Showing papers by "Jing Liu published in 2018"

Oxygen self-doped g-C3N4 with tunable electronic band structure for unprecedentedly enhanced photocatalytic performance.

Abstract: As a fascinating conjugated polymer, graphitic carbon nitride (g-C3N4) has attracted much attention for solving the worldwide energy shortage and environmental pollution. In this work, for the first time we report oxygen self-doping of solvothermally synthesized g-C3N4 nanospheres with tunable electronic band structure via ambient air exposure for unprecedentedly enhanced photocatalytic performance. Various measurements, such as XPS, Mott–Schottky plots, and density functional theory (DFT) calculations reveal that such oxygen doping can tune the intrinsic electronic state and band structure of g-C3N4via the formation of C–O–C bond. Our results show that the oxygen doping content can be controlled by the copolymerization of the precursors. As a consequence, the oxygen doped g-C3N4 shows excellent photocatalytic performance, with an RhB photodegradation rate of 0.249 min−1 and a hydrogen evolution rate of 3174 μmol h−1 g−1, >35 times and ∼4 times higher than that of conventional thermally made pure g-C3N4 (0.007 min−1 and 846 μmol h−1 g−1, respectively) under visible light. Our work introduces a new route for the rational design and fabrication of doping modified g-C3N4 photocatalyst for efficient degradation of organic pollutants and H2 production.

Probing conducting polymers@cadmium sulfide core-shell nanorods for highly improved photocatalytic hydrogen production.

Abstract: We report three types of conducting polymers (CPs), polyaniline (PANI), polypyrrole (PPY) and poly (3,4-ethylenedioxythiophene) (PEDOT) to modify the surface of the CdS nanorods to probe their photocorrosion inhibition and photocatalytic hydrogen production. Various characterizations, such as high resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV) and density function theory (DFT) calculations have been conducted to reveal the intrinsic structure of the as-constructed CPs@CdS (@ means CPs at the surface of CdS) core-shell nanorods. The results show that the PANI and PPY shells with abundant N and C atoms can significantly enhance the binding energy of Cd and S atoms on the surface of the CdS nanorods. However, there is no obvious enhancement of binding energy at the interface of the PEDOT shell and the CdS nanorods core. Therefore, PANI@CdS and PPY@CdS possess stronger driving force than PEDOT@CdS to inject the photogenerated holes in conducting polymer shells. As a result, the polyaniline (PANI) modified PANI@CdS core-shell nanorods demonstrate the most effectively enhanced hydrogen production rate of ∼9.7 mmol h−1 g−1 and effective photocorrosion inhibition in 30 h without deactivation under visible-light irradiation. The hydrogen production performance of PPY@CdS is not effectively promoted owing to the weak transmittance of light for the PPY shell. The PEDOT shell cannot improve the hydrogen production and stability property of the CdS nanorods. This work could shed some light on conducting polymers modifying metal sulfides nanostructures that is of inconceivable significance for effective photocorrosion inhibition and highly enhanced photocatalytic activities.

Seed-mediated synthesis of large-diameter ternary TePtCo nanotubes for enhanced oxygen reduction reaction

Abstract: Compared to Pt nanoparticles, Pt metal nanotubes (NTs) with hollow nanostructures and ultrathin side walls can greatly increase electrocatalytic activity and stability in oxygen reduction reaction (ORR). In this work, the large-diameter ternary TePtCo NT with a hollow and hierarchical structure is successfully prepared by a simple and cost-effective replacement way. The formed TePtCo NT not only proves the high Pt utilization with large surface area, but also improves the proton transfer in the ORR process. As expected, its specific activity and mass activity at 0.9 V (vs. RHE) are 4.6 folds and 3.9 folds over that of the commercial Pt/C catalyst, respectively. Moreover, it also shows an excellent catalytic stability, much higher than that of Pt/C. The density functional theory (DFT) calculation results reveal that Pt alloying with Te and Co facilitates the breakage of the O O bond and weakens the adsorption energy of hydroxyl, subsequently enhancing the ORR performance.