Research Progress----Shanghai Advanced Research Institute,Chinese Academy of Sciences

Researchers Develop Highly Efficient Ampere-Level CO2 Reduction to Multicarbon Products via Stepwise Hollow-Fiber Penetration Electrodes

Recent studies have shown that serial hollow-fiber penetration electrodes (HPEs) can improve the CO2ERR performance significantly. To promote the selectivity and current density for C2+ products simultaneously, a research team from the Shanghai Advanced Research Institute (SARI) of the Chinese Academy of Sciences developed a stepwise CO2ERR strategy using Ag and Cu HPEs to reach high-rate C2+ production.The results were published in Appl. Catal. B-Environ. on 28th May, 2023.

　　Though efficient C2+ production from CO2 electrocatalytic reduction reaction (CO2ERR) has become a promising approach to mitigate CO2 emissions and store intermittent renewable energy, it suffers from low selectivity and undesired side reactions.
　　Recent studies have shown that serial hollow-fiber penetration electrodes (HPEs) can improve the CO2ERR performance significantly by forcing CO2 to disperse and penetrate through the abundant pores on HPE wall, which greatly boosted CO2ERR kinetics.
　　To promote the selectivity and current density for C2+ products simultaneously, a research team led by Profs. CHEN Wei and WEI Wei from the Shanghai Advanced Research Institute (SARI) of the Chinese Academy of Sciences developed a stepwise CO2ERR strategy using Ag and Cu HPEs to reach high-rate C2+ production.
　　The results were published in Appl. Catal. B-Environ. on 28th May, 2023.
　　Specifically, for stepwise CO2 electroreduction, CO2 was firstly reduced into CO over a chloride ion regulated Ag hollow-fiber penetration electrodes with a 3.2 A？cm-2 partial current density and a 90.3% faradaic efficiency of CO. Then, a chloride ion regulated Cu hollow-fiber penetration further converted CO into C2+ products with a 1.8 A cm-2 partial current density and a 90.5% faradaic efficiency of C2+ products. Both steps were steadily conducted under total current density of 2 A？cm-2 for 200 hours.
　　Experimental results and density functional theory calculations show that synergetic combination of the unique penetration effect and the regulated electronic structures resulted in the superior performance toward C2+ production
　　This work shed light on designing electrocatalytic systems with exceedingly efficient CO2 electroreduction of high current density and selectivity as well as good durability, which might contribute to the scalable CO2 electroreduction applications towards high-value C2+ chemicals.
　　Schematic diagram for highly efficient ampere-level CO2 reduction to multicarbon products via stepwise hollow-fiber penetration electrodes (Image by SARI)
　　

2023-06-05 more+

Researchers Developed Linkage Engineering of Covalent Organic Frameworks for the Oxygen Reduction Reaction

A joint team lead by Prof. ZENG Gaofeng and Associate Prof. XU Qing from Shanghai Advanced Research Institute, CAS and Prof. JIANG Zheng from University of Science and Technology of China employed catalytic linkage engineering to modulate the catalytic behaviors and found the catalytic performance is determined solely by the electron states of carbon atoms in the linkages. The research results were published in Angew Chem Int Ed.

2023-06-02 more+

Researchers Constructed Noninterpenetrated Three-dimensional Covalent Organic Framework for Au Ions Capture

A research team led by Prof. ZENG Gaofeng and Associate Prof. XU Qing at the Shanghai Advanced Research Institute (SARI) of the Chinese Academy of Sciences constructed a novel non-interpenetration 3D COF towards Au ions capture by imine bonds in the frameworks. The research results were published in Adv. Funct. Mater. on Apr. 23rd.

2023-04-28 more+

Researchers Developed a Novel Graphene/Silicon Catalyst for Highly Selective Photoelectroreduction of Carbon Dioxide to Ethanol

a research team led by Profs. CHEN Wei and WEI Wei from the Shanghai Advanced Research Institute (SARI) of the Chinese Academy of Sciences reported efficient CO2 photoelectroreduction to ethanol (C2H5OH) over graphene/silicon carbide (SiC) catalysts under simulated solar irradiation with ethanol (C2H5OH) selectivity of >99% and a CO2 conversion rate of up to 17.1mmol gcat-1h-1. The results were published in Angew. Chem. Int. Ed.

Using sunlight to produce valuable chemicals and fuels from carbon dioxide (CO2), i.e., artificial photosynthesis (AP) is a promising strategy to achieve solar energy storage as well as a negative carbon cycle.However, the AP is quite complex and involves multiple sequential and parallel steps. What’s more, thermodynamically favorable C1 products can be produced from multiple AP intermediates, making it challenging to selectively produce target chemicals containing C-C bonds. Therefore, selective synthesis of C2 compounds with a high CO2 conversion rate remains challenging for current AP technologies.Motivated by such a challenge, a research team led by Profs. CHEN Wei and WEI Wei from the Shanghai Advanced Research Institute (SARI) of the Chinese Academy of Sciences reported efficient CO2 photoelectroreduction to ethanol (C2H5OH) over graphene/silicon carbide (SiC) catalysts under simulated solar irradiation with ethanol (C2H5OH) selectivity of >99% and a CO2 conversion rate of up to 17.1mmol gcat-1h-1.The results were published in Angew. Chem. Int. Ed.A graphene/silicon carbon (SiC) composite catalyst, which comprises a SiC substrate, interfacial layer (IL), and few-layer graphene overlayer can help to achieve the precise control of active intermediates for C？C coupling. An optimal IL structure allows photogenerated electrons from the SiC substrate to be facilely transferred to the active sites on the graphene overlayer. Reaction intermediates can then be efficiently formed and stabilized owing to their strong adsorption at the active sites and the high electron density of the graphene surface.Experimental results and first principles calculations show that CH3OH formation is largely suppressed in favor of C-C coupling. C2H5OH is therefore exclusively formed with a selectivity of>99% and a CO2 conversion rate of 17.1mmol gcat-1h-1 under simulated solar irradiation with a small bias (-50 mV bias vs. Ag/AgCl) and ambient conditions. Thus, the photoelectrocatalytic performance of the optimal catalyst in producing C2 products from CO2 was at least two orders of magnitude higher than those of the state-of-the-art AP catalysts.This work paves the way toward an advanced AP strategy to efficiently valorize greenhouse CO2.
　　Figure1. Schematic diagram a for highly selective photoelectroreduction of carbon dioxide over graphene/silicon carbide composites (image by SARI)
　　Figure 2. Synthetic Scheme, Raman spectra and CO2 photoelectrocatalytic performances. (image by SARI)
　　

