The coordinated configuration of atomic platinum (Pt) has always been identified as an active site with high intrinsic activity for hydrogen evolution reaction (HER). Herein, we purposely synthesize single vacancies in a carbon matrix (defective graphene) that can trap atomic Pt to form the Pt–C3 configuration, which gives exceptionally high reactivity for HER in both acidic and alkaline solutions. The intrinsic activity of Pt–C3 site is valued with a turnover frequency (TOF) of 26.41 s–1 and mass activity of 26.05 A g–1 at 100 mV, respectively, which are both nearly 18 times higher than those of commercial 20 wt % Pt/C. It is revealed that the optimal coordination Pt–C3 has a stronger electron-capture ability and lower Gibbs free energy difference (ΔG), resulting in promoting the reduction of adsorbed H+ and the acceleration of H2 desorption, thus exhibiting the extraordinary HER activity. This work provides a new insight on the unique coordinated configuration of dispersive atomic Pt in defective C matrix for superior HER performance.

This work focuses on developing a novel adsorbent for CO2 capture, by coating polyethylenimine (PEI) on glass fiber matrix and using epichlorohydrin (ECH) as cross-linking agent. The physicochemical properties of the fibrous adsorbent were characterized. The CO2 adsorption capacity was evaluated. Factors that affect the adsorption capacity of the fibrous adsorbent were studied. The experimental results show that this fibrous PEI adsorbent exhibits a much higher adsorption capacity for CO2 compared with another PEI fiber prepared in our previous work, which employed epoxy resin as the cross-linking agent. A CO2 adsorption capacity as high as 4.12 mmol CO2/g of adsorbent was obtained for this fibrous PEI adsorbent at 30 degrees C, equal to 13.56 mmol CO2/g of PEI, with a PEI/ECH ratio of 20:1. The adsorbent can be completely regenerated at 120 degrees C.

ABSTRACT:We successfully prepared a novel fibrous adsorbent for carbon dioxide (CO 2 ) capture by coating polyethylenimine (PEI) on a glass fiber matrix, using epoxy resin (EP) as crosslinking agent. The physicochemical properties of the fibrous adsorbents were characterized in terms of Fourier transform infrared spectrometry and thermogravimetric analysis. Factors that affected the adsorption capacity of the fibrous adsorbent were studied, including the crosslinking agent dosage, coating weight, moisture, adsorption temperature, and CO 2 concentration of the simulated flue gas. The experimental results indicate that the properly crosslinked fibrous adsorbent had a high thermal stability at about 2808C. With a PEI/EP ratio of 10:1, a maximum adsorption capacity of 276.96 mg of CO 2 /g of PEI was obtained at 308C. Moisture had a promoting influence on the adsorption of CO 2 from flue gas. The CO 2 adsorption capacity of the fibrous adsorbent in the presence of moisture could be 19 times higher than that in dry conditions. The fibrous adsorbent could be completely regenerated at 1208C. The CO 2 adsorption capacity of the regenerated fibrous adsorbent was almost the same as that of the fresh adsorbent.

Herein, a systematical investigation is devoted to explore nitrile butadiene rubber (NBR) hydrogenation activity and selectivity in different organic solvents, and the dependence between reactivity and solvent is revealed with the assistance of the density functional theory (DFT). The results show that the electron‐pair donor solvents have better performance in NBR hydrogenation activity than the weak electron‐pair acceptor solvents, but they do not modify the selectivity to HNBR that always keeps up to 100 %. A direct correlation between reactivity and hydrogen bond acceptance ability (β) is discovered in both solvent families and the higher β, the better hydrogenation performance. The preferred solvent is cyclohexanone with hydrogenation degree of 91.4 % in 10 minutes and the highest conversion of 94.2 %. Our contribution is to provide useful information about solvent and solvent effect on the hydrogenation of NBR and gain new insight into NBR hydrogenation reaction process.

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