Huihui Hu, Zhiye Wang, Lingyun Cao, Lingzhen Zeng, Cankun Zhang, Wenbin Lin & Cheng Wang Nature Chemistry volume 13, pages358–366 (2021) Metal–organic frameworks (MOFs) have been studied extensively in the hydrogen evolution reaction (HER) and the water oxidation reaction (WOR) with sacrificial reagents, but overall photocatalytic water splitting using MOFs has remained challenging, principally because of the fast recombination of photo-generated electrons and holes. Here we have integrated HER- and WOR-MOF nanosheets into liposomal structures for separation of the generated charges. The HER-MOF nanosheets comprise light-harvesting Zn–porphyrin and catalytic Pt–porphyrin moieties, and are functionalized with hydrophobic groups to facilitate their incorporation into the hydrophobic lipid bilayer of the liposome.

Neighboring Zn–Zr Sites in a Metal–Organic Framework for CO2 Hydrogenation Jingzheng Zhang, Bing An, Zhe Li, Yonghua Cao, Yiheng Dai, Wangyang Wang, Lingzhen Zeng, Wenbin Lin, and Cheng Wang* June 7, 2021 https://doi.org/10.1021/jacs.1c03283 ZrZnOx is active in catalyzing carbon dioxide (CO2) hydrogenation to methanol (MeOH) via a synergy between ZnOx and ZrOx. Here we report the construction of Zn2+–O–Zr4+ sites in a metal–organic framework (MOF) to reveal insights into the structural requirement for MeOH production. The Zn2+–O–Zr4+ sites are obtained by postsynthetic treatment of Zr6(μ3-O)4(μ3-OH)4 nodes of MOF-808 by ZnEt2 and a mild thermal treatment to remove capping ligands and afford exposed metal sites for catalysis.

Peican Chen,*ab Jiawei Chen,b Xuefu Hub and Cheng Wang Received 9th February 2021, Accepted 26th March 2021 DOI: 10.1039/d1fd00016k Hollow metal–organic frameworks (MOFs) with only a shell may be used for efficient catalysis. In this work, a general sequential synthesis was employed to successfully create Hf-based hollow MOFs, such as UiO-66, MOF-808, and PCN-223. Etchants including monocarboxylic acids and H2O are required to remove the interior of the MOFs to form hollow structures, while the different stability of the interior and surface of the MOFs partly resulting from surface epitaxy protection was responsible for the selective etching. With these insights, scale-up of hollow octahedral UiO-66 was realized. This work paves a way to rationally design hollow MOFs.

Xuefu Hu, Zhiye Wang, Yuming Su, Peican Chen, Yibin Jiang, Cankun Zhang, and Cheng Wang* Chem. Mater. 2021, 33, 5, 1618–1624 Publication Date:February 15, 2021 Two-photon absorption (TPA) of many chromophores can be enhanced by building them into the structure of metal–organic frameworks (MOFs). However, light scattering of MOFs defocuses the light beam and thus decreases the nonlinear optical effects like TPA. Nanoscale two-dimensional (2D) metal–organic layers (MOLs) are 2D analogues of MOFs with low light scattering. In this work, we obtained a MOL containing tri(4-carboxylic-biphenyl)-4′-amine (H3TCBPA) that exhibited a TPA cross-section of 13 000 ± 2000 GM, which is ∼7 times that of the H3TCBPA ligand in homogeneous solution (1850 ± 200 GM).

Ying Guo, Xinru He, Yuming Su, Yiheng Dai, Mingcan Xie, Shuangli Yang, Jiawei Chen, Kun Wang, Da Zhou*, and Cheng Wang* April 12, 2021 https://doi.org/10.1021/jacs.1c00339 Discovery and optimization of new catalysts can be potentially accelerated by efficient data analysis using machine-learning (ML). In this paper, we record the process of searching for additives in the electrochemical deposition of Cu catalysts for CO2 reduction (CO2RR) using ML, which includes three iterative cycles: “experimental test; ML analysis; prediction and redesign”. Cu catalysts are known for CO2RR to obtain a range of products including C1 (CO, HCOOH, CH4, CH3OH) and C2+ (C2H4, C2H6, C2H5OH, C3H7OH). Subtle changes in morphology and surface structure of the catalysts caused by additives in catalyst preparation can lead to dramatic shifts in CO2RR selectivity.