2023-03-20 more+

Researchers Propose an Effective and Reusable Tandem Catalyst for Plastic Waste Conversion

a research group led by Prof. WANG Hui and Associate Prof. LUO Hu at the Shanghai Advanced Research Institute, Chinese Academy of Sciences developed a tandem catalytic reaction to efficiently convert low-density polyethylene (LDPE) into naphtha, where a naphtha yield of 89.5% is obtained with 96.8% selectivity of C5？C9 hydrocarbons at 250 °C, catalyzed by mechanically mixed β zeolite and Pt@S-1 catalysts.The research results were published in Journal of the American Chemical Society recently.

　　The rapid growth of plastic waste is an ever-growing environmental and energy challenge. Selectively converting waste plastics to naphtha, a main feedstock for ethylene and the plastic industry, shows high potential to partially replace petroleum-route naphtha and alleviate global net carbon emissions. However, these active metals on supported catalysts with an open microenvironment showed less effect on the generation of intermediates and selectivity of naphtha.
　　Motivated by such a challenge, a research group led by Prof. WANG Hui and Associate Prof. LUO Hu at the Shanghai Advanced Research Institute, Chinese Academy of Sciences developed a tandem catalytic reaction to efficiently convert low-density polyethylene (LDPE) into naphtha, where a naphtha yield of 89.5% is obtained with 96.8% selectivity of C5-C9 hydrocarbons at 250 °C, catalyzed by mechanically mixed β zeolite and Pt@S-1 catalysts.
　　The research results were published in Journal of the American Chemical Society recently.
　　The selectivity of normal alkanes catalyzed by Pt@S-1 and β zeolite reached 34%, about 10-20% higher than that on Pt/S-1, and the alkane products were narrower. The differences between the two catalysts were possibly due to the confinement effect and shape-selectivity of Pt@S-1. Thus, combined density functional theory (DFT) and molecular dynamics simulations were used to reveal the shape-selectivity process, as the diffusion and shipping of olefin intermediates with the right size were boosted within Pt@S-1, which led to narrower-distributed products.
　　This catalyst system displayed stability and high performance for most abundant plastic waste like low-/high-density polyethylene and polypropylene at moderate conditions. With life cycle assessment (LCA), this approach showed 15% energy saving and 30% reduced greenhouse gas emissions compared with conventional routes for plastic production.
　　This work provides an upgrading strategy for retaining the value of waste plastics more efficiently and serving as a significant step to realize the circular economy.
　　DFT and molecular dynamics calculations (image by SARI)
　　

2023-01-19 more+

Researchers Propose a Novel Ordered MEA for High-performance PEMWE

a research team led by Prof. YANG Hui at Shanghai Advanced Research Institute (SARI) of the Chinese Academy of Sciences reported a novel ordered MEA based on anode with 3D membrane/catalytic layer (CL) interface and gradient tapered arrays, which not only greatly increases the electrochemical active area but also decreases the overpotentials of both mass transport and ohmic polarization.The research results were published in Nano Letters recently.

Proton exchange membrane water electrolysis (PEMWE) is under intensive investigation because of its advantages as high energy efficiency and hydrogen purity compared to the conventional alkaline water electrolysis. However, as the practical application of the PEMWEs usually runs at high current densities ( ≥1-2 A m-2), insufficient catalyst utilization, limited mass transport and high ohmic resistance of the conventional membrane electrode assembly (MEA) restrict the performance of PEMWE.
　　Motivated by such a challenge, a research team led by Prof. YANG Hui at Shanghai Advanced Research Institute (SARI) of the Chinese Academy of Sciences reported a novel ordered MEA based on anode with 3D membrane/catalytic layer (CL) interface and gradient tapered arrays, which not only greatly increases the electrochemical active area but also decreases the overpotentials of both mass transport and ohmic polarization.
　　The research results were published in Nano Letters recently.
　　An overall design of the MEA based on anode with ordered arrays, gradient CL and 3D membrane/CL interface structure was proposed and confirmed by scanning electron microscopy, energy disperse spectroscopy and X-ray photoelectron spectroscopy.
　　Benefiting from the maximized triple-phase interface, rapid mass transport and gradient CL, such an ordered structure not only greatly increases the electrochemical active area by 4.2 times but also decreases the overpotentials of both mass transport and ohmic polarization by 13.9% and 8.7%, respectively.
　　This ordered MEA ensures a performance of 1.801 V @ 2 A cm-2 even with Ir loading as low as 0.2 mg cm-2, which is comparable with conventional MEA with Ir loading of 2 mg cm-2. Further, it can operate stably over 300 h under 1 A cm-2.
　　The study provides a simple but effective strategy for the overall design of nanostructured MEA for high-performance and stable PEMWE with low Ir loading.
　　Structure and performance of the prepared MEA-GTAs-T1 (Image by SARI)
　　

2023-01-09 more+