Sulfur and carbon co-doped g-C_(3)N_(4)microtubes with enhanced photocatalytic H2 production activity

Metal-free graphitic carbon nitride(g-C_(3)N_(4))has captured significant attention as a low-cost and efficient hydrogen production photocatalyst through.Effectively regulating the microstructure and accelerating the separation of photogenerated carriers remain crucial strategies for promoting the photocatalytic performance of this material.Herein,a novel sulfur–carbon co-doped g-C_(3)N_(4)(SCCN)hierarchical microtubules filled with abundant nanosheets inside by thermal polymerization is reported.Numerous nanosheets create abundant pores and cavities inside the SCCN microtubes,thereby increasing the specific surface area of g-C_(3)N_(4)and providing sufficient reactant attachment sites.Besides,the hierarchical structure of SCCN microtubules strengthens the reflection and scattering of light,and the utilization of visible light is favorably affected.More importantly,co-doping S and C has greatly improved the photocatalytic performance of graphitic carbon nitride,optimized the band gap structure and enhanced the photogenerated carrier splitting.Consequently,the SCCN exhibits a remarkable photocatalytic H_(2)evolution rate of 4868μmol/(g·h).This work demonstrates the potential of multi-nonmetal doped g-C_(3)N_(4)as the ideal photocatalyst for H2 evolution.

Facile Synthesis of Cellulose Acetate Ultrafiltration Membrane with Stimuli-Responsiveness to pH and Temperature Using the Additive of F127-b-PDMAEMA

We fabricate a novel cellulose acetate （CA） ultrafiltration membrane modified by block copolymer F127-b- PDMAEMA, which is synthesized using F127 and DMAEMA via the ARGET ATRP method. Compared to conven- tional ultrafiltration membranes, the incorporation of both F 127 and PDMAEMA can not only readily increase the hydrophilicity of the membrane, but also exhibit stimuli-responsiveness to temperature and pH. Fourier transform infrared spectroscopy （FT-IR）, nuclear magnetic resonance spectroscopy （NMR）, and gel permeation chromatog- raphy （GPC） are employed to analyze the structure of the F 127-b-PDMAEMA. The membrane properties are eval- uated via scanning electron microscope （SEM） imaging, porosity test, automatic target recognition Fourier trans- form infrared spectroscopy （ATR-FTIR）, water contact angle test and permeation test. The results indicate that the F 127-b-PDMAEMA is an excellent pore agent, which contributes to an enhancement of the membrane in sensitivity to temperature and pH. The modified membrane also exhibits lower water contact angle （64.5~）, which is attributed to the good anti-fouling performance and high water permeation.

Catalytic Hydrogenation of Acetic Acid to Acetaldehyde: Synergistic Effect of Bifunctional Co/Ce-Fe Oxide Solid Solution Catalysts

The large-scale industrial production of acetic acid (HAc) from carbonylation of methanol has enabled intense research interest from direct hydrogenation of HAc to acetaldehyde (AA).Herein,a series of cerium-iron oxide solid solution supported metallic cobalt catalysts were prepared by modified sol-gel method and were applied in gas-phase hydrogenation of HAc to AA.A synergistic effect between the hydrogenation metal cobalt and Ce-Fe oxide solid solution is revealed.Specifically,oxygen vacancies provide the active sites for adsorption of HAc,while highly uniformly dispersed metallic Co adsorbs H2 and activates the reduction of HAc into AA.Moreover,the metallic Co can also assist the cyclical conversion between Fe3+/Fe2+ and Ce3+/Ce4+ on the surface of Ce1.xFexO2-δ supports.The unique effect substantially enhances the ability of the support material to rapidly capture oxygen atoms from HAc.It is found that the catalyst of 5% Co/Ce0.8Fe0.2O2-δ with the highest concentration of oxygen vacancy presents the best catalytic performance (i.e.acetaldehyde yield reaches 49.9%) under the optimal reaction conditions (i.e.623 K and H2 flow rate =10 mL/min).This work indicates that the Co/Ce-Fe oxide solid solution catalyst can be potentially used for the selective hydrogenation from HAc to AA.The synergy between the metallic Co and Ce1-xFexO2-δ revealed can be extended to the design of other composite catalysts.