Zhiye Wang, Cheng Wang First published: 31 March 2021 Excited state energy transfer in metal-organic frameworks (MOFs) is of great interest due to potential application of these materials in photocatalysis and fluorescence sensing. In photocatalysis, a light-harvesting antenna of MOFs can collect energy from a much larger area than a single reaction center and efficiently transport the energy to the active site to enhance photocatalytic efficiency, mimicking nature photosynthesis.

Lingyun Cao and Cheng Wang* October 30, 2020 https://doi.org/10.1021/acscentsci.0c01150 Metal–organic layers (MOLs) are two-dimensional analogues of metal–organic frameworks (MOFs) with a high aspect ratio and thickness down to a monolayer. Active sites on MOLs are more accessible than those on MOFs thanks to the two-dimensional feature of MOLs, which allows easier chemical modification around the catalytic center. MOLs can also be assembled with other functional materials through surface anchoring sites that can facilitate charge/energy transport through the hybrid material. MOLs are thus quite suitable for interfacial catalysis like electrocatalysis and photocatalysis.

Ying Guo, Yucheng Wang, Yan Shen, Zhuanyun Cai, Zhe Li, Jia Liu, Jiawei Chen, Chi Xiao, Huichong Liu, Wenbin Lin, and Cheng Wang* December 15, 2020 https://doi.org/10.1021/jacs.0c10719 The Co center is active in electrochemical CO2 reduction (CO2RR), and its activity can be tuned by changing its coordination environment. However, the coordination number around the Co center cannot be readily changed in homogeneous systems owing to bimolecular decomposition of reduced low-coordinate Co species. Herein we report the systematic tuning of N atom numbers from 2 to 5 in the first coordination sphere around Co centers supported on two-dimensional metal–organic layers (MOLs) for the electrochemical CO2RR. The N atoms come from a combination of bipyridine, terpyridine, and phenylpyridine ligands. The Co centers are isolated and stabilized on the MOL to prevent bimolecular decomposition.

Hao Wang, Liangmei Su, Mehmet Yagmurcukardes, Jiawei Chen, Yu Jiang, Zhe Li, Anchang Quan, Francois M. Peeters, Cheng Wang*, Andre K. Geim, and Sheng Hu* November 12, 2020 https://doi.org/10.1021/acs.nanolett.0c03342 Blue energy converts the chemical potential difference from salinity gradients into electricity via reverse electrodialysis and provides a renewable source of clean energy. To achieve high energy conversion efficiency and power density, nanoporous membrane materials with both high ionic conductivity and ion selectivity are required. Here, we report ion transport through a network of holey-graphene-like sheets made by bottom-up polymerization. The resulting ultrathin membranes provide controlled pores of <10 Å in diameter with an estimated density of about 1012 cm–2.

Ling Yang, Fa-Xue Ma, Fan Xu, Dong Li, Liangmei Su, Prof. Hai-Chao Xu, Prof. Cheng Wang Nano Lett. 2020, 20, 12, 8634–8639 Publication Date:November 12, 2020 The catalytic acceptorless dehydrogenation (CAD) is an attractive synthetic route to unsaturated compounds because of its high atomic efficiency. Here we report electrochemical acceptorless dehydrogenation of N-heterocycles to obtain quinoline or indole derivatives using metal-organic layer (MOL) catalyst. MOL is the two-dimensional version of metal-organic frameworks (MOF), and it can be const...

