohols synthesis.
　　Revealing the promoting role of S in higher alcohols synthesis over iron catalysts (Image by YAO Ruwei)
　　The proposed monometallic iron catalyst achieved a space-time yield of 78.5 mg gcat-1 h-1 for C2+ alcohols at a relatively mild condition, which was comparable to the composite catalysts such as FeCu and FeRh.
　　The synergistic effects of Na and S enabled the Fe sites in different electronic environment in one metal phase and helped provide matched dissociative and non-dissociative CO activation simultaneously required for higher alcohols synthesis.
　　"This work extends the understanding of the role of sulfur for iron catalysts and points to a new and general direction for catalyst design in higher alcohols synthesis," said Prof. SUN.
　　This work was supported by the National Natural Science Foundation of China, Strategic Priority Research Program of the Chinese Academy of Sciences, and Liaoning Revitalization Talents Program. (Text by YAO Ruwei)

　　Lead-free halide perovskites are widely used in the field of optoelectronics and photocatalysis. However, extremely moisture-sensitive nature of halide perovskites set a huge hurdle for realizing photoluminescence and photocatalytic activities in water.
　　Recently, a research group led by Prof. HAN Keli from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS) realized functional regulation of photoluminescence and photocatalysis in lead-free perovskites through ion substitution.
　　This study was published in Angewandte Chemie International Edition on August 5.
　　 
　　A tunable strategy to design a series of Cs2PtxSn1-xCl6 with controlling photoluminescence and photocatalytic hydrogen evolution activity (Image by YIN Hang)
　　The researchers synthesized a series of Cs2PtxSn1-xCl6 with high water-stability, which show switchable photoluminescence and photocatalytic functions by varying the amount of Pt4+ substitution.
　　They found that the photocatalytic function could be activated by low content of Pt4+ substitution (x=0.05), showing photocatalytic hydrogen evolution activity in water. And the photoluminescence function could be activated by high content of Pt4+ substitution (x=0.75).
　　"Optical spectroscopy study revealed that the switch between photoluminescence and photocatalysis function was controlled by sub-bandgap states," said Prof HAN.
　　This work was supported by National Natural Science Foundation of China, the National Key Research and Development Program of China, the Science Challenging Program and the Basic Research Program of Shandong University. (Text by YIN Hang)

　　Hydrogen sulfide (H2S) is one of the most important molecules in the solar nebula, and its photochemical process strongly relates to the production of the SH(X) radicals and sulfur atoms in the interstellar medium.
　　Previous studies found that the astronomical observation deduced SH(X) abundance ratios was lower than that predicted by the standard astrochemical models in turbulent dissipation regions and shocks.
　　Recently, a group led by Prof. YUAN Kaijun from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS), in collaboration with Prof. Mike Ashfold from the University of Bristol and Dr. Chris Hansen from the University of New South Wales, revealed strong rotational excitation dependence in the photodissociation dynamics of hydrogen sulfide. This provides an alternative explanation for the observation of SH(X) radical dissipation in the interstellar medium and the source of sulfur atoms in comets.
　　This study was published in Nature Communications on July 22 and was chosen as a featured article.
　　Rotational and nuclear-spin level dependent multi-channel product measurement and photodissociation mechanisms of H2S (Image by ZHAO Yarui and YUAN Kaijun)
　　The researchers applied high-resolution translational energy spectroscopies to elucidate the detailed photodissociation mechanisms of H2S. They found that the photochemical process of H2S was far more complicated than the current theoretical predictions, and the findings might need to be added into the related astrochemical models.
　　"Our experiments provide one of the most complete experimental studies of molecular photofragmentation processes reported to date, affording initial parent quantum state and nuclear -spin dependent, and detailed investigation of competing product channels," said Prof. YUAN. "It reveals heterogeneous and homogeneous predissociation pathways following excitation to a Rydberg state of H2S".
　　"This work is a landmark in photochemistry," said one of the reviewers of the study.
　　The above work was supported by the Strategic Priority Research Program of CAS, Chemical Dynamics Research Center, and the National Natural Science Foundation of China. (Text by ZHAO Yarui /YUAN Kaijun)

　　Perovskite film, a key layer of the perovskite solar cell (PSC), determines the performance and stability of the device.
　　In the preparation process of PSCs, many defects will inevitably be introduced at the grain boundaries and interfaces, which will act as non-radiative recombination centers and seriously damage the performance and stability of PSCs.
　　Recently, a research group led by Prof. LIU Shengzhong from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS) and his cooperators incorporated fluoroethylamine (FEA) cations into the perovskite film to form highly efficient and stable perovskite solar cells (PSCs).
　　This study was published in Advanced Energy Materials on June 23.
　　The researchers found that perovskite film with FEA passivation improved photoluminescence (PL) intensity, prolonged carrier-lifetime, suppressed nonradiative recombination, enlarged grain size and hydrophobicity, and hence delivered high device performances.
　　By engineering of different amounts of fluorine in the molecule, they revealed that different amounts of fluorine additives presented a gradient distribution in the film. The device employing 2-fluoroethylamine (1FEA) achieved an efficiency of 23.40%, while the device employing 2, 2, 2-trifluoroethylamine (3FEA) showed the best environmental stability, maintaining 87% of their initial efficiencies after 1200 h.
　　"This research paves a new way to fabricate high-efficiency and stabile PSCs," said Prof. LIU.
　　The above work was supported by the National Natural Science Foundation of China, the National Key Research and Development Program of China, the DNL Cooperation Fund CAS, the 111 Project, and the Changjiang Scholars and Innovative Research Team. (Text by SU Hang and DUAN Lianjie)