Non-Precious Metal-Doped Carbon Materials Derived From Porphyrin-Based Porous Organic Polymers for Oxygen Reduction Electrocatalysis.

The cathodic oxygen reduction reaction (ORR) is important in the development of renewable energy devices, to produce novel and non-precious metal catalysts with high electrocatalytic activity to reduce the consumption of non-renewable platinum (Pt) catalyst. In this work, we developed N-doped and Fe/N dual-doped porous carbons as catalysts for ORR simply by high-temperature pyrolysis of porphyrin-based conjugated microporous polymers (CMPs). By combination of heteroatom doping, highly porous structure and tubular morphology, the as-prepared carbon samples exhibited high electrocatalytic activity with 4-electron transfer mechanism, nearly close to the commercial Pt/C catalyst. In particular, among these samples, the Fe/N-CMP-1000 displayed a higher onset potential (0.95 eV), positive half-wave potential (0.85 eV) and limiting current density value (5.1 mA cm-2 ) as well as good durability and better methanol tolerance contrasting with Pt/C catalyst, suggesting that the as-prepared metal-free catalysts from porphyrin-based CMPs show great potential for ORR.

Nitrogen-doping hollow carbon nanospheres derived from conjugated microporous polymers toward oxygen reduction reaction.

The exploitation non-precious or metal-free electrocatalysts of oxygen reduction reaction (ORR) is of significance for construction of next-generation fuel cells. In this work, hollow-spherical conjugated microporous polymers (CMPs) comprising porphyrin units were synthesized as precursors to prepare N-doping porous carbon spheres (CMP-NP-x) by a direct pyrolysis method. The as-resulted CMP-NP-x exhibited spherical morphology with hollow structure similar to that of CMPs precursors. The BET surface area of CMP-NP-x can be tailored by the pyrolysis temperature varying from 868 m2 g-1 to 1118 m2 g-1. According to XPS analysis, the pyrrolic N content in the sample decreased but the graphitic N and pyridinic N increased with increasing of the pyrolysis temperature from 800 °C to 1000 °C. Taking advantages of porous structure with large accessible surface areas and N species active sites, the resulting CMP-NP-x showed superior ORR activity and methanol tolerance to commercial Pt/C catalyst. In particular, CMP-NP-900 possesses the highest onset potential (0.930 V), half-wave potential (0.857 V) and limiting current density of 4.45 mA cm-2, compared with Pt/C catalyst and other samples, making it a promising metal-free catalyst superior to commercial Pt/C catalyst in alkalic condition.

Efficient capture of airborne PM by nanotubular conjugated microporous polymers based filters under harsh conditions.

The exploitation of high-performance filters which can capture and remove airborne particulate matter (PM) in harsh conditions is greatly important to limit the serious effect of PM on human health. Herein, we demonstrate a simple approach for the creation of robust and hierarchically porous filters based on conjugated microporous polymers (CMPs) nanotubes for efficient PM capture. Taking advantage of their inherently superhydrophobic wettability, the CMPs-based filters possess high filtration efficiency of higher than 99.4% for PM0.3 and 99.9% for PM2.5 and PM10, respectively, even in high humidity environment (RH ≥ 94%). The CMPs-based filters show highly physicochemical and thermal stability, e.g., by calcination at 500 °C for 2 h, the filtration efficiency of the samples still reaches as great as 99.4% for both PM2.5 and PM10 with a low-pressure drop of only 10 Pa. In addition, these CMPs-based filters can be easily regenerated and their high PM filtration efficiency remains nearly unchanged by a simple methanol washing. More interestingly, the CMPs-based filters also exhibit superior antibacterial performance, which enables them to sterilize or eliminate the bacteria possibly loaded on PM pollutions, thus showing great potential for various applications such as PM removal, air purification and so on.

Self-cleaning and flexible filters based on aminopyridine conjugated microporous polymers nanotubes for bacteria sterilization and efficient PM2.5 capture.

The capture and elimination of harmful particulate matter (PM) both in air and water is of great importance for human health and environmental sustainability. Here, we demonstrate a novel strategy for the exploitation of conjugated microporous polymer bearing aminopyridine moiety (A-CMPs) as an advanced filter for bacteria sterilization and efficient PM capture. The A-CMPs network shows a hierarchically porous structure with mechanical robustness and flexibility, which facilitates to filtration especially for PM with different particle sizes. The capture efficiency of A-CMPs aerogels for PM2.5 and PM10 were respectively up to PM2.5 ≥ 99.57 ± 0.19% and PM10 ≥ 99.98 ± 0.01% in a long-term durability test and easy to be regenerated. Moreover, the A-CMPAs features excellent superhydrophobicity, which is difficult to saturate with water aerosols in humid air (RH: 89 ± 3%) and in turn shows superior stability and high-performance in terms to capture efficiency. More importantly, the A-CMP monolith exhibits excellent antimicrobial activity and high concentrations of bacterial suspension (e.g., using E. coli as probe bacterial) could be effectively captured and quickly killed during filtration, which endows the A-CMPs additional sterilization performance and thus is of great technological significance with remarkable potentials as a new kind of advanced filter for multifunctional filtration in both air and water.

Low-Resistance Thiophene-Based Conjugated Microporous Polymer Nanotube Filters for Efficient Particulate Matter Capture and Oil/Water Separation.

Air and water pollution poses a serious threat to public health and the sustainable development of the ecological environment. Here, we report the fabrication of new low-resistance nanofilters based on thiophene-based conjugated microporous polymer (T-CMP) nanotubes to remove harmful particulate matter (PM) from air effectively. T-CMP nanotube filters feature inherent superhydrophobicity and hierarchical pores and are prepared by a facile one-pot synthesis. The PM removal efficiency of T-CMP nanotube filters at 90 ± 5% relative humidity exceeds 99.798 ± 0.055% for PM0.3 and 99.998 ± 0.002% for PM2.5, while the lowest pressure drop in the filtration system is only 5 Pa, which is 1-2 orders of magnitude lower than that of traditional fiber-based filters. Benefitting from their excellent porous feature and intrinsic superhydrophobicity, T-CMP nanotube filters also display higher flux during continuous oil-water separation. Based on this superior separation performance, better physicochemical stability, facile manufacturing, and easy scaling-up, such T-CMP nanotube filters might hold great potential for a wide range of applications even under harsh conditions, including PM removal, water treatment, and so on.