Peican Chen, Zeyu Tang, Zhongming Zeng, Xuefu Hu, Liangping Xiao, Yi Liu, Xudong Qian, Chunyu Deng, Ruiyun Huang, Jingzheng Zhang, Yilong Bi, Rongkun Lin, Yang Zhou, Honggang Liao, Da Zhou, Cheng Wang, Wenbin Lin,Matter, Volume 2, Issue 6, 2020, Pages 1651-1666,
We studied nanoscale metal-organic frameworks (nMOFs) from Hf-oxo clusters and linear dicarboxylate ligands with the aid of machine-learning methods for data analysis. Ligand solubility and modulator concentration were found to quantitatively predict the growth of nMOFs with a specific morphology. we use epitaxy growth sequences to design nMOFs of desirable nanostructures with enhanced substrate transport and, hence, increased activities for catalytic olefin hydrogenation. This work provides guidance for morphology engineering of nMOFs and other nanomaterials in using machine learning.

Chen, P., Liu, Y., Hu, X. et al. Probing surface structure on two-dimensional metal-organic layers to understand suppressed interlayer packing. Nano Res. 13, 3151–3156 (2020).
We investigated the surface structures of a MOL built from Hf6(μ-O)4(μ-OH)4 secondary building units (SBUs) and benzene-tribenzoate (BTB) ligands by using a combination of surface sensitive technologies.We found a partial coverage of the monolayer surface by dangling tricarboxylate ligands, which prevent packing of the monolayers. This work provides new insight on controlling surface composition in synthesizing twodimensional metal-organic layers.

Xuefu Hu, Zhiye Wang, Yuming Su, Peican Chen, Jiawei Chen, Cankun Zhang, and Cheng Wang*, Inorg. Chem. 2020, 59, 7, 4181–4185
Metal-organic frameworks (MOFs) based on 9,10-diphenylanthracene-derived ligands had been reported to exhibit upconverted fluorescence through triplet-triplet annihilation. We found that zirconium MOFs based on 9,10-diphenylanthracene can also give upconverted fluorescence via two-photon absorption without adding a triplet photosensitizer when a femtosecond pulsed laser is used as the excitation source. Moreover, we observed different emission spectra by two-photon excitation compared to those by one-photon excitation, which indicates access to a unique initial excited state via two-photon excitation. These nanoscale MOFs may find application in two-photon fluorescence imaging.

Lingzhen Zeng, Zhiye Wang, Yongke Wang, Jing Wang, Ying Guo, Huihui Hu, Xuefeng He, Cheng Wang*, and Wenbin Lin, J. Am. Chem. Soc. 2020, 142, 1, 75–79
CO2 hydrogenation to ethanol is of practical importance but poses a significant challenge due to the need of forming one C-C bond while keeping one C-O bond intact. We report the use of low-intensity light to generate CuI species in the cavities of a metal-organic framework (MOF) for catalytic CO2 hydrogenation to ethanol. Upon light activation, this Cu-Ru-MOF hybrid selectively hydrogenates CO2 to EtOH with an activity of 9650 μmol gCu-1 h-1 under 2 MPa of H2/CO2 = 3:1 at 150 °C. This work suggests new opportunities in using light to stabilize metal centers of an intermediate oxidation state for selective chemical transformations.

Lingzhen Zeng, Yongke Wang, Zhe Li, Yang Song, Jingzheng Zhang, Jing Wang, Xuefeng He, Cheng Wang*, and Wenbin Lin, ACS Appl. Mater. Interfaces 2020, 12, 15, 17436–17442
We report the preparation of porous hydrous zirconia by treatment of zirconium-based metal-organic framework (MOF) UiO-66 with a strong base. NiII centers were then adsorbed onto the OH-rich hydrous zirconia and in situ converted to highly dispersed Ni0 for CO2 hydrogenation to CH4. The activated catalyst after an induction period showed a turnover frequency of 345 h-1 or a space-time yield of 5851 mmol·gNi-1·h-1 with a CH4 selectivity of over 99%.This work highlights the opportunity in using MOFs as precursors to prepare highly porous metal oxide/hydroxide supports for solid-gas phase catalysis.

Liangmei Su, Fan Xu, Jiawei Chen, Yang Cao* and Cheng Wang, New J. Chem., 2020,44, 5656-5660
We connected 2,3,6,7,10,11-Hexaiminotriphenylene (HATP) via aerobic oxidative coupling to form large-area polymeric 2D films using the Langmuir–Blodgett method and constructed a device of FET configuration. We systematically studied the photoelectric properties of the 2D HATP polymeric films. The device based on the thin films of HATP exhibits a broad absorption spectrum from 200 to 1000 nm and a stable and fast response to light. This work highlights opportunities to develop 2D polymeric organic semiconductors for constructing next generation electronic devices.

Wenjie Shi, Lingzhen Zeng, Lingyun Cao, Ying Huang, Cheng Wang & Wenbin Lin, Nano Res. (2020).
We report Pd-functionalized two-dimensional metal-organic layers (MOLs) as solid reagents and heterogeneous catalysts to efficiently fluorinate a broad scope of aromatic compounds. A terpyridine (TPY)- based ligand on the MOL, together with a 2-chloro-1,10-phenanthroline (phenCl) as a co-ligand, chelates PdII to form a reactive center. After treatment with Selectfluor/H2O, an (N-fluoroxy)-(2-chloro)-phenanthrolinium [N-(FO)-phenCl+] moiety is produced from the co-ligand on the Pd center. This active species serves as a stochiometric solid fluorination reagent, which shows different regioselectivities and reactivities as compared to homogeneous catalysts that involves PdIII/IV-F intermediates in catalytic cycles.

Bing An, Yaping Meng, Zhe Li, Yahui Hong, Tingting Wang, Shuai Wang, Jingdong Lin, Cheng Wang, Shaolong Wan, Yong Wang, Wenbin Lin, Journal of Catalysis, 2019, 373, 37-47
We report a mono-alkyl pyrocarbonate-bipyridinium salt intermediate to activate CO2 for synthesizing ethyl formate as a value-added product via tandem esterification and hydrogenation. The required basic bipyridine sites for CO2 activation and metallic Pd nanoparticles for hydrogenation were assembled in the same nano-cavity of a designer metal–organic framework (MOF). This MOF hybrid exhibits a high catalytic activity to generate ethyl formate (HCO2Et) (1333 μmol/gcat/h) with 93.5% selectivity at 412 K. The turnover frequency of HCO2Et based on the number of exposed Pd atoms is up to 22.2 h−1.

Bing An, Zhe Li, Yang Song, Jingzheng Zhang, Lingzhen Zeng, Cheng Wang & Wenbin Lin, Nature Catalysis, 2019, 2, 8, 709–717
We report cooperative CuI sites on a Zr12 cluster of a metal–organic framework (MOF) for selective hydrogenation of CO2 to ethanol. With the assistance of an alkali cation, the spatially proximate Zr12-supported CuI centres activate hydrogen via bimetallic oxidative addition and promote C–C coupling to produce ethanol. The Cs+-modified MOF catalyst, in 10 hours, produces ethanol with >99% selectivity and a turnover number (based on all Cu atoms) of 4,080 in supercritical CO2, with 30 MPa of CO2 and 5 MPa of H2 at 85 ℃, or a turnover number of 490 at 2 MPa of CO2/H2 (1/3) and 100℃.

Xuefu Hu, Peican Chen, Cankun Zhang, Zhiye Wanga and Cheng Wang, CHEMICAL COMMUNICATIONS, Chem. Commun., 2019, 55, 65, 9657-9660
We prepared two photocatalysts based on a 2D MOL (Zr-TCBPE-MOL). Efficient photo-reduction of CO2 to HCO2H and CO was observed, taking advantage of fast energy transport from the MOL to the reaction centres, which supports multi-electron injection in the 2ereduction of CO2. This work highlights the importance of constructing catalyst–antenna hybrids for efficient photocatalysis.

Ling Yang, Fa‐Xue Ma, Fan Xu, Dong Li, Liangmei Su, Prof. Hai‐Chao Xu, Prof. Cheng Wang, Chem. Asian J. 2019, 14, 20, 3557-3560
We report electrochemical acceptorless dehydrogenation of N‐heterocycles to obtain quinoline or indole derivatives using metal‐organic layer (MOL) catalyst.The MOL can be constructed on conductive multi‐walled carbon nanotubes via facile solvothermal synthesis to overcome the conductivity constraint for MOFs in electrocatalysis. TEMPO‐OPO32− was incorporated into the system through a ligand exchange with capping formate on the MOL surface to serve as the active catalytic centers. The hybrid catalyst is efficient in the organic conversion and can be readily recycled and reused.

Ying Guo, Wenjie Shi, Huijuan Yang, Quanfeng He, Zhongming Zeng, Jin-yu Ye, Xinru He, Ruiyun Huang, Cheng Wang*, and Wenbin Lin, J. Am. Chem. Soc. 2019, 141, 44, 17875–17883
We create cooperative cobalt-protoporphyrin (CoPP) and pyridine/pyridinium (py/pyH+) catalytic sites on metal–organic layers (MOLs) for an electrocatalytic CO2 reduction reaction (CO2RR). The MOL was postsynthetically functionalized with CoPP via carboxylate exchange with formate capping groups. The CoPP group and the pyridinium (pyH+) moiety coactivate CO2 by forming the [pyH+-–O2C-CoPP] adduct，which enhances the CO2RR and suppresses hydrogen evolution to afford a high CO/H2 selectivity of 11.8. Cooperative stabilization of the [pyH+-–O2C-CoPP] intermediate led to a catalytic current density of 1314 mA/mgCo for CO production at −0.86 VRHE, which corresponds to a turnover frequency of 0.4s–1.

Yibin Jiang, Lingyun Cao, Xuefu Hu, Zikun Ren, Cankun Zhang, and Cheng Wang*, Inorg. Chem. 2018, 57, 24, 15123–15132
Complete integration of diffraction signals from a continuum instead of discrete directions in the Bragg equation is thus required for proper data interpretation of 2D materials. Modeling of preferred orientation of the 2D crystals as well as geometric disorders are importance. we present a complete integration method in real space (CIREALS) for PXRD simulation of monolayer or multilayer 2D crystals, especially 2D metal-organic layers and 2D covalent organic frameworks. By working in real space instead of reciprocal space, we can capture the 2D geometry and preferred orientation of these materials. The predicted PXRD patterns by CIREALS facilitates structure analysis of these new types of 2D material.

Tingting Wang, Zhongming Zeng , Lingyun Cao, Zhe Li , Xuefu Hu , Bing An , Cheng Wang ,Wenbin Lin* Chem. Eur. J. 10.1002/chem.201804312
Selective reduction of O2 to H2O2 by a single [NiII(H2O)6]2+ cation that is dynamically associated with a negatively charged metal-organic layer (MOL) by hydrogen bonding and coulombic interactions is reported. In contrast, NiII centers covalently immobilized on the MOL reduce O2 to H2O in a four-electron process. Oxygen adsorption by [NiII(H2O)6]2+ followed by two‐electron reduction generates neutral [NiII(H2O)4(OH)(OOH)]0, which momentarily disconnects from the negatively charged MOL to avoid the injection of additional electrons. Release of H2O2 from [NiII(H2O)4(OH)(OOH)]0 regenerates [NiII(H2O)6]2+, which regains affinity to the MOL. Such dynamically associated NiII single‐metal electrocatalysts ensure high selectivity.